www.ti.com
4.1
Reference Voltage control via W6
5
EVM Operation
EVM Operation
Table 3. Pinout of J3 (continued)
Signal
Pin Number
Signal
+5VA
3
4
Unused
DGND
5
6
AGND
Unused
7
8
Unused
Unused
9
10
+5VD
For stand alone operation, power sources can be applied via various test points located on the EVM
(VANA to TP2 and VDIG to TP3). Refer to the schematic at the end of this document for details.
The option amplifier located at position U2 (user supplied) can be powered through J3 pins 1 and 2. See
the earlier discussion about the power supply restrictions in section 1.2 of this manual.
Note:
While filters are provided for all power supply inputs, optimal performance of the EVM
requires a clean, well-regulated power source.
The ADS78/8509 is normally configured to use its internal reference. Jumper W6 provides various options
to allow the EVM user to send the converter's reference voltage off board to external amplifier circuits (W6
pins 3-4, default state). An external reference sourceapplied to J1 pin 20 can be sent to the ADC by
moving the shunt at W6 to pins 1-2. An on board trim pot is provided at R8, and can be used with a shunt
jumper placed on W6 pins 5–6.
The max analog input swing is +/-10Vpp. The input range can be adjusted directly on the EVM by
configuring jumpers W1 through W5, with offset trim capability using W6. The EVM is set for the 0-10V
input range by default with the serial data stream supplied by the internal clock. Offset trim can be
accomplished on board via R8 or through an external input through J1. Single amplifier U2 in an industry
standard SOIC 8 package can be installed to do on board signal conditioning if necessary. Please refer to
Section 12 of Op Amps for Everyone (Doc. No. SLOD006) for information on various circuit applications.
Once power is applied to the EVM, the analog input source can be connected directly to J1 (top or bottom
side) or through optional amplifier and signal conditioning modules using the 5-6K Interface Board or
HPA449. Jumper W12 allows the EVM user to choose which analog signal applied to J1 is directed to the
input of the ADC, providing the ability to stack up to eight ADS78/8509 EVM's using the TAG features of
the device. When using the TAG feature, be sure to set the jumpers according to section 2.1 of this Users
Guide.
The digital control signals can be applied directly to J2 (top or bottom side). The ADS78/8509 EVM can
also be connected directly to the 5-6K Interface Board for use with a variety of C5000 and C6000 series
DSP Starter Kits (DSK). The analog and digital input connectors are designed to allow pattern generators
and/or logic analyzers to be connected to the EVM using standard ribbon type cables on 0.1" centers.
No specific evaluation software is provided with this EVM, however, various code examples are available
that show how to use this EVM with a variety of digital signal processors from Texas Instruments
Incorporated. Check the product folders or send e-mail to [email protected] for a listing of
available code examples. The EVM Gerber files are available on request.
shows the factory default jumper locations for the ADS78/8509 EVM:
4
SLAU140 – November 2004
ADS78/8509 EVM User's Guide