LTC7151S datasheet(10/44 Pages) AD

10 / 44 page

Data Sheet

LT83203/LT83205

analog.com

Rev. B

10 of 44

the shutdown feature is not used. An external resistor divider from VIN is used to

program a VIN threshold below which the LT83203/LT83205 shuts down.

The VC pin is the output of the internal error amplifier. The voltage on this pin controls

the peak switch current. Connect an RC network from this pin to ground to

compensate the control loop.

SET

This pin is the non-inverting input of the error amplifier and the regulation setpoint for

the LT83203/LT83205. SET sources a precision 100μA current that flows through an

external resistor connected between the SET and GND. The LT83203/LT83205’s output

voltage is determined by VSET = ISET× RSET when used in the default unity-gain

configuration. The SET pin voltage range is from 0V to 13V. For applications with

output voltages above 13V, see the Output Voltages Above 13V section. A capacitor

should be added from SET to GND for the best noise performance. Increasing this

capacitance further improves noise at the expense of increased start-up time. See the

SET Pin Capacitor: Noise and Soft-Start section for important information on how to

select this capacitor. For optimum load regulation, Kelvin connect the ground side of

the SET pin resistor directly to the load. This pin is pulled to ground with a 520Ω

MOSFET (RSET-PULLDOWN) during shutdown and fault conditions.

OUTS

Output Sense. This pin is the inverting input to the error amplifier. For optimal

transient performance and load regulation, Kelvin connect OUTS directly to the output

capacitor and the load.

PGFB

Power Good Feedback. The PG pin pulls low if PGFB increases above 537.5mV or

decreases below 462.5mV. Connecting an external resistor divider between VOUT, PGFB,

and GND sets the programmable power good threshold with the following transfer

function: 0.5V (±7.5%) × (1 + RPGFB(TOP)/RPGFB(BOT)). As discussed in the Applications

Information section, PGFB also activates the fast start-up circuitry. The PGFB pin must

be connected to INTVCC or 0.5V if power good and fast start-up functionalities are not

needed.

LTC7151S Datasheet(PDF) 10 Page - Analog Devices