Specifications
Display
HED 231: 4 Digit 10mm LCD
HED 233: 4 Digit 24mm LCD
HED 231R/233R: reflective
HED 231T/233T: backlight
Input Voltage
1.25 to 1.80VDC (clock)
4.5 to 5.5VDC (backlight)
Input Current
Typical 1µA (without backlight)
20µA max (without backlight)
80mA max (231T with backlight)
240mA max (233T with backlight)
Connections
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Solder centre pad to pad marked 12 hr to configure clock for 12hr display
Solder centre pad to pad marked 24 hr to configure clock for 24hr display
Application Circuit (see page 7)
Use the circuit shown for supply voltages above 5V. For voltages less than 8V, omit the
components within the dotted line.
Mount capacitor C3 as close to the unit as possible.
Note:
This product is ideally suited to battery powered applications. Should the product be used
in a circuit where an external power source is used, then the complete system will require
separate approval to meet the CE standards.
2
Buzzer frequency
2048Hz
Max output current
200µA
Alarm duration
60 Seconds
Snooze delay
8 Minutes
Accuracy
± 20ppm @ 20°C
Operating Temperature
-10°C to 50°C
Storage Temperature
-20°C to 70°C
+5VDC Backlight supply (231T, 233T only)
0V Backlight supply (231T, 233T only)
ON = Set Time
ON = Set Alarm
ON = Enable Snooze *
ON = Alarm Off - Disables alarm
ON = Advance Hours
ON = Advance Minutes
ON = Alarm Stop * - Silences alarm
0V Clock supply
+1.5VDC Clock supply
Connect Piezo buzzer as shown here,
{
or use transistor circuit shown on page 7)
Transistor drive output (see page 7)
*
If Snooze is enabled, Alarm Stop will cancel
alarm for 8 minutes, then alarm will sound
again
