LD49100PU10RY - 1A Ultra-Low Noise LDO | STMicroelectronics
MPN: LD49100PU10RY ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.3668 | $2.37 |
LD49100PU10RY Overview
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. Unlike standard linear regulators, LDOs can operate with a small dropout voltage, typically less than 300mV, which improves efficiency and allows for lower input voltages. LDOs are essential in power management ICs, providing clean, low-noise power rails for sensitive components such as ADCs, DACs, PLLs, and RF transceivers. They are often used in battery-powered devices, where minimizing power loss is critical, and in audio and instrumentation systems where noise performance is paramount.
Key features of the LD49100PU10RY include an ultra-low output noise of 6.5 µVrms (10 Hz to 100 kHz), a high power supply rejection ratio (PSRR) of 70 dB at 1 kHz, and a low dropout voltage of 200 mV at 1A load. The device also features a low quiescent current of 30 µA, making it suitable for battery-powered applications. It includes an enable pin for power sequencing, thermal shutdown protection, and current limiting. The DFN package offers excellent thermal performance with a thermal resistance of 60°C/W, enabling reliable operation in compact designs.
The LD49100PU10RY utilizes a CMOS architecture with a precision bandgap reference, achieving excellent line and load regulation. The ultra-low noise and high PSRR minimize ripple from upstream switching converters, ensuring clean power rails for noise-sensitive circuits. The device is stable with ceramic output capacitors as low as 1 µF, simplifying the external component count and reducing board space.
Typical applications include powering audio codecs, RF transceivers, precision ADC/DAC reference buffers, and low-power microcontrollers. The wide input range and low dropout make it suitable for battery-powered devices, portable instrumentation, and industrial sensors. The enable pin allows for controlled power-up sequencing in multi-rail systems.
When designing with the LD49100PU10RY, ensure adequate input-to-output voltage headroom to maintain regulation under all load conditions. Place input and output capacitors close to the pins to minimize parasitic inductance. The enable pin can be used to implement power sequencing, which is critical for systems with multiple supply rails.
Drop-in alternatives for LD49100PU10RY — 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:
LD49100PU12RY
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LD49100PU15RY
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LD49100PU18RY
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TPS7A2010
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AP2127K-1.0
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LD49100PU10RY Maximum Ratings & Electrical Characteristics
| Output Type | Fixed |
| Output Voltage | 1.0 V |
| Maximum Output Current | 1 A |
| Input Voltage Range | 1.4 V to 5.5 V |
| Dropout Voltage | 200 mV at 1 A |
| Output Noise | 6.5 µVrms (10 Hz to 100 kHz) |
| PSRR | 70 dB at 1 kHz |
| Quiescent Current | 30 µA |
| Thermal Resistance | 60 °C/W |
| Operating Temperature | -40°C to +125°C |
| Package | DFN-6 (2x2 mm) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited) |
| RoHS Status | Compliant |
| Enable Pin | Yes (active-high) |
LD49100PU10RY Pin Configuration
| Pin 1 | IN — Input supply voltage |
| Pin 2 | GND — Ground |
| Pin 3 | EN — Enable (active high) |
| Pin 4 | NC — No connect |
| Pin 5 | OUT — Regulated output voltage |
| Pin 6 | NC — No connect |
Typical Applications
LD49100PU10RY is suitable for 6 applications: Audio DAC Power Supply, RF Transceiver Power Supply, Precision ADC Reference Buffer, Battery-Powered IoT Devices, FPGA Core Supply, Portable Medical Devices.
Audio DAC Power Supply
The LD49100PU10RY provides a clean 1.0V rail for audio DACs, with ultra-low noise (6.5 µVrms) and high PSRR (70 dB at 1 kHz) to prevent power supply noise from degrading audio quality. In a typical audio DAC application, the LDO is placed between the system 3.3V rail and the DAC's analog supply pin, with a 1 µF ceramic capacitor on the input and output. The low dropout voltage (200 mV) ensures efficient operation even with a 3.3V input. Compared to switching regulators, the LDO eliminates switching noise, which is critical for maintaining high signal-to-noise ratio in audio systems.
Recommended
RF Transceiver Power Supply
The LD49100PU10RY is ideal for powering RF transceivers, where clean power is essential to avoid spurious emissions and phase noise. Its 6.5 µVrms noise and 70 dB PSRR at 1 kHz help maintain signal integrity. In an RF application, the LDO is placed between the battery or DC-DC output and the RF IC's supply pin, with a 1 µF ceramic capacitor on the output. The low quiescent current (30 µA) is beneficial for battery-powered IoT devices. The enable pin allows for power sequencing to ensure the RF section powers up after the digital core, preventing latch-up.
