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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

STMicroelectronics L5988D

Name: L5988D
Brand: STMicroelectronics
SKU: L5988D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L5988D

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 16-PowerTSSOP (0.173", 4.40mm Width)

Datasheet:: L5988D.pdf

Description:: IC REG BUCK ADJ 4A 16HTSSOP

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Product details

Overview

L5988D from STMicroelectronics is a monolithic synchronous step-down DC-DC switching regulator delivering 4 A continuous output current (5 A pulsed), operating from 2.9 V to 18 V input, with programmable 100–1000 kHz switching frequency and 0.6 V to VIN adjustable output voltage. It integrates high-side PMOS and low-side NMOS power switches in HTSSOP16, enabling 100% duty cycle operation without external bootstrap capacitor-used in LCD TV power rails, industrial DC-DC modules, and HC LED drivers.

For engineers reviewing the L5988D datasheet, L5988D pinout, L5988D application, or L5988D equivalent, key selection criteria include its dual-switch current limiting (4.0 A HS / 4.6 A LS), 200 ns minimum on-time, UVLO programmability for 3.3/5/12 V buses, voltage-mode control architecture, and MLCC-compatible design for compact, low-ESR output filtering.

Technical Context

The L5988D implements a voltage-mode PWM control loop using an internal sawtooth oscillator synchronized via the SYNCH pin, with feed-forward compensation to maintain stability across wide VIN/VOUT ratios. Its error amplifier drives the COMP pin for external Type II or Type III compensation networks.

It features a multifunction U/O/S pin that configures UVLO thresholds (2.8 V/8.6 V turn-on), OVP latching behavior, and sink capability activation-all determined by analog voltage level. Current limiting is implemented independently on both high-side and low-side MOSFETs with externally adjustable thresholds via ILIM-ADJ.

Key Specifications

Parameter	Value and Actual Design Meaning
Output current	4 A continuous (5 A pulsed); enables single-chip supply for mid-power digital loads like SoC cores or display bias rails.
Input voltage range	2.9 V to 18 V; supports wide-input industrial and automotive-derived supplies without pre-regulation.
Switching frequency	100 kHz to 1 MHz (resistor-programmable); allows optimization of size vs. efficiency-e.g., 600 kHz for compact 2.2 µH inductors.
Feedback reference	0.6 V ±0.5%; sets precise output regulation point; external resistor divider scales output up to VIN.
R_DS(on) HS / LS	85 mΩ / 67 mΩ typical; reduces conduction loss at 4 A, supporting >90% efficiency at 12 V→3.3 V/4 A.
Min. on-time	200 ns; enables stable 3.3 V output from 12 V input at 1 MHz (D ≈ 28%), critical for high-ratio conversion.
UVLO thresholds	Configurable for 3.3 V (2.8 V ON), 5 V, or 12 V (8.6 V ON) buses; prevents erratic startup during brown-out conditions.
Thermal resistance	R_thJA = 40 °C/W (HTSSOP16 on demo board); enables 4 A operation with moderate PCB copper area and no forced air.

Pinout & Package

Package: HTSSOP16 with exposed thermal pad (mechanical outline per DocID15324 Rev 4, Table 16). Pin count: 16-pin thermally enhanced surface-mount package optimized for power dissipation and layout simplicity.

