EVM Power-Supply Inputs
4
EVM Power-Supply Inputs
J3 is the power-supply input connector.
lists the configuration details for J3.
Table 4. J3: Power-Supply Interface Header
Pin Number
Pin Name
Function
Required
J3.3
+5VA
5-V analog supply
Yes
J3.5
GND
Digital ground input
Yes
J3.6
GND
Analog ground input
Yes
J3.7
1.8 VD
1.8-V digital supply
Optional
J3.9
3.3 VD
3.3-V digital supply
Yes
J3.10
5 VD
5-V digital supply
No
P3.1-2, P3.4, and P3.7-8
Unused
Unused
No
4.1
Analog Power Options
The ADS8861EVM board is designed to function with a 5-V analog power supply connected to J3.3. The
ADS8861 is limited to 3.6 V as an analog supply. Therefore, the board regulates down the 5-V analog
supply with an onboard 3.3-V LDO (TPS78833).
4.2
Digital Power Options
The ADS8861EVM connects the digital power supply of the ADS8861 to 3.3 VD (J3.10) with a 0-
Ω
resistor. This 3.3-V supply matches the 3.3-V logic level of the MMB0 motherboard.
4.3
Analog and Digital Grounds
The EVM only has one ground plane for analog and digital supplies; thus, pins J3.5 and J3.6 are tied
together to this ground plane. Therefore, both supply grounds should be connected to pins J3.5–6 in order
to share the same ground.
7
SBAU214 – October 2013
ADS8861EVM-PDK
Copyright © 2013, Texas Instruments Incorporated