STMicroelectronics FERD40U45CT

Overview

FERD40U45CT from STMicroelectronics is a dual-field-effect rectifier in TO-220AB package, rated for 45 V repetitive peak reverse voltage and 2 × 20 A average forward current per diode. It delivers low forward voltage drop (0.31 V typ. at 10 A, 125 °C) and stable leakage current up to 100 mA at 125 °C, enabling high-efficiency operation in automotive switch-mode power supplies.

For engineers reviewing the FERD40U45CT datasheet, FERD40U45CT pinout, FERD40U45CT application, or FERD40U45CT equivalent, key selection criteria include thermal resistance (1.6 °C/W j-c per diode), junction-to-case coupling (0.5 °C/W), and pulse-tested VF/IR trade-off validated across 25–125 °C operating range.

Technical Context

This dual rectifier uses ST's proprietary field-effect rectifier process to optimize VF/IR balance on silicon surface area-achieving lower conduction loss than conventional Schottky or fast recovery diodes at comparable ratings. Its architecture avoids thermal runaway under DC forward bias when heatsinked, with dPtot/dTj < 1/Rth(j-a) condition enforced.

Thermal design relies on junction-to-case conduction (Rth(j-c) = 1.6 °C/W per diode) and inter-diode coupling (Rth(c) = 0.5 °C/W), requiring explicit derating when both diodes operate simultaneously: ΔTj(diode1) = P(diode1) × Rth(j-c) + P(diode2) × Rth(c).

Key Specifications

Pinout & Package

Package: TO-220AB - Insulated case, single-row 3-terminal through-hole package with metal tab (K) for thermal and electrical connection. Mounting torque: 0.4–0.6 N·m.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-field-effect rectifier applications.

Compared with STTH30L06CW and MBR4045CT, FERD40U45CT uniquely balances low VF (0.31 V), tight thermal coupling (0.5 °C/W), and TO-220AB mountability-making it optimal for space- and efficiency-constrained automotive SMPS where dual-rail thermal synchronization matters.

Availability

FERD40U45CT is available at Aetrix Electronics and suitable for automotive DC-DC converters, on-board charger auxiliary supplies, and industrial switch-mode power supplies requiring stable component supply and long-term production continuity.

Supply support for FERD40U45CT 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, designing and manufacturing microcontrollers, power devices, sensors, and analog ICs for industrial, automotive, and consumer markets.

FERD40U45CT belongs to ST's Field Effect Rectifier (FER) product line-engineered specifically to replace Schottky diodes in high-efficiency, high-temperature automotive and industrial power conversion where VF/IR optimization is critical.

FAQ

Is FERD40U45CT pin-compatible with standard TO-220AB dual diodes like MBR4045CT?

Yes-FERD40U45CT uses identical TO-220AB mechanical dimensions and terminal layout (A1–K–A2), enabling drop-in replacement in existing PCB footprints. However, its common-cathode configuration and lower VF require verification of thermal coupling effects in dual-diode operation.

What is the maximum continuous power dissipation per diode at Tc = 150 °C?

At Tc = 150 °C, each diode dissipates up to 12.8 W continuously, calculated using PF(AV) = 0.28 × IF(AV) + 0.009 × IF(RMS)² with IF(AV) = 20 A and IF(RMS) ≈ 28.3 A (δ = 0.5). This aligns with the 1.6 °C/W Rth(j-c) and 20 °C temperature rise above case.

Does FERD40U45CT require a heatsink in automotive under-hood applications?

Yes-due to ambient temperatures exceeding 105 °C and power dissipation >5 W per diode, a mechanically secured heatsink is mandatory. The metal tab (K) serves as primary thermal path; isolation pads must be rated for ≥200 °C and ≤0.5 mm thickness to maintain Rth(j-c) performance.

Can FERD40U45CT be used in synchronous rectification circuits?

No-it is a passive rectifier, not a MOSFET-based synchronous device. While it replaces Schottky diodes in non-synchronous topologies (e.g., flyback, forward), it cannot be actively driven like a gate-controlled MOSFET; its field-effect behavior is intrinsic to silicon structure, not controllable externally.