Evm Dc Voltage Setup; Trf6900 Evm Dc Voltage Setup - Texas Instruments TRF6900 User Manual

2.3 EVM DC Voltage Setup

The evaluation board should be used with a dc power supply voltage of 8 V
nominal. Figure 2–1 details the dc voltage supply setup for the TRF6900 EVM.
Figure 2–1. TRF6900 EVM DC Voltage Setup
V out for LM317 voltage regulator is equal to:
V out = 1.25(1+(R44/R43))
V at terminal 3 of LM317 should be 2 to 3 volts
higher than V out
With V equal to 8 volts
in
V= 7.2 volts
POWER
8.0V
RED
V in is equal to 8.0 volts
min. to 10 volts max.
GROUND CLIPS
GND1 GND2 GND3 GND4
,
VR1
LM317MDT
CR5
3
VIN VOUT
S1JB
ADJ
C41
ZR1 C42
0.1 µ F
10µ F 1
SMBJ8.5CA
1
2
3
VR2
1
VI NC
2
VO VO
3 VO
VO
4
NC
ADJ
LM317LBD
GND5
R48
360 Ω
EVM DC Voltage Setup
2
JP8
C43 C44
R43 C45
0.1 µ F
360 Ω 1µ F 0.01µ F
R44
500 Ω
220 Ω
R34
220 Ω
V adj Used to Change
V out From 2.2 V to 3.6 V
8
7
6
5
R47
C46
C47 C48
220 Ω
0.1 µ F
1µ F 0.01µ F
Evaluation Board
Connect JP8
For Power
ON LED
2.2 – 3.6V (3.0V TYP)
VCC1
0
LED3
VCC
LN1271R–(TR)
R45
3.3V
VCC2