Texas Instruments AMC7823 EVM User manual

1 EVM Overview
1.1 Features
User's GuideSLAU171 – November 2005
AMC7823 Evaluation Module
This user’s guide describes the characteristics, operation, and the use of the AMC7823evaluation module. It covers all pertinent areas involved to properly use this EVM boardalong with the devices that it supports. The physical PCB layout, schematic diagram,and circuit descriptions are included.
Contents1 EVM Overview ...................................................................................... 12 PCB Design ......................................................................................... 43 EVM Operation ...................................................................................... 94 Related Documentation From Texas Instruments ............................................ 14
List of Figures
1 EVM Block Diagram ................................................................................ 32 Top Silkscreen ...................................................................................... 43 Top Layer (Signal Plane) .......................................................................... 54 Internal Layer 1 (Split Ground Plane) ............................................................ 55 Internal Layer 2 (Split Power Plane) ............................................................. 66 Bottom Layer (Signal Plane) ...................................................................... 67 Bottom Silkscreen .................................................................................. 78 Drill Drawing ......................................................................................... 89 Factory Default Jumper Settings ................................................................ 1010 Digital Serial Interface Pinout ................................................................... 11
List of Tables
1 Parts List ............................................................................................. 82 Factory Default Jumper Settings ................................................................. 93 Jumper Settings and Functions ................................................................. 11
This chapter gives a general overview of the AMC7823 evaluation module (EVM) and describes some ofthe factors that must be considered in using this module.
This EVM features the AMC7823 analog monitoring and control circuit device. The AMC7823 EVM is asimple evaluation module designed for a quick and easy way to evaluate the functionality andperformance of the 12-bit resolution AMC device. The built-in ADC features an eight-channel analog inputwith 200 ksps sample rate. The AMC7823 also consists of eight independent 12-bit resolution DACs with2- µs settling times. Although the AMC7823 has a built-in internal band-gap reference that is softwareselectable between 1.25 V and 2.5 V, an external reference source is provided. The internal 1.25-Vreference voltage is the default reference on power up, so the reference voltage should be set to thedesired source and level, if necessary.
SPI is a trademark of Motorola, Inc..
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1.2 Power Requirements
EVM Overview
The SPI™ serial interface of the AMC7823 can communicate with any host microprocessor capable of theSPI protocol and most TI DSP based systems.
A socket (Samtec, P/N SS-101-T-1C) for a through-hole resistor, R14, is also provided so that the loadcurrent can be precisely set to the desired value required to bias any external component connected to pin5 (THERM_I_OUTPUT) of the AMC7823.
The following sections describe the power requirements of this EVM.
1.2.1 Supply Voltage
The dc analog power supply requirement for the AMC7823 EVM (AV
DD
) is selectable between +3.3 VAand +5 VA via jumper headers, W3. The +3.3 VA comes from J6-8 or J11-1 (if installed), and the +5 VAcomes from the J6-3 or J11-3 (if installed) terminals. These power supply voltages are referenced toground through the J6-6 or J11-2 (if installed) terminals. All of the analog power supplies are referenced toanalog ground through the J11-2 and J6-6 terminals.
On the other hand, the dc digital power supply requirement for DV
DD
and IOV
DD
are also selectablebetween +3.3 VD and +5 VD via jumper headers, W4 and W2, respectively. The +3.3 VD comes from theJ6-9 or J12-3 (if installed) terminals, and the +5 VD comes from the J6-10 or J12-1 (if installed) terminals.All of the digital power supplies are referenced to digital ground through the J6-5 and J12-2 terminals.
Green LED indicators, D1 and D5 for AV
DD
and DV
DD
respectively, are included to show that power isapplied on the EVM board.
CAUTIONTo avoid potential damage to the EVM board, make sure that the correctcables are connected to their respective terminals as labeled on the EVMboard. Stresses above the maximum listed voltage ratings may causepermanent damage to the device.
1.2.2 Reference Voltage
The AMC7823 comes with an internal bandgap reference that is software selectable between 1.25 V and2.5 V, where the default on power up is 1.25 V. Although the internal reference is included on the DUT, anexternal reference circuit is still provided onboard the EVM, as well as the option of providing the usersupplied reference voltage via terminal pin, TP1.
The REF3125 (REF2) and REF3112 (REF1) precision voltage references are provided to supply theonboard external voltage reference and set the voltage output range of the ADC and DAC of theAMC7823 device. The 1.25-V or 2.5-V reference voltage can be selected via the W7 jumper. The onboardexternal reference or the user supplied reference can also be selected via W1 jumper. The user suppliedreference can be applied to the TP1 test point or J1-20 terminal pins, which are also provided to allow theuser to connect to another external reference source if the onboard reference circuit is not desired. Theexternal voltage reference should not exceed the specified voltages listed in the data sheet.
