1 V1 Collector terminal
2 V2 Shunt emitter terminal
3 V3 Amplifier sense input
4 Osc Oscillator input
5 STM Test mode switch
6 VS Supply voltage
7 GND Reference point, GND
8 LED Charge mode indicator
Pin 1, Collector Voltage V1
Pin 1 is an open collector output. When V1 ≤ 3 V, the
charge cycle is switched off until it is above the supply
voltage, as shown in figure 6.
Pin 2, Shunt Emitter
Pin 4 Oscillator
The constant current source is supplied by the internal
operational amplifier. The voltage across R3 is deter-
mined via the internal reference source.
Ich = V3/R3 (V3 = Vsense)
Pin 3, Amplifier Sense Input (Inverted)
Pin 5 Test – Mode
Figure 2. Quick test timer 1/3
The voltage-regulated current source has a closed loop at
Pin 2, Pin 3, and resistor R3.
Pin 4, Oscillator Input R4, C4
Selection of current charge versus timing is carried out by
using the external circuit at Pins 2, 3, and 4. Typical
values are given in charge characteristics (see table next
Pin 5, Test-Mode Switch for Charging Time
The charging time, tch, is given by the following equation.
fosc = oscillator frequency (see figure 2)
n = frequency divider
= 26, if STM open
= 17, if STM = GND
= 8, if STM = VS
The first eight divider stages can be tested directly.
256 input tact signals at Pin 4 create one tact signal at
Assume a charge time of 6 h.
Select the values of R4 and C4 from the tables next page.
WR4 = 470 k
C4 = 680 pF
There is a frequency of approximately 3100 Hz at Pin 4.
It is possible to test the charge time of 6 h by running
through the charge cycle for a very short time. By
connecting Pin 5 with GND, the test time is 42 s. By
connecting Pin 5 with Pin 1 (V1), the test time is reduced
to about 82.4 ms. R5 is connected in parallel to the LED2
and provides a protective bypass function for the LED
(see figure 1).
Pin 6, Supply Voltage, VS
[VS 3.1 V power-on reset release (turn-on)
[VS 2.9 V under-voltage reset
[VS 13 V supply voltage limitation
Pin 7, Ground
Rev. A1, 20-Mar-96