Datasheet CS4172XN16, CS4172XDWFR16, CS4172XDWF16 Datasheet (Cherry Semiconductor)

1

Features

■ Serial Input Bus

■ 2 MHz Operating

Frequency

■ Tangential Drive

Algorithm

■ 80mA Drive Circuits

■ 0.5¡ Accuracy (Typ.)

■ Power-On-Reset

■ Protection Features

Output Short Circuit
Overtemperature

Package Options

Single Air-Core Gauge Driver

CS4172

Description

The CS4172 is a monolithic BiCMOS
integrated circuit used to translate a
digital 10-bit word from a micropro­cessor/microcontroller to complemen­tary DC outputs. The DC outputs
drive an air-core meter commonly
used in vehicle instrument panels. The
10 bits of data are used to linearly con­trol the quadrature coils of the meter
directly with a 0.35¡ resolution and
±1.0¡ accuracy over the full 360¡ range
of the gauge. The interface from the
microcontroller is by a Serial Periph­eral Interface (SPI) compatible serial
connection using up to a 2MHz shift
clock rate.

The digital code, which is directly pro­portional to the desired gauge pointer
deflection, is shifted into a DAC and
multiplexer. These two blocks provide
a tangential conversion function to
change the digital data into the appro­priate DC coil voltage for the angle
demanded. The tangential algorithm
creates approximately 40% more
torque in the meter movement than
does a sin-cos algorithm at 45¡, 135¡,

225¡, and 315¡ angles. This increased
torque reduces the error due to pointer
droop at these critical angles.

Each output buffer is capable of sup­plying up to 80mA per coil and are
controlled by a common enable pin.
When OE is low the output buffers are
turned off but the logic portion of the
chip remains powered and continues
to operate normally.

The Serial Gauge Driver is self-protect­ed against output short circuit condi­tions. The output drivers are disabled
anytime the on-chip protection circuit­ry detects a short circuit condition. The
outputs remain off until a falling edge
is presented on CS. If the short circuit
is still present the output drivers auto­matically disable themselves again. A
thermal protection circuit limits the
junction temperature to approximately
160¡C for conditions of high supply
voltage and high ambient temperature.

The status pin (ST) reflects the state of
the outputs and is low whenever the
outputs are disabled.

Block Diagram

16 Lead PDIP

SIN

-

SIN

+

Gnd

V

BB

Gnd

NC

SO

SI

V

CC

COS

+

COS

-

CS

SCLK

OE

Gnd

ST

SIN

-

SIN

+

Gnd

V

BB

Gnd

Gnd

SO

SI

V

CC

COS

+

COS

-

CS

SCLK

OE

1

Gnd

ST

16 Lead SO Wide

(internally fused leads)

Rev. 4/19/99

CS4172

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

¨

V

POR

CC

LOGIC

V

BB

1

+

SI

SCLK

CS

SO

ST

OE

Serial

to

D0 Ð D6

Parallel

Shift

Register

D7 Ð D9

RS

FAULT

Latch

S

7 Bit
DAC

POR

Gnd

V

TOP

MUX

V

VAR

V

BAT

OC

Output

Amplifiers

SIN

SIN

COS

COS

Ð

+

Ð

2

Absolute Maximum Ratings

Supply Voltage

V

BB

....................................................................................................................................................................-1.0V to 15.0V

VCC......................................................................................................................................................................-1.0V to 6.0V

Digital Inputs ..............................................................................................................................................................-1.0V to 6.0V

Ground Potential Difference (|AGnd-DGnd|)....................................................................................................................0.5V

Steady State Output Current ............................................................................................................................................±100mA

Forced Injection Current (Inputs and Supply).................................................................................................................±10mA

Operating Junction Temperature (TJ) ..................................................................................................................................150¡C

Storage Temperature Range .................................................................................................................................-65¡C to 150¡C

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

ESD Susceptibility (Human Body Model)..............................................................................................................................2kV

CS4172

Electrical Characteristics: -40¡C ² TA² 105¡C; 7.5V ² VBB² 14V; 4.5V ² VCC² 5.5V (unless otherwise specified)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

