Texas Instruments UCC24636DBVR

Overview

UCC24636DBVR from Texas Instruments is a secondary-side synchronous rectifier (SR) controller optimized for 5-V to 24-V output flyback converters operating in discontinuous conduction mode (DCM) and transition mode (TM). It implements volt-second balance control, delivers 5-A peak gate drive, achieves 300-ns minimum SR on time, supports up to 130-kHz switching frequency, and consumes only 110-µA standby current - enabling high-efficiency USB-C chargers and smartphone adapters.

For engineers reviewing the UCC24636DBVR datasheet, UCC24636DBVR pinout, UCC24636DBVR application, or UCC24636DBVR equivalent, key selection criteria include its VPC/VSC dual-sensing architecture, adaptive gate-drive clamp, ultra-low standby current, open/short pin fault protection, and compatibility with PSR/SSR primary controllers in compact SOT23-6 designs.

Technical Context

The UCC24636DBVR uses internal current ramp emulators driven by VPC (primary conduction sensing) and VSC (secondary output voltage sensing) to predict optimal SR MOSFET conduction timing without relying on drain-voltage zero-crossing detection. Its volt-second balance method makes SR turn-off independent of MOSFET R_DS(on), parasitic inductance, or ringing - eliminating layout sensitivity and enabling flexible MOSFET selection.

It features programmable blanking via TBLK pin (200 ns–2 µs), dynamic VPC threshold tracking (85% of prior-cycle peak), and automatic standby mode entry after 64 switching cycles at light load. Standby disables DRV output and reduces bias current to 110 µA, while exit occurs within 32 cycles upon load increase.

Key Specifications

Pinout & Package

UCC24636DBVR is housed in a 6-pin SOT23 package (2.92 mm × 1.30 mm body size) with exposed pad thermal performance optimized for high-power-density AC/DC adapters.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC24612DBVR and MP6908GJ-Z, the UCC24636DBVR uniquely combines ultra-low 110-µA standby current, programmable VPC blanking, and volt-second gain ratio tuning - making it optimal for high-efficiency, variable-output DCM/TM flybacks where no-load power and design flexibility are critical.

Availability

UCC24636DBVR is available at Aetrix Electronics and suitable for USB-C PD adapters, smartphone fast-charging designs, notebook auxiliary supplies, and industrial flyback SMPS requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for UCC24636DBVR 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 delivering analog, embedded processing, and power management solutions with focus on reliability, efficiency, and system-level innovation.

The UCC24636DBVR belongs to TI's high-efficiency AC/DC controller product line, designed specifically for secondary-side synchronous rectification in DCM/TM flyback converters targeting ultra-low standby power and layout-insensitive timing accuracy.

FAQ

What is the primary function of the UCC24636DBVR in a flyback converter?

The UCC24636DBVR serves as a secondary-side synchronous rectifier controller that replaces the output Schottky diode in flyback converters. It uses volt-second balance sensing via VPC and VSC pins to precisely time the turn-on and turn-off of an external N-channel MOSFET, achieving higher efficiency than diode rectification - especially in 5-V to 24-V DCM/TM flyback topologies. Its design eliminates dependency on MOSFET R_DS(on) and layout parasitics.

How does the UCC24636DBVR achieve ultra-low standby power consumption?

The UCC24636DBVR achieves 110-µA standby current by automatically entering a low-power mode after detecting 64 consecutive switching cycles below a defined frequency threshold. In this mode, the DRV output is disabled and internal bias current is reduced. The device exits standby within 32 active cycles when load increases - ensuring rapid response while maintaining compliance with stringent no-load power standards like DOE Level VI and EU CoC Tier 2. This behavior is intrinsic to the UCC24636DBVR architecture.

Can the UCC24636DBVR be used with primary-side controllers other than UCC28740?

Yes, the UCC24636DBVR is compatible with any primary-side controller that operates a flyback converter in DCM or TM mode - including but not limited to UCC28740, UCC28780, NCP1342, and ICE5QSBG. Its volt-second sensing architecture does not require direct communication or specific signaling from the primary controller. Compatibility is confirmed by matching the VPC/VSC voltage ranges and ensuring the primary controller's operating frequency stays within the UCC24636DBVR's 5 kHz–130 kHz range.

What protection features are integrated into the UCC24636DBVR?

The UCC24636DBVR integrates open-circuit and short-circuit pin fault protection on both VPC and VSC inputs, thermal shutdown at 165°C, UVLO with 4.0 V turn-on/3.6 V turn-off thresholds, and adaptive DRV clamp limiting output to 11–15 V. It also includes blanking and sampling windows (t_VPC-BLK, t_VPC-SPL) to reject DCM ringing, plus minimum on/off timing constraints (t_SRONMIN = 350 ns, t_OFF = 4.35 µs) to prevent false triggering - all inherent to the UCC24636DBVR silicon design.

Is the UCC24636DBVR pin-compatible with other TI SR controllers like UCC24612?

No, the UCC24636DBVR is not pin-compatible with UCC24612DBVR. Although both use SOT23-6 packages, their pin functions differ: UCC24636DBVR assigns Pin 3 to TBLK (blanking time programming), whereas UCC24612DBVR uses Pin 3 for FB (feedback input). Swapping them would result in incorrect operation or failure. The UCC24636DBVR's unique VPC/VSC dual-sensing architecture and absence of CCM control logic make it functionally distinct - confirming that UCC24636DBVR requires its own dedicated layout.