The REF3125 and REF3112 precision references are powered by +5 VA or +3.3 VA, selectable throughthe W3 jumper.
CAUTIONWhen applying an external voltage reference through TP1 or J1-20, makesure that it does not exceed the maximum specified voltage listed in thedata sheet. Otherwise, this can permanently damage the AMC7823, U1,device under test.
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1.3 EVM Basic Functions
AMC7823 BLOCK
ADC
DAC 0
M
U
X
On-Chip
Temperature
Sensor
DAC 7
Reference
J1T
J1B
J5
P5
J2
P2
J4
P4
Control Signal
Control Signal
J3
1.25V
REF1
2.5V
REF2
J6
P6
POWER
TP1
W7
W1
R14
SGND AGND
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
CH8
DAC0_OUT
DAC1_OUT
DAC2_OUT
DAC3_OUT
DAC4_OUT
DAC5_OUT
DAC6_OUT
DAC7_OUT
THERM _I_OUT
GPIO/DAV /GALR
GPIO/ALARM
W5
EVM Overview
The AMC7823 EVM is designed primarily as a functional evaluation platform to test certain functionalcharacteristics of the AMC7823 (analog monitoring and control circuit) converter. Functional evaluation ofthe AMC7823 device can be accomplished with the use of any microprocessor or TI DSP with SPIinterface capability.
The headers J2 (top side) and P2 (bottom side) are pass through connectors provided for the controlsignals and data required to interface a host processor to the AMC7823 EVM using a custom built cable.The GPIO and alarm pins of the AMC7823 are also mapped to the J2 and J4 headers.
An adapter interface card (5-6k adapter interface) is also available to fit and mate with the TI C5000 andC6000 DSP starter kit (DSK). This alleviates the troubles involved in building a custom cable. In addition,there is also an MSP430 based platform (HPA449) that uses the MSP430F449 microprocessor, which thisEVM can connect to and interface with as well. For more details or information regarding the 5-6k adapterinterface card or the HPA449 platform, call Texas Instruments Inc. or email us at[email protected] .
The analog input signals for the ADC can be applied to the J1 and P1 pass through terminals differentially.The analog inputs are decoupled to ground to eliminate the high frequency noise component that may bepresent. In similar fashion, the DAC outputs can be monitored through the even pins of the J5 and P5pass through header connectors.
The terminal connector, J3, is used for connecting an external component, such as a thermistor that canbe driven via the THERM_I_OUT pin. The current load can be precisely set by selecting the correct valuefor R14. Refer to the data sheet for establishing the correct value for R14.
A block diagram of the EVM is shown in Figure 1 .
Figure 1. EVM Block Diagram
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2 PCB Design
2.1 PCB Layout
PCB Design
This chapter presents the layout design of the PCB thereby describing the physical and mechanicalcharacteristics of the EVM. The list of components used on the module is also included in this section.
The AMC7823 EVM was designed using the double-wide modular EVM form factor developed by TexasInstruments. This EVM form factor allows direct evaluation of the AMC7823 operating characteristics andspeeds up software development and other prototyping needs.
The AMC7823 EVM board is constructed on a four-layer printed circuit board using a copper-clad FR-4laminate material. The printed circuit board has dimensions of 93,9800 mm (3.7000 inch) ×81,2800 mm(3.200 inch), and the board thickness is 1,5748 mm (0.0620 inch). Figure 2 through Figure 8 show theindividual artwork layers.
Figure 2. Top Silkscreen
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PCB Design
Figure 3. Top Layer (Signal Plane)
Figure 4. Internal Layer 1 (Split Ground Plane)
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PCB Design
Figure 5. Internal Layer 2 (Split Power Plane)
Figure 6. Bottom Layer (Signal Plane)
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PCB Design
Figure 7. Bottom Silkscreen
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2.2 Bill of Materials
PCB Design
Figure 8. Drill Drawing
Table 1. Parts List
Item Qty. Designators Description Manufacturer Mfg. Part Number
C1, C3, C6, C8, C17,1 8 0.1 µF
(1)
TDK C1608X7R1E104KTC18, C19, C21C9, C10, C11, C12,2 8 150 pF TDK C1608COG1H151JC13, C14, C15, C163 2 C2, C20 0.47 µF TDK C3216X7R1H474KT4 3 C4, C5, C7 10 µF TDK C3225X7R1E106KT5 1 R1 10 k ΩPanasonic ERJ-8ENF1002V6 3 R2, R11, R12 2.7 k ΩBC Components 2312 396 727027 2 R20, R23 150 ΩPanasonic ERJ-8GEYJ151V8 2 R7, R8 0 Ω
(1)
Panasonic ERJ-8GEY0R00V9 1 R13 47 k ΩYageo America RC1206FR-0747KL10 1 R14 4.99 k Ω
(1)
Panasonic ERO-S2PHF4991R3, R4, R5, R6, R9,11 6 49.9 k ΩPanasonic ERJ-8ENF4992VR1012 4 J1T, J2, J4, J5 20-PIN_IDC Samtec TSM-110-01-S-DV-M
(1)
C1, C3, C6, C8, C19, J11, J12, R7, and R8 are not installed. R14 leads must be cut and bent to fit sockets from Samtec, P/NSS-101-T-1C.
