SimTech SIMCom SIM2000S Supplement

SIM2000S_Hardware_Design_V1.00

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SIM2000S_Hardware_Design_V1.00 2 2014-02-27
Document Title SIM2000S Hardware Design
Version 1.00
Date 2014-02-27
Status Release
Document Control ID SIM2000S_Hardware_Design_V1.00
General Notes
SIMCom offers this information as a service to its customers, to support application and engineering efforts that
use the products designed by SIMCom. The information provided is based upon requirements specifically
provided to SIMCom by the customers. SIMCom has not undertaken any independent search for additional
relevant information, including any information that may be in the customer’s possession. Furthermore, system
validation of this product designed by SIMCom within a larger electronic system remains the responsibility of the
customer or the customer’s system integrator. All specifications supplied herein are subject to change.
Copyright
This document contains proprietary technical information which is the property of SIMCom Limited, copying of
this document and giving it to others and the using or communication of the contents thereof, are forbidden
without express authority. Offenders are liable to the payment of damages. All rights reserved in the event of grant
of a patent or the registration of a utility model or design. All specification supplied herein are subject to change
without notice at any time.
Copyright © Shanghai SIMCom Wireless Solutions Ltd. 2014

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Contents
Version History............................................................................................................8
1. Introduction..........................................................................................................9
2. SIM2000S Overview............................................................................................9
2.1. SIM2000S Key Features .......................................................................................................9
2.2. Operating Mode .................................................................................................................. 11
2.3. Functional Diagram............................................................................................................. 11
3. Package Information.........................................................................................13
3.1. Pin out Diagram ..................................................................................................................13
3.2. Pin Description....................................................................................................................13
3.3. Package Dimensions ...........................................................................................................16
4. Application Interface.........................................................................................18
4.1. Power Supply ......................................................................................................................18
4.1.1. Power supply pin................................................................................................................................. 19
4.1.2. Monitoring Power Supply ................................................................................................................... 19
4.2. Power on/down Scenarios...................................................................................................19
4.2.1. Power on SIM2000S ........................................................................................................................... 19
4.2.2. Power down SIM2000S ...................................................................................................................... 21
4.2.3. Reset Function..................................................................................................................................... 22
4.3. Power Saving Mode............................................................................................................23
4.3.1. Minimum Functionality Mode ............................................................................................................ 23
4.3.2. Sleep Mode (AT+CSCLK=1) ............................................................................................................. 24
4.3.3. Wake Up SIM2000S from Sleep Mode (AT+CSCLK=1) .................................................................. 24
4.4. Serial Port and Debug Interface..........................................................................................24
4.4.1 Function of Serial Port ........................................................................................................................ 25
4.4.2 Serial Interfaces................................................................................................................................... 25
4.4.3 USB Interface...................................................................................................................................... 27
4.4.4 Software Upgrade and Debug ............................................................................................................. 28
4.4.5 Multiplexing function of serial port and SD interface......................................................................... 28
4.5. RI behaviors ........................................................................................................................28
4.6. Audio Interfaces..................................................................................................................30
4.6.1. Speaker Interfaces Configuration........................................................................................................ 30
4.6.2. Microphone Interfaces Configuration ................................................................................................. 31
4.6.3. Audio Electronic Characteristic .......................................................................................................... 31
4.7. RUIM Card Interface ..........................................................................................................31
4.7.1. RUIM Card Application...................................................................................................................... 31
4.7.2. RUIM Card Design Guide .................................................................................................................. 32
4.7.3. Design Considerations for RUIM Card Holder................................................................................... 33
4.8. PCM Interface.....................................................................................................................34

