5616

5616

2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK

DATA

BACKPLANE

adge1

COLON

ad3

SELECT

GROUND

IGNITION

GROUND

OSC.

{

2040 x 3040

0.080 x 0.120 in

DISCONTINUED PRODUCT

— FOR REFERENCE ONL

2-FUNCTION, 4-DIGIT

LCD AUTOMOTIVE CLOCK—PROGRAMMABLE

The SCL5616HW is a 2-function digital automotive clock circuit.

Fabricated on a single monolithic chip using silicon-gate CMOS PROM

technology, it offers low cost, low power, and high reliability. It also

includes digital frequency correction, stored in the internal nonvolatile

memory, for easy adjustment of the oscillator nominal frequency.

The SCL5616HW is supplied in wafer form and is rated for

continuous operation over the automotive temperature range of

-40

C to +85

FEATURES

Digital Tuning of Crystal Frequency

PROM for Storing Frequency Correction Information

12 or 24 Hour Timekeeping Option

Flashing Colon

Two Switches Control All Setting Functions

High Noise Immunity

Internal Power-Up Reset Circuitry

Internal Voltage Regulation

Dwg. No. PC-001

Always order by complete part number:

SCL5616HW

Caution: These CMOS devices have static pro-

tection, but are susceptible to damage if exposed

to extremely high static electrical charges.

ABSOLUTE MAXIMUM RATINGS

Supply Current, I

.......................... 2.0 mA

Input Voltage Range, V

(except V

) ...................... -0.3 V to V

(Programming

Power Voltage, V

) .................. 18.5 V

Input Current (except V

), I

.........

10 mA

Power Dissipation, P

................... 300 mW

Operating Temperature Range,

.................................. -40

C to +85

Storage Temperature Range,

................................ -65

C to +150

5616

Data Sheet

26110

5616

2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK

Limits

Characteristic

Symbol

Test Conditions

Min.

Typ.

Max.

Units

Operating Voltage Range

= +25

4.5

—

Zener Voltage

= 1.0 mA

5.5

—

6.8

Segment Output Current

OUT

= 5.0 V, V

OUT

= 4.8 V

-20

—

= 5.0 V, V

OUT

= 0.2 V

120

—

Backplane Output Current

OUT

= 5.0 V, V

OUT

= 4.8 V

-80

—

= 5.0 V, V

OUT

= 0.2 V

240

—

LCD Drive Signal

DISP

≥

5.0 V

4.0

—

Input Current

S1, S2, DATA, or SELECT

-55

—

-700

Oscillator Frequency

OSC

—

4.194 304

—

MHz

Oscillator Starting Time

OSC

= Zener voltage

—

200

Oscillator Stability

∆

OSC

∆

100 mV

—

1.0

ppM

Backplane Frequency

—

Switch Debounce Time

—

62.5

Osc. Feedback Resistance

OSC

—

Ω

Osc. Input Capacitance

OSCI

—

Osc. Output Capacitance

OSCO

—

Supply Current

= 5.0 V

—

1.0

NOTE: Negative current is defined as coming out of (sourcing) the specified device terminal.

ELECTRICAL CHARACTERISTICS at T

= -40

C to +85

C, in Typical Application

(unless otherwise noted).

DISPLAY FORMAT

COLON

Dwg. No. OC-001

5616

2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK

115 Northeast Cutoff, Box 15036

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

FUNCTIONAL DESCRIPTION

DATA Logic Levels are V

and Ground

Power-Up Reset.

When power up occurs, the hours and minutes

counters are reset, and the clock starts running:

Operation

12-Hour mode and counting starts from 1:00 AM

Programming Modes.

Data is loaded by pulling DATA low (1

s pulse

duration) n times to set the desired bits for frequency correction into

the data input register. This information is latched in the RAM, thus

allowing the testing of the oscillator frequency adjustment without

storing the selected pattern in the PROM cells. The data latched in the

RAM is stored in the PROM cells when DATA is held low for a mini-

mum of 10 ms.

