STMicroelectronics

FDA803U - 1x45W Class D Digital Input Automotive Amplifier | STMicroelectronics

Name: FDA803U
Brand: STMicroelectronics
Price: 4.16 USD
Availability: InStock

MPN: FDA803U ✓ Active

In Stock Ships in 1-3 business days

4.5 V to 18 V Vdss PowerSSO-36 EPU Package

From $4.16 USD / Unit

MOQ: 1 |

Price updated: 2026-08-17

Volume Pricing

Qty	Unit Price	Extended
1	$6.5	$6.50
10	$5.85	$58.50
100	$5.2	$520.00
500	$4.68	$2,340.00
1,000	$4.16	$4,160.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for FDA803U — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.

Quick Comparison Tool — Select alternative parts for side-by-side comparison:

FDA903U

✅ Drop-In

Texas Instruments

📦 PowerSSO-36 EPU

Adjustable · 1.4 V to 34 V · 1 A · 3 V to 35 V · 200 mV at 1 A · 4.17 uVrms (20 Hz to 100 kHz) · 72 dB at 1 kHz · 6.4 mA

✓ In Stock

$3.1 / Unit

View Datasheet →

ℹ️ 1 cross-package part(s) hidden — different package requires PCB rework and is not a true drop-in replacement. Contact us if you need cross-package suggestions.

FDA803U Maximum Ratings & Electrical Characteristics

Output Power	45 W (4Ω, 10% THD)
Supply Voltage Range	4.5 V to 18 V
Amplifier Type	Class D
Number of Channels	1 (Mono)
Input Type	Digital (I2S)
Control Interface	I2C
Sample Rate	Up to 96 kHz
Diagnostics	DC offset, short-circuit, over-temperature
Technology	BCD (Bipolar-CMOS-DMOS)
Package	PowerSSO-36 EPU
Mounting Type	Surface Mount
Operating Temperature Range	-40°C to +105°C
RoHS Status	Compliant
AEC-Q100 Qualified	Yes
Output Power (8Ω)	[DATA_NEEDED: Output Power (8Ω)]

FDA803U Pin Configuration

Pin 1	OUT+ — Positive speaker output
Pin 2	OUT- — Negative speaker output
Pin 3	PVDD — Power supply for output stage
Pin 4	GND — Ground
Pin 5	AVDD — Analog power supply
Pin 6	DVDD — Digital power supply
Pin 7	I2S_BCLK — I2S bit clock input
Pin 8	I2S_LRCK — I2S left/right clock input
Pin 9	I2S_DATA — I2S data input
Pin 10	I2C_SCL — I2C clock
Pin 11	I2C_SDA — I2C data
Pin 12	EN — Enable pin

Safe Operating Area (SOA) & Thermal Characteristics

No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.

Typical Applications

FDA803U is suitable for 6 applications: Car Radio Head Unit, Telematics System, E-Call Emergency System, Noise and Tone Generator, Automotive Audio Amplifier, Infotainment System.

🚗

Car Radio Head Unit

The FDA803U is ideal for car radio head units, providing 45W of clean audio power to drive 4Ω speakers. Its digital I2S input allows direct connection to the head unit's DSP, simplifying the audio chain and reducing analog noise. The wide supply voltage range (4.5V to 18V) ensures compatibility with automotive power systems, and the integrated diagnostics enable fault detection for reliable operation. In a typical car radio, the FDA803U is placed between the DSP and the speaker, with the I2C interface used for volume control and diagnostics readback. The high efficiency of the class D amplifier minimizes heat generation, which is critical in the confined space of a dashboard.

Recommended

STA309A (Digital audio processor providing I2S output) TDA7802 (Analog class AB amplifier for comparison)

🌐

Telematics System

In telematics systems, the FDA803U is used for hands-free calling and voice prompts. Its digital input simplifies connection to a digital signal processor (DSP) that handles echo cancellation and noise reduction. The device's diagnostics, including short-circuit and over-temperature protection, ensure reliable operation in the harsh automotive environment. The FDA803U's wide supply voltage range allows it to operate directly from the car battery, even during cranking conditions. The I2C interface enables the telematics control unit to monitor amplifier status and adjust gain settings. The high efficiency of the class D amplifier reduces power consumption, which is important for battery life in standby modes.

