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1.4 ADS5231/32/37 EVM Operational Procedure
* dBFS + 20 log
ǒ
captured max code * captured min code
2
N
Ǔ
, N is the number of bits
2 Circuit Description
2.1 Schematic Diagram
2.2 Circuit Function
Circuit Description
The ADS5231/32/37 EVM provides a flexible means of evaluating the ADS5231/32/37 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 :
2. Connect supplies to the EVM as follows:
• 3.3-V ADC output buffer supply to J17 and return to J18.
• 3.3-V ADC analog supply to J11 and return to J10.
3. Switch power supplies on
4. Use a function generator with 50- Ω output to input a 45-MHz, 1.5-V offset, 3-V square-wave signal into
J3. The frequency of the clock must be within the specification for the device speed grade. Caution:
the ADS5231/32/37 does not work with a sinusoidal clock source.
5. Use frequency generators with a 50- Ω output to provide a 10.1-MHz, 0-V offset, –1-dBFS amplitude,
sine-wave signal into J15 and J16. This provides a transformer-coupled differential input signal to both
channels of the ADC. A full-scale input tone into channel A or channel B can be calculated by using
the following formula:
6. The digital patterns on output connectors J8 and J21 should now represent a sine wave and can be
monitored using a logic analyzer or TSW1100.
Table 1. Three-Pin Jumper List
Jumper Function Location: Pins 1- 2 Location: Pins 2-3 Default
W1 Reference select Internal reference External reference 1-2
W2 Channel B output enable Output disabled Output enabled 2-3
W3 Power down select Power-down mode Operate mode 2-3
W4 Channel A output enable Output disabled Output enabled 2-3
SJP1 Common-mode voltage-path provider Common-mode voltage to CHA Provide common-mode voltage 2-3
differential amplifier to transformer T1
W9 Invert most significant bit 2s complement Offset binary 2-3
SJP3 Common-mode voltage path Provide common-mode voltage Provide common-mode voltage 2-3
to CHB differential amplifier to transformer T2
The schematic diagram for the EVM is attached to the end of this document.
The following paragraphs describe the function of individual circuits. See the ADS5232 Dual, 12-Bit,
65MSPS, +3.3V Analog-to-Digital Converter data sheet (SBAS294 ), the ADS5231 Dual, 12-Bit, 40MSPS,
+3.3V Analog-to-Digital Converter data sheet (SBAS295 ), or the ADS5237 Dual, 10-Bit, 65MSPS, +3.3V
Analog-to-Digital Converter data sheet (SBAS420 ) for device operating characteristics.
6 ADS5231/32/37 EVM SBAU111B – May 2006 – Revised November 2007
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