Texas Instruments AMC1305 EVM Series User manual

User's Guide
SBAU237–September 2014
AMC1305xxEVM User's Guide
This user's guide describes the characteristics, operation, and use of the AMC1305EVM populated with
either the AMC1305L25, AMC1305M05 or AMC1305M25. See Table 1 for additional details about the
analog input range and bandwidth for each component in the AMC1305 family. The AMC1305EVM is
designed for prototyping and evaluation. A complete circuit description, schematic diagram, and bill of
materials are included.
Throughout this document, the abbreviation EVM and the term evaluation module are synonymous with
the AMC1305EVM.
The following related documents are available through the Texas Instruments web site at www.ti.com.
Related Documentation
Device Literature Number
AMC1305 SBAS654
AMC1210 SBAS372
SN6501 SLLSEA0
TMS320F28377D SPRS880A
TLV70450 SBVS148C
Contents
1 Overview...................................................................................................................... 2
2 Analog Interface.............................................................................................................. 2
3 Digital Interface .............................................................................................................. 3
4 Power Supplies .............................................................................................................. 3
5 EVM Set-Up and Operation ................................................................................................ 7
6 Bill of Materials, Schematic, and Layout.................................................................................. 8
List of Figures
1 AMC1305EVM Schematic: Analog Input Section ....................................................................... 2
2 Power, Clock Input, and Digital Data Output............................................................................. 3
3 JP1 in Ext Position........................................................................................................... 4
4 JP1 in Iso Position........................................................................................................... 4
5 Forward Voltage of the Rectifier Diode ................................................................................... 6
6 AMC1305EVM Silk Screen Drawing ...................................................................................... 8
List of Tables
1 AMC1305 Family Information .............................................................................................. 7
2 AMC1305EVM Bill of Materials ........................................................................................... 9
1
SBAU237–September 2014 AMC1305xxEVM User's Guide
Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated

Overview www.ti.com
1 Overview
1.1 Features
• Full-featured evaluation module for the AMC1305 single-channel, isolated, delta-sigma (ΔΣ) modulator
• Screw terminals for easy access to analog inputs, clock input, and modulator data output
• Optional isolated power to the AMC1305 analog voltage supply input derived from the controller-side
power supply
1.2 Introduction
The AMC1305 is a single-channel, second-order, switched-capacitor, ΔΣ modulator with an output
separated from the input interface circuitry by a capacitive isolation barrier. The isolation barrier provides
galvanic isolation of up to 7000 VPEAK. The AMC1305 can be used to achieve 16 bits of resolution with a
dynamic range of 80 dB (13 ENOB) at a data rate of 78 kSPS when paired with a digital filter (such as the
ΔΣ filter module in the TMS320F28377D or the AMC1210).
2 Analog Interface
The analog input to the AMC1305 is routed from the two-wire screw terminal at J2. This screw terminal
gives the user access to the inverting and noninverting inputs of the AMC1305 device installed at U1.
2.1 Analog Inputs
The analog input to the AMC1305EVM printed circuit board (PCB) consists of a simple RC filter circuit.
The input circuitry to the AMC1305 is shown in Figure 1.
Figure 1. AMC1305EVM Schematic: Analog Input Section
Note that the RC filter circuit is not required in every application; the input amplifier of the AMC1305
already provides a limited input bandwidth. See Table 1 for additional details about the analog input
bandwidth for each component in the AMC1305 family.
All trademarks are the property of their respective owners.
2AMC1305xxEVM User's Guide SBAU237–September 2014
Submit Documentation Feedback
Copyright © 2014, Texas Instruments Incorporated

www.ti.com Digital Interface
3 Digital Interface
The AMC1305EVM is designed for use with digital filters (such as the ΔΣ filter module in the
TMS320F28377D or the AMC1210). The power, clock input, and modulator data output of the AMC1305
device are routed to the two-wire screw terminals at J1, J3, and J4, as Figure 2 shows.
Figure 2. Power, Clock Input, and Digital Data Output
Note that component R2 in Figure 2 is marked as DNP (do not populate) because Figure 2 corresponds to
an AMC1305EVM populated with a CMOS variant of the AMC1305. Refer to Table 1 for additional details
about the analog input ranges and interfaces available in the AMC1305 family.
4 Power Supplies
Power for the controller side of the AMC1305 device is supplied through the two-wire screw terminal at J1.
The user has two options to provide power for the high side of the AMC1305 device. One option is to
supply the high side of the AMC1305 through the two-wire screw terminal at J5; to accomplish that, the
user must set jumper JP1 to the position labeled Ext; see Figure 3.
3
SBAU237–September 2014 AMC1305xxEVM User's Guide
Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated

