TL852CN sonar receiver pinout

DIP-16. Sonar echo receiver and amplifier. HERO Jr U308.

Amplifies the echo from the transducer under gain control (GCA-GCD) from U307 and hands it back to U307 on REC; the echo then reaches the CPU through U304 and U215 pin 18 (CB1). R358 sets the bias, R359 the gain, R361 the detect level, and L302/C337 tune it. On HERO Jr it runs from +5SW (pin 5). A weak or missing echo points here or at the transducer leads.

Open the interactive TL852 pinout

Pins

Pin	Name	Type	Signal
1	G1IN	io	First-stage amplifier input; a resistor from G1IN to GADJ sets gain.
2	XIN	io	Clamp input for the transducer transformer secondary during transmit.
3	GADJ	io	Gain adjust: the gain resistor connects here from G1IN.
4	LC	io	Parallel LC tank to VCC sets the tuned gain and Q.
5	VCC	power	Supply, 4.5-6.8 V.
6	G1OUT	io	First-stage output; AC-coupled (0.01 µF) to G2IN.
7	G2IN	io	Second-stage amplifier input.
8	BIAS	io	Bias reference: 68 kohm 5% to ground.
9	REC	io	Receive output; 1000 pF to ground integrates the received signal.
10	NC	nc	No internal connection.
11	NC	nc	No internal connection.
12	GCC	ctrl	Gain control bit C.
13	GCB	ctrl	Gain control bit B.
14	GCA	ctrl	Gain control bit A (LSB).
15	GCD	ctrl	Gain control bit D (MSB); all four gain inputs must change together.
16	GND	ground	Ground.

Fitted in

HERO Jr U308

Sources

TI TL852 Sonar Ranging Receiver, SLSS003 (1988), p. 1