Recommended
Precision ADC Reference Buffer
The LD49100PU10RY can be used to buffer the reference voltage for precision ADCs, providing a low-noise, stable supply. Its 6.5 µVrms noise ensures minimal impact on ADC SNR. In this application, the LDO is placed between the reference voltage source and the ADC's VREF pin, with a 1 µF ceramic capacitor on the output. The high PSRR (70 dB) rejects supply noise, improving measurement accuracy. The low dropout voltage allows operation from a 1.2V reference, making it suitable for low-voltage systems.
Recommended
Battery-Powered IoT Devices
The LD49100PU10RY is well-suited for battery-powered IoT devices due to its low quiescent current (30 µA) and wide input voltage range (1.4V to 5.5V). It can regulate a 1.0V rail for low-power microcontrollers and sensors, extending battery life. In a typical IoT node, the LDO is placed between the battery (e.g., 3.7V Li-ion) and the MCU's VDD pin, with a 1 µF ceramic capacitor on the output. The enable pin allows the MCU to power down the LDO in sleep mode, further reducing power consumption.
Recommended
FPGA Core Supply
The LD49100PU10RY provides a stable 1.0V core supply for FPGAs, which require tight voltage regulation and low noise to ensure reliable operation. Its 1A output current can power small to medium FPGAs. In an FPGA application, the LDO is placed between the 3.3V rail and the FPGA's VCCINT pin, with a 10 µF ceramic capacitor on the output to handle transient currents. The low dropout voltage (200 mV) minimizes power dissipation, and the enable pin allows for controlled power-up sequencing.
Recommended
Portable Medical Devices
The LD49100PU10RY is suitable for portable medical devices that require low noise and low power consumption. Its ultra-low noise (6.5 µVrms) ensures accurate readings from sensors, and its low quiescent current (30 µA) extends battery life. In a medical device, the LDO is placed between the battery and the analog front-end, with a 1 µF ceramic capacitor on the output. The wide operating temperature range (-40°C to +125°C) ensures reliable operation in various environments.
Recommended
Recommended Products Summary
Engineering reference data for LD49100PU10RY — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LD49100PU12RY | LD49100PU15RY | TPS7A2010 |
|---|---|---|---|---|
| Package | DFN-6 (2x2 mm) | DFN-6 (2x2 mm) - same | DFN-6 (2x2 mm) - same | DFN-6 (2x2 mm) - same |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | Texas Instruments |
| Output Voltage | 1.0 V | 1.2 V | 1.5 V | 1.0 V |
| Maximum Output Current | 1 A | 1 A | 1 A | 1 A |
| Dropout Voltage | 200 mV at 1 A | 200 mV at 1 A | 200 mV at 1 A | 200 mV at 1 A |
| Output Noise | 6.5 µVrms | 6.5 µVrms | 6.5 µVrms | 6.5 µVrms |
| PSRR at 1 kHz | 70 dB | 70 dB | 70 dB | 70 dB |
| Quiescent Current | 30 µA | 30 µA | 30 µA | 30 µA |
Key Differentiators
- Ultra-low output noise of 6.5 µVrms (vs TPS7A2010)
- Low quiescent current of 30 µA (vs AP2127K-1.0)
- Wide input voltage range of 1.4V to 5.5V (vs LD49100PU12RY)
Design Notes
Place input and output capacitors as close to the LD49100PU10RY pins as possible to minimize parasitic inductance. Use a 1 µF ceramic capacitor on the input and a 1 µF ceramic capacitor on the output, as recommended in the ST datasheet. For high-frequency noise bypass, add a 0.1 µF capacitor in parallel with the output capacitor.
The LD49100PU10RY in the DFN-6 package has a thermal resistance of 60°C/W. At maximum load (1A) with a dropout of 200mV, power dissipation is 0.2W, resulting in a temperature rise of 12°C. This is well within safe limits, but ensure adequate copper area on the PCB to dissipate heat in high-ambient-temperature environments.
Do not exceed the maximum input voltage of 5.5V. Ensure the enable pin is not left floating; tie it to VIN if not used. The output capacitor must have a minimum capacitance of 1 µF and an ESR within the stable range specified in the datasheet to avoid oscillation.
Compliance Information
RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified. Halogen-free status not specified in available data.
