Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > DC DC Switching Controllers

STMicroelectronics L6728AH

Name: L6728AH
Brand: STMicroelectronics
SKU: L6728AH
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: L6728AH

Manufacturer:: STMicroelectronics

Category:: DC DC Switching Controllers

Package:: 10-VFDFN Exposed Pad

Datasheet:: L6728AH.pdf

Description:: IC REG CTRLR BUCK 10DFN

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:2,648

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

L6728AH from STMicroelectronics is a single-phase synchronous buck PWM controller with integrated high-current gate drivers, designed for DC-DC step-down conversion in CPU/DSP and subsystem power supplies. It features a fixed 600 kHz switching frequency, 0.8 V internal reference with ±0.8% output voltage accuracy, sensorless over-current protection via low-side R_DS(on) sensing, and Power Good (PGOOD) status monitoring via dedicated VSEN pin.

For engineers reviewing the L6728AH datasheet, L6728AH pinout, L6728AH application, or L6728AH equivalent, key selection considerations include its VFDFPN10 3×3 mm package, 5–12 V VCC supply range, 1.5 V minimum input capability, adaptive dead-time control, and LS-LESS pre-bias startup support - all critical for stable, compact, high-efficiency point-of-load regulation.

Technical Context

L6728AH implements voltage-mode control with a 15 MHz gain-bandwidth error amplifier and 8 V/μs slew rate to enable fast transient response. Its oscillator is fixed at 600 kHz (±10%), and duty cycle is limited to 67% maximum to ensure safe operation across input ranges.

The controller uses PHASE pin for adaptive dead-time detection and HS turn-off monitoring, while LGATE serves dual roles as low-side driver output and programmable over-current threshold set point via external ROCSET resistor. VSEN provides independent feedback monitoring for OVP/UVP/PGOOD, decoupled from FB for enhanced reliability.

Key Specifications

Parameter	Value and Actual Design Meaning
Switching Frequency	Fixed 600 kHz ±10%; enables compact magnetics and predictable EMI profile without external timing components.
Output Voltage Accuracy	±0.8% over line/temperature; ensures tight regulation for sensitive loads like CPU cores and memory I/O.
VCC Supply Range	5 V to 12 V; supports direct connection to common system rails without auxiliary LDOs.
Min Input Voltage	1.5 V; allows use in ultra-low-input applications such as post-regulated distributed supplies.
Gate Drive Capability	HS: 1.5 A source / 1.1 Ω sink; LS: 1.5 A source / 0.65 Ω sink; drives N-channel MOSFETs directly with minimal external components.
OCP Threshold Range	50 mV to 550 mV (programmable via ROCSET); eliminates need for sense resistors and reduces board area/cost.
PGOOD Window	0.680–0.740 V (low), 0.860–0.920 V (high); provides robust power-good signaling with hysteresis for noise immunity.

Pinout & Package

Package: VFDFPN10 (3 mm × 3 mm, 0.5 mm pitch, exposed thermal pad). Compact footprint optimized for space-constrained point-of-load designs.

Pin/Terminal	Circuit Role	Design Meaning
1 BOOT	HS driver bootstrap supply	Connects via 100 nF capacitor to PHASE node; enables floating high-side gate drive without isolated supply.
2 PHASE	HS return / current sense / dead-time monitor	Senses LS R_DS(on) drop for OCP; monitors HS turn-off timing for adaptive dead-time control.
3 UGATE	High-side MOSFET gate driver output	Direct drive to HS gate; supports fast switching with 1.5 A peak source/sink capability.
4 LGATE / OC	Low-side gate driver output & OCP programming	Drives LS MOSFET gate; sources 10 µA during startup to set programmable OCP threshold via ROCSET.
5 GND	Power and signal reference ground	Common return for all internal circuits; must connect to low-impedance PCB ground plane.
6 VCC	Controller and driver supply input	Accepts 5–12 V; powers logic, EA, oscillators, and gate drivers; requires ≥1 µF MLCC bypass.
7 COMP / DIS	Error amplifier output & disable input	Compensates control loop via RF-CF-CP network; pulled <0.75 V to disable controller.
8 FB	Inverting input of error amplifier	Connects to resistor divider from VOUT; sets regulated output voltage (min 0.8 V) using internal 0.8 V reference.
9 VSEN	Dedicated voltage sense for protections	Monitors output independently for PGOOD, OVP (0.9–1.1 V), and UVP (0.5–0.7 V); improves fault detection reliability.
10 PGOOD	Open-drain power-good status output	Pulled low when VSEN is outside PGOOD window; requires external pull-up ≤ VCC; active after soft-start completes.

