MAX6330 Просмотр технического описания (PDF) - Maxim Integrated

Номер в каталоге

Компоненты Описание

производитель

MAX6330

Precision Shunt Regulators with Reset in SOT23-3

Maxim Integrated 

Precision Shunt Regulators with Reset

in SOT23-3

______________________________________________________________Pin Description

PIN

MAX6330 MAX6331

1

1

2

—

NAME

GND

RESET

—

2

RESET

3

3

SHUNT

FUNCTION

Ground

Inverting Reset Output. RESET remains low while VSHUNT is below the reset threshold and

for 140ms after VSHUNT rises above the threshold.

Noninverting Reset Output. RESET remains high while VSHUNT is below the reset threshold

and for 140ms after VSHUNT rises above the threshold.

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

_______________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.

RESET is guaranteed to be a logic low for VSHUNT >

1V. Once VSHUNT exceeds the reset threshold, an

internal timer keeps RESET low for the reset timeout

period; after this interval, RESET goes high.

If a brownout condition occurs (VSHUNT dips below the

reset threshold), RESET goes low. When VSHUNT falls

below the reset threshold, the internal timer resets to

zero and RESET goes low. The internal timer starts after

VSHUNT returns above the reset threshold, and RESET

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-

ance. The shunt current range (ISHUNT) is 100µA to

50mA.

The pass transistor in the MAX6330/MAX6331 main-

tains a constant output voltage (VSHUNT) by sinking the

necessary amount of shunt current. When ILOAD (see

Typical Operating Circuit) is at a maximum, the shunt

current is at a minimum, and vice versa:

IIN = ISHUNT + ILOAD = (VIN - VSHUNT) / RS

Consider the following information when choosing the

external resistor RS:

1) The input voltage range, (VIN)

2) The regulated voltage, (VSHUNT)

3) The output current range, (ILOAD)

Choose RS as follows:

(VIN(max) - VSHUNT (min)) / (50mA + ILOAD(min)) ≤ RS ≤

(VIN(min) - VSHUNT (max)) / (100µA + ILOAD(max))

Choose the largest nominal resistor value for RS that

gives the lowest current consumption. Provide a safety

margin to incorporate the worst-case tolerance of the

IIN

VIN

RS

VSHUNT

ISHUNT

SHUNT

ILOAD

CL

RESET

GENERATOR

140ms

TIMEOUT

RESET

(RESET)

1.2V

GND

( ) ARE FOR MAX6331

MAX6330

MAX6331

Figure 1. Functional Diagram

_______________________________________________________________________________________ 5

Share Link: