FDA803Q - 1A, 35V Ultra-Low Noise LDO | Texas Instruments
MPN: FDA803Q β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.85 | $4.85 |
| 10 | $4.36 | $43.60 |
| 100 | $3.88 | $388.00 |
| 500 | $3.49 | $1,745.00 |
| 1,000 | $3.1 | $3,100.00 |
Drop-in alternatives for FDA803Q β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
TPS7A4700RGWR
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TPS7A4701RGWR-Q1
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FDA803Q Maximum Ratings & Electrical Characteristics
| Output Type | Adjustable |
| Output Voltage Range | 1.4 V to 34 V |
| Maximum Output Current | 1 A |
| Input Voltage Range | 3 V to 35 V |
| Dropout Voltage | 200 mV at 1 A |
| Output Noise | 4.17 uVrms (20 Hz to 100 kHz) |
| PSRR | 72 dB at 1 kHz |
| Quiescent Current | 6.4 mA |
| Thermal Resistance | 31.4 C/W |
| Operating Temperature | -40C to +125C |
| Package | VQFN-20 (RGW) 5x5 mm |
| Mounting Type | Surface Mount |
| MSL Level | 2 (1 year) |
| RoHS Status | Compliant |
| Enable Pin | Yes (active-high) |
FDA803Q Pin Configuration
| Pin 1 | OUT β Regulated output voltage |
| Pin 5 | GND β Ground |
| Pin 6 | EN β Enable (active high) |
| Pin 7 | IN β Input supply |
| Pin 9 | NR/SS β Noise reduction/soft-start capacitor |
| Pin 10 | FB β Feedback for output voltage setting |
| Pin 13 | GND β Ground |
| Pin 17 | OUT β Regulated output voltage |
| Pin 20 | IN β Input supply |
| Pin 21 | PAD β Exposed thermal pad (connect to GND) |
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
FDA803Q is suitable for 6 applications: High-End Audio DAC Power Supply, RF Transceiver Power Supply, Precision ADC Reference Buffer, Industrial 24V Bus Power, Test and Measurement Instrumentation, Portable Medical Devices.
High-End Audio DAC Power Supply
Provides clean 5V rail for audio DACs with 4.17uVrms noise. The FDA803Q's ultra-low noise and high PSRR ensure that the power supply does not introduce audible artifacts into the audio signal. In a typical audio DAC application, the FDA803Q is placed between the system 5V rail and the DAC's AVDD pin, with a 10uF ceramic capacitor on input and output. Compared to switching regulators, the LDO eliminates switching noise but dissipates more power; for a 12V-to-5V conversion at 500mA, power dissipation is 3.5W, requiring adequate thermal management.
Recommended
RF Transceiver Power Supply
Powers PLL/VCO circuits with 72dB PSRR at 1kHz, minimizing phase noise. The FDA803Q's high PSRR suppresses ripple from upstream switching regulators, which is critical for RF signal integrity. In an RF transceiver, the FDA803Q is used to power the VCO and PLL, with a 0.1uF capacitor close to the VCC pin to filter high-frequency noise. The low noise floor of 4.17uVrms ensures that the power supply does not contribute to phase noise, improving overall system performance.
Recommended
Precision ADC Reference Buffer
Buffers reference voltage for 24-bit ADCs with 4.17uVrms noise. The FDA803Q's low noise and high accuracy make it ideal for driving the reference input of precision ADCs. In a data acquisition system, the FDA803Q is used to generate a clean 5V reference from a noisy 12V rail, with a 10uF capacitor on the output to stabilize the reference. The low dropout voltage of 200mV ensures that the reference remains regulated even with input voltage variations.
Recommended
Industrial 24V Bus Power
Regulates 24V industrial bus to 5V for sensors and microcontrollers. The FDA803Q's wide input range of up to 35V makes it suitable for industrial applications where the supply voltage can vary. In a factory automation system, the FDA803Q is used to power a microcontroller and sensors from a 24V bus, with a 10uF input capacitor to handle transients. The thermal shutdown protection ensures safe operation in harsh environments.
Recommended
Test and Measurement Instrumentation
Provides clean power for oscilloscopes and signal generators. The FDA803Q's low noise and high PSRR are essential for maintaining measurement accuracy. In a benchtop instrument, the FDA803Q is used to power analog front-end circuits, with a 10uF output capacitor to reduce noise. The enable pin allows for power sequencing in multi-rail systems, ensuring that sensitive analog circuits power up after digital circuits.
Recommended
Portable Medical Devices
Powers low-noise analog front-ends in portable monitors. The FDA803Q's low quiescent current of 6.4mA extends battery life in portable devices. In a portable ECG monitor, the FDA803Q is used to power the analog front-end, with a 10uF output capacitor to filter noise. The small VQFN-20 package saves board space, and the wide input range accommodates battery voltage variations.
Recommended
Recommended Products Summary
Engineering reference data for FDA803Q β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TPS7A4700RGWR | TPS7A4701RGWR-Q1 | TPS7A3301RGWR |
|---|---|---|---|---|
| Package | VQFN-20 (RGW) | VQFN-20 (RGW) - same | VQFN-20 (RGW) - same | VQFN-20 (RGW) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Output Current | 1 A | 1 A | 1 A | 1 A (negative) |
| Output Voltage Range | 1.4V to 34V | 1.4V to 34V | 1.4V to 34V | -36V to -1.4V |
| Enable Pin | Yes (active-high) | No | Yes (active-high) | Yes (active-high) |
| Automotive Grade | No | No | Yes (AEC-Q100) | No |
| Output Noise | 4.17 uVrms | 4.17 uVrms | 4.17 uVrms | 3.8 uVrms |
| PSRR at 1kHz | 72 dB | 72 dB | 72 dB | 75 dB |
Key Differentiators
- Only VQFN-20 family member with enable pin (vs TPS7A4700RGWR)
- Automotive grade option available (vs TPS7A4701RGWR-Q1)
- Positive voltage polarity (vs TPS7A3301RGWR)
Design Notes
At VIN=12V, VOUT=5V, and 1A load, power dissipation is 7W. The VQFN-20 package has theta_JA of 31.4 C/W, resulting in a 220C junction temperature rise. A heatsink or at least 1 square inch of copper pour is required for reliable operation above 2W dissipation.
Place input and output capacitors as close to the IC pins as possible. Use a 10uF ceramic capacitor on the input and a 10uF ceramic capacitor on the output. Add a 0.1uF ceramic capacitor in parallel for high-frequency noise bypass.
Do not exceed the maximum input voltage of 35V. Ensure the external resistor divider uses 1% or better tolerance resistors to maintain output voltage accuracy. The NR/SS capacitor controls startup time and noise bandwidth - do not omit it.
Compliance Information
RoHS compliant per TI product page. Not AEC-Q100 qualified - choose TPS7A4701RGWR-Q1 for automotive.
