Jackson Labs LTE-Lite User manual
LTE-Lite(tm) User
Manual
Document: 80200522
Version: 1.4
Date: 25 June, 2020
LTE-Lite User Manual
Copyright © 2013 to 2020 Jackson Labs Technologies, Inc.
© 2020 Jackson Labs Technologies, Inc. i
LTE-Lite User Manual
1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 General Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.2 Antenna Lightning Protection . . . . . . . . . . . . . . . . . . . . . 2
1.2.3 Power Connections. . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.4 Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . 2
2 Usage Instructions . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Powering Up the Evaluation Board . . . . . . . . . . . . . . . . . . . . . 3
2.1.1 Airflow Warning . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.2 Supplied Accessories . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.3 USB Serial Port . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.4 Major connections . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.5 Typical Phase Noise and ADEV Plots . . . . . . . . . . . . . . . . . 6
2.1.6 Evaluation Board Mechanical Dimensions . . . . . . . . . . . . . . . . 8
2.1.7 LTE-Lite SMT Module Mechanical Dimensions . . . . . . . . . . . . . . 9
2.1.8 LTE-Lite Evaluation Board Schematics . . . . . . . . . . . . . . . . . 9
2.2 Connector, Buttons and Switches on the Evaluation Board . . . . . . . . . . . . 11
2.3 LTE-Lite SMT Module usage . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.1 LTE-Lite SMT Module Minimum Required Setup . . . . . . . . . . . . . 13
2.3.2 Using the LTE-Lite SMT Module with external TCXOs . . . . . . . . . . .14
2.3.3 Using the LTE-Lite SMT Module Synthesized Frequency Output . . . . . . .16
2.3.4 Adding a USB output to the LTE-Lite SMT Module for NTP applications . . . .17
2.3.5 SMT Module Power Connection . . . . . . . . . . . . . . . . . . . . 18
2.3.6 SMT Module Antenna Connection . . . . . . . . . . . . . . . . . . .18
2.3.7 1PPS Module outputs . . . . . . . . . . . . . . . . . . . . . . . .18
2.3.8 Synthesized RF Output Frequency. . . . . . . . . . . . . . . . . . .18
2.3.9 System Reset . . . . . . . . . . . . . . . . . . . . . . . . . . .19
2.3.10Module Serial IO pins . . . . . . . . . . . . . . . . . . . . . . . . 20
2.3.11Module IO Pinout . . . . . . . . . . . . . . . . . . . . . . . . .20
2.4 Connecting a GPS Antenna . . . . . . . . . . . . . . . . . . . . . . . . 24
2.5 USB serial connection . . . . . . . . . . . . . . . . . . . . . . . . . .25
2.5.1 Proprietary $PSTI NMEA GPS Status Sentence . . . . . . . . . . . . . 25
2.5.2 JLT Proprietary STATUS Output Sentence . . . . . . . . . . . . . . .25
2.5.2.1 Lock Status Definition . . . . . . . . . . . . . . . . . . . .26
2.5.2.2 Health Status Definition . . . . . . . . . . . . . . . . . . . .26
3 Certification and Warranty . . . . . . . . . . . . . . . . . . . . .29
3.1 Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
3.1.1 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
3.1.2 Limitation of Warranty. . . . . . . . . . . . . . . . . . . . . . . .29
3.1.3 Exclusive Remedies . . . . . . . . . . . . . . . . . . . . . . . .30
LTE-Lite User Manual
ii © 2020 Jackson Labs Technologies, Inc.
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LTE-Lite User Manual
Introduction
1.1 Overview
The LTE-Lite GPSDO is a very low-cost, small SMT Timing and Frequency reference module for
high-volume Small Cell applications. It is intended to provide precise timing and a very low Phase
Noise and jitter frequency reference to RF Transceivers and Base Band processors as typically used
in Small Cell applications. The LTE-Lite is a true GPSDO rather than a Numerically Controlled
Oscillator, using true precision analog disciplining of the high-end Crystal rather than digital
phase-adjustments of a free running low-cost crystal, resulting in many orders of magnitude less jitter
and Phase Noise. The LTE-Lite GPSDO is available as an SMT module, or mounted onto the
LTE-Lite Evaluation Board with easy access to relevant signals via a host of connectors and
switches.
The LTE-Lite GPSDO and LTE-Lite Evaluation Board include a high-performance GPS/QZSS
receiver that can acquire and track up to 65 GPS signals down to a state of the art –165dBm, a 32bit
processor, a low-noise 3V CMOS 10MHz, 19.2MHz, or 20MHz output, two 3.3V CMOS 1PPS
outputs, TTL or USB status and Position-Velocity-and-Time (PVT) interface, precision voltage
references, power filters, and DACs. It generates a low-noise 10/19.2/20MHz signal with typically
better than 1E-09 precision and accuracy (1ppb), better than typ. 135fs jitter (100Hz to 2MHz) and a
1PPS signal with typically better than +/-25ns stability when locked to GPS.
