ST2109 300KHz PWM/PFM Boost Controller

Name: ST2109 300KHz PWM/PFM Boost Controller
Brand: STST
SKU: ST2109

ST2109

The ST2109 is a CMOS step-up switching regulator controller consisting of a reference voltage source, an oscillation circuit, an error amplifier, a phase compensation circuit and a PWM/PFM switching control circuit. With an external low-ON-resistance N-channel power MOSFET, it is ideal for applications requiring high efficiency and high output current. Under light load it automatically switches to PFM control at a 15% duty ratio to prevent efficiency loss from IC operating current. It runs at 300KHz, provides a 1.5V~6.5V output range with ±2% accuracy, guarantees start-up from 0.9V (IOUT=1mA) and includes a 2ms soft-start. Housed in an ultra-small SOT23-5 package needing only a coil, diode, capacitors and a transistor, it suits mobile phones, Bluetooth equipment, PDAs, portable modems, portable games, digital cameras and notebook computers.

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Specifications

Input Voltage (VIN)0.9V~6V

Output Current (Typ.)-

Modulation ModePWM/PFM (switching control)

Output Voltage (VOUT)1.5V~6.5V (ST2109F FB=1.25V)

FB/VOUT Accuracy±2%

Oscillation Frequency (Typ.)300KHz (255~345KHz)

Power MOS CharacteristicsExternal N-channel power MOSFET (low RDSon, external); RDS(on) determined by external FET

PackageSOT23-5

Product details

Overview

The ST2109 series is a CMOS step-up switching regulator which mainly consists of a reference voltage source, an oscillation circuit, an error amplifier, a phase compensation circuit, and a PWM/PFM switching control circuit. With an external low-ON-resistance N-channel power MOSFET, this product is applicable to applications requiring high efficiency and high output current. The ST2109 series switches its operation to the PFM control circuit whose duty ratio is 15% with the PWM/PFM switching control circuit under a light load, to prevent decline in efficiency caused by IC operation current.

Features

Low voltage operation: start-up guaranteed from 0.9V (IOUT=1mA)
Duty ratio: built-in PWM/PFM switching control circuit, 15% to 78%
Oscillator frequency: 300KHz
Output voltage range: 1.5V~6.5V
Output voltage accuracy: ±2%
Soft start function: 2ms
External parts: coil, diode, capacitor, and transistor
Ultra-small SOT23-5 package