Toshiba Semiconductor and Storage CRS20I40B(TE85L,QM

Overview

CRS20I40B from Toshiba Electronic Devices & Storage Corporation is a Schottky barrier diode optimized for secondary rectification and reverse-current protection in compact DC-DC converters and mobile power circuits. It delivers V_RRM = 40 V, I_F(AV) = 2.0 A, V_FM ≤ 0.52 V at 2.0 A, R_th(j-a) = 70 °C/W (on ceramic board), and uses the ultra-thin S-FLAT (3-2A1S) surface-mount package.

For engineers reviewing the CRS20I40B datasheet, CRS20I40B pinout, CRS20I40B application, or CRS20I40B equivalent, this page provides verified electrical specs, thermal behavior under real mounting conditions, junction-to-lead thermal resistance data, and validated use cases in high-density portable power systems.

Technical Context

This Schottky diode employs a low-barrier metal-semiconductor junction to minimize forward conduction loss while maintaining fast switching response-critical for high-frequency synchronous rectification in buck converters operating above 300 kHz. Its 40 V V_RRM rating targets 5–24 V output rails where low V_F directly improves efficiency over silicon PN diodes.

The S-FLAT package enables direct thermal coupling to PCB copper via cathode lead, with R_th(j-ℓ) = 20 °C/W enabling effective heat extraction in space-constrained layouts. Junction temperature must be derated per Toshiba's reliability guidelines when ambient exceeds 85 °C or surge current exceeds 25 A.

Key Specifications

Pinout & Package

Package: S-FLAT (TOSHIBA designation 3-2A1S), ultra-thin surface-mount package with exposed cathode lead for thermal enhancement. Dimensions: 2.9 mm × 1.6 mm × 0.6 mm (L × W × H), weight 0.013 g (typ.).

Key Features

Applications

Equivalent & Alternatives

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

Compared with RB055LAM-40TR and SS24-HF, the CRS20I40B uniquely balances ultra-low profile (0.6 mm), precise 2.0 A rating, and optimized thermal resistance for space-limited mobile and wearable power stages-making it irreplaceable where Z-height and PCB copper area are constrained.

Availability

CRS20I40B is available at Aetrix Electronics and suitable for USB-C PD adapters, smartphone PMIC subsystems, and industrial IoT sensor node power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for CRS20I40B 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 designs and manufactures discrete semiconductors, power devices, and logic ICs with emphasis on energy efficiency, miniaturization, and automotive-grade reliability.

The CRS20I40B belongs to Toshiba's S-FLAT Schottky diode product line, engineered specifically for high-density DC-DC converter secondary-side rectification and reverse-current protection in portable and battery-powered electronics.

FAQ

What is the maximum allowable junction temperature for CRS20I40B during continuous operation?

The absolute maximum junction temperature (T_j) for CRS20I40B is 150 °C. However, Toshiba recommends limiting steady-state T_j to ≤120 °C (80 % of rating) to ensure long-term reliability. This requires proper PCB thermal design-especially using the cathode lead for heat transfer-and derating I_F(AV) when ambient temperature exceeds 85 °C. The CRS20I40B datasheet provides Ta(max)-IF(AV) derating curves for both ceramic and FR-4 board conditions.

Does CRS20I40B support high-frequency switching applications such as those found in GaN-based USB-C PD adapters?

Yes, CRS20I40B is explicitly designed for high-frequency switching applications. Its Schottky structure provides negligible reverse recovery time, enabling efficient operation at frequencies up to 1 MHz. The 62 pF junction capacitance at 10 V and low V_FM make it suitable for 200–500 kHz GaN-based USB-C PD adapters where low conduction loss and minimal switching noise are critical. CRS20I40B has been validated in secondary rectification roles in commercial 45 W adapters.

What is the thermal resistance from junction to ambient (R_th(j-a)) for CRS20I40B, and how does mounting affect it?

CRS20I40B exhibits R_th(j-a) = 70 °C/W when mounted on a 50 mm × 50 mm ceramic board with 2 mm × 2 mm solder land. On a standard 50 mm × 50 mm FR-4 board with 6 mm × 6 mm land, R_th(j-a) rises to 140 °C/W. Mounting directly impacts thermal performance: increasing cathode land size or adding internal copper layers lowers R_th(j-a), while insufficient copper area risks exceeding T_j limits. CRS20I40B's R_th(j-ℓ) = 20 °C/W highlights its reliance on cathode-to-PCB conduction.

Can CRS20I40B be used as a direct replacement for conventional silicon diodes in existing 5 V/2 A power supplies?

CRS20I40B can replace silicon diodes in 5 V/2 A supplies-but only after verifying layout compatibility and thermal margins. Its S-FLAT package (2.9 mm × 1.6 mm × 0.6 mm) differs from common SOD-123 or SMA footprints. Electrical benefits include lower V_FM (0.52 V vs. ~0.7–1.1 V), reducing conduction loss by ~0.4 W. However, higher reverse leakage (≤100 µA) requires checking if downstream circuitry tolerates it. CRS20I40B is not a drop-in mechanical replacement without land pattern revision.

What marking code identifies CRS20I40B on the physical device?

The CRS20I40B is marked with the code "SU" on its top surface, per Toshiba's official marking specification. This two-character laser mark appears adjacent to the cathode band and is consistent across all production lots. The full part number "CRS20I40B" appears in Toshiba's packaging labels and reel documentation, but only "SU" is laser-etched on the S-FLAT package body for traceability and space constraints.