Power Management ICs

5.5 V Input, 300 mA Voltage Regulator with Soft-start Function S-1137 Series

S-1137 Series, developed using the CMOS technology, is a positive voltage regulator IC which has the low dropout voltage (LDO), the high-accuracy output voltage and the soft-start function (300 mA output current). A 1.0 µF small ceramic capacitor can be used. It operates with low current consumption of 45 µA typ. The overcurrent protection circuit prevents the load current from exceeding the capacitance of output transistor. The power-off circuit ensures longer battery life. Compared to the conventional CMOS technology regulator ICs, various capacitors including small ceramic capacitors can be used for this IC. Furthermore a small SOT-89-5, SOT-23-5, and SNT-6A(H) packages realize high-density mounting.


Output voltage
1.2 V to 3.5 V, selectable in 0.05 V step
Input voltage
1.7 V to 5.5 V
Output voltage accuracy
±1.0% (1.2 V to 1.45 V output product : ±15 mV)
Dropout voltage
210 mV typ. (products having the output of 2.8 V, IOUT = 300 mA)
Current consumption
During operation: 45 µA typ., 65 µA max.
During power-off: 0.1 µA typ., 1.0 µA max.
Output current
Possible to output 300 mA (at VIN ≥ VOUT(S) + 1.0 V)*1
Input and output capacitors
A ceramic capacitor of 1.0 μF or more can be used.
Ripple rejection
70 dB typ. (at 1.0 kHz)
Built-in soft-start circuit
Soft-start time: 0.7 ms (CSS = 1.0 nF)
Built-in overcurrent protection circuit
Limits overcurrent of output transistor.
Built-in ON / OFF circuit
Ensures long battery life.
Discharge shunt function “available” / “unavailable” is selectable.
Pull-down function “available” / “unavailable” is selectable.
Operation temperature range
Ta = −40°C to +85°C
Lead-free, Sn 100%, halogen-free

*1. Attention should be paid to the power dissipation of the package when the output current is large.


  • Power supply for battery-powered devices
  • Power supply for cellular phones, portable devices
  • Power supply for digital still cameras, TVs, DVD recorders