■ Supply Voltages and Currents

VBBQuiescent Current Output disabled (OE = 0V) 1 5 mA

[R

COS

, R

SIN

= R

L(MIN)

] @45¡ 175 mA

(code = XÕ080) VBB= 14V

VCCQuiescent Current OE = high, V

BB

= 0V

SCLK = 2.0MHz 1 mA

■ Digital Inputs and Outputs

Output High Voltage SO, I

OH

= 0.8mA V

CC

- 0.8 V

Output Low Voltage SO, I

OL

=0.8mA 0.4 V

ST, I

OL

= 2.5mA 0.8 V

Output High Current ST, V

CC

= 5.0V 25 µA

Input High Voltage CS, SCLK, SI, OE 0.7 ´ V

CC

V

Input Low Voltage CS, SCLK, SI, OE 0.3 ´ V

CC

V

Input High Current CS, SCLK, SI, OE; V

IN

= 0.7 ´ V

CC

1µA

Input Low Current CS, SCLK, SI, OE; V

IN

= 0.3 ´ V

CC

1µA

■ Analog Outputs

Output Function Accuracy -1.2 +1.2 deg
Output Shutdown Current, V

BB

= 14.0V 70 250 mA

Source

Output Shutdown Current, V

BB

= 14.0V 70 250 mA

Sink

Output Shutdown Current, V

BB

= 7.5V 43 250 mA

Source

Output Shutdown Current, V

BB

= 7.5V 43 250 mA

Sink

Coil Drive Output Voltage 0.748 ´ V

BB

V

Minimum Load Resistance TA= 105¡C 229 ½

TA= 25¡C 171 ½
TA= -40¡C 150 ½

3

Package Pin Description

PACKAGE PIN# PIN SYMBOL FUNCTION

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Shift Clock Frequency 2.0 MHz
SCLK High Time 175 ns
SCLK Low Time 175 ns
SO Rise Time 0.75V to V

CC

- 1.2V; CL = 90pF 150 ns

SO Fall Time 0.75V to V

CC

- 1.2V; CL = 90pF 150 ns
SO Delay Time CL = 90pF 150 ns
SI Setup Time 75 ns
SI Hold Time 75 ns
CS Setup Time 0 ns
CS Hold Time 75 ns

16 Lead SO Wide 16 Lead PDIP

1 1 SIN

-

Negative output for SINE coil.

2 2 SIN

+

Positive output for SINE coil.

34V

BB

Analog supply. Nominally 13.5V.

4,5,12,13 3,13,14 Gnd Ground.

6 6 SI Serial data input. Data present at the rising edge of the

clock signal is shifted into the internal shift register.

77V

CC

5V logic supply. The internal registers and latches are
reset by a POR generated by the rising edge of the voltage
on this pin.

8 8 OE Controls the state of the output buffers. A logic low on

this pin turns them off.

9 9 SCLK Serial clock for shifting in/out of data. Rising edge shifts

data on SI into the shift register and the falling edge
changes the data on SO.

10 10 CS When high allows data at SI to be shifted into part with

the rising edges of SCLK. The falling edge transfers the
shift register contents into the DAC and multiplexer to
update the output buffers. The falling edge also re-enables
the output drivers if they have been disabled by a fault.

11 11 ST STATUS reflects the state of the outputs and is low any-

time the outputs are disabled, either by OE or the internal
protection circuitry. Requires external pull-up resistor.

14 5 SO Serial data output. Existing 10-bit data is shifted out when

new data is shifted in. Allows cascading of multiple
devices on common serial port.

15 15 COS

-

Negative output for COSINE coil.

16 16 COS

+

Positive output for COSINE coil.