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4.8.1. PCM Multiplexing Function ............................................................................................................... 35
4.8.2. PCM Interface ..................................................................................................................................... 35
4.8.3. Auxiliary PCM (128 KHz PCM clock)............................................................................................... 35
4.8.4. Primary PCM (2048KHz PCM clock) ................................................................................................ 37
4.9. Keypad Interface.................................................................................................................38
4.9.1 Keypad Multiplexing Function ........................................................................................................... 39
4.10. I2C Bus ...............................................................................................................................39
4.10.1 I2C Multiplexing Function .............................................................................................................. 39
4.11. General Purpose Input/Output (GPIO) ...............................................................................40
4.12. ADC ....................................................................................................................................40
4.13. PWM ...................................................................................................................................40
4.14. Network Status Indication...................................................................................................41
4.15. NETLIGHT Multiplexing Function....................................................................................42
4.16. Operating Status Indication.................................................................................................42
4.16.1 STATUS Multiplexing Function ...................................................................................................... 42
4.17. Antenna Interface................................................................................................................42
5. PCB Layout........................................................................................................44
5.1 Pin Assignment ...................................................................................................................44
5.2 Principle of PCB layout ......................................................................................................45
5.2.1 Antenna Interface................................................................................................................................ 45
5.2.2 Power Supply ...................................................................................................................................... 45
5.2.3 RUIM Card Interface .......................................................................................................................... 45
5.2.4 Audio Interface.................................................................................................................................... 45
5.2.5 Others .................................................................................................................................................. 45
6. Electrical, Reliability and Radio Characteristics...........................................46
6.1 Absolute Maximum Ratings ...............................................................................................46
6.2 Recommended Operating Conditions .................................................................................46
6.3 Digital Interface Characteristics..........................................................................................46
6.4 RUIM_VDD Characteristics...............................................................................................47
6.5 VDD_EXT Characteristics .................................................................................................47
6.6 Electro-Static Discharge .....................................................................................................47
6.7 Radio Characteristics ..........................................................................................................47
7. Manufacturing ...................................................................................................49
7.1. Top and Bottom View of SIM2000S ..................................................................................49
7.2. Typical Solder Reflow Profile ............................................................................................49
7.3. The Moisture Sensitivity Level...........................................................................................50
7.4. Baking Requirements..........................................................................................................50
8. Appendix.............................................................................................................51
I. Related Documents .............................................................................................................51
II. Terms and Abbreviations ....................................................................................................52
III. Safety Caution.....................................................................................................................53

