TDA7851

TDA7851 is a dual-channel automotive power amplifier IC from Philips/NXP (car audio applications).
Key points:
- Dual BTL (bridge-tied load) class-AB amplifiers to drive two speakers.
- Designed for 12 V automotive environments; typical supply range ~8–18 V.
- On-chip protections: short-circuit/overcurrent, thermal shutdown, and sometimes undervoltage lockout.
- Features to reduce pops: mute/standby control and smooth start-up.
- Outputs suitable for 4 Ω or 8 Ω loads; suitable for car radio/head-unit use.
- Commonly used in car radios, aftermarket stereos, and embedded automotive audio systems.
Note: Specific output power, quiescent current, and package type vary by revision; consult the datasheet for exact figures and package options.

Closest equivalents are other members of the Philips/NXP TDA785x family, notably the TDA7850 and TDA7852. They’re similar dual-channel automotive audio amplifiers with BTL outputs and comparable protection features. There isn’t an exact pin-for-pin cross; check datasheets for pinout and spec differences.

Here are the key features of the TDA7851 (car-audio power amplifier):
- Quad, bridge-tied-load (BTL) car audio power amplifier
- Output: up to ~22 W per channel into 4 Ω (typical at 14.4 V); supports other loadings with lower power
- 4 channels (or bridged operation for higher power)
- Automotive supply range: broad 6–18 V, tolerant to load-dumps
- Pop-free turn-on with built-in mute/standby control
- Protection: short-circuit/current limit, overtemperature/thermal protection, overvoltage and undervoltage protection
- Diagnostic/status outputs for fault conditions
- Differential inputs with noise rejection (single-ended input supported)
- No external output coupling capacitors required (BTL configuration)
- Efficient class-AB operation with low idle current
- Suitable for compact automotive head-unit/consoles due to integrated protection and diagnostics
Note: exact quiescent/peak values vary with supply and load; consult the datasheet for precise specifications.

- Pin count: 28 pins (in a 28‑pin package such as SO‑28/Multiwatt‑28)
- Function: Automotive dual power amplifier with bridge-tied-load (BTL) outputs for two audio channels; includes differential inputs and typical features like mute/standby for car radios.

- Manufacturer: NXP Semiconductors (originally Philips Semiconductors).
- What kind of company: A Dutch multinational semiconductor company that designs, develops, and manufactures integrated circuits and microchips for automotive, communications, and consumer electronics. Headquartered in Eindhoven, Netherlands.

Primarily used in automotive audio. Key application areas:
- Car radios/head‑units and OEM infotainment systems
- Aftermarket car amplifiers and integrated car speaker setups
- Consumer multimedia speakers and compact hi‑fi systems needing high‑power, robust amplification
- Rugged automotive/vehicle audio equipment with built‑in protection (short‑circuit, thermal) and good efficiency
These cover typical uses where a high‑quality, automotive‑grade audio power amplifier is required.

TDA7851 uses a 16‑pin power package, typically the Multiwatt16 (Power DIP16) package.