12 NC No connection.

Electrical Characteristics: -40¡C ² TA² 105¡C; 7.5V ² VBB² 14V; 4.5V ² VCC² 5.5V (unless otherwise specified)

CS4172

4

The SACD is for interfacing between a microcontroller or
microprocessor and air-core meter movements commonly
used in automotive vehicles for speedometers and
tachometers. These movements are built using 2 coils
placed at a 90¡ orientation to each other. A magnetized
disc floats in the middle of the coils and responds to the
magnetic field generated by each coil. The disc has a shaft
attached to it that protrudes out of the assembly. A point­er indicator is attached to this shaft and in conjunction
with a separate printed scale displays the vehicleÕs speed
or the engineÕs speed.

The disc (and pointer) respond to the vector sum of the
voltages applied to the coils. Ideally, this relationship fol-

lows a equation. Since this is a transcendental and
non-linear function, devices of this type use an approxi­mation for this relationship. The SACD uses a tangential
algorithm as shown in Figure 1. Only 1 output varies in
any 45 degree range.

Figure 1. Major gauge outputs.

Quadrant I

q = Tan

-1

For q = 0.176¡ to 44.824¡:

V

SIN

= Tanq´0.748 ´ V

BB

V

COS

= 0.748 ´ V

BB

For q = 45.176¡ to 89.824¡:

V

SIN

= 0.748 ´ V

BB

V

COS

= Tan(90¡ Ð q) ´ 0.748 ´ V

BB

Quadrant II

q = 180¡ Ð Tan

-1

For q = 90.176¡ to 134.824¡:

V

SIN

= 0.748 ´ V

BB

V

COS

= -Tan(q Ð 90¡) ´ 0.748 ´ V

BB

For q = 135.176¡ to 179.824¡:

V

SIN

= Tan(180¡ Ð q) ´ 0.748 ´ V

BB

V

COS

= -0.748 ´ V

BB

Quadrant III

q = 180¡ + Tan

-1

For q = 180.176¡ to 224.824¡:

V

SIN

= -Tan(q Ð 180¡) ´ 0.748 ´ V

BB

V

COS

= -0.748 ´ V

BB

For q = 225.176¡ Ð 269.824¡:

V

SIN

= -0.748 ´ V

BB

V

COS

= -Tan(270¡ Ð q) ´ 0.748 ´ V

BB

Quadrant IV

q = 360¡ Ð Tan

-1

For q = 270.176¡ to 314.824¡:

V

SIN

= -0.748 ´ V

BB

V

COS

= Tan(q Ð 270¡) ´ 0.748 ´ V

BB

For q = 315.176¡ Ð 359.824¡:

V

SIN

= -Tan(360¡ Ð q) ´ 0.748 ´ V

BB

V

COS

= 0.748 ´ V

BB

Graph 1. Major gauge response.

]

V

SIN+

Ð V

SIN-

V

COS+

Ð V

COS-

[

]

V

SIN+

Ð V

SIN-

V

COS+

Ð V

COS-

[

]

V

SIN+

Ð V

SIN-

V

COS+

Ð V

COS-

[

]

V

SIN+

Ð V

SIN-

V

COS+

Ð V

COS-

[

sine

cosine

Theory of Operation

Applications Information

CS4172

0° 45° 90° 135° 180° 225° 270° 315° 360°

Max (128)

+

SIN
Output

SIN
Output

COS
Output

COS
Output

Min (0)

Max (128)

Ð

Min (0)

Max (128)

+

Min (0)

Max (128)

Ð

Min (0)

000 001 010 011 100 101 110 111 000

Degrees of Rotation

MUX bits (D9 Ð D7)

V

COS+

360/0°

0.748V

BB

270°

V

SINÐ

IV

0.748V

III

q

I

0.748V

0.748V

BB

II

BB

BB

180°

V

COS-

V

90°

SIN+

CS4172

Applications Information: continued

5

To drive the gaugeÕs pointer to a particular angle, the
microcontroller sends a 10-bit digital word into the serial
port. These 10 bits are divided as shown in Figure 2.
However, from a software programmers viewpoint, a
360¡ circle is divided into 1024 equal parts of .35¡ each.
Table 1 shows the data associated with the 45¡ divisions
of the 360¡ driver.

Figure 2. Definition of serial word.