Pin/Terminal	Circuit Role	Design Meaning
1, 16 OUT	Power output node	Connects directly to LC filter output; carries full 4 A load current and high di/dt switching transients.
2, 3 VIN	Main power input	Accepts 2.9–18 V unregulated input; requires local ceramic bypass (≥10 µF) near pins 2/3 for EMI suppression.
4 VCC	Bias supply input	Provides internal circuitry power; decoupled separately from VIN to avoid noise coupling into control logic.
5 SS/INH	Soft-start enable/disable	Active-low inhibit; floating = soft-start enabled (22 µA constant-current charge of external capacitor).
6 COMP	Error amplifier output	Drives external compensation network (Type II/III); high-impedance node requiring short trace routing.
7 ILIM-ADJ	Current limit programming	Resistor-to-VREF or GND adjusts both HS and LS current thresholds simultaneously for matched protection.
8 FB	Voltage feedback input	Senses output via resistive divider; 0.6 V reference enables accurate regulation across temperature and load.
9 SYNCH	Frequency synchronization I/O	Accepts external clock (70 ns min pulse width) or outputs master sync signal (100 ns pulse) when floating.
10 FSW	Frequency set resistor terminal	Pull-up/down resistor selects f_SW from 100 kHz to 1 MHz; floating defaults to 400 kHz ±10%.
11 U/O/S	Multifunction configuration	Analog voltage selects UVLO bus (3.3/5/12 V), OVP latch mode, and sink enable-no external logic required.
12 VREF	1.8 V precision reference	Stable 1.8 V ±2% output; used for biasing external components and as reference for FSW/ILIM-ADJ resistors.
13 SGND	Signal ground	Reference for FB, COMP, and analog pins; must be separated from PGND to minimize noise injection.
14, 15 PGND	Power ground	High-current return path for MOSFETs and output capacitor; tied to exposed pad for thermal conduction.

Key Features

Feature	Design Value
100% duty cycle operation	Enabled by integrated high-side PMOS switch-eliminates need for external bootstrap circuitry and supports VIN ≈ VOUT applications.
Pre-bias start-up capability	Sink function disabled during soft-start; allows safe ramp-up even when output is pre-charged (e.g., hot-swap or backup rail scenarios).
Voltage feed-forward control	Compensates for input voltage variation in real time, improving transient response and reducing output deviation during line steps.
Zero-load quiescent current	35 µA standby current; maintains regulation with no load-critical for always-on systems like set-top box standby rails.
MLCC-compatible design	No minimum ESR requirement on output capacitor; enables use of small, low-profile ceramic capacitors instead of bulkier electrolytics.
Programmable current limit	Independent adjustment of high-side and low-side current thresholds ensures robust protection across extreme duty cycles (e.g., 12 V→1.2 V).

Applications

Consumer LCD TV Power Rail

Industrial DC-DC Module

Use Scenario: Generating 3.3 V/4 A main logic rail from 12 V bus in LCD TV main board.

IC Role / Device Role / Timing Role: Primary synchronous buck regulator with voltage-mode control and feed-forward compensation.

Use Value: Delivers stable 3.3 V at 4 A with <1% load regulation and 200 ns min on-time, enabling direct 12 V→3.3 V conversion at 600 kHz without intermediate stages.

Use Scenario: Compact, high-efficiency 5 V/4 A isolated or non-isolated module for factory automation controllers.

IC Role / Device Role / Timing Role: Monolithic power stage with integrated MOSFETs and programmable protections for ruggedized embedded power.

Use Value: HTSSOP16 thermal pad and 40 °C/W R_thJA allow full 4 A output with minimal heatsinking; UVLO and OVP configurability simplify compliance with industrial voltage tolerance specs.

Networking Router Core Supply

HC LED Driver Bias Rail

Use Scenario: Providing 1.2 V/4 A core voltage for multi-core MIPS/ARM SoCs in enterprise routers.

IC Role / Device Role / Timing Role: High-current, high-frequency buck converter with fast transient response for dynamic CPU load changes.

Use Value: 1 MHz switching capability and 200 ns min on-time support 12 V→1.2 V conversion; Type III compensation ensures phase margin >60° under full load.

Use Scenario: Driving high-current white LED strings (e.g., backlight or signage) requiring stable 5–12 V bias with tight ripple control.

IC Role / Device Role / Timing Role: Efficient, low-noise step-down regulator powering LED driver ICs or constant-current sources.

Use Value: MLCC compatibility and zero-load operation reduce output ripple (<10 mV_pp) and eliminate standby power waste-key for energy-certified lighting designs.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP2315DJ-LF-Z (Monolithic Power)	3 A continuous, 4.5–24 V input, fixed 500 kHz f_SW, no UVLO programming or multifunction pin.	Lacks configurable UVLO/OVP/sink; suited for simpler 5 V/3 A applications where bus flexibility is not required.	Select when cost sensitivity outweighs programmability needs and 3 A output suffices.
TPS54560BQDDARQ1 (TI)	5 A continuous, 3.5–60 V input, adjustable f_SW (100–2500 kHz), integrated boot diode, but no 100% duty cycle support.	Requires external bootstrap capacitor; unsuitable for VIN ≈ VOUT; better for high-input automotive systems.	Choose for >36 V input or AEC-Q100 qualification; avoid when 100% duty cycle or 2.9 V start-up is mandatory.