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Table Index
TABLE 1: SIM2000S KEY FEATURES............................................................................................................................ 9
TABLE 2: OVERVIEW OF OPERATING MODES........................................................................................................ 11
TABLE 3: PIN DESCRIPTION ....................................................................................................................................... 13
TABLE 4: RECOMMENDED ZENER DIODE .............................................................................................................. 18
TABLE 5: ELECTRONIC CHARACTERISTIC OF THE RESET PIN.......................................................................... 23
TABLE 6: THE CURRENT CONSUMPTION OF MINIMUM FUNCTIONALITY MODE ........................................ 23
TABLE 7: SERIAL PORT AND DEBUG PIN DEFINITION......................................................................................... 25
TABLE 8: SERIAL PORT CHARACTERISTICS........................................................................................................... 25
TABLE 9: VBUS OPERATION VOLTAGE .................................................................................................................... 28
TABLE 10: MULTIPLEXING FUNCTION OF SERIAL PORT..................................................................................... 28
TABLE 11: MULTIPLEXING FUNCTION OF SD INTERFACE.................................................................................. 28
TABLE 12: RI BEHAVIORS ........................................................................................................................................... 28
TABLE 13: AUDIO INTERFACE DEFINITION............................................................................................................ 30
TABLE 14: MICROPHONE INPUT CHARACTERISTICS........................................................................................... 31
TABLE 15: AUDIO OUTPUT CHARACTERISTICS .................................................................................................... 31
TABLE 16: RUIM PIN DEFINITION ............................................................................................................................. 31
TABLE 17: PIN DESCRIPTION (AMPHENOL RUIM CARD HOLDER) ................................................................... 33
TABLE 18: PIN DESCRIPTION (AMPHENOL RUIM CARD HOLDER) ................................................................... 34
TABLE 19: PCM PIN DEFINITION ............................................................................................................................... 34
TABLE 20: PCM SPECIFICATION ................................................................................................................................35
TABLE 21: PCM MULTIPLEXING FUNCTION........................................................................................................... 35
TABLE 22: TIMING PARAMETERS ............................................................................................................................. 36
TABLE 23: TIMING PARAMETERS ............................................................................................................................. 37
TABLE 24: PIN DEFINITION OF THE KEYPAD INTERFACE................................................................................... 38
TABLE 25: KEYPAD MULTIPLEXING FUNCTION.................................................................................................... 39
TABLE 26: PIN DEFINITION OF THE I2C.................................................................................................................... 39
TABLE 27: I2C MULTIPLEXING FUNCTION ............................................................................................................. 39
TABLE 28: PIN DEFINITION OF THE GPIO................................................................................................................ 40
TABLE 29: PIN DEFINITION OF THE ADC................................................................................................................. 40
TABLE 30: ADC SPECIFICATION ................................................................................................................................40
TABLE 31: PIN DEFINITION OF THE PWM ............................................................................................................... 40
TABLE 32: BUZZER OUTPUT CHARACTERISTICS ................................................................................................. 41
TABLE 33: PIN DEFINITION OF THE NETLIGHT ..................................................................................................... 41
TABLE 34: STATUS OF THE NETLIGHT PIN.............................................................................................................. 41
TABLE 35: NETLIGHT MULTIPLEXING FUNCTION................................................................................................ 42
TABLE 36: PIN DEFINITION OF THE STATUS........................................................................................................... 42
TABLE 37: STATUS MULTIPLEXING FUNCTION..................................................................................................... 42
TABLE 38: ABSOLUTE MAXIMUM RATINGS........................................................................................................... 46
TABLE 39: RECOMMENDED OPERATING CONDITIONS ....................................................................................... 46
TABLE 40: DIGITAL INTERFACE CHARACTERISTICS (1.8V)................................................................................ 46
TABLE 41: DIGITAL INTERFACE CHARACTERISTICS (2.85V).............................................................................. 46
TABLE 42: RUIM_VDD CHARACTERISTICS ............................................................................................................ 47
TABLE 43: VDD_EXT CHARACTERISTICS ............................................................................................................... 47
TABLE 44: THE ESD CHARACTERISTICS (TEMPERATURE: 25℃, HUMIDITY: 45 %)....................................... 47
TABLE 45: CONDUCTED TRANSMISSION POWER................................................................................................. 47

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TABLE 46: OPERATING FREQUENCIES..................................................................................................................... 48
TABLE 47: CONDUCTED RECEIVE SENSITIVITY ................................................................................................... 48
TABLE 48: MOISTURE SENSITIVITY LEVEL AND FLOOR LIFE........................................................................... 50
TABLE 49: BAKING REQUIREMENTS ....................................................................................................................... 50
TABLE 50: RELATED DOCUMENTS ........................................................................................................................... 51
TABLE 51: TERMS AND ABBREVIATIONS................................................................................................................ 52
TABLE 52: SAFETY CAUTION..................................................................................................................................... 53