Table 1. Nominal output for major gauge (V

BB

= 14V).

The 10 bits are shifted into the deviceÕs shift register MSB
first using an SPI compatible scheme. This method is
shown in Figure 3. The CS must be high and remain high
for SCLK to be enabled. Data on SI is shifted in on the ris­ing edge of the synchronous clock signal. Data in the shift

register changes at SO on the falling edge of SCLK. This
arrangement allows the cascading of devices. SO is
always enabled. Data shifts through without affecting the
outputs until CS is brought low. At this time the internal
DAC is updated and the outputs change accordingly.

Figure 3. Serial data timing diagram.

Figure 4. Power-up sequence.

Input Code Ideal Nominal V

SIN

V

COS

(Decimal) Degrees Degrees (V) (V)

0 0 0.176 0.032 10.476
128 45 45.176 10.476 10.412
256 90 90.176 10.476 -0.032
384 135 135.176 10.412 -10.476
512 180 180.176 -0.032 -10.476
640 225 225.176 -10.476 -10.412
768 270 270.176 -10.476 0.032
896 315 315.176 -10.476 10.476

1023 359.65 359.826 -0.032 10.476

Application Diagram

MSB LSB

Major

D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Gauge

(360°)

D9 Ð D7 select

which octant

Divides a 45° octant into 128 equal parts

to achieve a .35° resolution

Code 0 Ð 127

10

CS

SO

(Rise, Fall)

10% - 90%

10 Bits

REGISTERS

SET TO ZERO

CS

Hold

OUTPUTS
ENABLED

CS

Setup

SCLK

SI

(Setup)

SI

SO

SI

(Hold)

SO

(tpd)

V

CC

CS

SI

OE

ST

REGISTERS

SET TO ZERO

10 Bits

OUTPUTS
ENABLED

V

BAT

V

CS-8156

REG

5V
12V

ENABLE

360° Gauge

Microcontroller

10k

SIN-

SIN+
ST
CS
SI
SCLK

OE

CS4172

COS+

COS-

V
V

SO

BB

CC

Next Driver

Thermal 16 Lead 16 Lead
Data PDIP SO Wide*

R

QJC

typ 42 18 ûC/W

R

QJA

typ 80 75 ûC/W

CS4172

6

Part Number Description

CS4172XN16 16 Lead PDIP
CS4172XDWF16 16 Lead SO Wide*
CS4172XDWFR16 16 Lead SO Wide* (tape & reel)

D

Lead Count Metric English

Max Min Max Min
16 Lead PDIP 19.69 18.67 .775 .735
16 Lead SO Wide* 10.50 10.10 .413 .398

© 1999 Cherry Semiconductor Corporation

Rev. 4/19/99

Ordering Information

Package Specification

PACKAGE DIMENSIONS IN mm (INCHES)

PACKAGE THERMAL DATA

Cherry Semiconductor Corporation reserves the right to
make changes to the specifications without notice. Please
contact Cherry Semiconductor Corporation for the latest
available information.

*Internally Fused Leads

Surface Mount Wide Body (DW); 300 mil wide

Plastic DIP (N); 300 mil wide

0.39 (.015)
MIN.

2.54 (.100) BSC

1.77 (.070)

1.14 (.045)

D

Some 8 and 16 lead
packages may have
1/2 lead at the end
of the package.
All specs are the same.

.203 (.008)

.356 (.014)

REF: JEDEC MS-001

3.68 (.145)

2.92 (.115)

8.26 (.325)

7.62 (.300)

7.11 (.280)

6.10 (.240)

.356 (.014)

.558 (.022)

1.27 (.050) BSC

7.60 (.299)

7.40 (.291)

10.65 (.419)

10.00 (.394)

D

0.32 (.013)

0.23 (.009)

1.27 (.050)

0.40 (.016)

REF: JEDEC MS-013

2.49 (.098)

2.24 (.088)

0.51 (.020)

0.33 (.013)

2.65 (.104)

2.35 (.093)

0.30 (.012)

0.10 (.004)