Compared with MP2315 and TPS54560B, the L5988D uniquely combines 4 A output, 2.9 V start-up, 100% duty cycle, and analog-configurable protections in a thermally optimized HTSSOP16-making it optimal for space-constrained, wide-input consumer and industrial buck designs where flexibility and reliability are prioritized over ultra-high input voltage or automotive qualification.

Availability

L5988D is available at Aetrix Electronics and suitable for LCD TV power rails, industrial DC-DC modules, and networking router core supplies requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for L5988D 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, specializing in power management, microcontrollers, and analog ICs with vertical manufacturing and broad automotive/industrial qualification coverage.

The L5988D belongs to ST's high-current synchronous buck regulator product line, designed specifically for compact, efficient, and flexible point-of-load conversion in consumer, industrial, and networking equipment where thermal performance and feature integration are critical.

FAQ

What is the minimum input voltage required for L5988D startup?

The L5988D starts switching at 2.9 V nominal input, with UVLO threshold configurable down to 2.8 V for 3.3 V bus operation. Below this, the device remains inhibited-even if VCC rises above 2.9 V later, it will not initiate soft-start until the UVLO condition is met. This ensures reliable cold-start behavior in battery-powered or brown-out-prone systems.

Can L5988D operate with 100% duty cycle, and what enables this?

Yes-the L5988D supports true 100% duty cycle operation due to its integrated high-side PMOS switch, which eliminates the need for an external bootstrap capacitor. Unlike NMOS-based high-side drivers requiring gate voltage > VIN, the PMOS is self-biased and fully enhanced at VIN = VOUT, enabling seamless dropout operation in applications like 3.3 V output from 3.6 V Li-ion battery rails.

How does the U/O/S pin configure UVLO, OVP, and sink functions?

The U/O/S pin accepts an analog voltage (0–1.8 V) to select eight distinct configurations: three UVLO thresholds (for 3.3/5/12 V buses), two OVP modes (latched/unlatched), and two sink states (enabled/disabled). For example, 0.35 V selects 3.3 V bus UVLO + unlatched OVP + sink disabled-determined by internal resistor ladder and comparator thresholds per Table 6 in the datasheet.

Is external compensation required, and what topology is recommended?

Yes-external compensation is mandatory via the COMP pin. ST recommends Type III for wide-input, high-precision applications (e.g., 12 V→1.2 V) and Type II for simpler 5 V→3.3 V designs. Component values depend on f_SW, inductor, and output capacitor; design equations and Bode plots are provided in Sections 6.4.1–6.4.2 of DocID15324 Rev 4.

L5988D Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 16-PowerTSSOP (0.173", 4.40mm Width)

Packaging:: Tube

Product Status:: Active

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 2.9V

Voltage - Input (Max):: 18V

Voltage - Output (Min/Fixed):: 0.6V

Voltage - Output (Max):: 18V

Current - Output:: 4A

Frequency - Switching:: 100kHz ~ 1MHz

Synchronous Rectifier:: Yes

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-HTSSOP

L5988D FAQ

1.How can I place an order for L5988D through Aetrix?

Please submit a Request for Quotation (RFQ) for L5988D on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for L5988D reliable?

The price and inventory of L5988D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L5988D is usually 5 days.

3.What payment methods are accepted for L5988D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L5988D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L5988D?

L5988D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L5988D order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for L5988D?

For technical support, including L5988D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L5988D requirements.

6.How does Aetrix verify that L5988D is sourced from the original manufacturer or authorized distributors?

All L5988D products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that L5988D meets industry standards.

7.What is the process for return or replacement of L5988D?

All L5988D units undergo pre-shipment inspection (PSI). If there is an issue with L5988D, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The L5988D part is unused and in its original packaging.

Return procedure for L5988D:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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