Toshiba Semiconductor and Storage CMS15I40A(TE12L,QM

Overview

CMS15I40A from Toshiba is a Schottky barrier diode optimized for secondary rectification and reverse-current protection in compact DC-DC converters and mobile power rails, featuring VRRM = 40 V, IF(AV) = 1.5 A, VFM(max) = 0.49 V at 1.5 A, Rth(j-a) = 60 °C/W (ceramic board), and housed in the ultra-thin M-FLAT (3-4E1S) package.

For engineers reviewing the CMS15I40A datasheet, CMS15I40A pinout, CMS15I40A application, or CMS15I40A equivalent, key selection criteria include low forward voltage under high pulsed current, thermal performance on small PCB land patterns, suitability for space-constrained mobile and portable power designs, and compliance with derating guidance for junction temperature control below 120 °C.

Technical Context

The CMS15I40A employs a planar Schottky junction structure to achieve fast switching (no minority-carrier storage) and low conduction loss, enabling high-efficiency operation in synchronous and non-synchronous buck converters operating up to several hundred kHz. Its 40 V VRRM rating targets 5 V–12 V output rails where reverse recovery immunity and low VF are critical.

Thermal design relies on direct lead-to-board conduction via its two-terminal M-FLAT package: cathode lead serves as primary heat path (Rth(j-ℓ) = 16 °C/W), while ambient dissipation depends strongly on solder land size and board material-6 mm × 6 mm copper on 1.6 mm FR-4 yields Rth(j-a) = 135 °C/W versus 2 mm × 2 mm on ceramic at 60 °C/W.

Key Specifications

Pinout & Package

Package: M-FLAT (Toshiba designation 3-4E1S), surface-mount, 2-terminal, ultra-thin profile (0.023 g typical), designed for high-density board assembly with minimal Z-height.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RB055LAM-40TR and SS14-HF, the CMS15I40A delivers superior thermal performance on ceramic substrates and tighter VF consistency across production lots, making it preferred for space- and thermally sensitive 1.5 A mobile power rails where board-level reliability under sustained load is critical.

Availability

CMS15I40A is available at Aetrix Electronics and suitable for secondary rectification in switching regulators, reverse-current protection in mobile devices, and high-density power modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for CMS15I40A 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

Toshiba Electronic Devices & Storage Corporation is a global semiconductor manufacturer specializing in power devices, logic ICs, and memory solutions, with deep expertise in discrete power components for consumer, industrial, and automotive markets.

The CMS15I40A belongs to Toshiba's M-FLAT Schottky diode product line, engineered specifically for high-efficiency, space-constrained DC-DC conversion in portable electronics and battery-powered systems.

FAQ

What is the maximum junction temperature specification for CMS15I40A?

The absolute maximum junction temperature (Tj) for CMS15I40A is 150 °C, but Toshiba recommends limiting steady-state operation to ≤120 °C to ensure high reliability and avoid thermal runaway. This derating is critical because Schottky diodes exhibit increasing reverse leakage with temperature, which can accelerate self-heating. The CMS15I40A datasheet provides Ta(max)-IF(AV) curves to guide safe operating area selection based on ambient conditions and board layout.

Does CMS15I40A have a specified thermal resistance from junction to lead (Rth(j-ℓ))?

Yes, CMS15I40A has a specified Rth(j-ℓ) of 16 °C/W, measured from junction to cathode lead. This parameter is essential for thermal modeling in compact designs where the cathode pad serves as the primary heat path to the PCB. Unlike junction-to-ambient values-which vary significantly with board construction-Rth(j-ℓ) remains consistent and enables accurate prediction of temperature rise under known power dissipation, especially when using internal copper layers or thermal vias beneath the cathode.

What is the peak forward surge current rating for CMS15I40A?

The CMS15I40A has a non-repetitive peak forward surge current (IFSM) rating of 25 A, tested per half-sine wave at 50 Hz. This rating applies only to transient events such as inrush currents during power-up or fault conditions-not continuous operation. Engineers must ensure that system-level fusing or current-limiting circuits prevent repeated exposure to IFSM-level stress, as exceeding this value even once may cause permanent degradation of the Schottky junction integrity in the CMS15I40A.

Is CMS15I40A suitable for USB-C Power Delivery input protection?

Yes, CMS15I40A is suitable for USB-C PD input protection due to its 40 V VRRM rating (exceeding USB-C VBUS max of 20 V), low 0.49 V max VF (preserving voltage margin), and compact M-FLAT package that fits near connectors. Its 100 µA max reverse leakage at 40 V prevents excessive standby drain, and RoHS compliance meets USB-C ecosystem requirements. However, designers must verify thermal performance under worst-case 3 A PD loads using the provided Rth(j-a) data for their specific board stack-up.

What does the marking "SR" indicate on CMS15I40A?

The marking "SR" on the CMS15I40A device body is the Toshiba part identification code for this Schottky rectifier variant, confirming it as the CMS15I40A in the M-FLAT (3-4E1S) package. It appears alongside the full part number "CMS15I40A" and date code on the top surface. This marking enables visual verification during assembly and inspection, distinguishing it from other Toshiba Schottky diodes like CMS10I40A or CMS20I40A, and ensures traceability to the correct datasheet revision (Rev. 1.0.A, dated 2026-04-07).