Power Management ICs

5.5 V Input, 500 mA Voltage Regulator S-1155 Series

DatasheetJan. 05, 2018


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The S-1155 Series, developed based on CMOS technology, is a positive voltage regulator with a super low dropout voltage (LDO), high output voltageaccuracy, and low current consumption. The S-1155 Series provides the very small dropout voltage and the large output current due to the built-in transistor with low on-resistance. The overcurrent protector prevents the load current from exceeding the capacitance of output transistor. The thermal shutdown circuit prevents damage caused by heat, the rush current control circuit limits the excessive rush current during start-up. The ON/OFF circuit ensures longer battery life. Various capacitors, also small ceramic capacitors, can be used for this IC more than for the conventional regulator ICs which have CMOS technology. The small package SOT-89-5 enables high-density mounting.


Output voltage
1.0 to 5.0 V, selectable in 0.05 V step.
Low equivalent series resistance capacitor
Ceramic capacitor of 4.7 µF or more can be used as the I/O capacitor.
Input voltage
1.5 to 5.5 V
High-accuracy output voltage
±1.0% (1.0 to 1.45 V output product±15 mV)
Low dropout voltage (LDO)
70 mV typ. (3.0 V output product, at IOUT = 200 mA)
Low current consumption
During operation: 70 µA typ., 90 µA max. (3.0 V output product) ;
During shutdown: 0.1 µA typ., 1.0 µA max.
Output current
500 mA (3.0 V output product, at VIN ≥ VOUT(S) + 1.0 V)*1
High ripple rejection
70 dB typ. (at 1.0 kHz, VOUT = 1.0 V)
Built-in overcurrent protection circuit
limits overcurrent of output transistor
Built-in thermal shutdown circuit
prevents damage caused by heat
Built-in rush current control circuit
limits excessive rush current during start-up
Built-in power on/off circuit
Longer battery life
Lead-free product

*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 TV, notebook PCs and home electric appliances
  • Constant-voltage power supply for portable equipment

Standard Circuit

Standard Circuit