Datasheet

TPS7201Q, TPS7225Q, TPS7230Q
TPS7233Q, TPS7248Q, TPS7250Q, TPS72xxY
MICROPOWER LOW-DROPOUT (LDO) VOLTAGE REGULATORS
SLVS102G – MARCH 1995 – REVISED JUNE 2000
29
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
output voltage programming
The output voltage of the TPS7201 adjustable regulator is programmed using an external resistor divider as
shown in Figure 33. The output voltage is calculated using:
V
O
V
ref
1
R1
R2
(1)
Where:
V
ref
= 1.188 V typ (the internal reference voltage)
Resistors R1 and R2 should be chosen for approximately 7-µA divider current. Lower value resistors can be
used but offer no inherent advantage and waste more power. Higher values should be avoided as leakage
currents at FB increase the output voltage error. The recommended design procedure is to choose
R2 = 169 kΩ to set the divider current at 7 µA and then calculate R1 using:
R1
V
O
V
ref
1 R2
(2)
V
O
V
I
PG
OUT
FB
R2
GND
EN
IN
<0.4 V
>2.7 V
TPS7201
Power-Good Indicator
0.1 µF
250 kΩ
OUTPUT
VOLTAGE
(V)
R1 R2
2.5
3.3
3.6
4
5
6.4
191
309
348
402
549
750
169
169
169
169
169
169
OUTPUT VOLTAGE
PROGRAMMING GUIDE
DIVIDER RESISTANCE
(kΩ)
†
†
1% values shown.
10 µF
CSR = 1 Ω
IN
5
6
4
2
8
7
1
3
+
OUT
R1
Figure 33. TPS7201 Adjustable LDO Regulator Programming