降压开关稳压器控制器IC芯片 S-8521B33MC-ATST2G SEIKO品牌 全新原装 进口

S-8521B33MC-ATST2G

General Description: 

The S-8521 Series consists of CMOS step-down switching regulator-controller with PWM/PFM-switched control. These devices contain a reference voltage source, oscillation circuit, error amplifier, and other components.

The S-8521 Series works with either PWM control or PFM control, and can switch from one to other. It normally operates using PWM control with a duty ratio of 25% to 100%, but under a light load, it automatically switched to PFM control with a duty ratio of 25%. This series ensures high efficiency over a wide range of conditions, from standby mode to operation of peripheral equipment.

With the addition of an external Pch Power MOSFET or PNP transistor, a coil, capacitors, and a diode connected externally, these ICs can function as step-down switching regulators. They serve as ideal power supply units for portable devices when coupled with the SOT-23-5 minipackage, providing such outstanding features as low current consumption. Since this series can accommodate an input voltage of up to 16V, it is also ideal when operation via an AC adapter.

Features: 

• Low current consumption: 

In operation: 60uA max. (A&B Series)

 21uA max. (C&D Series)

 100uA max. (E&F Series)

When powered off: 0.5uA max.

• Input voltage: 

 2.5V to 16V (B, D, F Series)

 2.5V to 10V (A, E, C Series)

• Output voltage: 

Selectable between 1.5V abd 6.0V in 0.1V step

• Duty ratio: 

25% to 100% PWM/PFM-switched control

• The only peripheral components that can be used with this IC are a Pch power MOSFET or PNP transistor, a coil, a diode, and capacitors (If a PNP transistor is used, a base resistance and a capacitor will also be required)
• Oscillator frequency: 

180kHz typ. (A&B Series), 60 kHz typ. (C&D Series), or 300 kHz typ. (E&F Series).

• Soft-start function: 

8 ms. typ. (A&B Series), 12 ms. typ. (C&D Series), or 4.5 ms. typ. (E&F Series).

• With a power-off function
• With a built-in overload protection circuit. Overload detection time: 

4 ms. typ. (A&B Series), 14 ms. typ. (C&D Series), or 2.6 ms. typ. (E&F Series).

Applications: 

• On-board power supplies of battery devices for portable telephones, electronic notebooks, PDAs, and the like;
• Power supplies for audio equipment, including portable CD players and headphone stereo equipment;
• Fixed voltage power supply for cameras, video equipment and communications equipment;
• power supplies for microcomputers;
• Conversion from four NiH or NiCd cells or two lithium-ion cells to 3.3V/3V;
• Conversion of AC adapter input to 5V/3V.