onsemi CM1218-04SO

Overview

CM1218-04SO from onsemi is a 4-channel low-capacitance transient voltage suppressor (TVS) array designed for ESD protection of high-speed data lines. It features ±15 kV IEC 61000−4−2 contact discharge rating, 7 pF typical channel input capacitance, 5.5 V reverse stand-off voltage, and SOT-23-5 surface-mount package. It is used to safeguard USB, serial, and IEEE1394 interface pins against electrostatic discharge.

For engineers reviewing the CM1218-04SO datasheet, pinout, applications, or equivalent options, key selection criteria include channel count, I/O capacitance, ESD withstand level, leakage current at 5 V, and compatibility with space-constrained PCB layouts using SOT-23-5 footprint.

Technical Context

The CM1218-04SO integrates four bidirectional TVS diodes in a single SOT-23-5 package, with a common anode (VN) terminal and four cathode terminals (CH1–CH4). Each channel provides clamping during both positive and negative ESD transients, with small-signal clamp voltages of +6.8 V (positive) and −0.8 V (negative) at ±10 mA.

It operates across −40°C to +85°C, supports ≤1000 ESD strikes per pin, and exhibits 1 µA max leakage at 5.0 VDC. Its 7 pF typical input capacitance ensures minimal signal integrity impact on high-speed interfaces such as USB 2.0.

Key Specifications

Pinout & Package

SOT-23-5 package (Case 527AH), 5-pin surface-mount device with gull-wing leads. Dimensions: 2.90 mm × 2.80 mm × 1.45 mm. RoHS-compliant and Pb-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPD4E001DRYR, CM1218-04SO offers higher power handling (0.225 W vs. 0.15 W) and proven robustness in industrial environments, while ESD5Z4.5T5G demands four placements and introduces inter-channel skew - making CM1218-04SO the optimal balance of integration, performance, and manufacturability for 4-line protection.

Availability

CM1218-04SO is available at Aetrix Electronics and suitable for USB interface protection, industrial serial port hardening, and docking station signal line safeguarding requiring stable component supply and long-term production continuity.

Supply support for CM1218-04SO 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 silicon solutions for automotive, industrial, cloud, and consumer markets.

The CM1218 family is part of onsemi's transient protection product line, engineered specifically for high-speed digital interface ESD hardening in space- and performance-critical applications.

FAQ

What is the maximum operating temperature range for the CM1218-04SO?

The CM1218-04SO is rated for continuous operation from −40°C to +85°C, as specified in Table 2 of its datasheet. This range covers standard commercial and industrial ambient conditions, and thermal derating is not required within these limits. The device maintains its ±15 kV ESD rating and 7 pF capacitance stability across the full span, making CM1218-04SO suitable for deployment in uncontrolled environments like factory floors or consumer living spaces.

Does the CM1218-04SO require external components for basic ESD protection?

No, the CM1218-04SO is a fully integrated 4-channel TVS array that functions without external resistors, capacitors, or ferrites. Its internal bidirectional diode structure provides complete clamping from each cathode (CH1–CH4) to the common anode (VN), which must be connected directly to a low-impedance ground plane. This self-contained architecture eliminates component count and layout dependencies, and CM1218-04SO delivers full IEC 61000−4−2 compliance out-of-the-box.

How does the CM1218-04SO compare to discrete TVS diodes in terms of board space?

The CM1218-04SO occupies a single SOT-23-5 footprint (2.90 × 2.80 mm), whereas four discrete 0402 or SOD-523 TVS diodes plus associated traces and pads would consume ≥12 mm² - more than double the area. CM1218-04SO also removes inter-trace coupling risks and routing congestion near connectors. For high-density PCBs like ultrabooks or compact IoT gateways, this consolidation directly enables smaller form factors and faster layout completion, and CM1218-04SO is routinely selected for such space-constrained deployments.

Is the CM1218-04SO compatible with lead-free reflow soldering processes?

Yes, the CM1218-04SO is Pb-free and qualified for standard lead-free reflow profiles, including JEDEC J-STD-020-compliant peak temperatures up to 260°C. Its SOT-23-5 package uses matte tin plating and passes MSL-1 moisture sensitivity classification, eliminating bake requirements prior to assembly. onsemi provides detailed soldering guidelines in the Soldering and Mounting Techniques Reference Manual (SOLDERRM/D), and CM1218-04SO has been validated in high-volume manufacturing with no tombstoning or voiding issues.

Can the CM1218-04SO protect 3.3 V logic interfaces without affecting signal integrity?

Yes - with a 5.5 V reverse stand-off voltage and only 1 µA leakage at 5.0 V, the CM1218-04SO remains fully non-conductive at 3.3 V nominal operation. Its 7 pF typical capacitance introduces negligible loading on 3.3 V LVCMOS or LVTTL signals, preserving rise/fall times and noise margins. Real-world validation shows no measurable jitter or eye diagram degradation on 3.3 V UART or SPI lines, confirming CM1218-04SO's suitability for mixed-voltage systems where both 3.3 V and 5 V interfaces coexist.