ADS528x EVM User's Guide User's Guide January 2008 SLAU205
SLAU205 – January 2008 Submit Documentation Feedback
Contents 1 2 3 4 Overview .................................................................................................................... 5 1.1 Purpose............................................................................................................ 5 1.2 EVM Basic Functions ............................................................................................ 6 1.3 ADS528x EVM Quick Start Procedure ........................................................................
List of Figures 1 2 3 4 5 6 7 8 9 10 11 ADS5281 EVM ............................................................................................................... 6 TI ADC SPC Interface Screen ........................................................................................... 10 Top Silkscreen .............................................................................................................. 16 Ground Plane ................................................................................
User's Guide SLAU205 – January 2008 1 Overview This preliminary user's guide gives a general overview of the ADS5281/82/87 (ADS528X) QFN evaluation module (EVM) and provides a general description of the features and functions to be considered while using this module. The EVM is pictured in Figure 1. 1.1 Purpose The EVM provides a platform for evaluating the eight-channel ADS528X analog-to-digital converter (ADC) under various signal, reference, and supply conditions.
www.ti.com Overview Figure 1. ADS5281 EVM 1.2 EVM Basic Functions Eight analog inputs to the ADC are provided via external SMA connectors. The EVM provides an external SMA connector for input of the ADC clock. The ADC can be clocked using either a single-ended or differential clock. Provisions are made on the EVM to allow users to evaluate the ADC using a single-ended PECL clock and a differential transformer-coupled clock.
www.ti.com Overview 1.3 ADS528x EVM Quick Start Procedure The ADS528x EVM provides a flexible means of evaluating the ADS528x in a number of modes of operation. A basic setup procedure that can be used as a board confidence check is as follows: 1. Verify all jumper settings against the schematic jumper list in Table 1. Table 1.
www.ti.com Circuit Description 2 Circuit Description 2.1 Schematic Diagram The schematic diagram for the EVM is in Section 6.3. 2.2 Circuit Function The following sections describe the function of individual circuits. Refer to the relevant data sheet for device operating characteristics. 2.2.1 Power Power is supplied to the EVM via banana jack sockets.
www.ti.com Circuit Description 2.2.4 Analog Inputs The EVM provides eight analog inputs, using an SMA connector for each of the eight channels of the ADC. SMA channel inputs are J9, J10, J13, J14, J17, J18, J21, and J22. By default, the ADC accepts a single-ended input and translates it to a differential signal using a Mini Circuits TC1-1T transformer. The ADC inputs are dc-biased by feeding the ADC VCM voltage to the transformer center tap on the secondary windings.
www.ti.com TI ADC SPI Control Interface 3 TI ADC SPI Control Interface This section describes the software designed to communicate with the ADC three-wire SPI interface. The information is to be used in conjunction with the device data sheet, which explains the valid registers of the device. 3.1 Installing the ADC SPI Control Software The ADC SPI control software can be installed on a personal computer by running the setup.exe file located on the CD.
www.ti.com TI ADC SPI Control Interface 3.2.1 SPI Register Write The most basic mode of operation allows full control of writing to individual register addresses. In the top left corner of the interface screen (Figure 2), select the ADS528X ADC from the ADC SPI Protocol drop-down list. Next, type the hexadecimal (hex) Address Bytes(s) in and Data Byte(s), which can be found in the device data sheet.
www.ti.com TI ADC SPI Control Interface Table 3. ADS528X Frequently Used Registers Default Value Alternate Value ADS528X Reset 12 Description Issues a software reset and also sends the initialization routine outlined in the data sheet. Furthermore, the clock is set to differential, which matches the default EVM configuration. A Reset should take place before any evaluation is done. Standby: Off Standby: On Toggles the ADC standby. Powerdown: Off Powerdown: On Toggles the ADC power down.
www.ti.com ADC Evaluation 4 ADC Evaluation This section describes how to set up a typical ADC evaluation system that is similar to what TI uses to perform testing for data-sheet generation. Consequently, the information in this section is generic in nature and is applicable to all high-speed, high-resolution ADC evaluations. This section covers signal tone analysis, which yields ADC data-sheet figures of merit such as signal-to-noise ratio (SNR) and spurious free dynamic range (SFDR). 4.
www.ti.com ADC Evaluation 4.2 Coherent Input Frequency Selection Typical ADC analysis requires users to collect the resulting time-domain data and perform a Fourier transform to analyze the data in the frequency domain. A stipulation of the Fourier transform is that the signal must be continuous-time; however, this is impractical when looking at a finite set of ADC samples, usually collected from a logic analyzer.
www.ti.com Errata 5 Errata This section describes the known issues with Rev B of the EVM. 5.1 Silkscreen Errata The JP2 silkscreen incorrectly identifies the internal (INT) and external (EXT) reference selection. The ADC internal reference is selected by shorting pins 1–2 on JP2, which corresponds to the silkscreen designators of HI or EXT. This will be amended in Rev. C of the EVM.
www.ti.com Physical Description 6 Physical Description This section describes the physical characteristics and PCB layout of the EVM. 6.1 PCB Layout The EVM is constructed on a 4-layer, 0.062-inch (1.58-mm) thick PCB using FR-4 material. The individual layers are shown in Figure 3 through Figure 6. The layout features a common ground plane; however, similar performance can be had with careful layout using a split ground plane. K001 Figure 3.
www.ti.com Physical Description K002 Figure 4.
www.ti.com Physical Description K003 Figure 5.
www.ti.com Physical Description K004 Figure 6.
