LTC1703I 查看數據表（PDF） - Linear Technology

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LTC1703I

Dual 550kHz Synchronous 2-Phase Switching Regulator Controller with 5-Bit VID

Linear Technology 

LTC1703

PI FU CTIO S

VIDn pin includes an on-chip 40kΩ pull-up resistor in

series with a diode (see Block Diagram).

VCC (Pin 18): Power Supply Input. All internal circuits

except the output drivers are powered from this pin. VCC

should be connected to a low noise power supply voltage

between 3V and 7V and should be bypassed to SGND with

at least a 1µF capacitor in close proximity to the LTC1703.

FB2 (Pin 19): Controller 2 Feedback Input. FB2 should be

connected through a resistor divider network to VOUT2 to

set the ouput voltage. The loop compensation network for

controller 2 also connects to FB2.

COMP2 (Pin 20): Controller 2 Loop Compensation. See

COMP1.

RUN/SS2 (Pin 21): Controller 2 Run/Soft-Start. See RUN/

SS1.

FAULT (Pin 22): Output Overvoltage Fault (Latched). The

FAULT pin is an open-drain output with an internal 10µA

pull-up. If either regulated output voltage rises more than

15% above its programmed value for more than 25µs, the

FAULT output will go high and the entire LTC1703 will be

disabled. When FAULT is high, both BG pins will go high,

turning on the bottom MOSFET switches and pulling down

the high output voltage. The LTC1703 will remain latched

in this state until the power is cycled. When FAULT mode

is active, the FAULT pin will be pulled up with an internal

10µA current source. Tying FAULT directly to SGND will

disable latched FAULT mode and will allow the LTC1703 to

resume normal operation when the overvoltage fault is

removed.

PGND (Pin 23): Power Ground. The BGn drivers return to

this pin. Connect PGND to a high current ground node in

close proximity to the sources of external MOSFETs, QB1

and QB2, and the VIN and VOUT bypass capacitors.

SW2 (Pin 24): Controller 2 Switching Node. See SW1.

TG2 (Pin 25): Controller 2 Top Gate Drive. See TG1.

BG2 (Pin 26): Controller 2 Bottom Gate Drive. See BG1.

BOOST2 (Pin 27): Controller 2 Top Gate Driver Supply.

See BOOST1.

IMAX2 (Pin 28): Controller 2 Current Limit Set. See IMAX1.

TEST CIRCUIT

fOSC

MEASURED

VFB1

6

Test Circuit 1

5V

2000pF

0.1µF

IBOOST1 ICC

VCC

BOOST1

IPVCC

PVCC

BOOST2

TG1

TG2

BG1

BG2

2000pF

SW1

IMAX1

FCB

SW2

IMAX2

LTC1703

NC VID0:4

FAULT

NC RUN/SS1

2k

COMP1

RUN/SS2

COMP2

FB1

FB2

SENSE

GND PGND

+

IBOOST2

100µF

2000pF

2000pF

NC

2k

VFAULT

VFB2

1703 TC

1703fa

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