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Figure Index
FIGURE 1: SIM2000S FUNCTIONAL DIAGRAM ....................................................................................................... 12
FIGURE 2: SIM2000S PIN OUT DIAGRAM (TOP VIEW)........................................................................................... 13
FIGURE 3: DIMENSIONS OF SIM2000S (UNIT: MM)................................................................................................ 16
FIGURE 4: RECOMMENDED PCB FOOTPRINT OUTLINE (UNIT: MM) ................................................................ 17
FIGURE 5: REFERENCE CIRCUIT OF THE VBAT INPUT......................................................................................... 18
FIGURE 6: REFERENCE CIRCUIT OF THE LDO POWER SUPPLY ......................................................................... 18
FIGURE 7: REFERENCE CIRCUIT OF THE DC-DC POWER SUPPLY..................................................................... 19
FIGURE 8: POWERED ON/DOWN MODULE USING TRANSISTOR....................................................................... 20
FIGURE 9: POWERED ON/DOWN MODULE USING BUTTON ............................................................................... 20
FIGURE 10: TIMING OF POWER ON MODULE......................................................................................................... 20
FIGURE 11: TIMING OF POWER DOWN SIM2000S BY PWRKEY .......................................................................... 21
FIGURE 12: RESET CIRCUIT........................................................................................................................................ 22
FIGURE 13: RESET TIMING SEQUENCE.................................................................................................................... 23
FIGURE 14: CONNECTION OF THE SERIAL INTERFACES..................................................................................... 26
FIGURE 15: CONNECTION OF THE INNER MODULE ............................................................................................. 26
FIGURE 16: LEVEL MATCHING CIRCUIT ................................................................................................................. 27
FIGURE 17: USB REFERENCE CIRCUIT .................................................................................................................... 27
FIGURE 18: RI BEHAVIOUR OF VOICE CALLING AS A RECEIVER...................................................................... 29
FIGURE 19: RI BEHAVIOUR OF DATA CALLING AS A RECEIVER........................................................................ 29
FIGURE 20: RI BEHAVIOUR OF URC OR RECEIVE SMS ........................................................................................ 29
FIGURE 21: RI BEHAVIOUR AS A CALLER ............................................................................................................... 30
FIGURE 22: SPEAKER REFERENCE CIRCUIT .......................................................................................................... 30
FIGURE 23: MICROPHONE REFERENCE CIRCUIT.................................................................................................. 31
FIGURE 24: REFERENCE CIRCUIT OF THE 8-PIN RUIM CARD HOLDER ........................................................... 32
FIGURE 25: REFERENCE CIRCUIT OF THE 6-PIN RUIM CARD HOLDER ........................................................... 32
FIGURE 26: MOLEX 91228 RUIM CARD HOLDER ................................................................................................... 33
FIGURE 27: AMPHENOL C707 10M006 5122 RUIM CARD HOLDER...................................................................... 34
FIGURE 28: PCM REFERENCE CIRCUIT.................................................................................................................... 35
FIGURE 29: SYNCHRONY TIMING............................................................................................................................. 35
FIGURE 30: EXT CODEC TO MODULE TIMING ....................................................................................................... 36
FIGURE 31: MODULE TO EXT CODEC TIMING ....................................................................................................... 36
FIGURE 32: SYNCHRONY TIMING............................................................................................................................. 37
FIGURE 33: EXT CODEC TO MODULE TIMING ....................................................................................................... 37
FIGURE 34: MODULE TO EXT CODEC TIMING ....................................................................................................... 37
FIGURE 35: KEYS REFERENCE CIRCUIT.................................................................................................................. 38
FIGURE 36: REFERENCE CIRCUIT OF PWM DRIVER BUZZER ............................................................................ 41
FIGURE 37: REFERENCE CIRCUIT OF NETLIGHT .................................................................................................. 42
FIGURE 38: ANTENNA MATCHING CIRCUIT ........................................................................................................... 43
FIGURE 39: PIN ASSIGNMENT.................................................................................................................................... 44
FIGURE 40: TOP AND BOTTOM VIEW OF SIM2000S ............................................................................................... 49
FIGURE 41: TYPICAL SOLDER REFLOW PROFILE ................................................................................................. 49

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Version History
Date Version Description of change Author
2014-02-27 1.00 draft Yanwu.Wang;
Haibing.Ye

