FDA903D - 1A, 35V Ultra-Low Noise LDO | Texas Instruments
MPN: FDA903D 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 FDA903D 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
β Drop-Inπ Reference alternative (not in catalog)
TPS7A4701RGWR-Q1
β Drop-Inπ Reference alternative (not in catalog)
LT3045EDC
β Drop-Inπ Reference alternative (not in catalog)
ADM7150ARDZ
β Drop-Inπ Reference alternative (not in catalog)
FDA903D 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) |
FDA903D 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 | 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
FDA903D is suitable for 6 applications: High-End Audio DAC Power Supply, RF Transceiver Power Rail, Precision ADC/DAC Reference, Industrial Sensor Interface, Battery-Powered Portable Device, Test and Measurement Instrumentation.
High-End Audio DAC Power Supply
Provides clean 5V rail for audio DACs with 4.17uVrms noise. The FDA903D'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 FDA903D 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 FDA903D provides a clean supply for PLL/VCO circuits, minimizing phase noise. Its 72 dB PSRR at 1 kHz and 4.17 uVrms noise are critical for maintaining signal integrity in RF transceivers. In a typical RF application, the FDA903D is used to power the VCO and PLL, with careful layout to minimize parasitic inductance. The low dropout voltage ensures stable operation even when the input rail is close to the output voltage, which is common in battery-powered RF devices.
Recommended
Precision ADC/DAC Reference
The FDA903D buffers reference voltages for high-resolution ADCs and DACs, ensuring accuracy. Its low noise and high PSRR prevent power supply variations from affecting conversion results. In a precision data acquisition system, the FDA903D is used to generate a clean 5V reference from a noisy digital rail. The enable pin allows the reference to be powered down during standby, saving power. The thermal shutdown protection ensures safe operation in harsh environments.
Recommended
Industrial Sensor Interface
The FDA903D powers sensor signal conditioning circuits, providing a stable supply for op-amps and ADCs. Its wide input range (3V to 35V) makes it suitable for industrial 24V bus systems. In a typical industrial sensor interface, the FDA903D regulates the 24V bus down to 5V for the analog front end, with a 10uF capacitor on the output to handle transient loads. The low quiescent current (6.4 mA) is beneficial for power-sensitive loop-powered transmitters.
Recommended
Battery-Powered Portable Device
The FDA903D provides a low-noise supply for portable audio and instrumentation, extending battery life with its low quiescent current. In a portable device, the FDA903D regulates the battery voltage (e.g., 3.7V Li-ion) down to 3.3V for the analog section, with a dropout of only 200 mV at 1A, maximizing usable battery range. The enable pin allows the regulator to be shut down when the device is in standby, reducing power consumption to near zero.
Recommended
Test and Measurement Instrumentation
The FDA903D ensures clean power for precision measurement circuits, reducing measurement errors. Its ultra-low noise and high PSRR are essential for bench-top instruments like multimeters and oscilloscopes. In a typical instrument, the FDA903D is used to power the analog front end, with multiple LDOs for different voltage rails. The thermal shutdown protection prevents damage during prolonged operation at high ambient temperatures.
Recommended
Recommended Products Summary
Engineering reference data for FDA903D 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) |
| Automotive Grade | No | No | No | Yes (AEC-Q100) | No | No |
| 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 | 94 dB |
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.
