APL5316_11 Datasheet, PDF (9/16 Pages) Anpec Electronics Coropration – Low Dropout 300mA Linear Regulator With Power-Ok Indicator

APL5316
Typical Application Circuit (Cont.)
2.
V_IN
C_IN
1F
APL5316
1 _VIN
VOUT ⁵
3 _SHDN
POK 4
GND
2
R₁
1K
POK
V_OUT
C_OUT
2.2 F
Function Description
Internal Soft-Start
An internal soft-start function controls rising rate of the
output voltage to limit the surge current at start-up. The
typical soft-start interval is about 60µs.
Power-ok (POK)
The APL5316 indicates the status of the output voltage.
As the V_OUT rises and reaches the Power-ok threshold
(V_POK), the IC turns off the internal NMOS of the POK to
indicate the output is ok. As the V_OUT falls and reaches the
falling Power-ok threshold (V ), the IC immediately
PNOK
turns on the NMOS of the POK to indicate the output is not
ok. The resistance of the resistor R1 connected from V_OUT
to POK or V_IN to POK should be in the range from 1K to
50K.
For normal operation, the device power dissipation should
be externally limited by the design to keep the junction
temperature below 125^οC.
Shutdown Control
The APL5316 has an active-low shutdown function. Forc-
ing SHDN high (>1.6V) enables the V_OUT; forcing SHDN
low (<0.4V) disables the V_OUT. SHDN is internally pulled
low by a resistor (3MΩ typical). If shutdown control is not
necessary, please connect SHDN pin to VIN for normal
operation.
Thermal Shutdown
A thermal shutdown circuit limits the junction tempera-
ture of the APL5316. When the junction temperature ex-
ceeds +160^οC, a thermal sensor turns off the output
PMOS, allowing the device to cool down. The regulator
regulates the output again through initiation of a new soft-
start cycle after the junction temperature cools by 40^οC.
The thermal shutdown is designed with a 40^οC hyster-
esis to lower the average junction temperature during
continuous thermal overload conditions, extending life
time of the device.
Copyright © ANPEC Electronics Corp.
9
Rev. A.3 - Jun, 2011
www.anpec.com.tw