1

Features

SINE-

SINE+

Gnd

SINE

Output

COS

Output

7.0V

COS-

COS+

Gnd

Gnd

CP+

Input

Comp.

Gnd

CP-

Voltage

Regulator

High Voltage

Protection

BIAS

Charge Pump

Func.

Gen.

+

Ð

+

Ð

s

Direct Sensor Input

s

High Torque Output

s

Low Pointer Flutter

s

High Input Impedance

s

Overvoltage Protection

s

Accurate to 8V

Functional to 6.5V (typ)

Package Options

16 Lead PDIP

(internally fused leads)

20 Lead SOIC

(internally fused leads)

Low Voltage Precision Air-Core

Tach/Speedo Driver

1

CP+

2

3

4

5

6

7

8

Gnd

Gnd

COS+

COS-

16

15

14

13

12

11

10

9

CP-

Gnd

Gnd

SINE+

SINE-

BIAS

1

CP+

2

3

4

5

6

7

8

Gnd

Gnd

Gnd

Gnd

COS+

16

15

14

13

12

11

10

CP-

Gnd

Gnd

Gnd

Gnd

SIN+

9

COS-

SIN-

17

18

BIAS

19

20

CS4121

Description

The CS4121 is specifically designed

for use with air-core meter move-

ments. The IC provides all the func-

tions necessary for an analog

tachometer or speedometer. The

CS4121 takes a speed sensor input

and generates sine and cosine relat-

ed output signals to differentially

drive an air-core meter.

Many enhancements have been

added over industry standard

tachometer drivers such as the

CS289 or LM1819. The output uti-

lizes differential drivers which elim-

inates the need for a zener reference

and offers more torque. The device

withstands 60V transients which

decreases the protection circuitry

required. The device is also more

precise than existing devices allow-

ing for fewer trims and for use in a

speedometer.

The CS4121 is compatible with the

CS8190, and provides higher accu-

racy at a lower supply voltage (8.0V

min. as opposed to 8.5V). It is func-

tionally operational to 6.5V.

Block Diagram

Absolute Maximum Ratings

Operating Temperature .............................................................Ð40¡C to +105¡C

Storage Temperature..................................................................Ð40¡C to +165¡C

Junction Temperature .................................................................Ð40¡C to+150¡C

ESD (Human Body Model) .............................................................................4kV

Lead Temperature Soldering

Wave Solder (through hole styles only)............10 sec. max, 260¡C peak

Reflow (SMD styles only).............60 sec. max above 183¡C, 230¡C peak

Cherry Semiconductor Corporation

2000 South County Trail, East Greenwich, RI 02818

Tel: (401)885-3600 Fax: (401)885-5786

Email: info@cherry-semi.com

Web Site: www.cherry-semi.com

A

Company

¨

Rev 12/4/96