5616
2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK
5616
Data Sheet
26110
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.
c1
BACKPLANE
COLON
SELECT
GROUND
ABSOLUTE MAXIMUM RATINGS
Supply Current, I
DD
..........................
2.0 mA
Input Voltage Range, V
IN
(except V
PP
) ......................
-0.3 V to V
DD
(Programming
Power Voltage, V
PP
) ..................
18.5 V
Input Current (except V
PP
), I
IN
.........
±
10 mA
Power Dissipation, P
D
...................
300 mW
Operating Temperature Range,
T
A
..................................
-40
°
C to +85
°
C
Storage Temperature Range,
T
S
................................
-65
°
C to +150
°
C
Caution: These CMOS devices have static pro-
tection, but are susceptible to damage if exposed
to extremely high static electrical charges.
U Y
D L
O N
R O
P E
D C
E N
U E
N ER
I
T F
N E
O R
C R
S O
I
D F
—
b2
e2
d2
c2
g3
The SCL5616HW is supplied in wafer form and is rated for
continuous operation over the automotive temperature range of
-40°C to +85°C.
T
C
f3
adge1
e3
c3
PM
ad3
b3
g4
2040 x 3040
µm
0.080 x 0.120 in
AM
a2
g2
b1
f2
e4
d4
c4
FEATURES
f4
a4
S2
b4
S1
DATA
s
Digital Tuning of Crystal Frequency
s
PROM for Storing Frequency Correction Information
s
12 or 24 Hour Timekeeping Option
s
Flashing Colon
s
Two Switches Control All Setting Functions
s
High Noise Immunity
s
Internal Power-Up Reset Circuitry
s
Internal Voltage Regulation
IGNITION
V
DD
GROUND
NU
NU
V
PP
Dwg. No. PC-001
OSC.
{
Always order by complete part number:
SCL5616HW
.
5616
2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK
TYPICAL APPLICATION
4.194304 MHz
C
L
= 15 pF, R
S
= 50
Ω
6.8 kΩ
+
47
µF
IGNITION
+12 V
1 MΩ
MINUTES
S2
HOURS
S1
VDD
BACKPLANE
AM
SEGMENTS
PM
GROUNDS
Dwg. EC-001
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
W
Copyright © 1990, 1995, Allegro MicroSystems, Inc.
5616
2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK
ELECTRICAL CHARACTERISTICS at T
A
= -40°C to +85°C, in Typical Application
(unless otherwise noted).
Limits
Characteristic
Operating Voltage Range
Zener Voltage
Segment Output Current
Symbol
V
DD
V
DD
I
OUT
Test Conditions
T
A
= +25°C
I
DD
= 1.0 mA
V
DD
= 5.0 V, V
OUT
= 4.8 V
V
DD
= 5.0 V, V
OUT
= 0.2 V
Backplane Output Current
I
OUT
V
DD
= 5.0 V, V
OUT
= 4.8 V
V
DD
= 5.0 V, V
OUT
= 0.2 V
LCD Drive Signal
Input Current
Oscillator Frequency
Oscillator Starting Time
Oscillator Stability
Backplane Frequency
Switch Debounce Time
Osc. Feedback Resistance
Osc. Input Capacitance
Osc. Output Capacitance
Supply Current
V
DISP
I
IN
f
OSC
t
OSC
∆f
OSC
f
BP
t
DB
R
OSC
C
OSCI
C
OSCO
I
DD
V
DD
= 5.0 V
V
DD
= Zener voltage
∆V
DD
=
±100
mV
V
DD
≥5.0
V
S1, S2, DATA, or SELECT
Min.
4.5
5.5
-20
120
-80
240
4.0
-55
—
—
—
—
0
—
—
—
—
Typ.
—
—
—
—
—
—
—
—
4.194 304
—
—
64
—
16
15
30
—
Max.
—
6.8
—
—
—
—
—
-700
—
200
±1.0
—
62.5
—
—
—
1.0
Units
V
V
µA
µA
µA
µA
V
µA
MHz
ms
ppM
Hz
ms
MΩ
pF
pF
mA
NOTE: Negative current is defined as coming out of (sourcing) the specified device terminal.
DISPLAY FORMAT
a1
a2
a3
a4
AM
PM
e1
b1
g1
f2
g2
b2
f3
b3
g3
f4
g4
b4
COLON
c1
e2
c2
e3
c3
e4
c4
d1
d2
d3
d4
Dwg. No. OC-001
5616
2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK
FUNCTIONAL DESCRIPTION
DATA Logic Levels are V
DD
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
µs
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
PP
) is reduced from 18 V to V
DD
. Clearing the
data input register does not affect the data latched in the RAM.
Program
V
PP
18 V
18 V
V
DD
DATA
V
D
Pulse
Ground
V
DD
SELECT
V
S
Ground
V
DD
Ground
Operation
DATA load for frequency correction
DATA store
Verify stored data
FREQUENCY CORRECTION
FREQUENCY CORRECTION
V
PP
t
PHDL
V
D
1
2
3
127 MAX
t
DHL
t
wD
t
DHPL
t
DLH
V
S
t
SVDL
t
PLSX
VERIFY CYCLE (V
PP
= V )
DD
V
S
t
SLDV
SEGMENT OUTPUTS
Dwg. No. WC-001-1
t
SHDX
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
5616
2-FUNCTION, 4-DIGIT LCD AUTOMOTIVE CLOCK
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
S
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
BP
- 64
128 x 10
-6
where f
BP
is the measured frequency at BACKPLANE. Prior to trim-
ming, it must be between 64.000 128 Hz and 64.016 256 Hz.
Operating Modes.
The operating modes of the clock are controlled
by the voltages applied to V
PP
, SELECT, IGNITION, and switches S1
and S2.
Program
V
PP
V
DD
V
DD
18 V
SELECT
V
S
V
DD
V
DD
Ground
S1
Open
Ground
Open
S2
Open
Ground
Open
IGNITION
X
12 V
X
Mode
Clock running
Diagnostic
Programming
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.
S1
S2
IGNITION
X
Ground
12 V
12 V
12 V
Operation
Clock running
Setting disabled
Set hours
Set Minutes
Change counting sequence (12 to 24 hour
or 24 to 12 hour)
Open
Open
X
X
Ground Open
Open
Ground
Ground Ground
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.
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