A1425(2005) 查看數據表（PDF） - Allegro MicroSystems

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产品描述 (功能)

生产厂家

A1425
(Rev.:2005)

High Accuracy Analog Speed Sensor with Integrated Filter Capacitor and Dual Zero-Crossing Output Signal

Allegro MicroSystems 

A1425

High Accuracy Analog Speed Sensor with Integrated Filter Capacitor and Dual Zero-Crossing Output Signal

Applications Information

Target Selection

The zero-crossing switchpoints and ac-coupled operation of this

device make target selection important. For high-density target

geometries or small target features that produce a sinusoidal

magnetic signal, the high-pass filter is capable of filtering offsets

that may be induced in the final sensor output. If such offset is

present, and the target has larger features, then the high-pass

filter may not be effective at higher speeds and an accuracy shift

may occur. These relationships are shown in figure 2.

Power Supply Protection

The A1425 contains an on-chip voltage regulator and can oper-

ate over a wide supply voltage range. In applications that operate

the device from an unregulated power supply, transient protec-

tion must be added externally. For applications using a regulated

line, EMI/RFI protection may still be required. The circuit

shown in figure 3 is the most basic configuration required for

proper device operation.

Large Feature (Tooth)

Valley

+B

(a)

0

–B

+V

VCC

1

0.1 uF

RPU

0

t

4

2

A1425

VOUT

Output Edge

+B

Shift

(b)

0

–B

+V

3

(Required)

Figure 3. Basic application circuit. A pull-up resistor, RPU, is

required with the output driver.

0

t

Figure 2. Large Feature Effects. (a) Large target feature but no sensor offset,

normal edge position. (b) Large target feature with sensor offset, shifted

(advanced) output edge position.

A1425-DS

Allegro MicroSystems, Inc.

11

115 Northeast Cutoff, Box 15036

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

www.allegromicro.com

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