Texas Instruments TPS71257DRCT

Overview

TPS71257DRCT from Texas Instruments is a dual-channel, fixed-output 2.85 V/2.85 V low-dropout linear regulator in a 10-pin SON package, delivering up to 250 mA per channel with 125 mV typical dropout at full load, 32 µV_RMS output noise (with 0.01 µF NR capacitor), and 65 dB PSRR at 10 kHz - designed for RF-sensitive analog power rails in portable wireless systems.

For engineers reviewing the TPS71257DRCT datasheet, TPS71257DRCT pinout, TPS71257DRCT application, or TPS71257DRCT equivalent, key selection criteria include dual independent enable control, thermal shutdown with hysteresis, ultra-low noise performance under 250 mA load, stability with 2.2 µF ceramic output capacitors, and operation across –40°C to +125°C junction temperature.

Technical Context

The TPS71257DRCT integrates two independent PMOS-based LDOs sharing a common input and ground, each with dedicated EN, OUT, and NR pins. Its architecture enables simultaneous or staggered startup, independent shutdown, and channel-to-channel isolation exceeding 40 dB above 100 Hz.

Each regulator uses an internal 1.225 V reference filtered via a 250 kΩ resistor to the NR pin, allowing external bypass capacitance to reduce spectral noise density below 10 nV/√Hz (10 Hz–100 kHz). Dropout is maintained below 230 mV across –40°C to +125°C at 250 mA.

Key Specifications

Pinout & Package

TPS71257DRCT is housed in a thermally enhanced 3 mm × 3 mm × 1 mm SON-10 (DRC) package with exposed thermal pad (Pin 5 = GND, Pad = GND). The package supports high-power dissipation with θ_JA = 49.6°C/W on JEDEC high-K board.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-LDO voltage regulation applications.

Compared with TPS71256DRCT, TPS71257DRCT provides 50 mV higher output voltage critical for margin-sensitive RF ICs; versus TPS7A4700RGWR, it delivers dual-rail flexibility and smaller 3 mm × 3 mm footprint at the cost of slightly higher noise - making it optimal for space-constrained dual-supply systems.

Availability

TPS71257DRCT is available at Aetrix Electronics and suitable for cellular transceivers, wireless audio subsystems, and DSP/FPGA power management requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for TPS71257DRCT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in precision power management ICs.

The TPS712xx family was engineered specifically for noise-sensitive RF and portable applications, emphasizing ultra-low noise, high PSRR, fast transient response, and dual-channel independence in compact thermally enhanced packages.

FAQ

What is the maximum input voltage rating for the TPS71257DRCT?

The TPS71257DRCT has an absolute maximum input voltage of 6.0 V. However, its recommended operating range is 2.7 V to 5.5 V per the Electrical Characteristics table. Exceeding 5.5 V risks violating safe operating area limits and may trigger undervoltage lockout or thermal shutdown. For reliable operation at 2.85 V output, VIN should be ≥3.0 V to maintain 125 mV dropout margin.

Does the TPS71257DRCT require external feedback resistors?

No, the TPS71257DRCT does not require external feedback resistors. It is a fixed-output device delivering 2.85 V per channel, with internal resistor dividers setting the output voltage. Pins FB1/NC and FB2/NC are no-connect terminals - connecting them would damage functionality or violate the fixed-voltage design.

How does the NR pin affect noise performance in the TPS71257DRCT?

The NR pin connects internally to the 1.225 V reference through a 250 kΩ resistor. Adding a 0.01 µF ceramic capacitor from NR to GND forms a low-pass filter that reduces reference noise, lowering total output noise from 80 × V_OUT (no NR cap) to 11.8 × V_OUT. For TPS71257DRCT's 2.85 V outputs, this yields 32 µV_RMS (10 Hz–100 kHz), critical for RF bias applications.

Can both outputs of the TPS71257DRCT be enabled independently?

Yes, the TPS71257DRCT features independent EN1 and EN2 pins. Driving EN1 high enables only OUT1; driving EN2 high enables only OUT2. Both must be high for dual-channel operation. This allows dynamic power gating - for example, keeping RF bias active while shutting down baseband logic to extend battery life in portable devices.

What thermal considerations apply to the TPS71257DRCT in continuous 500 mA operation?

At 500 mA total load (250 mA per channel) with 3.3 V input and 2.85 V output, power dissipation is ~225 mW. With θ_JA = 49.6°C/W, junction temperature rise is ~11.2°C above ambient. To stay within the +125°C max TJ limit, ambient must remain ≤114°C. Use of the exposed thermal pad and ≥1 in² copper pour is essential for reliability at full load.