L6730 datasheet(4/52 Pages) STMICROELECTRONICS

4 / 52 page

Summary description

L6730 - L6730B

4/52

Doc ID 11938 Rev 3

Summary description

The controller is an integrated circuit designed using BiCMOS-DMOS, v5 (BCD5)

technology that provides complete control logic and protection for high performance, step-

down DC/DC and niPOL converters.

It is designed to drive N-Channel MOSFETs in a synchronous rectified

buck converter

topology. The output voltage of the converter can be precisely regulated down to 600 mV,

with a maximum tolerance of ±0.8%, or to 1.2 V, when one of the internal references is used.

It is also possible to use an external reference from 0 V to 2.5 V.

The input voltage can range from 1.8 V to 14 V, while the supply voltage can range from 4.5

V to 14 V. High peak current gate drivers provide for fast switching to the external power

section and the output current can be in excess of 20 A, depending on the number of the

external MOSFETs used. The PWM duty cycle can range from 0% to 100% with a minimum

on-time (TON(MIN)) lower than 100 ns, making conversions with a very low duty cycle and

very high switching frequency possible.

The device provides voltage-mode control. It includes a 400 kHz free-running oscillator that

is adjustable from 100 kHz to 1 MHz. The error amplifier features a 10 MHz gain-bandwidth-

product and 5 V/µs slew-rate that permits to realize high converter bandwidth for fast

transient response. The device monitors the current by using the RDS(ON) of both the high-

side and low-side MOSFET(s), eliminating the need for a current sensing resistor and

guaranteeing an effective over current-protection in all the application conditions. When

necessary, two different current limit protections can be externally set through two external

resistors. A leading edge adjustable blanking time is also available to avoid false over-

current-protection (OCP) intervention in every application condition.

It is possible to select the HICCUP mode or the constant current protection (L6730B) after

the soft-start phase.

During this phase constant current protection is provided. It is possible to select the sink-

source or the source-only mode capability

(before the device powers on) by acting on a

multifunction pin (L6730). The L6730 disables the sink mode capability during the soft-start

in order to allow a proper start-up also in pre-biased output voltage conditions. The L6730B

can always sink current and, so it can be used to supply the DDR memory BUS termination.

Other features include Master-Slave synchronization (with 180° phase shift), Power-Good

with adjustable delay, over voltage-protection, feed back disconnection, selectable UVLO

threshold (5 V and 12 V Bus), and thermal shutdown. The HTSSOP20 package allows the

realization for very compact DC/DC converters.

L6730 数据表(PDF) 4 Page - STMicroelectronics

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