Renesas RD4.7JS-T4

Overview

RD4.7JS-T4 from Renesas Electronics is a 4.7 V, ±5% tolerance, 400 mW glass-encapsulated Zener diode in DO-34 package, designed for precision voltage regulation and waveform clipping in low-noise analog circuits. It delivers sharp breakdown characteristics with 10 Ω dynamic impedance at 5 mA and supports reverse surge power up to 2.4 W (10 µs pulse).

For engineers reviewing the RD4.7JS-T4 datasheet, RD4.7JS-T4 pinout, RD4.7JS-T4 application, or RD4.7JS-T4 equivalent, this component is selected for stable reference generation in power supply feedback loops, overvoltage protection clamping, and low-jitter signal conditioning where tight V_Z tolerance and low noise (<50 µV) are critical.

Technical Context

The RD4.7JS-T4 operates as a two-terminal voltage reference device relying on controlled avalanche breakdown in silicon. Its DO-34 glass package ensures hermetic sealing and thermal stability up to 175 °C junction temperature, with a nominal Zener voltage of 4.7 V measured at 5 mA test current under pulsed conditions (40 ms).

It exhibits a negative temperature coefficient of −0.02 %/°C near 4.7 V, enabling predictable drift behavior in ambient ranges from −65 °C to +175 °C. The device maintains low dynamic impedance (Z_z = 10 Ω) and knee impedance (Z_zk = 150 Ω), supporting stable regulation under varying load currents.

Key Specifications

Pinout & Package

RD4.7JS-T4 uses a DO-34 axial glass package (JEDEC standard) with cathode indicated by a blue band. Total body length ≤2.4 mm; lead diameter 0.4 mm; marking color: blue.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RD4.7JS-T4, the 1N4732A offers greater thermal robustness at the cost of board area, while BZX55-C4V7 provides RoHS alignment and modest power uplift but with reduced low-current regulation precision due to higher Z_z.

Availability

RD4.7JS-T4 is available at Aetrix Electronics and suitable for switch-mode power supplies, overvoltage protection circuits, and low-noise analog bias networks requiring stable component supply and long-lifecycle support.

Supply support for RD4.7JS-T4 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

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and timing solutions for industrial, automotive, and consumer systems.

The RD4.7JS-T4 belongs to Renesas' legacy Zener diode family optimized for precision voltage reference and clamping in cost-sensitive, high-reliability industrial applications.

FAQ

What is the Zener voltage tolerance and test condition for RD4.7JS-T4?

The RD4.7JS-T4 has a Zener voltage tolerance of ±5% at a test current of 5 mA, measured using a 40 ms pulse to minimize self-heating effects. This tolerance applies to the AB1, AB2, and AB3 suffix variants, with nominal V_Z ranging from 4.42 V to 4.90 V depending on grade. RD4.7JS-T4 maintains this specification across its full operating temperature range when used within rated power limits.

Does RD4.7JS-T4 support surge protection, and what are its pulse ratings?

Yes, RD4.7JS-T4 supports transient surge protection with a non-repetitive surge reverse power rating of 2.4 W at a pulse width of 10 µs. This capability allows it to absorb short-duration overvoltage events such as ESD or inductive switching spikes without degradation. RD4.7JS-T4 must be used within its absolute maximum ratings, and repeated surges require derating per Fig. 9 in the datasheet.

What is the thermal resistance and maximum junction temperature of RD4.7JS-T4?

RD4.7JS-T4 has a junction-to-ambient thermal resistance (R_th) of approximately 375 °C/W on a standard 3 mm × 3 mm copper pad (0.035 mm thick), and its maximum rated junction temperature is 175 °C. This allows reliable operation in environments up to +125 °C ambient when power dissipation remains within derated limits per Fig. 5. RD4.7JS-T4's glass DO-34 package contributes to stable thermal performance over time.

How does the noise performance of RD4.7JS-T4 compare to other 4.7 V Zeners?

RD4.7JS-T4 delivers sub-50 µV RMS noise in the 10–500 kHz band, significantly lower than standard 4.7 V Zeners like the 1N4732A (typically >100 µV). This low-noise characteristic stems from its DHD (Double Heatsink Diode) construction and optimized silicon process. RD4.7JS-T4 is therefore preferred in audio biasing, sensor excitation, and precision reference applications where noise directly impacts system SNR.

Is RD4.7JS-T4 RoHS compliant, and what is its quality grade?

RD4.7JS-T4 is classified as "Standard" quality grade per Renesas documentation, intended for computers, office equipment, communications gear, and industrial robots. While the original datasheet predates RoHS enforcement, Renesas confirms legacy DO-34 Zeners including RD4.7JS-T4 meet RoHS Directive 2011/65/EU requirements. RD4.7JS-T4 contains no lead exemptions and is fully compliant with lead-free soldering processes.