Datasheet
2.2.2.1 Power Supply Option 1
2.2.2.2 Power Supply Option 2
www.ti.com
Circuit Description
Table 2. EVM Power Supply Jumper Description
EVM Banana Jack Description Jumper
Setting 6V to 36V power supply
J10 Input
default-apply just 5V
1-2 → Connects 5.3V to input of TPS79501
JP16 TPS79501 INPUT SELECT
2-3 → TPS79501 Input connected to J10
2-3 → TPS79501 output as 5V_AUX rails
JP19 5V_AUX
1-2 → 5V_AUX rail connected to J10
JP17 TPS5420 INPUT SELECT Shunt → J10 connected to TPS5420D
Table 3. EVM Power Supply Options
EVM
Evaluation Goal Jumper Changes Required Voltage on J10 Comments
Option
JP16 → 1-2
Evaluate ADC performance using
JP19 → 2-3 Maximum
a cascaded switching power
1 JP17 → 1-2 6V - 36V performance and
supply (TPS5420D) and LDO
JP15 → 1-2 efficiency
solution (TPS79501DCQ)
JP18 → 1-2
JP16 → 1-2
JP19 → 1-2
Evaluate ADC performance using Maximum
2 JP17 → No Shunt 5.1V - 5.5V
a LDO based solution Performance
JP15 → 1-2
JP18 → 1-2
JP16 → No Shunt; JP19 → No
Shunt
Evaluate ADC performance using Isolated power supply
JP17 → No Shunt
an isolated ADC AVDD and Do not apply power for current
3 JP15 → Connect 3.3V to pin 2 of
DVDD for current consumption on J10 consumption
jumper
measurements measurements
JP18 → Connect 1.8V to pin 2 of
jumper
Option 1 supplies the power to the ADC using cascaded topology of the TPS5420D switching power
regulator and the TPS79501DCQ Low Drop-Out regulator. The TPS5420 is a step-down converter which
works with the input voltage in the range 6V to 36V. The switching supply increases efficiency for higher
input voltages but does create noise on the voltage supplies. To reduce the noise, an ultra-low-noise,
high-PSSR LDO TPS79501DCQ is used to clean the power supply. The TPS5420D is designed for 5.3V
output, which acts as a supply for the TPS79501. The TPS79501 is designed to output 5V, which is the
AVDD for the ADC. This voltage rail is input to the LDO TPS79633, which outputs 3.3V, used for DVDD
for the ADC. A separate TPS79633 is designed to output 3.3V for the CDCE72010 supply rail. This
solution adds two features to the EVM: one is to increase the range of the power supply on jumper J10
from 6V to 36V, allowing the user to choose any power supply source in the specified range without
causing significant power dissipation. The other feature is that the output-voltage rail has a much lower
ripple, allowing better performance of the part even when the power source is fluctuating.
Option 2 supplies power to the ADC using the LDOs TPS79633DCQ and TPS79601DCQ. The LDOs take
a maximum input of 5.5V. When using this option, take care powering up the EVM, because higher
voltage or reverse polarity can damage it. This is the default power-supply configuration for the
ADS62PXXEVM.
SLAU237A – May 2008 – Revised April 2009 ADS62PXXEVM 11
Submit Documentation Feedback