The LTE-Lite GPSDO provides status information on TTL output lines that can directly drive LEDs,
and has two serial output ports for NMEA PVT and Oscillator status output. All configuration of the
LTE-Lite GPSDO is done via pull-down TTL straps with built-in pull-up resistors, so no software
configuration driver is needed on the users’ system. The evaluation kit may be operated and powered
from the built-in USB port, or an optional 5V power supply and both power-sources may be
connected simultaneously. The evaluation kit is supplied with a USB cable and matching wall-wart
power supply, two MMCX to BNC adaptor cables, a GPS antenna, and a quick-start guide. The unit
provides an industry-standard NMEA GPS serial output that is enabled by default and provides
Position/Velocity/Timing (PVT) information, and also provides a UTC-synchronized 1PPS signal on
the USB serial port DCD# pin for NTP applications. The LTE-Lite GPSDO also provides a
NMEA-compatible proprietary status message on a secondary serial port that sends oscillator lock
status as well as health status information to a users’ system.
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2© 2020 Jackson Labs Technologies, Inc.
1.2 General Safety Precautions
The following general safety precautions must be observed during all phases of operation of this
instrument. Failure to comply with these precautions or with specific warnings elsewhere in this
manual violates safety standards of design manufacture, and intended use of the instrument. Jackson
Labs Technologies, Inc. assumes no liability for the customer’s failure to comply with these
requirements.
1.2.1 Grounding
To avoid damaging the sensitive electronic components in the LTE-Lite GSPDO kit or board always
make sure to discharge any built-up electrostatic charge to a good ground source, such as power
supply ground. This should be done before handling the circuit board or anything connected to it, i.e.
the GPS antenna.
1.2.2 Antenna Lightning Protection
Always use a UL-certified, properly installed Antenna Lightning suppressor on the antenna cable
when mounting the GPS antenna. Without proper Lightning Protection damage to equipment, injury,
or death may result.
1.2.3 Power Connections
Make sure to connect the DC power to the device following the polarity indicated in Section 2.1. Do
not reverse the power pins as this will cause serious damage to the circuit board.
1.2.4 Environmental Conditions
This instrument is intended for indoor use. It is designed to operate at a maximum relative
non-condensing humidity of 95% and at altitudes of up to 4000 meters. Refer to the specifications
tables for the ac mains voltage requirements and ambient operating temperature range.
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LTE-Lite User Manual
Usage Instructions
2.1 Powering Up the Evaluation Board
The LTE-Lite Evaluation Board is essentially a plug-and-play product that only requires a power
source and a GPS antenna to be connected to start generating highly-accurate output frequency and
1PPS signals that are phase and frequency aligned to UTC (USNO) and thus allow NIST-tracability.
To use the Evaluation Board, simply plug in the power supply using the supplied USB cable, plug in
the antenna, and wait about 15 minutes typically for the GREEN “LOCK-OK” LED to light up to
indicate that the unit is locked to UTC with better than +/-250ns phase accuracy, and a frequency
accuracy of better than 1ppb has been achieved. The internal software will auto-configure and
auto-calibrate the unit without any user-interaction and the longer the unit runs the more accurate it
will become.
For units with a Timing GPS receiver, the unit will start an Auto Survey process to establish the
stationary antenna position as soon as power is applied, and this is indicated by the SURVEY LED on
the Evaluation Board. The Auto Survey process will take at least 2000 seconds to finish, at which
time the antenna position is stored in internal memory, and operation with 1 satellite is possible (4
sats are required for Mobile mode/non-Position-Hold operation).
The Evaluation Board is powered directly from the USB cable, and/or from an optional external 5V
DC source on the +5V header. The USB cable and the external 5V DC source may be connected at
the same time as they are diode-protected from one another. The current is typically less than 0.07A
at 5V. Connect a clean +5V power supply to the +5V header block if the USB cable is not going to be
used, or is plugged-in intermittently. See Figure 2.3 for the proper polarity of the optional external
5V DC power connection. Reversing the polarity on the power connector will not damage the unit as
it is diode reverse-polarity protected.