Power Supplies www.ti.com
Figure 3. JP1 in Ext Position
The second option is to supply the high side of the AMC1305 with the filtered signal coming from the
isolated side of the onboard transformer T1. Note that the filtered signal on the isolated side of T1 is
generated from the power supplied to the controller side of the AMC1305 device by using the SN6501
transformer driver located at U3. To take advantage of this isolated, onboard supply, the user must set
jumper JP1 to the position labeled Iso, as shown in Figure 4.
Figure 4. JP1 in Iso Position
4AMC1305xxEVM User's Guide SBAU237–September 2014
Submit Documentation Feedback
Copyright © 2014, Texas Instruments Incorporated

www.ti.com Power Supplies
The design of the isolated, unregulated power source to the AMC1305 analog supply input closely follows
the TIPD121 Design Reference Guide, 0-5 A, Single-Supply, 2 kV Isolated Current Sensing Solution
(SLAU521).
The SN6501 transformer driver is used because it is designed for low-power, push-pull converters with
input voltages in the range of 3 V to 5.5 V; such voltage ranges fit well within the AMC1305 controller-side
supply range. Three important components in the dc-dc converter are the isolation transformer, the
rectifier diode, and the linear regulator.
4.1 Transformer Selection
To prevent the isolation transformer from saturating, its volt-seconds (V-t) product must be greater than
the maximum volt-seconds product applied by the SN6501. The maximum voltage delivered by the
SN6501 is the nominal converter input plus a 10% margin. The maximum time this voltage is applied to
the primary is half the period of the lowest frequency at the specified input voltage. The minimum
switching frequency of the SN6501 at 5-V operation is 300 kHz. Therefore, the transformer minimum V-t
product under these conditions, as determined by equations (1) and (2) in the SN6501 data sheet, is 9.1
Vμs. The specified V-t product of the isolation transformer selected (DA2304) is well above this 9.1-Vμs
requirement.
When searching for a suitable transformer, the minimum turns ratio required must be determined; such a
ratio allows the push-pull converter to operate over the specified current and temperature range. The
minimum turns ratio required can be expressed through the ratio of secondary to primary voltage
multiplied by a correction factor that takes into account the transformer typical efficiency. Equations (3)
through (8) in the SN6501 data sheet show the specific requirements for determining the minimum turns
ratio for a given application. The DA2304 has a 1:2.2 turns ratio; such a ratio produces an unregulated,
open-circuit voltage output well within the input range of the low-dropout regulator used in this design.
4.2 Rectifier Diode Selection
The chosen rectifier diode must possess low forward voltage to provide as much voltage to the converter
output as possible. When used in high-frequency switching applications, the rectifier must also possess a
short recovery time. Schottky diodes meet both of these requirements. The MBR0520L with a typical
forward voltage of approximately 200 mV at 8-mA forward current is used in this design. Figure 5
illustrates the forward voltage versus forward current characteristics of the MBR0520L diode.
5
SBAU237–September 2014 AMC1305xxEVM User's Guide
Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated

Power Supplies www.ti.com
Figure 5. Forward Voltage of the Rectifier Diode
4.3 Linear Regulator Selection
A linear voltage regulator is included to ensure that a stable supply voltage is delivered to the AMC1305
high side (AVDD pin). The TLV70450 fits this application well because of its low quiescent current and
regulation capabilities.
6AMC1305xxEVM User's Guide SBAU237–September 2014
Submit Documentation Feedback
Copyright © 2014, Texas Instruments Incorporated