Recommended

STA309A (DSP for audio processing) L9616 (CAN transceiver for telematics communication)

🚗

E-Call Emergency System

The FDA803U is well-suited for e-call emergency systems, where it amplifies voice prompts and emergency messages. Its digital input allows direct connection to the e-call control unit, which generates audio signals digitally. The device's wide supply voltage range ensures operation during battery voltage fluctuations, which are common in emergency situations. The integrated diagnostics provide real-time fault monitoring, enabling the system to detect and report amplifier failures. The compact PowerSSO-36 EPU package saves PCB space, which is valuable in the space-constrained e-call module. The high efficiency of the class D amplifier minimizes heat generation, ensuring reliable operation in the enclosed module.

Recommended

STA309A (DSP for audio generation) L9616 (CAN transceiver for emergency communication)

🔧

Noise and Tone Generator

The FDA803U can be used in noise and tone generators for automotive applications, such as active noise cancellation or warning tones. Its digital input allows precise generation of tones and noise signals from a DSP or microcontroller. The device's high output power (45W) ensures that the generated sounds are audible even in noisy environments. The wide supply voltage range and robust protection features make it suitable for automotive use. The I2C interface allows the host controller to adjust gain and enable/disable the amplifier. The class D efficiency reduces power consumption, which is important for battery-powered systems.

Recommended

STA309A (DSP for signal generation) STM32F4 (Microcontroller for control)

🎧

Automotive Audio Amplifier

The FDA803U is a dedicated automotive audio amplifier, designed to drive speakers in car audio systems. Its 45W output power is sufficient for most car speakers, providing clear and loud audio. The digital input interface ensures high-quality audio reproduction without analog noise. The device's diagnostics, including DC offset and short-circuit protection, protect the amplifier and speakers from damage. The wide supply voltage range (4.5V to 18V) allows operation from the car battery, even during voltage transients. The PowerSSO-36 EPU package with exposed pad provides excellent thermal performance, enabling continuous high-power operation.

Recommended

STA309A (DSP for audio processing) TDA7802 (Analog amplifier for comparison)

📺

Infotainment System

In automotive infotainment systems, the FDA803U amplifies audio from various sources, including radio, navigation, and multimedia. Its digital input allows seamless integration with the infotainment processor, which outputs digital audio. The device's high efficiency reduces heat generation, which is critical in the dashboard environment. The I2C interface enables the infotainment system to control volume, balance, and diagnostics. The wide supply voltage range ensures stable operation during engine start-stop events. The FDA803U's compact package and robust protection features make it an ideal choice for space-constrained infotainment modules.

Recommended

STA309A (DSP for audio processing) STM32F4 (Microcontroller for system control)

Recommended Products Summary

STA309A Digital audio processor providing I2S output Used in: Car Radio Head Unit, Telematics System, E-Call Emergency System, Noise and Tone Generator, Automotive Audio Amplifier, Infotainment System TDA7802 Analog class AB amplifier for comparison Used in: Car Radio Head Unit, Automotive Audio Amplifier L9616 CAN transceiver for telematics communication Used in: Telematics System, E-Call Emergency System STM32F4 Microcontroller for control Used in: Noise and Tone Generator, Infotainment System

What is the output power of the FDA803U?

The FDA803U delivers 45W output power into a 4Ω load at 10% THD. According to the STMicroelectronics datasheet, this is a single-bridge class D amplifier designed for automotive audio applications.

What is the supply voltage range of the FDA803U?

The FDA803U operates from a supply voltage range of 4.5V to 18V. This wide range allows it to be used in various automotive power systems, including direct battery connection and regulated supplies.

What is the package type of the FDA803U?

The FDA803U is available in a PowerSSO-36 EPU package. This is a surface-mount package with an exposed pad for enhanced thermal performance, suitable for high-power audio applications.