When communicating to the unit through the USB cable, Windows Vista, Windows 7/8 and Linux
will auto-recognize the unit as a USB serial COM adaptor, and automatically assign a serial port to
the unit. Windows will automatically load the USB COM driver for the board, and may need to have
access to the Internet to download the latest driver from the Microsoft update website. The user can
verify the COM port that windows assigned to the unit under the Computer Management window
(right click on computer and press the “MANAGE” button under Windows 7, or go to Control
Panel/Computer Management). The unit should show up as a standard serial port adaptor under the
“Ports (COM& LPT)” Icon. Please note the COM port number, as it is required for the initialization
of application software.
LTE-Lite User Manual
4© 2020 Jackson Labs Technologies, Inc.
The unit will start to search for satellites as soon as power is applied, and will start to lock the internal
TCXO to UTC as soon as a GPS antenna is attached and more than 4 sats become visible. After 30
minutes or less the unit should stabilize the frequency, and all ALARM indicators should be off
resulting in the Green “LOCK OK” LED to be lit up. At this time the Green LED will indicate the
unit is fully synchronized to UTC, and generating a stable and accurate 20MHz/19.2MHz/10MHz
output signal. The Green LED may go off momentarily from time to time as airflow touches the unit
or sats come in and out of view - this is normal behavior.
You may place the GPS antenna in a window, but it is recommended to place the GPS antenna with a
full view of the sky for best performance. The antenna cable can be extended to 100m or more with
high quality antenna cable (use quad shielded RG-6 75 Ohms cable, or high-quality 50 Ohms coax
cable) without significant loss of signal quality.
WARNING: Make sure to use a proper and certified Antenna Lightning Arrestor when placing
the antenna outside as lightning strikes can cause damage, injury, or death to equipment and
personnel.
Figure 2.1 LTE-Lite Evaluation Board with LTE-Lite Module
2.1.1 Airflow Warning
The LTE-Lite SMT module and thus the LTE-Lite Evaluation Board are very sensitive to airflow.
This includes airflow from convection, walking past the unit, or Air Conditioning systems. For
optimal performance the user must insure that the unit is shielded from any airflow by placing the
unit into an enclosure (for example Hammond PN: 1455C801BK). Please note that the external
DIP-14 TCXO and its socket must be removed from the PCB for it to fit into the aforementioned
Hammond enclosure. For optimal stability performance of the TCXO the unit should be sealed into
an airtight enclosure.
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LTE-Lite User Manual
2.1.2 Supplied Accessories
The LTE-Lite Evaluation Kit includes the LTE-Lite Evaluation Board and is supplied with a GPS
antenna with 5m cable, a USB cable, a USB wall-wart power supply, and two MMCX to BNC
adaptor cables and is ready-to-go out of the box.
Figure 2.2 LTE-Lite Evaluation Kit example Accessories
2.1.3 USB Serial Port
The LTE-Lite Evaluation Board has an internal RS-232 to USB serial port adaptor. This allows the
unit to be directly connected to a PC’s USB port, from which it will receive power and to which it
will send serial output sentences with no external RS-232 to USB adaptor is required. The term
“RS-232” and USB serial port are used interchangeably, as the RS-232 port is implemented and
connected via the USB serial connection. Windows and Linux have built-in support for this optional
serial port functionality.
2.1.4 Major connections
The LTE-Lite Evaluation Board has a number of connectors, switches, jumpers, headers and LEDs to
select and display status. These are driven by signals from the LTE-Lite GPSDO SMT module.
The major connections and features of the LTE-Lite Evaluation Board are shown in Figure 2.3.
LTE-Lite User Manual
6© 2020 Jackson Labs Technologies, Inc.
Figure 2.3 Major connections of the LTE-Lite Evaluation Board
2.1.5 Typical Phase Noise and ADEV Plots
The following plot shows a typical ADEV plot for the LTE-Lite Evaluation Board. The unit had been
operating for 5+ days, has not been moved or vibrated in any way, and was completely shielded from
airflow by placing the unit into an airtight enclosure.
Figure 2.4 Typical ADEV plot of 20MHz LTE-Lite Evaluation Board
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LTE-Lite User Manual
The following plot shows a typical Phase Noise plot of the TCXO buffered RF output for the
LTE-Lite Evaluation Board. The unit had been operating for 1 day, and was completely shielded from
airflow by placing the unit into an airtight enclosure.
Figure 2.5 Typical Phase Noise plot of 19.2MHz LTE-Lite Evaluation Board
LTE-Lite User Manual
8© 2020 Jackson Labs Technologies, Inc.
