LM32 datasheet(8/14 Pages) NSC

8 / 14 page

Typical Applications (Continued)

TLH7768 – 14

FIGURE 4 Time Out on Power Up (Relay Energized

Until

Rt Ct Seconds After VCC is Applied)

TLH7768 – 15

FIGURE 5 5V Logic Supply Driving 28V Relay

30V Supply Interfacing with 5V Logic

Figure 6 indicates the ability of the timer to interface to digi-

tal logic when operating off a high supply voltage VOUT

swings between a5V and ground with a minimum fanout of

5 for medium speed TTL If the logic is sensitive to risefall

time of the trailing edge of the output pulse the trigger pin

should be low at that time

TLH7768 – 16

FIGURE 6 30V Supply Interfacing with 5V Logic

Astable Operation

The LM122 can be made into a self-starting oscillator by

feeding the output back to the trigger input through a capac-

itor as shown in

Figure 7 Operating frequency is 1(Rt a

R1)(Ct) The output is a narrow negative pulse whose width

is approximately 2R2 Cf For optimum frequency stability Cf

should be as small as possible The minimum value is deter-

mined by the time required to discharge Ct through the inter-

nal discharge transistor A conservative value for Cf can be

chosen from the graph included with

Figure 20 For frequen-

cies below 1 kHz the frequency error introduced by Cf is a

few tenths of one percent or less for Rt t 500k

See Chart

TLH7768 – 17

TLH7768 – 18

FIGURE 7 Oscillator

One Hour Timer with Reset and Manual Cycle End

Figure 8 shows the LM122 connected as a one hour timer

with manual controls for start reset and cycle end S1

starts timing but has no effect after timing has started S2 is

a center off switch which can either end the cycle prema-

turely with the appropriate change in output state and dis-

charging of Ct or cause Ct to be reset to 0V without a

change in output In the latter case a new timing period

starts as soon as S2 is released

Dearborn

Electronics

LP9A1A476K

Polycarbonate

TLH7768 – 19

FIGURE 8 One Hour Timer with Reset

and Manual Cycle End

LM32 数据表(PDF) 8 Page - National Semiconductor (TI)

LM32 数据表(HTML) 8 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14

数据表下载