Texas Instruments LP3988IMF-2.5

Overview

LP3988IMF-2.5 from Texas Instruments is a micropower, ultra-low-dropout CMOS voltage regulator delivering 150 mA at fixed 2.5 V output, with integrated Power Good (PG) flag and logic-controlled enable. It operates from 2.5 V to 6 V input, achieves 80 mV typical dropout at full load, consumes ≤1 µA in shutdown, and targets space-constrained battery-powered RF subsystems such as GSM/CDMA handset baseband IC power rails.

For engineers reviewing the LP3988IMF-2.5 datasheet, LP3988IMF-2.5 pinout, LP3988IMF-2.5 application, or LP3988IMF-2.5 equivalent, key selection criteria include guaranteed 2.5 V ±3% output tolerance over −40°C to +125°C, open-drain PG response time of 10 µs, compatibility with 1-µF ceramic output capacitors, and SOT-23-5 package thermal performance (R_θJA = 170.5°C/W).

Technical Context

The LP3988IMF-2.5 integrates a PMOS pass transistor with internal reference and error amplifier to regulate output voltage, while its dedicated open-drain PG output monitors V_OUT against dual thresholds (90–95% for low, 92–98% for high) with 10 µs typical delay. Enable control uses TTL-compatible logic thresholds (V_IL ≤ 0.5 V, V_IH ≥ 1.2 V), and the device enters dropout when VIN falls below V_OUT + 80 mV (typical at 150 mA).

It features thermal shutdown at ~160°C with 20°C hysteresis, short-circuit current limit of 600 mA (typ), and PSRR of 65 dB at 1 kHz / 45 dB at 10 kHz under 50 mA load. Ground current rises only slightly in dropout, preserving battery life in portable systems where input voltage decays near regulation limits.

Key Specifications

Pinout & Package

LP3988IMF-2.5 is packaged in a 5-pin SOT-23 (DBV) with 2.90 mm × 1.60 mm body size and exposed pad thermal path via lead 2 (GND). Pin 1 = IN, Pin 2 = GND, Pin 3 = EN, Pin 4 = PG, Pin 5 = OUT.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout regulator applications.

Compared with LP3988IMF-2.5, TPL7407LPGEDR serves a fundamentally different system role (driver + LDO), while MCP1700-2502E/TO trades off critical micropower and ultra-low-dropout performance for lower unit cost and through-hole assembly - neither matches LP3988IMF-2.5's combination of PG flag, SOT-23 size, 80 mV dropout, and ≤1 µA shutdown.

Availability

LP3988IMF-2.5 is available at Aetrix Electronics and suitable for CDMA/GSM handset power management, portable medical sensor nodes, and IoT edge microcontroller rails requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for LP3988IMF-2.5 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 power management IC design for portable and industrial applications.

The LP3988 product line delivers micropower, ultra-low-dropout regulators with integrated Power Good for battery-powered wireless devices - engineered specifically to maximize runtime, minimize board area, and simplify power sequencing in space- and energy-constrained systems.

FAQ

What is the output voltage tolerance of LP3988IMF-2.5 over temperature?

The LP3988IMF-2.5 guarantees ±3% output voltage tolerance over the full operating junction temperature range of −40°C to +125°C. This specification is verified per TI's production test flow and applies to all units shipped in the SOT-23-5 (DBV) package. The tolerance remains stable across input voltage variations from 2.5 V to 6 V and load currents up to 150 mA, making LP3988IMF-2.5 suitable for precision logic supply applications where voltage margin is tightly constrained.

Does LP3988IMF-2.5 require an external pullup resistor on the PG pin?

Yes, LP3988IMF-2.5 requires an external pullup resistor on the PG pin because it is an open-drain output. The resistor must connect PG to a valid logic rail (e.g., VIN or VOUT) and be sized to ensure VOL ≤ 0.1 V at IPULLUP = 100 µA under fault conditions. Typical values range from 10 kΩ to 100 kΩ depending on rise time requirements and bus loading. Leaving PG floating or connecting it directly to GND disables the Power Good functionality entirely.

Can LP3988IMF-2.5 operate with a 1-µF ceramic output capacitor?

Yes, LP3988IMF-2.5 is explicitly designed and production-validated to remain stable with a 1-µF ceramic output capacitor (X7R, Y5V, or Z5U dielectric). The device's internal compensation and low-ESR tolerance (5–500 mΩ) ensure phase margin >45° across temperature and load conditions. Using 1 µF reduces PCB area by >50% versus typical 10–22 µF tantalum solutions and eliminates ESR-related aging effects common in electrolytic types.

What is the maximum allowable input voltage for LP3988IMF-2.5?

The absolute maximum input voltage for LP3988IMF-2.5 is 6.5 V, but the recommended operating maximum is 6 V per TI's SNVS161E datasheet. Exceeding 6 V risks violating the absolute rating on the IN pin and may accelerate parametric drift or cause latent failure. For continuous operation, VIN should be maintained between 2.5 V (minimum for 2.5 V output) and 6 V, with derating advised above 5.5 V in high-temperature environments due to thermal dissipation limits.

How does the enable function behave when driven by a 1.8-V GPIO?

LP3988IMF-2.5 reliably enables with a 1.8-V GPIO because its VIH threshold is specified at 1.2 V (min) over temperature. At 1.8 V, the EN pin draws only 0.1 µA (max), imposing negligible load on the driving source. The device achieves full output regulation within 100 µs (typ) after EN crosses VIH, and PG asserts high within an additional 10 µs. This makes LP3988IMF-2.5 fully compatible with modern low-voltage MCUs without level-shifting.