Programmable
Single-/Dual-/Triple- Tone Gong
Preliminary Data
Bipolar IC
Features
q
Supply voltage range 2.8 V to 18 V
q
Few external components (no electrolytic capacitor)
q
1 tone, 2 tones, 3 tones programmable
q
Loudness control
q
Typical standby current 1
A
q
Constant current output stage (no oscillation)
q
High-efficiency power stage
q
Short-circuit protection
q
Thermal shutdown
Semiconductor Group
1
09.94
w
New type
Functional Description
The SAE 800 is a single-tone, dual-tone or triple-tone gong IC designed for a very wide supply
voltage range. If the oscillator is set to
f
0
= 13.2 kHz for example, the IC will issue in triple-tone-
mode the minor and major third e
2
C sharp a, corresponding to 660 Hz 550 Hz 440 Hz, in
dual-tone-mode the minor third e
2
C sharp, and in single-tone-mode the tone e
2
(derived from
the fundamental frequency
f
0
;
f
1
=
f
0
/ 20,
f
2
=
f
0
/ 24,
f
3
=
f
0
/ 30).
When it is not triggered, the IC is in a standby state and only draws a few
A. It comes in a compact
P-DIP-8-1 or P-DSO-8-1 (SMD) package and only requires a few external components.
P-DIP-8-4
P-DSO-8-1
SAE 800
Type
Ordering Code
Package
w
SAE 800
Q67000-A8339
P-DIP-8-4
w
SAE 800 G
Q67000-A8340
P-DSO-8-1 (SMD)
Semiconductor Group
2
SAE 800
Pin Configuration
(top view)
Pin Definitions and Functions
Functional Description (cont'd)
An RC combination is needed to generate the fundamental frequency (pin
R
OSC
,
C
OSC
). The volume
can be adjusted with another resistor (pin L). The loudspeaker must be connected directly between
the output Q and the power supply
V
S
. The current-sink principle combined with an integrated
thermal shutdown (with hysteresis) makes the IC overload-protected and shortcircuit-protected.
There are two trigger pins (E1, E2) for setting single-tone, dual-tone or triple-tone mode.
Pin
Symbol
Function
1
GND
Ground
2
Q
Output
3
V
S
Supply Voltage
4
L
Loudness Control
5
R
OSC
Oscillator Resistor
6
C
OSC
Oscillator Capacitor
7
E2
Trigger 2 (dual tone)
8
E1
Trigger 1 (single tone)
SAE 800
SAE 800 G
Semiconductor Group
3
Block Diagram
SAE 800
Semiconductor Group
4
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:
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.
Voltages on Pin
C
OSC
E1
E2
Mode
Issued Sequence
Triggered
Triggered
Triple-tone
Minor and major third
Grounded/open
Triggered
Dual-tone
Minor third
Triggered
Grounded/open
Single-tone
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
)
SAE 800
Semiconductor Group
5
Logic
The logic unit contains the complete sequence control. The oscillator produces the power-on reset
and the clock frequency. Single-tone, dual-tone or triple-tone operation is programmed on inputs
E1 and E2. The 4-bit digital/analog converters are driven in parallel. In the event of oscillator
disturbance, and after the sequence, the dominant stop output is set. By applying current to pin L,
the sequence can be shortened by a factor of 30 for test purposes.
The following figure shows the envelope of the triple-tone sequence:
Envelope of the Triple-Tone Sequence
Envelope of maximum amplitudes of three
superimposed tones on Q (time scale for
f
OSC
= 13.2 kHz)
Ratio of maximum amplitudes
M3 : M2 : M1 = 1 : 0.89 : 0.67
SAE 800
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