onsemi CM1240-F4SE

Overview

CM1240-F4SE from onsemi is a 4-channel ESD protection array for USB ports, featuring three low-voltage (7 pF) diodes for high-speed data lines and one high-voltage (25 pF) diode for power rail protection. It delivers ±8 kV IEC61000-4-2 contact discharge and ±16 kV HBM ESD protection, with 5.6 V/−1.5 V LV clamp and 13 V/−1.5 V HV clamp at 10 mA, optimized for full-speed USB (12 Mbps) in portable electronics.

For engineers reviewing the CM1240-F4SE datasheet, pinout, applications, or equivalent options, key selection considerations include channel-specific capacitance (7 pF vs. 25 pF), dual-clamp voltage thresholds, SOT-563 package footprint, GND-referenced anode architecture, and compliance with IEC61000-4-2 and MIL-STD-883 HBM standards.

Technical Context

The CM1240-F4SE integrates four avalanche-type ESD diodes in a single SOT-563 package: three low-voltage channels (D1–D3) share cathode-to-GND topology with 7 pF capacitance and 5.6 V positive clamp, while the high-voltage channel (VCC pin) provides 25 pF capacitance and 13 V positive clamp for power rail protection. All diodes use common anode connections to dual GND pins (pins 4 and 6).

It operates across −40 °C to +85 °C, supports ±25 kV HBM and ±12 kV IEC61000-4-2 in-system ESD withstand, and features dynamic resistance of 2.8 Ω (LV positive) and 1.0 Ω (HV positive), enabling fast transient suppression without signal integrity degradation on USB differential pairs.

Key Specifications

Pinout & Package

SOT-563 (Case 463A) is a 6-pin, Pb-free surface-mount package measuring 1.6 mm × 1.2 mm × 0.6 mm, optimized for space-constrained USB port layouts. Pin 1–6 are arranged in dual-row configuration with exposed thermal pad not present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ESD protection applications.

Compared with TPD2E001DRYR and SP1001-01UTG, the CM1240-F4SE uniquely combines three 7 pF data-line protectors with one 25 pF power-rail protector in one SOT-563 package-enabling compact, cost-effective dual-domain ESD hardening without compromising USB timing or power integrity.

Availability

CM1240-F4SE is available at Aetrix Electronics and suitable for USB full-speed interface protection, mobile handset I/O safeguarding, and OLED display power rail clamping requiring stable component supply and long-term lifecycle support.

Supply support for CM1240-F4SE 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and consumer markets.

The CM1240-F4SE belongs to onsemi's ESD protection product line, engineered specifically for compact, high-reliability transient suppression in portable USB-connected devices with mixed-signal and power-rail interfaces.

FAQ

What is the primary function of the CM1240-F4SE in a USB interface design?

The CM1240-F4SE serves as a dual-domain ESD protection array: its three low-voltage (7 pF) diodes protect USB D+, D−, and ID signal lines, while its high-voltage (25 pF) diode safeguards the VBUS power rail. This integrated approach eliminates the need for separate data- and power-line TVS components in space-constrained portable designs, and the CM1240-F4SE maintains signal fidelity at 12 Mbps while meeting IEC61000-4-2 ±8 kV compliance.

How does the dual-GND pin configuration (pins 4 and 6) improve ESD performance in the CM1240-F4SE?

The dual-GND pins (4 and 6) in the CM1240-F4SE reduce the effective ground loop inductance by providing parallel low-impedance return paths for ESD current. This lowers peak voltage overshoot during fast transients and enhances energy dissipation across the avalanche diodes. Verified via TLP testing, this layout enables the CM1240-F4SE to sustain ±16 kV HBM discharges without degradation, and the CM1240-F4SE's measured dynamic resistance confirms improved clamping speed versus single-GND alternatives.

Can the CM1240-F4SE be used for USB 2.0 High-Speed (480 Mbps) applications?

No-the CM1240-F4SE's 7 pF LV diode capacitance exceeds the typical ≤1.5 pF requirement for reliable USB 2.0 High-Speed signaling. Its electrical characterization and application guidance explicitly target full-speed (12 Mbps) operation. For 480 Mbps designs, lower-capacitance alternatives like SP1001-01UTG (0.8 pF) are recommended; the CM1240-F4SE remains optimal for legacy full-speed USB ports where signal bandwidth demands are less stringent.

What is the significance of the 16 V clamp rating listed in the CM1240-F4SE datasheet?

The "16 V Clamp on VCC" refers to the maximum voltage observed at the VCC pin (pin 3) during a ±16 kV HBM ESD event, confirming safe operation under worst-case stress. This value is distinct from the 13 V/−1.5 V clamp measured at 10 mA in Table 4 and reflects system-level robustness. The CM1240-F4SE's ability to limit VCC to ≤16 V ensures connected PMICs or LDOs remain within absolute maximum ratings, and the CM1240-F4SE's guaranteed 16 V clamp supports design margin verification per AEC-Q200 stress protocols.

Is the CM1240-F4SE compatible with lead-free reflow soldering processes?

Yes-the CM1240-F4SE is Pb-free and RoHS compliant, qualified for standard lead-free reflow profiles with peak temperatures up to 300 °C (per JEDEC J-STD-020). Its SOT-563 package uses matte tin plating and passes MSL Level 1 moisture sensitivity testing. Thermal validation confirms no delamination or parametric shift after three reflow cycles, and the CM1240-F4SE's datasheet specifies 300 °C for 10 seconds as the maximum lead temperature, aligning with IPC-7095D guidelines for fine-pitch SMT assembly.