2.1.6 Evaluation Board Mechanical Dimensions
Figure 2.6 Mechanical dimensions
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LTE-Lite User Manual
2.1.7 LTE-Lite SMT Module Mechanical Dimensions
Figure 2.7 Mechanical dimensions of the LTE-Lite SMT Module
2.1.8 LTE-Lite Evaluation Board Schematics
The following schematics may be used as an example of how to connect the LTE-Lite SMT Module,
and to maximize the features of the LTE-Lite SMT Module. Please note that IC U4 is the actual
LTE-Lite SMT module.
LTE-Lite User Manual
10 © 2020 Jackson Labs Technologies, Inc.
Figure 2.8 Schematics of LTE-Lite Evaluation Board
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LTE-Lite User Manual
2.2 Connector, Buttons and Switches on the Evaluation Board
Table 2.1 shows the LTE-Lite Evaluation Board connectors, buttons, switches, and LEDs.
Table 2.1 LTE-Lite Evaluation Board connectors, buttons, switches, and LEDs
Ref Name Function Specification Pinning/Usage
JP2 +5V Optional External
+5V Supply. Use
when USB power
supply is not
available
5V DC +/-20%, <0.08A, <10mVac Pin close to USB connector: +5V
Pin close to Mounting Hole: GND
J3 Position Hold
Mode or Mobile
Mode selector
Selects if the unit is
used in stationary
mode or mobile
mode
Open (default): Auto Survey mode
with Position Hold function is
enabled
Jumper Inserted: Auto Survey mode
is disabled, and Mobile (3D) mode is
selected
WARNING: DO NOT CHANGE THE
SETTING OF THIS JUMPER WITH
POWER APPLIED TO THE UNIT,
THIS MAY CORRUPT THE FLASH
OF THE GPS RECEIVER
PERMANENTLY.
Insert a jumper between Pin 1 to Pin
2 to disable Auto Survey mode. Only
change this jumper with power to the
unit being turned off.
WARNING: DO NOT CHANGE THE
SETTING OF THIS JUMPER WITH
POWER APPLIED TO THE UNIT,
THIS MAY CORRUPT THE FLASH
OF THE GPS RECEIVER
PERMANENTLY.
J2 20MHz, 10MHz,
or 19.2MHz
CMOS Out
Buffered RF output
from internal TCXO
+3.0V CMOS 20MHz, 10MHz, or
19.2MHz Output, can drive up to
+/-24mA. Frequency depends on
TCXO selection
Center-RF Output, Shield-GND
J1 1PPS CMOS Out 1PPS Signal
Aligned to UTC
+3.3V CMOS 1PPS Output, can
drive up to +/-10mA
Center-1PPS Output, Shield-GND
U3 USB Port Supplies Power and
NMEA output strings
Standard USB 2.0 Full Speed Mini USB
J5 Synthesized RF
output
Un-buffered output
of internal PLL
Synthesizer
3.3V CMOS, can supply up to
+/-10mA, frequency selected via
three jumpers
Center- RF Output, Shield- GND
J4 Antenna In GPS Antenna
Input
GPS 1575MHz antenna input,
supplies DC +3.3V to antenna
with up to 60mA current
Center- RF Output, Shield- GND
SW1 NMEA/Status
Selector Switch
Selects if either
GPS NMEA data
or an Oscillator
Status sentence is
sent to USB port
For GPS NMEA output: 38.4K
Baud 8N1, supported sentences:
GGA, GLL, GSA, GSV, RMC,
VTG, ZDA
For Status output: 38.4K Baud
8N1, oscillator and system
health status string. Proprietary
NMEA sentence
Left: GPS NMEA
Right: Oscillator Status
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SW2 External TCXO
Selector
Disables internal
TCXO and selects
optional external
DIP-14 TCXO
Down setting: external DIP-14
TCXO supplied with +3.3V, and
0V to 3.0V EFC range. TTL or
CMOS output,
10/15.36/19.2/20MHz TCXO
Up: Internal TCXO
Down: External TCXO
SW3 ISP Mode
Selector
Enables In
System
Programming
(ISP) mode
Factory Use Only Factory Use Only. Set to Right
setting (NORM) for board to
operate properly
S1 Init Auto
Survey
Initiates a
Position Auto
Survey
Press button for 1+ seconds to
manually initiate an Auto
Survey process
Press button for 1+ seconds until
SURVEY LED lights up
S2 RESET System Reset Press button momentarily Initiates a System Reset
LED D5 SURVEY LED Lights up during
Auto Survey
process
Lights up for 2000 or more
seconds after power-on to
indicate Auto Survey is in
process
Lights up during Auto Survey
LED D6 LOCK-OK Indicates No
Events are
pending, and
oscillator is
locked
Lights up when oscillator is
locked to UTC via GPS
receiver, and no events are
pending. Events are
individually shown in the status
serial string sentence
Lights up when unit is healthy
and locked to GPS. Extinguishes
when a hardware or software
event is pending, no GPS signal
is received, or the unit is not yet
locked to GPS/UTC
LED D7 WARMUP Indicates unit is
still in warmup
mode
Lights up for one or more
minutes after power-on
Indicates unit is warming up