Key Features

Feature	Design Value
LS-LESS Pre-bias Startup	Enables controlled discharge of pre-charged outputs by delaying LS activation until HS begins switching - prevents negative voltage spikes and load damage.
Sensorless Dual-Level OCP	Programmable first-level trip (50–550 mV) with automatic 1.5× second-level latch; eliminates sense resistors while providing graded fault response.
Adaptive Dead-Time Control	Monitors PHASE and LGATE to dynamically adjust HS/LS overlap; minimizes body diode conduction and improves efficiency without Schottky diodes.
Integrated Soft-Start	Linearly ramps internal 0.8 V reference over 4.5 ms (typ.); limits inrush current and ensures monotonic VOUT rise even with large output capacitance.
VSEN-Dedicated Protection Path	Separate analog path from FB for OVP/UVP/PGOOD; avoids false trips due to compensation network instability or FB trace noise.

Applications

Memory and Termination Supply

CPU and DSP Power Supply

Use Scenario: Providing tightly regulated 1.2 V or 1.5 V to DDR memory modules and termination networks on high-speed data buses.

IC Role / Device Role / Timing Role: Synchronous buck controller managing dynamic load transients up to 20 A with sub-100 ns response time via 15 MHz GBWP error amplifier.

Use Value: ±0.8% output accuracy and dedicated VSEN monitoring ensure signal integrity and compliance with JEDEC VDDQ tolerance specs under varying temperature and load.

Use Scenario: Delivering core voltage (e.g., 0.8–1.3 V) to modern CPUs and DSPs with aggressive transient requirements and strict power sequencing.

IC Role / Device Role / Timing Role: Primary voltage regulator IC implementing LS-LESS startup to avoid negative undershoot on pre-biased rails during cold boot or reset cycles.

Use Value: Eliminates need for external sense resistors and discrete protection ICs, reducing BOM count and PCB area while maintaining ±0.8% regulation accuracy.

Subsystem Power Supply (MCH, IOCH, PCI)

Distributed Power Supply

Use Scenario: Generating 3.3 V or 5 V for chipset components including memory controller hubs (MCH), I/O controller hubs (IOCH), and PCI interface circuitry.

IC Role / Device Role / Timing Role: Single-phase buck controller operating from 5 V or 12 V intermediate bus with 600 kHz fixed-frequency switching for predictable EMI filtering.

Use Value: High-current integrated drivers (1.5 A HS/LS) enable direct drive of multiple paralleled MOSFETs, supporting >30 A output with minimal external components.

Use Scenario: Local regulation in distributed architectures where intermediate bus (e.g., 5 V, 12 V) feeds multiple point-of-load converters across a large PCB or backplane.

IC Role / Device Role / Timing Role: Compact VFDFPN10 controller enabling dense placement near load; VCC range flexibility allows shared rail usage across multiple L6728AH instances.

Use Value: 3×3 mm footprint and exposed thermal pad support thermal management in high-density layouts; PGOOD signals simplify system-level power sequencing and health monitoring.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ISL6269CRZ-T	Fixed 500 kHz frequency; no LS-LESS feature; requires external sense resistor for OCP; 0.6 V reference.	Lacks pre-bias startup support and sensorless OCP; less suitable for systems with hot-pluggable or pre-charged rails.	Prefer L6728AH when LS-LESS, R_DS(on)-based OCP, or tighter output accuracy (±0.8% vs ±1.5%) are required.
TPS54620RGYR	Adjustable 200–1600 kHz frequency; integrated FETs (not controller-only); 0.8 V reference; no dedicated VSEN pin.	Monolithic design eliminates external MOSFETs but limits max current and thermal flexibility; lacks independent protection sensing.	Choose L6728AH for higher current scalability, superior thermal management via discrete FETs, and independent VSEN-based fault detection.