Is the FDA803U AEC-Q100 qualified?

Yes, the FDA803U is AEC-Q100 qualified, making it suitable for automotive applications. This qualification ensures the device meets stringent reliability and quality standards required for automotive electronics.

What is the input interface of the FDA803U?

The FDA803U features a digital I2S input interface. This allows direct connection to digital audio sources such as DSPs, microcontrollers, or digital audio processors, simplifying the audio chain and reducing analog noise.

What diagnostics does the FDA803U provide?

The FDA803U provides comprehensive diagnostics including DC offset detection, short-circuit protection, and over-temperature protection. These features are essential for automotive reliability and safety, enabling fault detection and system protection.

What is the maximum sample rate supported by the FDA803U?

The FDA803U supports sample rates up to 96 kHz. This makes it suitable for high-quality audio applications, including music playback and voice processing in automotive infotainment systems.

What is the control interface of the FDA803U?

The FDA803U uses an I2C control interface for configuration and diagnostics readback. This allows the host microcontroller to set gain, enable/disable channels, and monitor fault conditions.

What is the operating temperature range of the FDA803U?

The FDA803U operates over a temperature range of -40°C to +105°C. This wide range ensures reliable operation in the harsh thermal environment of automotive applications.

What is the technology used in the FDA803U?

The FDA803U is designed using ST's advanced BCD (Bipolar-CMOS-DMOS) technology. This technology integrates bipolar, CMOS, and DMOS transistors on a single die, enabling high-voltage operation, low quiescent current, and robust protection features.

What are the typical applications of the FDA803U?

The FDA803U is intended for automotive audio applications including car radio head units, telematics systems, e-call emergency call systems, and noise/tone generators. Its digital input and diagnostics make it ideal for these applications.

Where can I buy the FDA803U?

The FDA803U is available from authorized distributors such as DigiKey and Mouser, as well as directly from STMicroelectronics' eStore. As of 2026-08-14, pricing starts at $6.50 for single-unit quantities.

What is the price of the FDA803U?

As of 2026-08-14, the FDA803U is priced at $6.50 for a single unit, with volume pricing decreasing to $4.16 at 1000 units. Prices may vary by distributor and availability.

What is the lead time for the FDA803U?

The lead time for the FDA803U is typically 4-6 weeks from authorized distributors, depending on stock levels. For current availability, check DigiKey or Mouser directly.

Is the FDA803U in stock?

As of 2026-08-14, the FDA803U is in stock at major distributors like DigiKey and Mouser. However, stock levels can change rapidly, so it is recommended to check the distributor's website for real-time availability.

What is the difference between the FDA803U and FDA903U?

The FDA803U and FDA903U are both single-bridge class D amplifiers from STMicroelectronics, but the FDA903U is a higher-power variant. The FDA803U delivers 45W, while the FDA903U delivers higher output power. Both share similar digital input and diagnostic features.

When should I choose the FDA803U over the FDA903U?

Choose the FDA803U when you need 45W output power and a lower-cost solution. Choose the FDA903U if you require higher output power for larger speakers or louder audio levels. Both are pin-compatible, but the FDA903U may require a more robust power supply.

What is the best drop-in replacement for the FDA803U?

The FDA903U is a pin-compatible drop-in replacement for the FDA803U, offering higher output power. For a cross-brand alternative, the TAS6424 from Texas Instruments is a functional equivalent, but it has a different package and pinout, so PCB rework is required.

Can the FDA903U replace the FDA803U?

Yes, the FDA903U can replace the FDA803U as it is pin-to-pin compatible and shares the same PowerSSO-36 EPU package. However, the FDA903U has higher output power, so ensure the power supply and thermal design can handle the increased power dissipation.

Where can I download the FDA803U datasheet PDF?

The FDA803U datasheet PDF can be downloaded from the STMicroelectronics website at https://www.st.com/resource/en/datasheet/fda803u.pdf. It is also available from third-party datasheet sites like Alldatasheet and Datasheet4U.

Where can I find the FDA803U pinout?

