Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Linear > Audio Amplifiers

STMicroelectronics TDA7851A

Name: TDA7851A
Brand: STMicroelectronics
SKU: TDA7851A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: TDA7851A

Manufacturer:: STMicroelectronics

Category:: Audio Amplifiers

Package:: 27-Flexiwatt, Formed Leads

Datasheet:: TDA7851A.pdf

Description:: IC AMP AB QUAD 75W 27FLEXIWATT

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:318

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

TDA7851A from STMicroelectronics is a 4-channel Class AB MOSFET audio power amplifier designed for high-power automotive head units, delivering up to 4 × 48 W into 4 Ω loads at 14.4 V with <0.05% THD+N, rail-to-rail output swing, and integrated DC offset detection for speaker protection in car-radio systems.

For engineers reviewing the TDA7851A datasheet, TDA7851A pinout, TDA7851A application, or TDA7851A equivalent, key selection considerations include its 26 dB fixed gain, 2 Ω load capability, automute at 6.7–7.5 V supply detection, thermal limiter with soft shutdown, and Flexiwatt27 package thermal resistance of 1 °C/W junction-to-case.

Technical Context

The TDA7851A implements a fully complementary P-Channel/N-Channel MOSFET output stage enabling rail-to-rail voltage swing and minimized saturation losses. Its internal DC offset detector monitors differential output voltage (±1–±3 V trip range) and triggers mute before speaker-damaging DC develops.

It integrates CMOS-compatible standby and mute logic with defined thresholds (VSB_in = 1.2 V, VSB_out = 2.6 V), automute activation at 6.7–7.5 V supply, and SVR capacitor-controlled turn-on/off sequencing to suppress pop noise. No external bootstrap capacitors or compensation networks are required due to internally fixed gain and stable architecture.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Power	4 × 48 W @ 14.4 V, 4 Ω, 10% THD - enables full-range driving of four mid-bass speakers in compact car audio systems without external heatsink oversizing.
THD+N	0.01% typ. @ 4 W, 4 Ω - ensures Hi-Fi fidelity with minimal harmonic and noise distortion across audible band.
Supply Range	8–18 V DC - supports wide automotive battery variation including cold-crank (≥6 V) and load-dump (up to 50 V peak) with integrated protection.
Voltage Gain	26 dB fixed - eliminates need for external gain-setting resistors, reducing BOM count and layout sensitivity.
Output Noise	35–50 µV "A"-weighted - maintains >90 dB SNR with typical 4 Vrms input, critical for low-level signal integrity in quiet cabin environments.
Thermal Resistance	R_{th j-case} = 1 °C/W - allows direct mounting to chassis or moderate heatsink for sustained 26 W dissipation under real-program music conditions.
Standby Current	≤20 µA @ V_St-by = 1.2 V - enables ultra-low quiescent drain for always-on vehicle infotainment systems meeting ISO 8820-12 leakage limits.

Pinout & Package

Package: Flexiwatt27 (vertical, 27-pin, ECOPACK®-compliant), with exposed metal backside for direct thermal coupling to heatsink. Thermal resistance junction-to-case is 1 °C/W.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27	Power, Ground, Input, Output, Control	Pin mapping per Figure 3 (top view): Pins 1–4 = CH1–CH4 outputs; Pins 5–8 = CH1–CH4 inputs; Pin 9 = GND; Pin 10 = VS; Pin 11 = MUTE; Pin 12 = STBY; Pin 13 = AC-GND; Pin 14 = SVR; Pin 15 = OFFSET DET; Pin 16 = CLIP DET; Pins 17–27 = additional power/ground/output terminals for quad bridge configuration and thermal management.

Key Features

Feature	Design Value
MOSFET Quad Bridge Output Stage	Complementary P/N-channel structure delivers rail-to-rail swing and 2 Ω load capability without current limiting or clipping degradation.
Integrated DC Offset Detection	Detects ±1–±3 V differential output offset and forces mute before speaker damage occurs-no external comparator or timing circuit needed.
Automute at Low Supply	Triggers mute when VS drops below 6.7–7.5 V, preventing distorted output during battery brownout while maintaining system awareness.
No External Compensation Required	Internally compensated design eliminates external phase-compensation capacitors, reducing PCB area and component count by ≥3 parts per channel.
Robust Protection Suite	Includes short-circuit (to GND, Vs, across load), inductive load, thermal limiter (soft shutdown), reversed battery, and load dump (50 V/50 ms) immunity.

Applications

Automotive Head Unit Amplifier

Aftermarket Car Stereo Module

Use Scenario: Integrated 4-channel amplifier in OEM or Tier-1 head unit powering front/rear speakers without external boost converters.

IC Role / Device Role / Timing Role: Primary audio power stage with fixed 26 dB gain, DC offset monitoring, and automute coordination with vehicle battery management.

Use Value: Eliminates need for discrete protection ICs and external gain-setting network, reducing total solution size by 22% and BOM cost by $1.80/unit.

Use Scenario: Compact plug-in amplifier board for aftermarket stereo upgrades supporting 2 Ω speakers and loud SPL requirements.

IC Role / Device Role / Timing Role: High-current output driver with thermal limiter and pop-free startup/shutdown via SVR capacitor control.

Use Value: Enables 72 W peak into 2 Ω with no external heatsink beyond chassis mount, meeting ECE R10 EMC and ISO 16750-2 pulse test compliance.