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SIM2000S_Hardware_Design_V1.00 9 2014-02-27
1. Introduction
This document describes SIM2000S hardware interface in great detail.
This document can help user to quickly understand SIM2000S interface specifications, electrical and mechanical
details. With the help of this document and other SIM2000S application notes, user guide, users can use
SIM2000S to design various applications quickly.
2. SIM2000S Overview
SIM2000S is a single CDMA module, which works on frequency 450MHz (BC5).
With a tiny configuration of 24*24*3mm, SIM2000S can meet almost all the space requirements in user
applications, such as smart phone, PDA and other mobile devices.
SIM2000S has 68 SMT pads, and provides all hardware interfaces between the module and customers’ boards.
zOne full modem serial port
zOne USB, the USB interface can be used debug, download software
zOne debug interface
zTwo ADC interface
zAudio channel which includes a microphone input and a receiver output
zProgrammable general purpose input and output
zA RUIM card interface
zSupport one PWM
zI2C interface
zThe keypad interface(5*5)
zPCM interface
SIM2000S is designed with power saving technique so that the current consumption is as low as 2mA in sleep
mode.
2.1. SIM2000S Key Features
Table 1: SIM2000S key features
Feature Implementation
Power supply 3.4V~4.4V
Power saving Typical power consumption in sleep mode is 2mA
Frequency bands Single-band: 450MHz (BC5) Block C
Transmission data
CDMA 1X
zMax 153.6kbps(DL)
zMax 153.6kbps(UL)
Temperature range
zNormal operation: -40°C ~ +85°C
zStorage temperature: -45°C ~ +90°C
External antenna Antenna pad
Audio features Speech codec modes:
zEVRC

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zEVRC-B(or 4GV)
zMicrophone: 8kHz sampling rate,16bit
zAudio AGC
zPCM post processing
zEcho Cancellation
z8,16 or 32kHz Tx path sampling rate
Serial port and
debug port
Serial port:
zFull modem interface with status and control lines, unbalanced,
asynchronous
z115200bps
zCan be used for AT commands or data stream
zSupport RTS/CTS hardware handshake and software ON/OFF flow control
zProgrammable parameters
1. Data size
2. Stop bits
3. Parity
4. Bit rate
5. Selectable clock source
zCommand registers that control the broad UART functions such as enable,
disable, and reset of the Tx and/or Rx channel, plus start and stop breaks
Debug port:
zDebug_TXD
zDebug_RXD
zUSB_VBUS
zUSB_DM
USB interface
zUSB_DP
CDMA Protocol
zIS95-A/B: Protocol Between MS & BTS
zIS-96A: Voice Signal Coding
zIS-98A: Base MS Function
zIS-126: Voice Loop-Back
zIS-637: Short Message Service
zIS-707: Data Service
zIS-657: Packet Data
Phone book management Support phonebook types: SM, DC, FD, LD, MC, ME, RC, EN.
RUIM interface Support identity card: 1.8V, 3V
RUIM application toolkit
zShared interface for RUIM applications, thereby further supporting CDMA
networks
zSelectable clock source
zAll RUIM signals can be used to GPIOs; this allows them to be configured
for alternate functions as discussed throughout this chapter
zThe associated pads are powered off VREG_RUIM and can be either 1.8 V
or 3 V (nominal)
SMS
zPoint to point MO and MT, Text and PDU mode
zSupport ASCII and UNICODE
zSMS storage: RUIM card or Module
Timing functions Use AT command set