www.ti.com EVM Set-Up and Operation
5 EVM Set-Up and Operation
This section describes the general operation of the AMC1305EVM.
5.1 Power and Analog Inputs: J1, J2, and J5
In the EVM default configuration, the isolated onboard supply is used. In other words, power to pin 7 of the
AMC1305 is provided from the supply connected to J1 by means of an isolation transformer and the
SN6501 transformer driver. This configuration provides an isolated, regulated source to the AMC1305. For
power provided from high-side isolated rails (such as from a gate drive supply), move the shunt on jumper
JP1 to the Ext position (as shown in Figure 3) so that the two-wire screw terminal at J5 can be used.
Use a voltage between 3 V dc and 5.5 V dc for the supply provided to J1 and a voltage between 4.4 V dc
and 5.5 V dc for the supply provided to J5.
The analog inputs to the AMC1305EVM PCB can be applied directly to the two-wire screw terminal at J2.
CAUTION
Carefully review the AMC1305 product data sheet for the limitations of the
analog input range, and ensure that the appropriate analog and digital supply
voltages are applied before connecting any analog input to the EVM.
Note that the AMC1305EVM is designed for evaluation of the electrical
characteristics of the AMC1305 only. The EVM is not meant for isolation tests
and is not designed to be used in a high-voltage environment.
The transformer used to derive the isolated, unregulated power source to the
LDO input has isolation ratings different from those of the AMC1305. Consult
the transformer manufacturer for more information on the isolation capabilities
of the transformer.
5.2 Device Operation
When the analog and digital power sources are applied to the AMC1305EVM, the digital output activates
when an external modulator clock source is applied. The internal reference of the AMC1305 is used as the
conversion reference.
Additionally, an analog input signal can be applied directly at screw terminal J2. See Figure 1 for more
details. Table 1 lists additional details about the analog input ranges and interfaces available in the device
family.
Table 1. AMC1305 Family Information
Input Voltage
Product Range Interface Input Bandwidth
AMC1305M05 ±50 mV CMOS 1 MHz
AMC1305M25 ±250 mV CMOS 1.8 MHz
AMC1305L25 ±250 mV LVDS 1.8 MHz
When the input voltage approaches the upper end of the specified full-scale range (50 mV or 250 mV,
depending on the AMC1305 device type), the ones density of the modulator output approaches 90%.
When the input voltage approaches the lower end of the specified full-scale range (–50 mV or –250 mV,
depending on the AMC1305 device type), the ones density of the modulator output approaches 10%.
7
SBAU237–September 2014 AMC1305xxEVM User's Guide
Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated

Bill of Materials, Schematic, and Layout www.ti.com
6 Bill of Materials, Schematic, and Layout
This section contains the complete bill of materials (BOM), schematic diagram, and PCB layout for the
AMC1305EVM.
NOTE: Board layouts are not to scale. These layouts are intended to show how the board is laid out
and are not intended to be used for manufacturing AMC1305EVM PCBs.
6.1 Printed Circuit Board Layout
Figure 6 shows the PCB layout.
Figure 6. AMC1305EVM Silk Screen Drawing
6.2 Schematic
The AMC1305EVM schematic is appended to the end of this document.
8AMC1305xxEVM User's Guide SBAU237–September 2014
Submit Documentation Feedback
Copyright © 2014, Texas Instruments Incorporated

www.ti.com Bill of Materials, Schematic, and Layout
6.3 Bill of Materials
Note that items 14 and 16 of the bill of materials depend on the type of AMC1305 used in the EVM. Resistor R2 is populated only when the
AMC1305 used is the AMC1305L25. R2 is not populated for EVMs that use the AMC1305M05 or AMC1305M25.
Table 2. AMC1305EVM Bill of Materials
Item Qty Reference Designator Description Manufacturer Mfr Part Number
L25 M05 M25
1 1 1 1 — Printed circuit board Any N/A
2 1 1 1 C2 CAP, CERM, 2.2uF, 16V, +/-10%, X7R, 0805 Taiyo Yuden EMK212B7225KG-T
3 4 4 4 C1, C4, C7, C10 CAP, CERM, 0.1uF, 25V, +/-10%, X7R, 0805 Kemet C0805C104K3RACTU
4 1 1 1 C3 CAP, CERM, 5600pF, 25V, +/-5%, C0G/NP0, 0603 TDK C1608C0G1E562J
5 3 3 3 C6, C8, C9 CAP, CERM, 10uF, 16V, +/-10%, X5R, 0805 Taiyo Yuden EMK212BJ106KG-T
6 2 2 2 C5, C11 CAP, CERM, 4.7uF, 10V, +/-10%, X5R, 0805 Taiyo Yuden LMK212BJ475KD-T
7 2 2 2 D1, D2 Diode, Schottky, 20V, 0.5A, SOD-123 ON Semiconductor MBR0520LT1G
8 3 3 3 FID1, FID2, FID3 Fiducial mark. There is nothing to buy or mount. N/A N/A
9 5 5 5 J1, J2, J3, J4, J5 Conn Term Block, 2POS, 3.5mm, TH Phoenix Contact 1751248
10 1 1 1 JP1 Header, 3-Pin Sullins Connector Solutions GRPB031VWVN-RC
11 2 2 2 R1, R3 RES, 20.0 ohm, 0.1%, 0.1W, 0603 Yageo America RT0603BRD0720RL
12 1 1 1 SH-J1 Shunt, 1.27 mm Harwin Inc M50-2000005
13 1 1 1 T1 1:2.2 Isolation Transformer Coilcraft DA2304-AL
1 0 0 Isolated delta-sigma modulator, 16-pin DW (SOIC) Texas Instruments AMC1305L25
14 0 1 0 U1 Isolated delta-sigma modulator, 16-pin DW (SOIC) Texas Instruments AMC1305M05
0 0 1 Isolated delta-sigma modulator, 16-pin DW (SOIC) Texas Instruments AMC1305M25
15 1 1 1 U3 SN6501 transformer driver Texas Instruments SN6501
RES, 100, 1%, 0.1 W, 0603. Populated only on EVMs with LVDS
16 1 0 0 R2 Yageo America RC0603FR-07100RL
interface.
LOW-POWER 150-mA LOW-DROPOUT LINEAR REGULATOR,
17 1 1 1 U2 Texas Instruments TLV70450
DBV0005A
9
SBAU237–September 2014 AMC1305xxEVM User's Guide
Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated

1
1
2
2
3
3
4
4
5
5
6
6
D D
C C
B B
A A
2 3
Main Schematic
8/13/2014
AMC1305_Main.SchDoc
Sheet Title:
Size:
Mod. Date:
File:
Sheet: of
B http://www.ti.com
Contact: http://www.ti.com/support
AMC1305 Evaluation ModuleProject Title:
Designed for: Public Release
Assembly Variant: AMC1305EVM_M25
© Texas Instruments 2014
Drawn By:
Engineer:
Jose Duenas
Jose Duenas
Texas Instruments and/or its licensors do not warrant the accuracy or completeness of this specification or any information contained therein. Texas Instruments and/or its licensors do not
warrant that this design will meet the specifications, will be suitable for your application or fit for any particular purpose, or will operate in an implementation. Texas Instruments and/or its
licensors do not warrant that the design is production worthy. You should completely validate and test your design implementation to confirm the system functionality for your application.
Not in version controlSVN Rev:
6583150Number: Rev: A
Revision History
Revision Notes
1
2
J2
1
2
J1
GND
DGND
DGND
D2
MBR0520LT1G
D1
MBR0520LT1G
DVDD
DGND
DVDD
10µF
C8
DGND
GND
10µF
C9
2.2µF
C2
20.0
R1
20.0
R3
1
2
J3
1
2
J4
1
2
J5
1
2
3
JP1
GRPB031VWVN-RC
GND
10µF
C6
GND
GND
AVDD
AVDD
4.7µF
C5
4.7µF
C11
5600pF
C3
DVDD
GND
D1
1
VCC
2
D2
3
GND 4
GND 5
U3
SN6501DBV
0.1µF
C4
0.1µF
C7
0.1µF
C1
0.1µF
C10
NC
1
VINP
2
VINN
3
NC
4
NC
5
NC
6
AVDD
7
AGND
8
DGND 9
DOUT_N 10
DOUT 11
CLKIN_N 12
CLKIN 13
DVDD 14
NC 15
DGND 16
U1
AMC1305M25DW
1
GND
OUT
3IN 2
NC 4 NC
5
U2
TLV70450DBVT 4
2
3
15
6
7
8
T1
DA2304-ALB
100
R2
DNP
PIC101
PIC102
COC1
PIC201
PIC202
COC2
PIC301
PIC302
COC3
PIC401
PIC402
COC4
PIC501
PIC502
COC5
PIC601
PIC602
COC6
PIC701 PIC702
COC7
PIC801 PIC802
COC8
PIC901 PIC902
COC9
PIC1001PIC1002
COC10
PIC1101
PIC1102
COC11
PID101 PID102
COD1
PID201 PID202
COD2
PIJ101
PIJ102
COJ1
PIJ201
PIJ202
COJ2
PIJ301
PIJ302
COJ3
PIJ401
PIJ402
COJ4
PIJ501
PIJ502
COJ5
PIJP101
PIJP102
PIJP103
COJP1
PIR101 PIR102
COR1
PIR201
PIR202
COR2
PIR301 PIR302
COR3
PIT101
PIT102
PIT103
PIT104
PIT105
PIT106
PIT107
PIT108
COT1
PIU101
PIU102
PIU103
PIU104
PIU105
PIU106
PIU107
PIU108
PIU109
PIU1010
PIU1011
PIU1012
PIU1013
PIU1014
PIU1015
PIU1016
COU1
PIU201
PIU202PIU203
PIU204PIU205
COU2
PIU301
PIU302
PIU303
PIU304
PIU305
COU3