Datasheet

2.2.2.3 Power Supply Option 3
2.2.3 ADC Analog Inputs
Circuit Description www.ti.com
Option 3 is used to evaluate ADC performance using an isolated AVDD and DVDD power supply for
current-consumption measurements. This option must be used with caution, because reversing the power
supply or connecting to the wrong connector can damage the EVM. One common use of this option is to
measure the separate current consumption of the relative supplies under particular operating conditions.
For this option, the shunts on jumpers JP18 and JP15 are removed and the input power is supplied to the
center post of the jumper. For convenience, a ground post is provided next to the center post for header
connections that contain power and ground on 0.1" centers.
The EVM can be configured to use either a transformer-coupled input or a TH4509 amplifier input, both
from a single-ended source. The SMA connector J6 (for Channel A) and J3 (for Channel B) provide the
single-ended analog input to the transformer-coupled input circuit to the ADC. The SMA connector J7 and
J9 are not installed by default, but can be used to bring a differential input clock to the
transformer-coupled input or to bring a single ended input to the THS4509 input circuit. To use the
transformer for one of these options, the EVM must be configured for one of the options listed in Table 5 .
See the schematic located at the end of this document prior to making any jumper changes.
Table 4. Analog Input Jumper description
EVM Banana Jack Description Jumper Setting
J6 Analog Input single-ended
J3 Analog Input single-ended
Analog input, can be used with J6 for
J7 Not populated
differential input
Analog input, can be used with J3 for
J9 Not populated
differential input
2-3 → AMPOUT+ is selected as source of input to ADC
SJP1 AMPOUT+, +ve terminal of T4 1-2 → Use analog input from J3 as signal source to ADC
(use with appropriate SJP5 setting)
2-3 → AMPOUT- is selected as source of input to ADCC
SJP2 AMPOUT-, -ve terminal of T4 1-2 → Use analog input from J9 as signal source to AD
(use with appropriate SJP3 setting
1-2 → J3 supplies the analog signal to ADC
SJP5 INPUT -ve select
2-3 → -ve input to amplifier
1-2 → J9 supplies the analog signal to ADC
SJP3 INPUT +ve select
2-3 → +ve input to amplifier DEFAULT is no shunt
1-2 → Pulls up the pin (Normal operation or amplifier is ON)
SP3 Power down for amplifier THS4509
2-3 → Grounds the pin (Low-power mode or amplifier is off)
ADS62PXXEVM 12 SLAU237A – May 2008 – Revised April 2009
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