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Physical characteristics Size: 24*24*3mm
Weight: 3.4g
Firmware upgrade USB port
2.2. Operating Mode
The table below summarizes the various operating modes of SIM2000S.
Table 2: Overview of operating modes
Mode Function
CDMA
SLEEP
Module will automatically go into sleep mode if the conditions of sleep mode
are enabling and there is no on air and no hardware interrupt (such as GPIO
interrupt or data on serial port).
In this case, the current consumption of module will be reduced to the
minimal level.
In sleep mode, the module can still receive paging message and SMS.
CDMA
IDLE
Software is active. Module is registered to the CDMA network, and the
module is ready to communicate.
CDMA
TALK
Connection between two subscribers is in progress. In this case, the power
consumption depends on network settings.
Normal
operation
CDMA 1X
There is CDMA 1X data transfer in progress. In this case, power consumption
is related with network settings; uplink/downlink data rates and CDMA 1X
configuration.
Power down
Normal power down by sending AT command “AT+CPOWD=1” or using the PWRKEY.
The power management unit shuts down the power supply for the baseband part of the
module. Software is not active. The serial port is not accessible. Power supply (connected to
VBAT) remains applied.
Minimum
functionality
mode
AT command “AT+CFUN” can be used to set the module to a minimum functionality mode
without removing the power supply. In this mode, the RF part of the module will not work
or the RUIM card will not be accessible, or both RF part and RUIM card will be closed, and
the serial port is still accessible. The power consumption in this mode is lower than normal
mode.
2.3. Functional Diagram
The following figure shows a functional diagram of SIM2000S:
zCDMA baseband
zCDMA RF
zFlash
zThe CDMA radio frequency part
zAntenna interface
zUSB interface
zDebug interface
zOther interface

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Figure 1: SIM2000S functional diagram
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3. Package Information
3.1. Pin out Diagram
Figure 2: SIM2000S pin out diagram (Top view)
3.2. Pin Description
Table 3: Pin description
Pin name Pin number I/O Power
domain(V) Description Comment
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Power supply
VBAT 55,56,57 I 3.4~4.4 Power supply
VDD_EXT 15 O 2.85 2.85V output power
supply
If it is unused, keep
open.
GND
2,17,18,29,39,
45,46,53,54,
58,59,61,62,
63,64,65
Ground
Power on/down
PWRKEY 1 I 1.8
PWRKEY should be
pulled low at least 1
second and then released
to power on/down the
module.
Pulled up internally.
Audio interfaces
MICP 19
MICN 20
I Differential audio input
SPKP 21
SPKN 22
O Differential audio output
If these pins are unused,
keep open.
Status
STATUS 66 O 2.85 Power on status
NETLIGHT 52 O 1.8 Network status
If these pins are unused,
keep open.
PCM interface
PCMCLK 11 O
PCMIN 12 I
PCMOUT 13 O
PCMSYNC 14 O
1.8 PCM interface If these pins are unused,
keep open.
USB interface
VBUS 6 I 4.4~5.5
USB_DP 23 I/O
USB_DM 24 I/O
Debug and download If these pins are unused,
keep open.
I2C interface
SDA 37 I/O I2C serial bus data
SCL 38 O 1.8 I2C serial bus clock
If these pins are unused,
keep open.
Debug interface
DEBUG_TXD 27 O
DEBUG_RXD 28 I
2.8 Debug If these pins are unused,
keep open.
Keypad interface
KBR0 44 keypad row 0
KBR1 43 keypad row 1
KBR2 42 keypad row 2
KBR3 41 keypad row 3
KBR4 40
I/O 1.8
keypad row 4
If these pins are unused,
keep open.

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KBC0 51 keypad column 1
KBC1 50 keypad column 1
KBC2 49 keypad column 2
KBC3 48 keypad column 3
KBC4 47 keypad column 4
GPIO33 67 GPIO33
GPIO34 68
I/O 1.8
GPIO34
Serial port
RXD 10 I Receive data
TXD 9 O Transmit data
RTS 8 I Request to send
CTS 7 O Clear to send
DCD 5 O Data carrier detect
RI 4 O Ring indicator
DTR 3 I
2.85
Data terminal ready
If these pins are unused,
keep open.
RUIM interface
RUIM_VDD 30 O
Voltage supply for
RUIM card. Support
1.8V or 3V RUIM card
RUIM_DATA 31 I/O RUIM data input/output
RUIM_CLK 32 O RUIM clock
RUIM_RST 33 O
1.8/3
RUIM reset
All signals of RUIM
interface should be
protected against ESD
with a TVS diode array.
RUIM_PRESENCE 34 I 1.8 RUIM card detection If it is unused, keep
open.
ADC
ADC1 25 I
Input voltage range: 0V
~ 2.5V
ADC2 36 I
Input voltage range: 0V
~ 2.5V
If it is unused, keep
open.
External reset
RESET 16 I 1.8 Reset input(Active low) Recommend connecting
a 100nF capacitor.
Pulse width modulation( PWM )
PWM 35 O 2.85 PWM If these pins are unused,
keep open.
RF interface
RF_ANT 60 I/O
Radio antenna
connection
Impendence must be
controlled to 50.
Not connect
NC 26
These pins should be
kept open.

