FDA803U - 1A, 35V Ultra-Low Noise LDO | Texas Instruments
MPN: FDA803U 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 FDA803U 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:
TPS7A4701RGWR
β Drop-Inβ 99,999 In Stock
$3.1 / Unit
View Datasheet βTPS7A4700RGWR
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TPS7A4701RGWR-Q1
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TPS7A4701RGWT
β Drop-Inπ Reference alternative (not in catalog)
LT3045EDC
β Drop-Inπ Reference alternative (not in catalog)
ADM7150ARDZ
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FDA803U 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) |
FDA803U 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 10 | NR/SS β Noise reduction/soft-start capacitor |
| Pin 20 | GND β Ground (exposed pad) |
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: High-End Audio DAC Power Supply, RF Transceiver Power Rail, Precision ADC Reference Buffer, Industrial 24V Bus Power, Battery-Powered Portable Device, Test and Measurement Instrumentation.
High-End Audio DAC Power Supply
The FDA803U provides a clean 5V rail for audio DACs with 4.17uVrms noise and 72dB PSRR, ensuring no audible noise or interference. In a typical audio DAC application, the FDA803U 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 Rail
The FDA803U's ultra-low noise and high PSRR make it ideal for powering PLLs and VCOs in RF transceivers. It minimizes phase noise and spurious signals by providing a clean supply. In a typical RF application, the FDA803U is used to power the VCO supply pin, with a 0.1uF capacitor close to the pin for high-frequency bypass. The wide input range (3V to 35V) allows direct connection to battery or intermediate rails.
Recommended
Precision ADC Reference Buffer
The FDA803U can buffer the reference voltage for precision ADCs, providing a low-noise, stable supply. Its 4.17uVrms noise ensures minimal impact on ADC SNR. In a typical application, the FDA803U is used to generate a clean 5V reference from a noisy 12V rail, with a 10uF output capacitor to maintain stability. The enable pin allows power sequencing to ensure the reference is stable before ADC conversion starts.
Recommended
Industrial 24V Bus Power
The FDA803U's 35V input range makes it suitable for industrial applications powered by 24V buses. It can provide a clean 5V or 3.3V rail for microcontrollers and sensors. In a typical industrial sensor node, the FDA803U steps down 24V to 5V with low noise, ensuring reliable operation of sensitive analog sensors. The thermal shutdown protection prevents damage in harsh environments.
Recommended
Battery-Powered Portable Device
The FDA803U's low quiescent current (6.4mA) and wide input range make it suitable for battery-powered devices. It can regulate battery voltage (e.g., 3.7V Li-ion) down to a stable 3.3V rail for digital circuits. The low dropout voltage (200mV) maximizes battery utilization. In a typical portable device, the FDA803U is used to power the RF section, ensuring clean power for wireless communication.
Recommended
Test and Measurement Instrumentation
The FDA803U provides clean, low-noise power rails for precision test equipment such as oscilloscopes and spectrum analyzers. Its high PSRR rejects noise from switching supplies, ensuring accurate measurements. In a typical instrument, the FDA803U is used to power the analog front-end, with multiple devices paralleled for higher current. The enable pin allows controlled power-up to avoid glitches.
Recommended
Recommended Products Summary
Engineering reference data for FDA803U β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TPS7A4701RGWR | TPS7A4700RGWR | TPS7A4701RGWR-Q1 | LT3045EDC | ADM7150ARDZ |
|---|---|---|---|---|---|---|
| Package | VQFN-20 (RGW) | VQFN-20 (RGW) - same | VQFN-20 (RGW) - same | VQFN-20 (RGW) - same | VQFN-20 (RGW) - same | VQFN-20 (RGW) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices | Analog Devices |
| Output Current | 1 A | 1 A | 1 A | 1 A | 0.5 A | 0.6 A |
| Output Voltage Range | 1.4V to 34V | 1.4V to 34V | 1.4V to 34V | 1.4V to 34V | 0V to 15V | 1.2V to 5V |
| Enable Pin | Yes (active-high) | Yes (active-high) | No | Yes (active-high) | Yes (active-high) | Yes (active-high) |
| Output Noise | 4.17 uVrms | 4.17 uVrms | 4.17 uVrms | 4.17 uVrms | 0.8 uVrms | 1.6 uVrms |
| PSRR at 1 kHz | 72 dB | 72 dB | 72 dB | 72 dB | 79 dB | 88 dB |
| Automotive Grade | No | No | No | Yes (AEC-Q100) | No | No |
Key Differentiators
- Only VQFN-20 family member with enable pin (vs TPS7A4700RGWR)
- Automotive grade option available (vs TPS7A4701RGWR-Q1)
- Higher output current than cross-brand alternatives (vs LT3045EDC)
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.
