A1391 View Datasheet(PDF) - Allegro MicroSystems

Part Name

Description

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A1391

Micro Power 3 V Linear Hall Effect Sensors with Tri-State Output and User-Selectable Sleep Mode

Allegro MicroSystems 

A1391, A1392,

Micro Power 3 V Linear Hall Effect Sensors with

A1393, and A1395 Tri-State Output and User Selectable Sleep Mode

Device Low-Power Functionality

A139x are low-power Hall effect sensor ICs that are perfect for

power sensitive customer applications. The current consumption

of these devices is typically 3.2 mA, while the device is in the

active mode, and less than 25 μA when the device is in the sleep

mode. Toggling the logic level signal connected to the S¯¯L¯¯E¯¯E¯¯P pin

drives the device into either the active mode or the sleep mode.

A logic low sleep signal drives the device into the sleep mode,

while a logic high sleep signal drives the device into the active

mode.

In the case in which the VREF pin is powered before the VCC

pin, the device will not operate within the specified limits until

the supply voltage is equal to the reference voltage. When the

device is switched from the sleep mode to the active mode, a time

defined by tPON must elapse before the output of the device is

valid. The device output transitions into the high impedance state

approximately tPOFF seconds after a logic low signal is applied to

the S¯¯L¯¯E¯¯E¯¯P pin (see figure 1).

If possible, it is recommended to power-up the device in the

sleep mode. However, if the application requires that the device

be powered on in the active mode, then a 10 kΩ resistor in series

with the S¯¯L¯¯E¯¯E¯¯P pin is recommended. This resistor will limit the

current that flows into the S¯¯L¯¯E¯¯E¯¯P pin if certain semiconductor

junctions become forward biased before the ramp up of the volt-

age on the VCC pin. Note that this current limiting resistor is not

required if the user connects the S¯¯L¯¯E¯¯E¯¯P pin directly to the VCC

pin. The same precautions are advised if the device supply is

powered-off while power is still applied to the S¯¯L¯¯E¯¯E¯¯P pin.

VCC

VSLEEP

ICC

+B

B field 0

–B

VOUT

HIGH

IMPEDANCE

tPON

Figure 1. A139x Timing Diagram

tPOFF

HIGH

IMPEDANCE

tPON

HIGH

IMPEDANCE

tPOFF

Allegro MicroSystems, Inc.

10

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

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