Power Supplies - Texas Instruments ADS1258EVM-PDK User Manual

www.ti.com

5 Power Supplies

The default ADC power-supply voltages (DVDD and AVDD) are generated by the PHI controller using power
from the USB. The PHI provides 3.3-V and 5.5-V power rails. The 3.3-V power rail directly supplies the ADC
DVDD voltage. The 5.5-V power rail is supplied to the input of the TPS7A4700, a low-noise, configurable-output
LDO, to supply AVDD. The LDO output voltage depends on the internal reference voltage (V
V and the pin connections. Grounding any LDO pin between pins 4 through pin 12 adds that pin voltage to
V and increases the LDO output voltage, LDO
LDO_REF
pins 6 and 10 (3P2V and 0P4V, respectively) to set LDO
LDO_PWR
EVM_REG_5V5
JP1
TP7
5.5V
C37
10uF
GND
Figure 5-1. ADS1258EVM LDO Circuit and External Power Source Connections
Figure 5-1 shows that the 5V_LDO output is used for the AVDD connections across the EVM. Additionally, the
user can measure the AVDD current by connecting an ammeter between pins 1 and 2 of JP3 or the DVDD
current by connecting an ammeter between pins 1 and 2 of JP4.
External power sources can also be provided for each supply voltage:
• LDO: Remove the shunt on JP1 and connect external power to JP1:2
• AVDD: Remove the shunt on JP3 and connect external power to JP3:1
• DVDD: Remove the shunt on JP4 and connect external power to JP4:1
When using either internal or external power supplies, LEDs D1 and D2 indicate if power is connected to AVDD
and DVDD, respectively. These LEDs do not necessarily indicate if AVDD is 5 V or if DVDD s 3.3 V. Check the
AVDD voltage using test point TP3 and check the DVDD voltage using test point TP5.
portion of the ADS1258EVM schematic that includes the LEDs and test points.
SBAU126E – MAY 2007 – REVISED JUNE 2023
Submit Document Feedback
5-V Analog LDO
U5
15
IN OUT
16
IN OUT
13
EN SENSE/FB
12
0P1V
11
0P2V
10
0P4V
9
0P8V
8
1P6V NC
6
3P2V NC
5
6P4V1 NC
4
6P4V2 NC
GND
14
NR Thermal_Pad
TPS7A4700RGWR
C38
1µF
AVDD
TP3
AVDD
R63
6.65k
D1
Green
GND
Figure 5-2. ADS1258EVM AVDD and DVDD Indicator LEDs
Copyright © 2023 Texas Instruments Incorporated
. Figure 5-1 shows that the ADS1258EVM grounds
VOUT
equal to 5 V.
VOUT
5V_LDO
1
20
AVDD_PWR
3
R61
0.1
C39
22µF
2
17
18
19
DVDD_PWR
7
21
GND
DVDD
TP5
DVDD
R64
6.65k
D2
Green
GND
Power Supplies
) of 1.4
LDO_REF
EVM/PHI Power
5V
5V_LDO
AVDD
JP3
J4
GND
3.3V
EVM_DVDD DVDD
JP4
Figure 5-2 shows the
ADS1258EVM-PDK Evaluation Module
AVDD_OUT
GND
11