Precision Shunt Regulators with Reset

in SOT23-3

_______________________________________________________________________________________

5

______________________________________________________________Pin Description

PIN

FUNCTION

1

1

Ground

2

—

—

2

3

3

Regulated Shunt Voltage (+5V, +3.3V, or +3.0V)

NAME

GND

RESET

RESET

SHUNT

MAX6331

MAX6330

_______________Detailed Description

Reset Output

A microprocessor’s (µP’s) reset input starts the µP in a

known state. The MAX6330/MAX6331 µP supervisory

circuits assert reset to prevent code-execution errors

during power-up, power-down, or brownout conditions.

internal timer keeps RESET low for the reset timeout

period; after this interval, RESET goes high.

below the reset threshold, the internal timer resets to

zero and RESET goes low. The internal timer starts after

then remains low for the reset timeout period.

The MAX6331 has an active-high RESET output that is

the inverse of the MAX6330’s RESET output.

Shunt Regulator

The shunt regulator consists of a pass device and a

controlling circuit, as illustrated in Figure 1. The pass

device allows the regulator to sink current while regu-

lating the desired output voltage within a ±1.5% toler-

50mA.

The pass transistor in the MAX6330/MAX6331 main-

Typical Operating Circuit) is at a maximum, the shunt

current is at a minimum, and vice versa:

Consider the following information when choosing the

gives the lowest current consumption. Provide a safety

margin to incorporate the worst-case tolerance of the

MAX6330

MAX6331

SHUNT

RESET

GENERATOR

140ms

TIMEOUT

RESET

(RESET)

1.2V

GND

( ) ARE FOR MAX6331

Figure 1. Functional Diagram