The data stored in the data input register is cleared on any SELECT

transition (low to high or high to low). It is also cleared when the

program power voltage (V

) is reduced from 18 V to V

. Clearing the

data input register does not affect the data latched in the RAM.

Program

DATA

SELECT

Operation

18 V

Pulse

Ground

DATA load for frequency correction

18 V

Ground

DATA store

Ground

Verify stored data

FREQUENCY CORRECTION

Dwg. No. WC-001-1

VERIFY CYCLE (V = V )

DHPL

PLSX

SVDL

DLH

PHDL

SHDX

SLDV

SEGMENT OUTPUTS

DHL

FREQUENCY CORRECTION

127 MAX

5616

2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK

IGNITION

Operation

Open

Clock running

Ground

Setting disabled

Ground

Open

12 V

Set hours

Open

Ground

12 V

Set Minutes

Ground Ground

12 V

Change counting sequence (12 to 24 hour

or 24 to 12 hour)

Frequency Correction.

The on-chip oscillator circuit increases the

crystal frequency approximately 40 ppm. This ensures that the typical

crystal will operate within the tuning range. With V

at ground, data

pulses are then used to trim the internal clock frequency by 2 to 254

ppm to the required value. The quantity of data pulses needed (1 to

127) is

n = f

- 64

128 x 10

-6

where f

is the measured frequency at BACKPLANE. Prior to trim-

ming, it must be between 64.000 128 Hz and 64.016 256 Hz.

X = Irrelevant, ground or 12 V

Clock Running Mode.

During the clock running mode, setting

functions are achieved by either momentary or continuous operation

of switches S1 and S2, which are enabled by IGNITION. Hours or

minutes are incremented on S1 or S2 (respectively) depression and

continue at a 1 Hz rate while the switch is depressed.

X = Irrelevant, ground or 12 V for IGNITION, ground or open for S1 and S2

Diagnostic Mode.

To enter the diagnostic mode, S1 and S2 are oper-

ated with IGNITION connected to 12 V. All segments are displayed for

as long as S1 and S2 are depressed. On opening S1 and S2, the clock

will leave the diagnostic mode and go through a power-up sequence.

In the SCL5616HW, the counting sequence will change (from 12 hour

to 24 hour or from 24 hour to 12 hour). To inhibit the power-up reset,

hold the DATA input low (ground). The counting mode will change

without resetting the hours or minutes counters.

Program

SELECT

IGNITION

Mode

Open

Clock running

Ground

12 V

Diagnostic

18 V

Ground

Open

Programming

Operating Modes.

The operating modes of the clock are controlled

by the voltages applied to V

, SELECT, IGNITION, and switches S1

and S2.

5616

2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK

115 Northeast Cutoff, Box 15036

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

Frequency Selection Pulses

Segment

Characteristic

Symbol

Min.

Max.

Units

PROGRAM High (18 V) to DATA Low

PHDL

1.0

—

SELECT Valid to DATA Low

SVDL

—

DATA Low to DATA High

DLH

1.0

1.5

DATA High to DATA Low

DHL

1.0

—

DATA Store Pulse Duration

—

DATA High to PROGRAM Low

DHPL

1.0

—

PROGRAM Low to SELECT Change

PLSX

1.0

—

SELECT Low (Verify) to DATA Valid

SLDV

—

1.0

DATA Hold from End of Verify

SHDX

—

RECOMMENDED FLASH

PROGRAMMING CHARACTERISTICS

at T

= +25

C, Logic Levels are V

and Ground

(except PROGRAM High)

Stored Data Verification. In the verify mode, the complement value

of the information stored in the PROM cells is brought out directly to

the segment output terminals for easy verification of the stored data.

If a bit is programmed (high), the appropriate segment output is turned

ON (low). The segments represent the binary equivalent of the

number of frequency correction data pulses entered.

Allegro MicroSystems, Inc. reserves the right to

make, from time to time, such departures from the detail

specifications as may be required to permit improve-

ments in the design of its products.

The information included herein is believed to be

accurate and reliable. However, Allegro MicroSystems,

Inc. assumes no responsibility for its use; nor for any

infringements of patents or other rights of third parties

which may result from its use.