STMicroelectronics L6730

Overview

L6730 from STMicroelectronics is an adjustable synchronous step-down controller for high-current buck converter power stages using external N-channel MOSFETs. The IC supports a 1.8 V to 14 V converter input range, operates from a 4.5 V to 14 V controller supply, regulates output voltage down to 0.6 V, and provides fixed-frequency voltage-mode control for low-voltage distributed power systems.

For engineers reviewing the L6730 datasheet, L6730 pinout, L6730 application, or L6730 equivalent, this controller is most relevant for high-density DC/DC modules, low-voltage distributed power rails, niPOL converters, DDR memory supplies, DDR bus termination rails, and embedded high-current buck regulators requiring programmable 100 kHz to 1 MHz switching frequency, pre-biased startup support, RDS(on)-based current-limit sensing, source / sink selection, and HTSSOP20 exposed-pad assembly.

Technical Context

L6730 drives a synchronous buck stage through HGATE and LGATE outputs and uses fixed-frequency voltage-mode PWM control with external loop compensation. The device supports 0% to 100% duty-cycle operation, minimum on-time below 100 ns, selectable 0.6 V or 1.2 V internal reference, external reference input, and ±0.8% reference accuracy over line voltage and temperature from 0°C to 125°C.

The controller includes predictive anti-cross-conduction gate-drive control, programmable high-side and low-side MOSFET RDS(on) overcurrent protection, selectable UVLO threshold for 5 V or 12 V bus operation, soft-start and inhibit, PGOOD with programmable delay, overvoltage protection with selectable latched or non-latched behavior, thermal shutdown, and synchronization with 180° phase shift for master/slave converter operation.

Key Specifications

Pinout & Package

L6730 is supplied in an HTSSOP20 exposed-pad package. The 20-pin exposed-pad TSSOP format supports compact synchronous buck controller layouts by keeping gate-drive, phase-node, current-limit, oscillator, feedback, soft-start, synchronization, power-good, protection-setting, and supply pins accessible while improving board-level thermal transfer and grounding through the exposed pad.

Key Features

• Adjustable synchronous step-down controller for external N-channel MOSFET buck converter stages.
• 1.8 V to 14 V converter input range and 4.5 V to 14 V controller supply range.
• Output voltage adjustable down to 0.6 V with ±0.8% reference accuracy over line and temperature.
• Selectable 0.6 V or 1.2 V internal reference plus external voltage-reference input.
• Programmable 100 kHz to 1 MHz switching frequency with synchronization and 180° phase-shift capability.
• Minimum on-time below 100 ns and 0% to 100% duty-cycle operation for wide conversion-ratio support.
• Programmable high-side and low-side MOSFET RDS(on) overcurrent sensing without a dedicated sense resistor.
• Pre-biased startup support, selectable source / sink behavior after soft-start, PGOOD delay, OVP, UVLO, and thermal shutdown.

Applications

Equivalent & Alternatives

When evaluating L6730 equivalent devices, engineers should compare package, packing format, source / sink behavior, overcurrent response mode, switching-frequency range, reference options, MOSFET gate-drive requirements, UVLO setting, PGOOD delay, pre-biased startup behavior, and whether the existing PCB uses the L6730 HTSSOP20 pinout.

Compared with L6730TR, L6730 keeps the same controller architecture, pinout, HTSSOP20 package, and electrical function, with the main difference being tube versus tape-and-reel logistics. L6730 vs L6730B selection depends on whether the converter design needs the L6730 source / sink selection behavior or the L6730B constant-current / hiccup overcurrent-response option.

Quality

L6730 should be sourced as original STMicroelectronics components through traceable and controlled supply channels. Quality verification procedures may include HTSSOP20 exposed-pad package inspection, top-mark validation, tube label review, solderability testing, exposed-pad inspection, VCC and VCCDR continuity checks, HGATE / LGATE driver-function testing, oscillator-frequency verification, PGOOD timing inspection, current-limit threshold review, and incoming inspection according to synchronous buck converter production requirements.

