Cherry Semiconductor CS4121ENF16, CS4121EDWFR20, CS4121EDWF20 Datasheet

1

Features

■

Direct Sensor Input

■

High Torque Output

■

Low Pointer Flutter

■

High Input Impedance

■ Overvoltage Protection

■ Accurate to 8V

Functional to 6.5V (typ)

Package Options

16 Lead PDIP

(internally fused leads)

20 Lead SOIC

(internally fused leads)

CS4121

Low Voltage Precision Air-Core

Tach/Speedo Driver

1

CP+

2

3

4

5

6

7

8

SQ

OUT

FREQ

IN

Gnd

Gnd

COS+

COS-

V

CC

16

15

14

13

12

11

10

9

CP-

F/V

OUT

V

REG

Gnd

Gnd

SINE+

SINE-

BIAS

1

CP+

2

3

4

5

6

7

8

SQ

OUT

FREQ

IN

Gnd

Gnd

Gnd

Gnd

COS+

16

15

14

13

12

11

10

CP-

F/V

OUT

V

REG

Gnd

Gnd

Gnd

Gnd

SIN+

9

COS- SIN-

17

18

V

CC

BIAS

19

20

CS4121

Description

The CS4121 is specifically designed
for use with air-core meter move­ments. The IC provides all the func­tions necessary for an analog
tachometer or speedometer. The
CS4121 takes a speed sensor input
and generates sine and cosine relat­ed 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 uti­lizes 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 allow­ing for fewer trims and for use in a
speedometer.

The CS4121 is compatible with the
CS8190, and provides higher accu­racy at a lower supply voltage (8.0V
min. as opposed to 8.5V). It is func­tionally operational to 6.5V.

Block Diagram

Absolute Maximum Ratings

Supply Voltage (<100ms pulse transient)..........................................VCC= 60V

(continuous)..............................................................VCC= 24V

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: [phone] Fax: [phone]

Email: [e-mail]

Web Site: www.cherry-semi.com

A Company

¨

Rev 12/4/96

Voltage

Regulator

V

REG

7.0V

+

Ð

Ð

+

Output

+

Ð

SINE

F/V

CP-

V

REG

Gnd

Gnd

SINE+

SINE-

OUT

BIAS

SQ

FREQ

COS

COS

CP+

OUT

Gnd

Gnd

V

IN

+

CC

-

Charge Pump

Input

Comp.

+

Ð

Ð

+

COS

Output

+

Ð

Func.

Gen.

High Voltage

Protection

2

Electrical Characteristics: -40¡C ² TA² 85¡C, 8.0V ² VCC² 16V unless otherwise specified.

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

CS4121

■ Supply Voltage Section

ICCSupply Current VCC= 16V, -40¡C, No Load 50 125 mA
VCCNormal Operation Range

8.0 13.1 16.0 V

■ Input Comparator Section

Positive Input Threshold 1.0 2.0 3.0 V
Input Hysteresis 200 500 mV
Input Bias Current * 0V ² VIN² 8V -10 -80 µA
Input Frequency Range 0 20 kHz
Input Voltage Range in series with 1k½ -1 V

CC

V

Output V

SAT

ICC= 10mA 0.15 0.40 V
Output Leakage VCC= 7V 10 µA
Logic 0 Input Voltage 1 V

*Note: Input is clamped by an internal 12V Zener.

■ Voltage Regulator Section

Output Voltage 6.25 7.00 7.50 V
Output Load Current 10 mA
Output Load Regulation 0 to 10 mA 10 50 mV
Output Line Regulation 8.0V ² VCC² 16V 20 150 mV
Power Supply Rejection VCC= 13.1V, 1VP/P1kHz 34 46 dB

■ Charge Pump Section

Inverting Input Voltage 1.5 2.0 2.5 V
Input Bias Current 40 150 nA
Vbias Input Voltage 1.5 2.0 2.5 V
Non Invert. Input Voltage IIN= 1mA 0.7 1.1 V
Linearity* @ 0, 87.5, 175, 262.5, + 350Hz -0.10 0.28 +0.70 %
F/V

OUT

Gain @ 350Hz, CT = 0.0033µF, RT = 243k½ 7 10 13 mV/Hz
Norton Gain, Positive IIN= 15µA 0.9 1.0 1.1 I/I
Norton Gain, Negative IIN= 15µA 0.9 1.0 1.1 I/I

*Note: Applies to % of full scale (270¡).

