onsemi MMQA6V8T1

Overview

MMQA6V8T1 from ON Semiconductor is a quad monolithic common-anode ESD protection diode in SC−74 package, rated for 6.8 V nominal Zener voltage (6.46–7.14 V), 9.8 V max clamping voltage at 2.45 A surge current, and 24 W peak pulse power (1.0 ms). It protects four I/O lines simultaneously in space-constrained interfaces such as USB, keyboard, or microprocessor buses.

For engineers reviewing the MMQA6V8T1 datasheet, pinout, applications, or equivalent options, key selection factors include unidirectional clamping performance, 100–250 pF capacitance at 0 V bias, Class 3B ESD rating (>16 kV HBM), and SC−74 footprint compatibility with high-density PCB layouts.

Technical Context

The MMQA6V8T1 implements a quad-junction common-anode silicon structure enabling four independent unidirectional TVS paths sharing one anode terminal (pins 2 and 5). Each cathode-anode pair operates with 6.8 V breakdown and sub-10 V clamping under 2.45 A transient current per Figure 5 waveform.

Thermal design relies on FR-5 board derating (225 mW @ 25°C, R_JA = 556°C/W) or alumina substrate (300 mW, R_JA = 417°C/W). Its low leakage (<500 nA @ 4.3 V) and 100–250 pF junction capacitance support signal integrity in data-line protection up to ~100 MHz.

Key Specifications

Pinout & Package

SC−74 package (Case 318F, Style 1) measures 3.0 × 1.5 × 0.95 mm with gull-wing leads; optimized for automated SMT assembly and 8 mm tape-and-reel handling (3,000 units/reel).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ESD5V3U2M and TPD4E001DPYR, the MMQA6V8T1 offers balanced trade-offs: moderate 100–250 pF capacitance, 9.8 V clamping, and 24 W pulse rating-making it optimal for cost-sensitive, space-constrained 5 V interface protection where both robustness and signal integrity matter.

Availability

MMQA6V8T1 is available at Aetrix Electronics and suitable for USB interface protection, keyboard/mouse I/O shielding, and microprocessor bus safeguarding requiring stable component supply across industrial, computing, and peripheral OEM programs.

Supply support for MMQA6V8T1 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensors, and ESD protection solutions for automotive, industrial, and computing markets.

The MMQA6V8T1 belongs to ON Semiconductor's quad common-anode ESD protection diode family, engineered to deliver multi-line transient suppression in minimal PCB area for space-constrained digital interfaces.

FAQ

What is the maximum clamping voltage of the MMQA6V8T1 under standard ESD test conditions?

The MMQA6V8T1 exhibits a maximum clamping voltage of 9.8 V at 2.45 A peak pulse current, measured using the 10 × 1000 µs waveform per Figure 5 in the official datasheet. This value ensures protected circuitry remains within safe operating limits during IEC 61000-4-2 Level 4 ESD events. The MMQA6V8T1 maintains this clamping performance consistently across its specified temperature range (−55°C to +150°C).

How does the common-anode configuration of the MMQA6V8T1 simplify PCB layout compared to discrete diodes?

The MMQA6V8T1 integrates four independent cathode terminals (pins 1, 3, 4, 6) with two shared anode pins (2 and 5), allowing simultaneous protection of four signal lines using a single SC−74 footprint. This reduces required PCB area by ~75% versus four discrete SOD-323 diodes and eliminates four separate ground traces, lowering parasitic inductance and improving ESD response uniformity. The MMQA6V8T1 thus enables denser routing in compact consumer electronics.

Is the MMQA6V8T1 suitable for protecting high-speed data lines like USB 2.0?

Yes-the MMQA6V8T1's 100–250 pF junction capacitance at 0 V bias and 9.8 V clamping voltage make it appropriate for USB 2.0 full-speed (12 Mbps) interfaces. Its low leakage (<500 nA) prevents DC loading, and the SC−74 package's short internal traces minimize inductance. For USB 2.0, the MMQA6V8T1 is typically placed adjacent to the connector with direct trace routing to maintain signal integrity while delivering certified ESD immunity.

What is the thermal resistance and power derating behavior of the MMQA6V8T1 on standard FR-5 PCBs?

On FR-5 boards, the MMQA6V8T1 has a junction-to-ambient thermal resistance (R_JA) of 556°C/W and a total power dissipation rating of 225 mW at 25°C ambient. Power must be linearly derated above 25°C at 1.8 mW/°C, reaching zero at ~150°C. This derating curve (Figure 4) ensures safe operation in enclosed industrial enclosures where ambient temperatures may exceed 70°C, provided adequate copper pour is used around pins 2 and 5.

Does the MMQA6V8T1 meet automotive qualification standards?

The base MMQA6V8T1 is not AEC−Q101 qualified; however, its automotive-grade variant SZMMQA6V8T1G is fully qualified per AEC−Q101 and PPAP capable. Both share identical electrical specs and SC−74 packaging, but the SZ-prefix version undergoes additional stress testing (temperature cycling, humidity, mechanical shock) and traceable lot control. For automotive designs, specify SZMMQA6V8T1G-not MMQA6V8T1-to ensure compliance.