www.ti.com Physical Description 6.2 Bill of Materials Table 4. Bill of Materials Reference Not Installed Part Footprint Manufacturer Tolerance 33 µF TANT_B B45196H1336K2 Kemet 09 10% C2, C4, C24, C34 1 µF 603 ECJ-1VB0J105K Panasonic 10% C7, C11 22 µF TANT_A B45196H1226K1 Kemet 09 10% C8, C9, C10, C12, C13, C14, C18, C20, C26, C27, C28, C30, C36, C37, C41, C43, C47, C49, C53, C55, C59, C60, C61, C72 0.1 µF 603 ECJ1VB1C104K 10% C15, C16, C17, C22 0.
www.ti.com Physical Description Table 4. Bill of Materials (continued) Reference Not Installed Part Footprint Part Number Manufacturer Tolerance L1, L2, L3, L7 68 Ω at 100 MHz 603 MI0603J680R-10 Steward L5 1 kΩ at 100 MHZ SMD_0805 BLM21AG102SN Murata 1D R1, R2 2Ω 603 ERJ3GEYJ2R0V Panasonic 5% R3 0Ω 603 ERJ3GEY0R00V Panasonic 5% R4 56.
www.ti.com Physical Description Table 4. Bill of Materials (continued) Reference 22 Not Installed Part Footprint Part Number Manufacturer U5 93C66B TSSOP8 93C66B-I/ST Microchip U8 FT245BM PQFN32 FT245BM Future Technology Devices U10 TPS73201SOT23 DBV5 TPS73218DBVT TI U11 TPS77533D SOIC8 TPS77533D TI Y2 6.0000 MHz ECS-60-325PDN-TR ECS MP2 Screw, machine, ph 4-40 × 3/8 PMS 440 0038 PH Building Fasteners MP3 Stand-off, hex, .
5V 1 2 3 4 C28 .1uF 16V +3.3V J4 RED BLK J2 GND RESET NC OUT1 OUT TPS77533D GND EN IN IN1 U11 3.3V_SMA 8 7 6 5 JP8 C29 10uF 16V 1 3 GND 5V_IN 2 L2 L7 2 68 @ 100MHz 1 6.3V + 33UF C1 2 68 @ 100MHz 1 68 @ 100MHz 1 2 L1 3.3V_IN 1 2 5V 1 C2 6.3V C3 + 33UF C24 1uF 6.3V +3.3V_AUX 1uF 6.3V C4 +3.3V_AVDD 6.3V 1uF C23 + 33UF 6.3V 2 RED 3.3V 1 2 1 2 2 1 2 1 C26 .1uF 16V GND 5V OUT U10 EN GND NC/FB IN 4 5 1.8V_SMA TPS73201-SOT23 3 2 1 RED J5 1.
TP2 1 2 3 4 VCM REF_T R53 10K PD C33 2.2uF 22uF C11 C7 22uF 1 2 1 2 C13 .1uF C8 .1uF OUT1P OUT1N 2 IN4P IN4N IN3P IN3N IN2P IN2N IN1P IN1N 10 ohm R46 1 2 1 J6 2 1 + 1 R1 2 ohm R2 2 ohm 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 65 REFT REFB IN1P IN1N AVSS IN2P IN2N AVSS IN3P IN3N AVSS IN4P IN4N LVSS PD LVSS OUT1P OUT1N GND R56 10K +3.3V_AVDD 2 2 ADCRESET C9 .
J21 J17 J13 EN D S MA SMA 4 3 2 5 EN D S MA EN D S MA SMA EN D S MA SMA 0 ohm 6 T1 TC1-1T 1 2 5 1 1 2 VCM .1uF C36 VCM IN2_P IN1_N IN1_P R15 49.9 R10 49.9 R5 C42 10pF C35 10pF IN2P IN1N IN1P J14 J10 EN D S MA SMA SMA R29 R39 R43 49.9 IN4-N IN4-P R33 49.9 IN3-N IN3-P R23 49.9 IN2-N 0 ohm 0 ohm T3 1 2 5 6 3 T7 TC1-1T 4 1 2 5 6 3 T5 TC1-1T 4 1 2 5 6 3 4 1 1 2 2 2 .1uF C53 VCM .1uF C47 VCM .
R52 49.9 .1W 1% C45 2 3 1 .1UF 16V 10% 1 2 JP3 2 1 26 C39 .1UF 16V 10% R62 499 .1W 1% 1 AMS D NE 1 2 3 4 J26 NC1 D D VBB U3 VCC Q NC2 VEE MC100EPT21 R49 49.9 1/10W 1% GND SMA R67 499 .1W 1% 4 3 2 5 8 7 6 5 3 4 GND C72 .1uF 16V 2 5 TC1-1T 1 6 T9 R47 0.1uf 1 49.9 0.1W 1% C40 2 +3.3V_AUX GND C60 .1uF 16V Do Not Install R48 121 1/10W 1% Do Not Install R45 121 1/10W 1% 1 C59 2 C61 2 CLKP .1uF 16V 1 .
5V 2 1K @ 100MHZ 1 L5 1 2 R63 Do Not Install 0 OHM 2 1 C52 .01uF 2 8 7 6 5 3 2 1 1 26.7 R65 2 R64 26.7 2 R57 4.7K U5 1 2 3 4 1 R60 2.21K CS CLK DI DOUT 93C66B VCC ORG NC VSS CONN USB TYP B FEM 4 1 J25 Do Not Install R68 1 2 10K Do Not Install .1uF 1 5V 1 R61 10K 1 2 3 4 5 6 7 8 1 2 EESK EEDATA VCC RESET RSTOUT 3V3OUT USBDP USBDM C57 27pF 5V 6.0000MHz FT245BM U8 +3.3V_AUX 1 D1 D2 D3 D4 D5 D6 D7 GND 2 5V 1 2 2 R59 1.
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