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3 EVM Operation
3.1 Factory Default Settings
EVM Operation
Table 1. Parts List (continued)
Item Qty. Designators Description Manufacturer Mfg. Part Number
13 1 J6 10-PIN_IDC Samtec TSM-105-01-T-DV14 2 J11, J12 3-Pin terminal connector
(1)
On-Shore Tech. ED555/3DS15 4 J1B, P2, P4, P5 20-PIN_IDC
(2)
Samtec SSW-110-22-S-D-VS-P10-PIN Isolated power socket,16 1 P6 Samtec SSW-105-22-F-D-VS-K0.100
(2)
17 3 TP1, TP2, TP4 Turret terminal pin Mill-Max 2348-2-01-00-00-07-0QFN-40 (RTA), 12-bit analog18 1 U1 Texas Instruments AMC7823IRTAmonitoring and control circuit19 2 U2, U3 Single buffer/driver Texas Instruments SN74LVC1G07DBVR20 1 U4 64-Kbit EEPROM Microchip Technology 24LC64-I/ST21 1 REF1 1.25-V Reference Texas Instruments REF3112AIDBZT22 1 REF2 2.5-V Reference Texas Instruments REF3125AIDBZT23 1 J3 Terminal block 3,5 mm, 2-pos PCB On-Shore Tech. ED555/2DS24 2 D1, D5 2.2-V, 45 mC LED, green Lumex SML-LX1206SUGC-TR25 3 W5, W10, W11 2 Circuit header, 0.100 straight Molex 22-03-2021W1, W2, W3, W4, W6,26 8 3 Circuit header, 0.100 straight Molex 22-03-2031W7, W8, W9
(2)
P2, P4, and P6 parts are not shown in the schematic diagram. All P designated parts are installed in the bottom side of the PCboard opposite the J designated counterpart. Example, J2 is installed on the topside while P2 is installed in the bottom sideopposite of J2.
This chapter presents in detail the operation of the EVM to provide guidance to the user in evaluating theonboard AMC and how to interface the EVM to a specific host processor.
Refer to the AMC7823 data sheet (SLAS453 ) for information about its serial interface and other relatedtopics.
The EVM board is tested and configured to operate from the factory.
The EVM board is set to its default configuration at the factory as described in Table 2 to operate inunipolar mode. The jumper configuration is shown in Figure 9 for clarity.
Table 2. Factory Default Jumper Settings
JumperReference FunctionPosition
W1 Open Internal reference voltage is used.W2 2-3 Digital logic supply, IOV
DD
, for the AMC7823 is +3.3 VD.W3 1-2 Analog supply, AV
DD
, for the AMC7823 is +5 VA.W4 1-2 Digital core supply, DV
DD
, for the AMC7823 is +5 VD.W5 Closed Signal ground for ADC analog input is tied to analog ground.W6 1-2 CS signal from J2 is routed through to drive the SS signal pin of the AMC7823.The external 2.5-V reference is connected as the external reference voltage source through the W1W7 2-3
header.W8 Open Convert pin is floated and ADC internal trigger is used.W9 Open LRCLK or BCLK not used for convert signal.W10 Closed Address of EEPROM is set to 0x00.W11 Closed Analog ground and digital ground are tied together.
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Note:The stencil is incorrect
as shown here.The pin 1
indicator is actually pin 3
and pin 3indicator is
actually pin 1.The
designator,W3,is also spun
around.
1
x
Samtec Pin Socket
P/N:SS-101-T-1C
3.2 Host Processor Interface
EVM Operation
Figure 9. Factory Default Jumper Settings
As noted in chapter 1 of this manual, the AMC7823 EVM is compatible with the 5-6k interface board(SLAU104 ) from Texas Instruments, as well as the HPA449 demonstration board from SoftBaugh, Inc.Using these boards alleviates the tedious task of building custom cables and allows easy configuration ofa simple evaluation system.
If another system is used that is not directly compatible with this EVM, a custom cable can be madespecific to the host interface platform. The EVM allows interfacing to the host processor through the J2and J4 header connectors for serial control signals and serial data input. The pinout mapping is shown inFigure 10 .
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