Microchip Technology CDLL4624

Overview

CDLL4624 from Microsemi is a hermetically sealed, glass-encapsulated MELF (DO-213AA) Zener diode with nominal 4.7 V zener voltage, 250 µA test current, 1550 Ω maximum zener impedance at I_ZT, 10 µA maximum reverse leakage at 3.0 V, and 75 mA maximum DC zener current. It operates from −65°C to +175°C and is used for precision voltage reference and overvoltage protection in high-reliability aerospace and military power supplies.

For engineers reviewing the CDLL4624 datasheet, CDLL4624 pinout, CDLL4624 application, or CDLL4624 equivalent, key selection criteria include its ±5% zener tolerance, low 10 mW/°C derating above +125°C, hermetic DO-213AA package, 500 mW power rating at T_EC = +125°C, and compatibility with MIL-PRF-19500/435 Class JANTXV screening.

Technical Context

The CDLL4624 functions as a two-terminal, silicon planar junction Zener diode optimized for stable voltage regulation under low-current conditions (I_ZT = 250 µA). Its metallurgically bonded construction ensures long-term stability and low noise performance in harsh thermal environments.

Designed for operation with cathode (banded end) positive, it exhibits a zener impedance of 1550 Ω at 250 µA and maintains ≤10 µA reverse leakage at 3.0 V - critical for low-power biasing and reference circuits where leakage-induced error must be minimized.

Key Specifications

Pinout & Package

Package: DO-213AA (MELF, SOD-80, LL34), hermetically sealed glass case with tin/lead lead finish. Axial coefficient of expansion ≈ +6 ppm/°C; requires matched COE mounting surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4624UR-1, CDLL4624 offers identical core regulation performance but may require separate screening order fulfillment; compared with CDLL4623, CDLL4624 provides higher reference voltage with slightly higher zener impedance and relaxed leakage spec - enabling trade-offs between voltage headroom and low-voltage leakage sensitivity.

Availability

CDLL4624 is available at Aetrix Electronics and suitable for aerospace power conditioning, military voltage reference, and downhole sensor biasing requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CDLL4624 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

Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog, RF, and radiation-hardened components for defense, aerospace, and industrial markets.

The CDLL4624 belongs to Microsemi's legacy MIL-PRF-19500/435 Zener diode family, designed specifically for precision voltage regulation in mission-critical systems where hermeticity, thermal stability, and long-term parametric consistency are mandatory.

FAQ

What is the zener voltage tolerance for CDLL4624?

The CDLL4624 has a nominal zener voltage of 4.7 V with a tolerance of ±5%, as specified in Note 1 of the manufacturer's datasheet. This tolerance applies when measured at 25°C ± 3°C with the device junction in thermal equilibrium. Tighter tolerances (±2% or ±1%) are available with "C" or "D" suffixes, respectively - but those are distinct orderable variants, not inherent to the base CDLL4624 part number.

Is CDLL4624 suitable for surface-mount assembly?

Yes, CDLL4624 uses the DO-213AA (MELF) package, which is a leadless cylindrical surface-mount format also designated SOD-80 and LL34. Its glass body and axial symmetry allow compatible placement on SMT lines using standard MELF feeders and reflow profiles, though careful attention to thermal expansion matching is required due to its +6 ppm/°C COE.

What is the maximum power dissipation for CDLL4624 at +150°C?

At an end-cap temperature (T_EC) of +150°C, CDLL4624's maximum power dissipation is 250 mW. This follows the linear derating curve: 500 mW at +125°C, decreasing by 10 mW/°C above that point. So at +150°C, derating is 25 × 10 mW = 250 mW reduction, leaving 250 mW usable power - confirmed in Figure 2 of the official datasheet.

Does CDLL4624 have a defined forward voltage specification?

No, the CDLL4624 datasheet does not specify forward voltage. As a Zener diode intended for reverse-bias operation, its primary characterization is in breakdown mode. Forward conduction is not a rated function; however, typical silicon diode forward voltage (~0.7–1.1 V at 200 mA) may apply if forward-biased, but this is outside guaranteed specifications and not tested or warranted for CDLL4624.

Can CDLL4624 replace CDLL4625 in a 5.1 V reference circuit?

No, CDLL4624 cannot directly replace CDLL4625 in a 5.1 V reference circuit because its nominal zener voltage is 4.7 V - a 0.4 V difference outside typical system tolerance bands. Substituting would cause incorrect biasing or regulation. If redesign is possible, verify whether downstream circuitry can accommodate the lower voltage and reassess leakage, impedance, and power requirements at the new operating point.