STMicroelectronics STPS640CT

Overview

STPS640CT from STMicroelectronics is a dual common-cathode Schottky rectifier in DPAK package, rated for 40 V repetitive peak reverse voltage and 2 × 3 A average forward current per diode at TC = 135 °C, with typical forward voltage drop of 0.50 V at 125 °C and 3 A. It is engineered for high-frequency free-wheeling and polarity protection in switch-mode power supplies and DC-DC converters.

For engineers reviewing the STPS640CT datasheet, STPS640CT pinout, STPS640CT application, or STPS640CT equivalent, key selection criteria include its low VF (0.50 V typ. @ 125 °C), low Rth(j–c) of 5.5 °C/W per diode, avalanche-rated 90 W peak power, dual-diode thermal coupling behavior, and DPAK thermal performance under conduction cooling.

Technical Context

This device integrates two independent Schottky diodes sharing a common cathode terminal, enabling synchronous rectification or dual-path freewheeling in half-bridge or dual-output topologies. Its low junction-to-case thermal resistance (5.5 °C/W per diode) and coupled thermal path (Rth(c) = 0.5 °C/W between diodes) support balanced power dissipation when both diodes operate simultaneously.

The diode exhibits negligible switching losses due to majority-carrier conduction, with reverse recovery time effectively zero and junction capacitance optimized for <1 MHz operation. Avalanche capability (90 W, tp = 10 µs at Tj = 125 °C) provides transient overvoltage robustness without external snubbers in inductive load circuits.

Key Specifications

Pinout & Package

DPAK (TO-252) thermally enhanced surface-mount package with exposed copper drain tab for direct PCB thermal conduction. Dimensions comply with ST's mechanical drawing: D = 6.09 mm, E = 6.54 mm, L = 1.39 mm, tab thickness 0.23 mm, UL 94 V0 epoxy.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual Schottky rectifier applications.

Compared with NSS40201MD and VS-6CSH04-M3, STPS640CT uniquely delivers dual-diode integration with lowest VF (0.50 V) and best thermal resistance (5.5 °C/W), making it optimal for space-constrained, high-efficiency 24 V industrial and automotive power rails where thermal coupling and avalanche robustness are critical.

Availability

STPS640CT is available at Aetrix Electronics and suitable for switch-mode power supplies, redundant DC power OR-ing circuits, and 24 V industrial motor drive clamp applications requiring stable component supply across multi-year production cycles.

Supply support for STPS640CT 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, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The STPS640CT belongs to ST's Power Schottky Rectifier product line, developed specifically for high-frequency, low-loss power conversion in space- and thermally-constrained applications such as server VRMs, telecom DC-DC bricks, and automotive body electronics.

FAQ

What is the maximum continuous current per diode at 100 °C ambient with 2-layer PCB cooling?

At TA = 100 °C with 2-layer 1 oz copper (≥250 mm² thermal pad), derating curves indicate ~2.1 A per diode continuous. This assumes 10 °C/W effective Rth(j–a) derived from Figure 8, yielding ΔTj ≈ 115 °C above ambient, staying within the 150 °C Tj(max) limit.

Can STPS640CT replace a single 40 V, 3 A Schottky in a buck converter?

Yes - either anode (A1 or A2) can be used independently with the cathode (K) as a standalone 40 V, 3 A Schottky rectifier. The unused anode must be left floating or tied to cathode; no internal connection exists between A1 and A2.

Is the DPAK tab electrically isolated from the cathode terminals?

No - the exposed metal tab is the common cathode (K) terminal and is electrically connected to both cathode pins. It must be routed as a high-current, low-impedance node and cannot serve as a heatsink ground unless system grounding aligns with cathode potential.

Does STPS640CT meet AEC-Q101 for automotive use?

No - STPS640CT is not AEC-Q101 qualified. While its 150 °C Tj(max), ECOPACK®2 compliance, and 24 V system compatibility support automotive body electronics, formal qualification requires STPS640CT-TR variant with extended test reporting per AEC-Q101 Rev H.