General Description

The HM1460 is a voltage mode, fixed 300kHz switching frequency, synchronous buck converter. The HM1640 allows wide input voltage that is either a single 5~12V or two supply voltage(s) for various applications. A power-on-reset (POR) circuit monitors the VCC supply voltage to prevent wrong logic controls. A builtin soft-start circuit prevents the output voltages from overshoot as well as limits the input current. An internal 0.8V temperature-compensated reference voltage with high accuracy is designed to meet the requirement of low output voltage applications. The HM1640 provides excellent output voltage regulations against load current variation.

The controller’s over-current protection monitors the output current by using the voltage drop across the RDS(ON) of low-side MOSFET, eliminating the need for a current sensing resistor that features high efficiency and low cost. In addition,

the HM1460 also integrates excellent protection functions: The over-voltage protection (OVP) , under- voltage protection (UVP). OVP circuit which monitors the FB voltage to prevent the PWM output from overvoltage,and UVP circuit which monitors the FB voltage to prevent the PWM output from under-voltage or short-circuit.The HM1640 is available in SOP-8P and TDFN3x3-10 packages.

特性 Features

● Wide 5V to 12V Supply Voltage

● Power-On-Reset Monitoring on VCC

● Excellent Output Voltage Regulations 0.8V Internal Reference ±1 Over-Temperature Range

● Integrated Soft-Start

● Voltage Mode PWM Operation with External Compensation

● Up to 90 Duty Ratio for Fast Transient Response

● Constant Switching Frequency 300kHz ±10

● Drive Dual Low Cost N-MOSFETs with Adaptive Dead-Time Control

● 50 Under-Voltage Protection

● 125 Over-Voltage Protection

● Adjustable Over-Current Protection Threshold Using the RDS(ON) of Low-Side MOSFET

● Shutdown Control by COMP

● Power Good Monitoring (TDFN-10 3mmx3mm Package Only)

● SOP-8P and TDFN3x3-10 Packages

● Lead Free and Green Devices Available (RoHS Compliant)

Applications

● Graphic Cards

● DSL, Switch HUB

● Wireless Lan

● Notebook Computer

● Mother Board

● LCD Monitor/TV