Seiko Instruments' S-1172 CMOS Voltage Regulator Has High Ripple Rejection

Seiko's S-1172 is used as a power supply for battery powered devices, notebook PC's, home appliances and more.

Online PR News – 15-July-2010 – – Seiko Instruments has developed the S-1172 Series positive voltage regulator integrating a super low dropout voltage, a high output voltage accuracy, and a low current consumption. The super low dropout voltage and the high output current can be attributed to the built-in transistor with low on-resistance.

The over-current protector prevents the load current from exceeding the capacitance of the output transistor while the thermal shutdown circuit prevents damage caused by heat. The rush current control circuit limits the excessive rush current during start-up. Various capacitors and small ceramic capacitors can be used for this IC more than for conventional regulator ICs that have CMOS technology. Additionally, the ON/OFF circuit ensures longer battery life.

High-density mounting can be achieved using a small SOT-89-5 package and high-heat radiation HSOP-6 package.

Typical Features of the S-1172 Series Include:
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 : 70 mV typ. (3.0 V output product, at IOUT = 300 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: 1000 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 over-current protection circuit: Limits over-current 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
Small package: SOT-89-5, HSOP-6
RoHS Compliant
*1. Attention should be paid to the power dissipation of the package when the output current is large.
Typical Applications of the S-1172 Include:

• Power supply for battery-powered devices
• Power supply for TV, notebook PCs and electronic home appliances
• Constant-voltage power supply for portable equipment