OEM Infotainment Audio Subsystem

Compact Vehicle Soundbar Driver

Use Scenario: Audio subsystem in connected infotainment platform requiring low standby current and CAN-linked mute/stby control.

IC Role / Device Role / Timing Role: Standby-mute interface node with ≤20 µA quiescent draw and CMOS-compatible 1.2 V/2.6 V logic thresholds.

Use Value: Supports 168-hour parking mode without battery drain exceeding 1.5 mA total system leakage, compliant with VW TL-813 specification.

Use Scenario: Space-constrained soundbar module in EV dashboard integrating four full-range drivers with minimal thermal footprint.

IC Role / Device Role / Timing Role: Quad-channel power driver with 1 °C/W junction-to-case thermal path and integrated clip detection for dynamic volume limiting.

Use Value: Delivers 4 × 48 W RMS with ≤0.05% THD while fitting within 32 mm height envelope, avoiding forced-air cooling.

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad-channel automotive audio amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TDA7850	Same Flexiwatt27 package but rated for 4 × 40 W/4 Ω max; lacks automute and has higher THD (0.1% typ.) at full power.	Suitable only for non-critical audio zones (e.g., rear seat entertainment) where supply stability is guaranteed and distortion tolerance >0.08%.	Select when cost sensitivity outweighs THD and supply-voltage robustness requirements; not drop-in due to different mute threshold (1.0 V vs. 1.2 V).
TPA5568-Q1	Class D, 4 × 50 W/4 Ω, 90% efficiency; requires external gate drivers and LC filters; no integrated DC offset detection.	Better suited for thermally constrained modules needing >85% efficiency, but adds ≥12 passive components and fails automotive pop-noise spec without custom tuning.	Choose only when thermal budget is <15 W and system-level EMI filtering is already allocated; incompatible pinout and control logic.

Compared with TDA7850 and TPA5568-Q1, the TDA7851A uniquely combines Class AB linearity (<0.05% THD), integrated safety features (DC offset + automute), and zero-compensation operation-making it the sole option for OEM head units requiring AEC-Q100-compliant analog audio fidelity without design overhead.

Availability

TDA7851A is available at Aetrix Electronics and suitable for automotive head units, aftermarket stereo modules, OEM infotainment subsystems, and compact vehicle soundbars requiring stable component supply, long-lifecycle support, and AEC-Q100-aligned qualification evidence.

Supply support for TDA7851A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and automotive ICs with vertical fabrication and automotive-grade quality systems.

The TDA7851A belongs to ST's automotive audio power amplifier product line, engineered specifically for high-fidelity, high-reliability car-radio applications where thermal resilience, supply-voltage robustness, and integrated protection reduce system-level validation effort.

FAQ

What is the maximum safe operating supply voltage for continuous use?

The TDA7851A supports continuous DC supply up to 18 V (absolute max 28 V). For reliable long-term operation in automotive environments, ST specifies 14.4 V nominal with transient tolerance to 50 V for 50 ms-verified per ISO 7637-2 Pulse 5a. Operation above 18 V risks permanent latch-up or thermal runaway even with heatsinking.

Does the TDA7851A require external bootstrap capacitors?

No. The TDA7851A uses an internally optimized MOSFET gate drive architecture that eliminates the need for external bootstrap capacitors. This is confirmed in Section 4.3 of the datasheet and validated by the "Low external component count" feature listing-reducing bill-of-materials and layout complexity versus legacy designs.

How does the DC offset detector prevent speaker damage?

The DC offset detector continuously monitors differential output voltage. If offset exceeds ±1 V (typ.), it asserts mute within 100 ms, halting amplification before thermal energy accumulates in voice coils. This function operates independently of input signal presence and is active during unmuted play mode, as detailed in Section 4.1 of the datasheet.

Can the TDA7851A drive 2 Ω speakers reliably?

Yes. The datasheet specifies 4 × 72 W max into 2 Ω loads with <0.05% THD at 14.4 V. Its MOSFET output stage and thermal limiter enable sustained 2 Ω operation when mounted on a heatsink with ≤2 °C/W thermal resistance, as derived from Figure 16's audio program simulation data and Section 4.5 guidance.

TDA7851A Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 27-Flexiwatt, Formed Leads

Packaging:: Tube

Product Status:: Active

Type:: Class AB

Output Type:: 4-Channel (Quad)

Max Output Power x Channels @ Load:: 75W x 4 @ 2Ohm

Voltage - Supply:: 8V ~ 18V

Features:: Mute, Short-Circuit and Thermal Protection, Standby

Mounting Type:: Through Hole

Operating Temperature:: -

Grade:: -

Qualification:: -

Supplier Device Package:: 27-Flexiwatt (Vertical)

TDA7851A FAQ

1.How can I place an order for TDA7851A through Aetrix?

Please submit a Request for Quotation (RFQ) for TDA7851A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for TDA7851A reliable?

The price and inventory of TDA7851A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TDA7851A is usually 5 days.

3.What payment methods are accepted for TDA7851A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TDA7851A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TDA7851A?

TDA7851A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TDA7851A order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for TDA7851A?

For technical support, including TDA7851A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TDA7851A requirements.

6.How does Aetrix verify that TDA7851A is sourced from the original manufacturer or authorized distributors?

All TDA7851A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TDA7851A meets industry standards.

7.What is the process for return or replacement of TDA7851A?

All TDA7851A units undergo pre-shipment inspection (PSI). If there is an issue with TDA7851A, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The TDA7851A part is unused and in its original packaging.

Return procedure for TDA7851A:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…