Renesas NNCD7.5A-T1

Overview

NNCD7.5A-T1 from NEC (now Renesas Electronics) is an ESD noise clipping diode in DO-34 package with DHD construction, 400 mW power dissipation, 6.88–7.64 V breakdown voltage (V_BR), and 30 kV IEC 1000-4-2 ESD endurance-used for transient overvoltage protection on signal lines in consumer audio interfaces.

For engineers reviewing the NNCD7.5A-T1 datasheet, NNCD7.5A-T1 pinout, NNCD7.5A-T1 application, or NNCD7.5A-T1 equivalent, key selection criteria include dynamic impedance (4.0 Ω), reverse leakage (≤0.5 µA at 4.0 V), junction temperature rating (175 °C), and DO-34 thermal performance under PCB-mount conditions.

Technical Context

This diode operates as a bidirectional voltage-clamping device optimized for electrostatic discharge suppression per IEC 61000-4-2 Level 4 (±30 kV contact). Its DHD (Double Heatsink Diode) structure enhances thermal dissipation in the DO-34 axial package by improving heat transfer through both leads.

It exhibits low dynamic impedance (4.0 Ω typical at 5 mA) and low capacitance (90 pF at 0 V), enabling effective high-speed transient suppression without signal distortion in analog audio and low-speed digital I/O paths.

Key Specifications

Pinout & Package

DO-34 axial-leaded package (body length ≤2.4 mm, diameter ≤2.0 mm), cathode indicated by band. Two-terminal device: Anode and Cathode.

Key Features

Applications

Equivalent & Alternatives

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

Compared with P6KE7.5A and CM1213A-03SO, the NNCD7.5A-T1 offers balanced ESD robustness (30 kV), low capacitance (90 pF), and axial DO-34 compatibility with legacy through-hole designs-making it ideal for cost-sensitive, medium-speed analog and serial interfaces where leaded mounting is retained.

Availability

NNCD7.5A-T1 is available at Aetrix Electronics and suitable for audio line protection, USB 2.0 data lines, and industrial sensor interfaces requiring stable component supply and long-term obsolescence management.

Supply support for NNCD7.5A-T1 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

NEC Corporation (now part of Renesas Electronics) was a Japanese semiconductor pioneer known for high-reliability discrete devices and analog ICs before its 2010 merger.

The NNCD series was developed by NEC specifically for ESD-critical signal-line protection in consumer and industrial equipment, emphasizing robustness, thermal stability, and manufacturability in axial packages.

FAQ

What is the maximum ESD voltage the NNCD7.5A-T1 can withstand?

The NNCD7.5A-T1 is rated for ≥30 kV contact discharge per IEC 61000-4-2, verified under standardized test conditions (150 pF capacitor, 330 Ω series resistor). This rating applies to both positive and negative polarity pulses and reflects guaranteed minimum performance across production lots-not just typical values. The NNCD7.5A-T1 maintains functionality after repeated 30 kV strikes when properly mounted on a PCB with adequate copper area.

Does the NNCD7.5A-T1 have polarity markings, and how is it oriented in circuit?

Yes-the NNCD7.5A-T1 uses standard DO-34 marking: a cathode band indicates the cathode terminal. In bidirectional ESD protection, it is mounted between signal and ground with the banded end toward ground. This orientation allows conduction during positive transients (cathode-to-ground) and negative transients (anode-to-ground), making the NNCD7.5A-T1 function as a symmetrical clamping device despite its polarized construction.

What is the thermal resistance of the NNCD7.5A-T1 under typical PCB mounting?

Per the datasheet's Figure 2, the NNCD7.5A-T1 achieves ~375 °C/W junction-to-ambient thermal resistance on a minimal 3 mm × 3 mm PCB pad (t = 0.035 mm). With larger copper areas (e.g., 10 mm × 10 mm), thermal resistance drops to ~150 °C/W. This directly supports its 400 mW power rating at 25 °C ambient-critical for reliability in NNCD7.5A-T1 deployments where airflow is limited.

Can the NNCD7.5A-T1 be used for DC power rail protection?

No-the NNCD7.5A-T1 is not designed for continuous DC clamping or overvoltage shutdown. Its 7.5 V nominal breakdown is intended for transient suppression only; sustained reverse voltage above 4.0 V increases leakage exponentially, risking thermal runaway. For power rail protection, dedicated crowbar or resettable fuse solutions are required. The NNCD7.5A-T1 must be applied exclusively to signal lines with defined steady-state voltage windows well below V_BR.

Is the NNCD7.5A-T1 RoHS compliant and halogen-free?

The original NNCD7.5A-T1 (1996 datasheet) predates RoHS legislation and does not carry formal RoHS or halogen-free certification. However, Renesas Electronics' current manufacturing process for legacy-discrete equivalents complies with RoHS Directive 2011/65/EU and JEDEC JS709E. Customers requiring compliance documentation for NNCD7.5A-T1 should request Renesas' Product Change Notification (PCN) records confirming material content for the specific lot code.