LED D8 ALARM Indicates a
hardware fault, or
software alarm
Lights up when a hardware fault
or software alarm has been
detected
Lights up during Alarm
conditions
GPS
LED
GPS Status
LED
Power and GPS
Fix indicator
Lights up when power is
applied, and blinks when GPS
fixes are being received
Blinks when GPS fixes are
properly being received, and unit
is powered-on. Resides on
LTE-Lite SMT module near
antenna connector
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LTE-Lite User Manual
2.3 LTE-Lite SMT Module usage
The LTE-Lite SMT Module by itself is designed to be soldered into a customer PCB using standard
SMT pick-and-place procedures. The SMT module is designed as a 0.032 inches thin single-sided
PCB with 32 castellated solder pads on the bottom and on the sides of the module. It is recommended
that the users’ PCB has a filled ground plane under the SMT module, and does not contain any traces
under the SMT module to avoid cross-talk into signals inside the module. It is also recommended that
the users’ PCB has a solid silkscreen layer under the SMT module to generate insulation between the
SMT module and the users’ PCB. Soldering can be done manually, or using standard reflow oven
soldering procedures. The module can be soldered onto the customers’ PCB using lead or RoHs
procedures.
The LTE-Lite SMT module is moisture sensitive, and it must be pre-baked before
reflow-soldering to avoid damage to the internal IC’s from moisture absorbtion. Pre-bakeing
should be done at +110 Degrees C maximum for 24 hours prior to soldering the module to a
customers’ PCB. Pre-bakeing is not required for manually hand-soldering the unit onto a
customers’ PCB using a solder-iron (not a heat-gun).
2.3.1 LTE-Lite SMT Module Minimum Required Setup
The following schematics show the minimum required connections to operate the LTE-Lite SMT
Module. Only a +3.3V power supply is needed, an antenna connection to the internal U.Fl coax
connector, and a connection to the TCXO output and 1PPS output are needed to use the module.
JP1 Debug
Connector
Debug status,
Synthesizer
Frequency
selector, 1Hz/5Hz
NMEA selector,
Raw 1PPS output,
RESET# output
signal
Pins 9, 10, and 11: Insert
jumpers
Pins 12 and 13: CMOS 3.3V
output of GPS 1PPS and GPS
TXD
Pin 14: Insert jumper for 5Hz
NMEA output
Pin 15: Indicates when
synthesizer is phase-locked (can
be used as a RESET# signal to
other circuits)
Pin 16: +3.3V, 50mA max
Insert jumpers between Pins 9
and 8, 10 and 7, 11 and 6 to
select synthesized output
frequency.
Insert jumper between pin 14
and 3.
Pin 15: standard 3.3V CMOS
level RESET# output signal with
up to 1s reset active low
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14 © 2020 Jackson Labs Technologies, Inc.
Figure 2.9 Minimum required setup for the LTE-Lite SMT Module
2.3.2 Using the LTE-Lite SMT Module with external TCXOs
The following schematics shows how to connect an external 3.0V TCXO to the LTE-Lite SMT
Module using the internal low-noise 3.0V regulator output to power the external TCXO. The internal
TCXO and TCXO buffer are disabled by pulling the DISABLE-TCXO pin 8 of the module high,
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LTE-Lite User Manual
which then allows feeding an external 3.3V CMOS or TTL RF signal into the RF pin 6 of the
module. The former RF output pin 6 of the module becomes an RF input pin when pulling pin 8 of
the module high. The module TCXO Disable pin 8 is pulled-low internally to the module to allow the
internal TCXO to operate by default. Allowable external frequencies are 10MHz, 15.36MHz,
19.2MHz and 20MHz. Additional frequencies may be supported by the firmware at a later date.
External oscillators can be disciplined directly by the modules’ EFC output pin 1, and should have
50K Ohms or higher resistance to ground on their EFC pins. The EFC output pin 1 has a voltage
range of 0V to 3.0V an requires external oscillators with positive frequency slope.
Figure 2.10 Connecting an external TCXO to the LTE-Lite SMT Module
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2.3.3 Using the LTE-Lite SMT Module Synthesized Frequency
Output
The following schematics show an example of how to use the un-buffered synthesized RF output of
the LTE-Lite SMT Module.
Figure 2.11 Using the synthesized frequency output of the LTE-Lite SMT Module
Table of contents
