STMicroelectronics L5980

Overview

L5980 from STMicroelectronics is a 0.7 A step-down switching regulator with integrated P-channel MOSFET, designed for DC-DC conversion in space-constrained power rails. It operates from 2.9 V to 18 V input, delivers adjustable output down to 0.6 V, features 250 kHz base switching frequency (programmable up to 1 MHz), and supports 100% duty cycle low-dropout operation - used in LCD TV power supplies and FPGA core voltage regulation.

For engineers reviewing the L5980 datasheet, L5980 pinout, L5980 application, or L5980 equivalent, key selection criteria include its VFQFPN8 3×3 mm thermal performance (R_thJA ≈ 60 °C/W), internal soft-start duration (7.4–9.1 ms), overcurrent hiccup mode behavior, and voltage-mode control architecture with feedforward compensation.

Technical Context

The L5980 implements voltage-mode PWM control using an internal 0.6 V reference and sawtooth oscillator synchronized via the SYNCH pin. Its feedforward circuitry adjusts sawtooth slope with input voltage and switching frequency to maintain constant PWM gain across operating conditions.

Functional blocks include a high-side P-channel MOSFET driver (R_DS(on) = 140–220 mΩ), peak-current-limit protection with 200 ns blanking time, hysteretic thermal shutdown (150 °C trip, 130 °C recovery), and INH-controlled standby mode drawing ≤30 µA.

Key Specifications

Pinout & Package

Package: VFQFPN8 (Very Thin Quad Flat No-lead), 3 mm × 3 mm, 0.5 mm pitch, exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Compared with MP2307DN-LF-Z and TPS5430DDAR, the L5980 uniquely balances adjustability, integration (P-MOSFET + 0.6 V reference), and synchronization in a thermally efficient 3×3 mm package - making it optimal for mid-power, multi-rail embedded systems where board space and thermal management are constrained.

Availability

L5980 is available at Aetrix Electronics and suitable for LCD TV power supplies, FPGA core voltage regulation, DSL modem DC-DC modules, and consumer audio power rails requiring stable component supply across extended production lifecycles.

Supply support for L5980 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and consumer markets.

The L5980 belongs to ST's high-efficiency monolithic DC-DC converter product line, engineered for compact, thermally robust point-of-load regulation in space- and reliability-critical applications.

FAQ

What is the minimum input voltage required for reliable startup of the L5980?

The L5980 requires a minimum V_CC of 2.9 V to initiate operation, as defined by its V_CCON UVLO threshold. Below this, the internal bias circuitry remains inactive. Startup is guaranteed once V_CC exceeds 2.9 V with sufficient slew rate to avoid false triggering of the UVLO hysteresis (0.175–0.3 V).

How does the SYNCH pin behave when left unconnected?

When the SYNCH pin is left floating, it outputs a square wave signal with 180° phase shift relative to the internal power switch turn-on edge. This allows natural interleaving when two L5980s are synchronized by connecting their SYNCH pins - the higher-frequency unit becomes master, the other slave, achieving half-period phase offset.

Can the L5980 regulate output voltage below 0.6 V?

No - the internal reference is fixed at 0.6 V, and the feedback comparator only functions correctly when FB voltage is ≥0.593 V and ≤0.607 V. Attempting sub-0.6 V regulation violates the error amplifier's operating range and results in loss of regulation or latch-up.

What failure mode occurs during sustained output short-circuit?

Under sustained short-circuit, the L5980 enters hiccup mode: it disables switching for 2048 clock cycles (~8.2 ms at 250 kHz), then attempts one switching cycle. If overcurrent persists, it repeats the cycle - limiting average power dissipation and junction temperature while enabling automatic recovery once the fault clears.