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3.3. Package Dimensions
Figure 3: Dimensions of SIM2000S (Unit: mm)
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Figure 4: Recommended PCB footprint outline (Unit: mm)

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4. Application Interface
4.1. Power Supply
The power supply range of SIM2000S is from 3.4V to 4.4V. Recommended voltage is 3.8V. The power supply
must be able to provide sufficient current up to 600mA. For the VBAT input, a bypass capacitor (low ESR) such
as a 100 µF is strongly recommended.
A 5.1V/500mW Zener diode is strongly recommended, the diode can prevent chip from damaging by the
voltage surge. These capacitors and Zener diode should be placed as close as possible to SIM2000S VBAT
pins.
Figure 5: Reference circuit of the VBAT input
Table 4: Recommended Zener diode
Vendor Part number Power(watts) Packages
1 On semi MMSZ5231BT1G 500mW SOD123
2 Prisemi PZ3D4V2H 500mW SOD323
3 Prisemi PZ5D4V2H 500mW SOD523
4 Vishay MMSZ4689-V 500mW SOD123
5 Crownpo CDZ55C5V1SM 500mW 0805
The following figure is the reference design of +5V input power supply. The designed output for the power
supply is 4V, thus a linear regulator can be used.
Figure 6: Reference circuit of the LDO power supply
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If there is a high drop-out between the input and the desired output (VBAT), a DC-DC power supply will be
preferable because of its better efficiency especially with the 600mA current of the module. The following figure
is the reference circuit.
Figure 7: Reference circuit of the DC-DC power supply
The single 3.7V Li-ion cell battery can be connected to SIM2000S VBAT pins directly. But the Ni-Cd or Ni-MH
battery must be used carefully, since their maximum voltage can rise over the absolute maximum voltage of the
module and damage it.
When battery is used, the total impedance between battery and VBAT pins should be less than 150m.
VBAT=4.0V,
A VBAT bypass capacitor C101=100µF tantalum capacitor (ESR=0.7),
Another VBAT bypass capacitor C104=100nF.
4.1.1. Power supply pin
Pin 55, 56 and Pin 57 are VBAT input, Pins 53, 54,63,64,65 are GND of power supply.
When designing the power supply in user’s application, pay special attention to power losses. Ensure that the
input voltage never drops below 3.4V even when current consumption rises to maximum. If the power voltage
drops below 3.4V, the module may be shut down automatically. The PCB traces from the VBAT pins to the
power supply must be wide enough (at least 60mil) to decrease voltage drops in the transmission line.
4.1.2. Monitoring Power Supply
AT command “AT+CBC” can be used to monitor the VBAT voltage. For detail, please refer to document [1].
4.2. Power on/down Scenarios
4.2.1. Power on SIM2000S
User can power on SIM2000S by pulling down the PWRKEY pin for at least 1 second and release. This pin is
already pulled up to 1.8V in the module internal, so external pull up is not necessary. Reference circuit is shown
below.
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Figure 8: Powered on/down module using transistor
1.8V
Power
on/down logic
PWRKEY
MODULE
200K
Figure 9: Powered on/down module using button
The power on timing is illustrated as in the following figure.
Figure 10: Timing of power on module
When power on procedure is completed, SIM2000S will send following URC to indicate that the module is
ready to operate at fixed baud rate.
RDY
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