Features

• Vin Range: 2.7V to 5.5V

• Maximum Output Current 600mA

• High Efficiency Up to 98

• Low Quiescent Current

• High Switching Frequency: 1.6MHz

• Low Dropout in 100 Duty Cycle

• Shutdown Current < 1μA

• No Schottky Diode Required

• Output Auto Discharge when Disabled (Option)

• Integrated Soft-Start : 170μs

• Adjustable Output Voltage Down to 0.6V

• Short Circuit Protection

• Over-Temperature Protection

• Pb-Free Packages:

 KTB851 : UTDFN-6, 1.6x1.6x0.55mm

 KTB851 : TDFN-6, 1.6x1.6x0.75mm

 KTB851A/B : TSOT23-5

• RoHS and Green Compliant

• -40°C to +85°C Temperature Range

Applications

• Mobile Phones

• Portable Instruments

• Digital Still Cameras

• Microprocessor Power

• MP3 Players

Brief Description

The KTB851 is a high efficiency step down

converter, using constant frequency PWM current

mode control. It uses 1.6MHz high switching

frequency which allows the use of small external

components. The 2.7V to 5.5V input operating range

is ideal for Li-Ion/Polymer powered devices and

systems running from regulated 3.3V or 5V voltage

rails. 100 duty cycle operation provides the

greatest design flexibility for achieving the lowest

dropout.

Low output voltage down to 0.6V can be achieved

due to the KTB851’s low internal voltage reference.

The KTB851 is designed to maintain high efficiency

throughout the operating range, which is critical for

portable applications. In addition, the KTB851 has an

option for output auto discharge feature. This

enables the device to quickly discharge the output

when the device is disabled.

The KTB851 is available in a small 5-pin TSOT23,

6-pin TDFN 1.6 x 1.6 x 0.75mm and 6-pin UTDFN

1.6 x 1.6 x 0.55mm package.