Availability

L6730 is available at Aetrix Electronics and suitable for high-density DC/DC modules, low-voltage distributed power rails, niPOL converters, DDR memory supplies, DDR bus termination rails, and embedded high-current buck regulators requiring stable component supply and repeatable production support.

Supply support may include scheduled delivery planning, volume procurement support, BOM continuity assistance, traceable sourcing management, and long-term availability support for power-supply manufacturers, industrial equipment builders, computing hardware developers, repair groups, contract manufacturers, and legacy product owners using ST synchronous buck controller designs.

For production deployment, confirming the HTSSOP20 exposed-pad footprint, tube handling format, input-voltage range, MOSFET gate-drive requirement, oscillator setting, compensation network, RDS(on) current-limit design, source / sink selection, protection-mode network, thermal requirements, and sourcing continuity helps reduce procurement risk and improve manufacturing stability.

Manufacturer

STMicroelectronics supplies power-management ICs, synchronous buck controllers, converters, microcontrollers, sensors, RF devices, protection products, and discrete semiconductors for industrial, automotive, consumer, communication, and embedded applications. L6730 belongs to ST's power-management controller portfolio for high-current synchronous step-down conversion and low-voltage point-of-load power systems.

FAQ

What is L6730 used for?

L6730 is used to control high-current synchronous buck converters in high-density DC/DC modules, distributed point-of-load supplies, niPOL converters, DDR memory supplies, and DDR bus termination rails. It drives external N-channel MOSFETs and provides programmable frequency, soft-start, overcurrent protection, power-good monitoring, synchronization, and low-voltage output regulation.

What input and output voltage ranges does L6730 support?

L6730 supports a converter input voltage range from 1.8 V to 14 V and a controller supply range from 4.5 V to 14 V. The regulated output voltage can be adjusted down to 0.6 V using the feedback and reference system, making the IC suitable for low-voltage core, memory, and termination rail applications.

How is the switching frequency set on L6730?

L6730 uses the OSC pin to program the switching frequency from 100 kHz to 1 MHz. Frequency selection affects inductor size, switching loss, output ripple, transient response, MOSFET dissipation, and EMI behavior, so the oscillator setting should be chosen together with the external power-stage design.

How does L6730 implement overcurrent protection?

L6730 implements programmable high-side and low-side overcurrent protection using the RDS(on) of the external MOSFETs. OCH sets the high-side peak current limit, OCL sets the low-side current-limit behavior, and PHASE provides the switching-node reference. This avoids a dedicated sense resistor but requires careful MOSFET, layout, and temperature-margin selection.

What package is used by L6730?

L6730 uses an HTSSOP20 exposed-pad package. The package provides 20 pins for feedback, compensation, soft-start, oscillator, synchronization, PGOOD, protection configuration, gate-drive outputs, bootstrap supply, current-limit sensing, and controller supply connections, while the exposed pad improves grounding and board-level thermal behavior.

What is the difference between L6730 and L6730TR?

L6730 and L6730TR use the same controller function, HTSSOP20 package, pinout, and electrical architecture. The difference is packaging logistics: L6730 is supplied in tube packaging, while L6730TR is supplied in tape-and-reel format for automated SMT assembly.

What is the difference between L6730 and L6730B?

L6730 and L6730B are related ST synchronous step-down controller options in the HTSSOP20 package, but the multifunction protection pin differs. L6730 uses SINK/OVP/UVLO behavior for source / sink selection and protection configuration, while L6730B uses CC/OVP/UVLO behavior for selectable constant-current or hiccup overcurrent response after soft-start.

Can L6730 start into a pre-biased output rail?

Yes. L6730 includes pre-biased startup capability, which is useful when the output rail may already hold voltage before the controller starts. This behavior is important in DDR, multi-rail, and redundant power systems where uncontrolled sink current during startup could disturb the existing rail voltage.