FDA903D - 1A, 35V Ultra-Low Noise LDO | Texas Instruments
N.º de pieza: FDA903D ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $9.5455 | $9,55 |
| 10 | $6.8939 | $68,94 |
| 100 | $6.0985 | $609,85 |
| 500 | $5.8333 | $2.916,65 |
| 1.000 | $5.5682 | $5.568,20 |
FDA903D Descripción general
An LDO (Low-Dropout) linear regulator is a type of voltage regulator that maintains a stable output voltage even when the input voltage is very close to the output voltage. It is a subclass of linear regulators, which in turn are a type of voltage regulator within the broader power management IC (PMIC) category. LDOs are essential in noise-sensitive applications where switching regulators would introduce unacceptable ripple and EMI.
Key features include 4.17 uVrms output noise (20 Hz to 100 kHz), 72 dB PSRR at 1 kHz, and a low dropout voltage of 200 mV at full 1A load. The device also offers 6.4 mA quiescent current, an active-high enable pin for power sequencing, and thermal shutdown protection. The VQFN-20 package provides a thermal resistance of 31.4 C/W, enabling compact designs without external heatsinking at moderate power levels.
The FDA903D utilizes a bipolar architecture with a precision bandgap reference, achieving noise performance comparable to discrete reference designs while maintaining regulator simplicity. The high PSRR minimizes ripple from upstream switching converters, making it suitable for noise-sensitive analog and RF signal chains where clean power rails are critical.
Typical applications include high-end audio DAC power supplies, PLL/VCO power rails in RF transceivers, precision ADC/DAC reference buffering, and test and measurement instrumentation. The wide input range also supports industrial 24V bus systems with adequate headroom.
When designing with this device, ensure adequate input-to-output voltage headroom to maintain regulation under all load conditions. The enable pin allows sequential power-up in multi-rail systems, which is essential for processors requiring specific rail sequencing.
Alternativas directas para FDA903D — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
TPS7A4701RGWR
✓ En stock
$3.2467 / unidad
Ver hoja de datos →TPS7A4700RGWR
✓ En stock
$3.6591 / unidad
Ver hoja de datos →TPS7A4701RGWR-Q1
📋 Alternativa de referencia (no en el catálogo)
LT3045EDC
📋 Alternativa de referencia (no en el catálogo)
ADM7150ARDZ
📋 Alternativa de referencia (no en el catálogo)
FDA903D Valores máximos y características eléctricas
| Tipo de salida | Adjustable |
| Rango de tensión de salida | 1.4 V to 34 V |
| Corriente de salida máxima | 1 A |
| Rango de tensión de entrada | 3 V to 35 V |
| Tensión de dropout | 200 mV at 1 A |
| Ruido de salida | 4.17 uVrms (20 Hz to 100 kHz) |
| PSRR | 72 dB at 1 kHz |
| Corriente en reposo | 6.4 mA |
| Resistencia térmica | 31.4 C/W |
| Temperatura de funcionamiento | -40C to +125C |
| Encapsulado | VQFN-20 (RGW) 5x5 mm |
| Tipo de montaje | Surface Mount |
| Nivel MSL | 2 (1 year) |
| Estado RoHS | Compliant |
| Patilla de habilitación | Yes (active-high) |
Configuración de pines de FDA903D
| Pin 1 | OUT — Regulated output voltage |
| Pin 5 | GND — Ground |
| Pin 6 | EN — Enable (active high) |
| Pin 7 | IN — Input supply |
| Pin 10 | NR/SS — Noise reduction/soft-start capacitor |
| Pin 20 | PAD — Exposed thermal pad (connect to GND) |
Aplicaciones típicas
FDA903D es adecuado para 6 aplicacións: 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.
Recomendado
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.
Recomendado
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.
Recomendado
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.
Recomendado
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.
Recomendado
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.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para FDA903D — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | 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 |
Diferenciadores clave
- Only VQFN-20 family member with enable pin (frente a TPS7A4700RGWR)
- Automotive grade option available (frente a TPS7A4701RGWR-Q1)
- Higher output current than cross-brand alternatives (frente a LT3045EDC)
Notas de diseño
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.
Información de cumplimiento
RoHS compliant per TI product page. Not AEC-Q100 qualified - choose TPS7A4701RGWR-Q1 for automotive.
