Texas Instruments LP5900TLX-4.5/NOPB

Overview

LP5900TLX-4.5/NOPB from Texas Instruments is a 4.5-V fixed-output, 150-mA ultra-low-noise LDO regulator designed for RF and analog signal chains. It operates from 2.5 V to 5.5 V input, delivers ±2% output voltage tolerance, achieves 6.5 μV_RMS output noise (10 Hz–100 kHz), and requires only 0.47-μF ceramic input/output capacitors-no noise bypass capacitor needed. It is used in cellular phone power rails supplying sensitive RF transceivers.

For engineers reviewing the LP5900TLX-4.5/NOPB datasheet, LP5900TLX-4.5/NOPB pinout, LP5900TLX-4.5/NOPB application, or LP5900TLX-4.5/NOPB equivalent, key selection criteria include dropout voltage (80 mV typ. at 150 mA), enable logic thresholds (V_IL ≤ 0.4 V, V_IH ≥ 1.2 V), thermal shutdown (160°C), PSRR (75 dB @ 1 kHz), and DSBGA-4 package compatibility with space-constrained portable PCBs.

Technical Context

The LP5900TLX-4.5/NOPB employs an internal low-pass RC filter on its reference voltage path to suppress intrinsic noise before amplification, enabling 6.5 μV_RMS noise performance without external bypass capacitance. Its EN pin integrates a 1-MΩ pull-down resistor and accepts standard logic-level control (0.4 V/1.2 V thresholds) for precise power sequencing.

Stability is guaranteed with 0.47-μF X7R/X5R ceramic capacitors on both IN and OUT pins, with ESR between 5 mΩ and 500 mΩ. The device maintains regulation down to zero load current and features thermal-overload protection that cycles at ~160°C junction temperature with ~20°C hysteresis.

Key Specifications

Pinout & Package

LP5900TLX-4.5/NOPB uses a 4-pin DSBGA (YZR) package measuring 1.108 mm × 1.083 mm, with bottom-side thermal pad requiring connection to PCB ground plane via thermal vias for optimal thermal performance (R_θJB = 35.6°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with TPL7407LPGEDR and MCP1703T-4502E/MB, LP5900TLX-4.5/NOPB uniquely combines ultra-low noise (6.5 μV_RMS), no-bypass-capacitor operation, and DSBGA-4 footprint-making it irreplaceable for RF/analog co-location in space-constrained mobile designs.

Availability

LP5900TLX-4.5/NOPB is available at Aetrix Electronics and suitable for cellular transceiver power, RF front-end bias, and portable medical sensor applications requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for LP5900TLX-4.5/NOPB 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and digital signal processing technologies with over 90 years of innovation in power management ICs.

The LP5900 product line was developed specifically for ultra-low-noise, capacitor-minimized power delivery in RF and high-fidelity analog subsystems-targeting cellular handsets, wireless infrastructure, and precision instrumentation.

FAQ

What is the minimum input voltage required for LP5900TLX-4.5/NOPB to regulate at 4.5 V?

The LP5900TLX-4.5/NOPB requires a minimum input voltage of 4.58 V (4.5 V + 80 mV typical dropout) to maintain regulation at full 150 mA load. At lighter loads, regulation is maintained down to 4.5 V + 150 mV (max dropout). Below 2.5 V input, internal circuitry is nonfunctional and output is unregulated. Always ensure VIN ≥ VOUT + VDO across operating temperature and load conditions.

Can LP5900TLX-4.5/NOPB operate without an output capacitor?

No, LP5900TLX-4.5/NOPB requires a minimum 0.47-μF ceramic output capacitor (X5R/X7R, 5–500 mΩ ESR) for stability. Operation without C_OUT causes oscillation and loss of regulation. The "no bypass capacitor" specification refers only to the elimination of a separate 10-nF noise-filter capacitor-not the main output capacitor.

Is the thermal pad on LP5900TLX-4.5/NOPB electrically connected internally?

No, the exposed thermal pad on the LP5900TLX-4.5/NOPB DSBGA package is not electrically connected to any internal node. It must be soldered to a PCB copper area tied to GND (pin 3) or left floating-but never connected to any other potential. Thermal vias beneath the pad improve heat dissipation and reduce R_θJB to 35.6°C/W.

What happens to LP5900TLX-4.5/NOPB output during thermal shutdown?

When junction temperature reaches ~160°C, LP5900TLX-4.5/NOPB disables its output and enters thermal shutdown. Output voltage drops to near 0 V. Once junction temperature cools to ~140°C, the device automatically resumes regulation. This cycling protects against permanent damage during sustained overload or poor heatsinking.

Does LP5900TLX-4.5/NOPB support reverse current blocking?

No, LP5900TLX-4.5/NOPB does not include reverse current blocking. If V_OUT exceeds V_IN, current can flow backward from OUT to IN through the internal pass transistor. In systems with multiple power domains or hot-swap requirements, an external reverse-blocking diode or MOSFET must be added to prevent backfeed.