TL851CN sonar ranging control pinout
DIP-16. Sonar transmit control (ranging). HERO Jr U307 on the power/sense board.
Runs the ranging cycle: INIT (pin 14) starts a 16-pulse burst out of XMIT (pin 2) through Q313 and T301 to the transducer, then it steps the TL852 gain (GCA-GCD) and raises ECHO (pin 9) when REC sees an echo. Its resonator is Y301 at 420 kHz. On HERO Jr it runs from +5SW (pin 1), so no Sense Enable means no sonar. No echo at all usually means the transmit burst or the sense rail is missing.
Open the interactive TL851 pinoutPins
| Pin | Name | Type | Signal |
|---|---|---|---|
| 1 | VCC | power | Supply, 4.5-6.8 V. |
| 2 | XMIT | io | Transmit drive output (Darlington emitter follower, about 140 mA); sends a 16-pulse burst after each INIT. |
| 3 | GND | ground | Ground. |
| 4 | GCD | ctrl | Gain control bit D (MSB), open collector, to the receiver. |
| 5 | GCA | ctrl | Gain control bit A (LSB), open collector. |
| 6 | GCB | ctrl | Gain control bit B, open collector. |
| 7 | GCC | ctrl | Gain control bit C, open collector. |
| 8 | REC | io | Receive input from the receiver chip; internal 1.2 V level detector. |
| 9 | ECHO | ctrl | Echo output, open collector; goes high when an echo is detected. |
| 10 | OSC | clock | Oscillator output, enabled by INIT: resonator / 8.5 during transmit, then resonator / 4.5. |
| 11 | XTAL1 | clock | Ceramic resonator connection (420 kHz typical). |
| 12 | XTAL2 | clock | Ceramic resonator connection. |
| 13 | FILT | power | Internal filtered-supply node. The datasheet does not name the external part. UNVERIFIED |
| 14 | INIT | ctrl | Initiate: a high starts a ranging cycle (at least 5 ms after power-up). |
| 15 | BINH | ctrl | Blanking inhibit: high ends internal blanking early so near echoes are seen. |
| 16 | BLNK | ctrl | Blanking: high disables REC and resets ECHO low. |
Fitted in
- HERO Jr U307