MAX8704 Просмотр технического описания (PDF) - Maxim Integrated

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MAX8704

High-Current, Low-Voltage Linear Regulator with Power-Limited, External MOSFET

Maxim Integrated 

High-Current, Low-Voltage Linear Regulator

with Power-Limited, External MOSFET

INPUT

1.0V TO 5.5V

5V BIAS

SUPPLY

OFF ON

LOGIC

SUPPLY

POWER-

GOOD

N1

RSENSE

CIN

COUT

VIN

DRV

CSP

CSN

10Ω

VCC

C1

THERMAL

SHDN

CONTROL

5µA

BLOCK

SS/EN 0.5V

CSS

1kΩ RSS/EN

SHDN

CURRENT LIMIT

(FIGURE 3)

SHDN

FB

DUAL-MODE

FEEDBACK

ERROR

AMP

0.5V

GND

R3

PGOOD

POK 0.91 x

REF FB

DELAY

LOGIC

PLIM

MULTIPLIER

PLIM

MAX8704

OUTPUT

(VOUT)

R1

R2

RPLIM

CPLIM

Figure 2. Functional Diagram

is enabled. As the voltage on SS/EN continues to

increase, the current-limit threshold slowly ramps up,

effectively limiting the input inrush current during

power-up (Figure 3). The MAX8704 reaches the full cur-

rent limit when the SS/EN voltage exceeds 2V.

When SS/EN is pulled low—either by an external open-

drain output or by the internal power-OK (POK) lockout

signal—the MAX8704 pulls the driver (DRV) low and dis-

charges the output through a 10Ω discharge FET.

Drive SS/EN with a push/pull output to bypass soft-start.

Output Voltage and Dual Mode™ Feedback

The MAX8704’s Dual-Mode operation allows the selec-

tion of two common preset voltages without requiring

external components. Connect FB to VCC for a fixed

1.5V output, or connect FB to GND for a fixed 1.2V out-

put. Alternatively, the output voltage can be adjusted

using a resistive voltage-divider (Figure 2). The adjust-

ed output voltage is:

VOUT

=

VFB

1+

R1

R2 

Dual Mode is a trademark of Maxim Integrated Products, Inc.

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