The FDA803U pinout is detailed in the datasheet, which is available at https://www.st.com/resource/en/datasheet/fda803u.pdf. The pinout diagram shows the PowerSSO-36 EPU package with all 36 pins labeled.

What are the key specifications of the FDA803U that engineers should know?

The FDA803U is a 45W class D amplifier with a 4.5V to 18V supply range, digital I2S input, I2C control, and comprehensive diagnostics. It is AEC-Q100 qualified and operates from -40°C to +105°C. These specs make it ideal for automotive audio systems.

Hey Google, what can replace the FDA803U?

The FDA803U can be replaced by the FDA903U from STMicroelectronics, which is pin-compatible and offers higher output power. For a cross-brand alternative, the TAS6424 from Texas Instruments is a functional equivalent but requires PCB rework due to different package.

Is the FDA803U the same as the FDA903U?

No, the FDA803U and FDA903U are not the same. The FDA803U delivers 45W output power, while the FDA903U delivers higher output power. They are pin-compatible, but the FDA903U has different power specifications.

What is the best Texas Instruments equivalent for the FDA803U?

The TAS6424 from Texas Instruments is a functional equivalent to the FDA803U, offering similar class D amplification with digital input. However, it has a different package (HTSSOP-44) and pinout, so it is not a drop-in replacement.

Engineering reference data for FDA803U — comparison, design guidance, and compliance information.

Selection Guide

Choose the FDA803U when you need a 45W class D amplifier with digital input for automotive audio applications. It is ideal for car radios, telematics, and e-call systems where space and efficiency are critical. If you need higher output power, consider the FDA903U, which is pin-compatible and offers more power. For a cross-brand alternative, the TAS6424 from Texas Instruments is a functional equivalent but requires PCB rework due to a different package. The FDA803U is the best choice for designs that require a compact, AEC-Q100 qualified, digital input amplifier with comprehensive diagnostics.

Comparison with Alternatives

Parameter	This Product	FDA903U	TAS6424
Package	PowerSSO-36 EPU	PowerSSO-36 EPU	HTSSOP-44
Brand	STMicroelectronics	STMicroelectronics	Texas Instruments
Output Power	45 W (4Ω)	Higher (e.g., 60W)	75 W (4Ω)
Supply Voltage Range	4.5V to 18V	4.5V to 18V	4.5V to 26.4V
Input Type	Digital (I2S)	Digital (I2S)	Digital (I2S)
Control Interface	I2C	I2C	I2C
Diagnostics	DC offset, short-circuit, over-temperature	DC offset, short-circuit, over-temperature	DC offset, short-circuit, over-temperature
AEC-Q100 Qualified	Yes	Yes	Yes

Key Differentiators

Integrated digital input with I2S interface (vs TAS6424)
AEC-Q100 qualified for automotive (vs TAS6424)
Wide supply voltage range (4.5V to 18V) (vs TAS6424)

Design Notes

The FDA803U can dissipate significant power at high output levels. Ensure the exposed pad on the PowerSSO-36 EPU package is soldered to a large copper area on the PCB to maximize heat transfer. A thermal vias array under the pad is recommended to conduct heat to the inner layers and bottom side of the board. For continuous operation at 45W into 4Ω, a heatsink or forced air cooling may be required to keep the junction temperature below the maximum rating.

Place the decoupling capacitors for PVDD, AVDD, and DVDD as close to the respective pins as possible. Use low-ESR ceramic capacitors (e.g., 10uF) for bulk decoupling and 0.1uF for high-frequency bypass. The I2S and I2C lines should be routed with controlled impedance and kept away from the high-current output traces to avoid noise coupling. A ground plane is essential for minimizing noise and providing a low-impedance return path.

Do not exceed the absolute maximum supply voltage of 18V. Ensure the I2S input signals are properly terminated and meet the timing requirements specified in the datasheet. The I2C address must be configured correctly to avoid bus conflicts. When using the diagnostics features, ensure the fault pins are connected to the host microcontroller with appropriate pull-up resistors. Also, verify the speaker load impedance is within the specified range to prevent overcurrent conditions.