■ Function Generator Section: -40¡C ² T

A

² 85¡C, VCC= 13.1V unless otherwise noted.

Differential Drive Voltage 8.0V ² VCC² 16V 5.5 6.5 7.5 V

(V

COS

+ - V

COS

-) Q = 0¡

Differential Drive Voltage 8.0V ² VCC² 16V 5.5 6.5 7.5 V

(V

SIN

+ - V

SIN

-) Q = 90¡

Differential Drive Voltage 8.0V ² VCC² 16V -7.5 -6.5 -5.5 V

(V

COS

+ - V

COS

-) Q = 180¡

Differential Drive Voltage 8.0V ² VCC² 16V -7.5 -6.5 -5.5 V

(V

SIN

+ - V

SIN

-) Q = 270¡
Differential Drive Current 8.0V ² VCC² 16V, TA=25¡C 33 42 mA
Zero Hertz Output Angle -1.5 0.0 1.5 deg
Function Generator Error * VCC= 13.1V, TA=25¡C -2 0 +2 deg

Reference Figures 1,2,3,4 Q = 0¡ to 305¡

*Note: Deviation from nominal per Table 1 after calibration at 0¡ and 270¡.

3

PACKAGE LEAD # LEAD SYMBOL FUNCTION

CS4121

Electrical Characteristics: continued

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Package Lead Description

Typical Performance Characteristics

0 45 90 135 180 225 270 315

Output Voltage (V)

Degrees of Deflection (°)

7

6

5

4

3
2

1

0

-1

-2

-3

-4

-5

-6

-7

COS

SIN

045

90

135 180 225 270 315

F/V Output (V)

Frequency/Output Angle (°)

7

6

5

4

3

2

1

0

Figure 2: Charge Pump Output Voltage vs Output Angle

Figure 1: Function Generator Output Voltage

vs Degrees of Deflection

F/V

OUT

= 2.0V + 2 FREQ ´ CT´ RT´ (V

REG

- 0.7)

■ Function Generator Section: continued

Function Generator Error 13.1V ² V

CC

² 16V, TA=25¡C -2.5 0 +2.5 deg

Function Generator Error 13.1V ² V

CC

² 11V, TA=25¡C -1 0 +1 deg

Function Generator Error 13.1V ² V

CC

² 8V, TA=25¡C -3 0 +3 deg

Function Generator Error 25¡C ² T

A

² 85¡C -3 0 +3 deg

Function Generator Error 25¡C ² T

A

² 105¡C -5.5 0 +5.5 deg

Function Generator Error Ð40¡C ² T

A

² 25¡C -3 0 +3 deg

Function Generator Gain T

A

= 25¡C Q vs F/V

OUT

60 77 95 ¡/V

16L PDIP* 20L SO*

1 1 CP+ Positive input to charge pump.

22SQ

OUT

Buffered square wave output signal.

3 3 FREQ

IN

Speed or rpm input signal.

4, 5, 12, 13 4-7, 14-17 Gnd Ground Connections.

6 8 COS+ Positive cosine output signal.

7 9 COS- Negative cosine output signal.

810VCCIgnition or battery supply voltage.

9 11 BIAS Test point or zero adjustment.

10 12 SIN- Negative sine output signal.

11 13 SIN+ Positive sine output signal.

14 18 V

REG

Voltage regulator output.

15 19 F/V

OUT

Output voltage proportional to input signal frequency.

16 20 CP- Negative input to charge pump.

*Internally Fused Leads