Datasheet

t (s) =
SS
V C
I
REF SS
SS
×
0.8V C (F)
0.44 A
SS
m
×
=
Thermal
Limit
Soft-Start
Discharge
OUT
V
OUT
FB
PG
IN
BIAS
SS
EN
Hysteresis
andDeglitch
Current
Limit
UVLO
0.44 Am
0.8V
Reference
0.9 ´ V
REF
GND
C
SS
R
1
R
2
(1) where t
SS
(s) = soft-start time in seconds.
TPS74801
www.ti.com SBVS074J –JANUARY 2007– REVISED JANUARY 2012
BLOCK DIAGRAM
Table 1. Standard 1% Resistor Values for Programming the Output Voltage
(1)
R
1
(kΩ) R
2
(kΩ) V
OUT
(V)
Short Open 0.8
0.619 4.99 0.9
1.13 4.53 1.0
1.37 4.42 1.05
1.87 4.99 1.1
2.49 4.99 1.2
4.12 4.75 1.5
3.57 2.87 1.8
3.57 1.69 2.5
3.57 1.15 3.3
(1) V
OUT
= 0.8 × (1 + R
1
/R
2
).
Table 2. Standard Capacitor Values for Programming the Soft-Start Time
(1)
C
SS
SOFT-START TIME
Open 0.1ms
270pF 0.5ms
560pF 1ms
2.7nF 5ms
5.6nF 10ms
0.01μF 18ms
Copyright © 2007–2012, Texas Instruments Incorporated Submit Documentation Feedback 5
Product Folder Link(s): TPS74801