SAE800_05 参数 Datasheet PDF下载

SAE 800

Circuit Description

Trigger

Positive pulses on inputs E1 and/or E2 trigger the IC. The hold feedback in the logic has a delay of

several milliseconds. After this delay has elapsed, the tone sequence is started. This prevents

parasitic spikes from producing any effect on the trigger pins.

The following

table

shows the trigger options:

E1

Triggered

Grounded/open

Triggered

Oscillator

This is a precision triangle oscillator with an external time constant (R x C). Capacitor

C

C

on pin

C

OSC

is charged by constant current to 1 V and then discharged to 0.5 V. The constant current is obtained

on pin

R

OSC

with an external resistor

R

R

to ground.

When the voltage on

C

OSC

is building up, the logic is reset at 350 mV. This always ensures that a

complete tone sequence is issued. If the oscillator pin is short-circuited to GND during operation,

the sequence is repeated.

E2

Triggered

Triggered

Grounded/open

Mode

Triple-tone

Dual-tone

Single-tone

Issued Sequence

Minor and major third

Minor third

1st tone of minor third

The following applies:

∆V

C

x

C

C

=

I

C

x T/2 with

I

C

=

V

R

/2

R

R

= 1.2 V/2

R

R

f

0

= 5/8 x 1/(

R

R

x

C

C

)

Voltages on Pin

C

OSC

Semiconductor Group

4