Compared with ISL6269CRZ-T and TPS54620RGYR, L6728AH uniquely combines LS-LESS startup, sensorless dual-level OCP, and VSEN-dedicated protection - delivering higher system reliability in pre-biased, high-transient, and space-constrained point-of-load applications.

Availability

L6728AH is available at Aetrix Electronics and suitable for CPU core regulation, memory termination, and subsystem power supply applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for L6728AH 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 specializing in power management, microcontrollers, and analog ICs, with manufacturing and R&D operations across Europe, Asia, and the Americas.

L6728AH belongs to ST's high-frequency DC-DC controller product line, engineered specifically for efficient, compact, and reliable point-of-load regulation in computing, communications, and industrial embedded systems.

FAQ

What is the purpose of the VSEN pin, and how does it differ from the FB pin?

VSEN provides an independent analog path for output voltage monitoring used exclusively for Power Good signaling, overvoltage, and undervoltage protection. Unlike FB - which feeds the error amplifier for closed-loop regulation - VSEN operates separately to avoid false trips caused by compensation network instability or layout noise. Its dedicated comparator thresholds (e.g., 0.68–0.74 V low, 0.86–0.92 V high) ensure robust fault detection even during transient events.

How does LS-LESS startup prevent negative voltage spikes during pre-biased output conditions?

During LS-LESS startup, the low-side MOSFET remains disabled until the high-side begins switching. If the output is pre-biased above the target voltage, the HS will not switch initially, so the LS is enabled only after soft-start timeout to safely discharge the output to the regulated level. This sequence avoids reverse inductor current flow that would otherwise cause dangerous negative undershoot at the load, protecting downstream components and ensuring clean power sequencing.

Can the L6728AH operate with input voltages below 5 V, and what are the limitations?

Yes - L6728AH supports power conversion inputs as low as 1.5 V, but its VCC supply must remain within 5–12 V. For sub-5 V input rails, an auxiliary bias supply (e.g., from a separate LDO or auxiliary winding) is required to power VCC. The 1.5 V minimum applies to the power conversion path (VIN to VOUT), not the controller's own supply, ensuring flexibility in multi-rail architectures without compromising gate drive strength or protection functionality.

What is the function of the LGATE / OC pin, and how is over-current threshold programmed?

LGATE / OC serves dual functions: it outputs the low-side gate drive signal and sources a precise 10 µA current during startup to program the first-level over-current threshold. Connecting an ROCSET resistor between LGATE and GND develops a voltage (V = 10 µA × ROCSET) that is sampled and held internally. This sets the PHASE-node voltage threshold for OCP detection (range: 50–550 mV), with a second-level threshold automatically set at 1.5× that value for immediate latch on severe faults.

L6728AH Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 10-VFDFN Exposed Pad

Packaging:: Tube

Product Status:: Active

Output Type:: Transistor Driver

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Number of Outputs:: 1

Output Phases:: 1

Voltage - Supply (Vcc/Vdd):: 5V ~ 12V

Frequency - Switching:: 600kHz

Duty Cycle (Max):: 67%

Synchronous Rectifier:: Yes

Clock Sync:: No

Serial Interfaces:: -

Control Features:: Enable, Phase Control, Power Good

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 10-VFDFPN (3x3)

L6728AH FAQ

1.How can I place an order for L6728AH through Aetrix?

Please submit a Request for Quotation (RFQ) for L6728AH 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 L6728AH reliable?

The price and inventory of L6728AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6728AH is usually 5 days.

3.What payment methods are accepted for L6728AH?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6728AH transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6728AH?

L6728AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6728AH 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 L6728AH?

For technical support, including L6728AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6728AH requirements.

6.How does Aetrix verify that L6728AH is sourced from the original manufacturer or authorized distributors?

All L6728AH 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 L6728AH meets industry standards.

7.What is the process for return or replacement of L6728AH?

All L6728AH units undergo pre-shipment inspection (PSI). If there is an issue with L6728AH, 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 L6728AH part is unused and in its original packaging.

Return procedure for L6728AH:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…