Microchip Technology CDLL4133

Overview

CDLL4133 from Microsemi is a hermetically sealed, surface-mount silicon Zener diode in DO-213AA (MELF/LL34) package, rated for 87 V nominal Zener voltage at 250 µA test current, 1000 Ω maximum Zener impedance, and 4.4 mA maximum Zener current, used for precision voltage regulation in aerospace and high-reliability power supply circuits.

For engineers reviewing the CDLL4133 datasheet, CDLL4133 pinout, CDLL4133 application, or CDLL4133 equivalent, key selection criteria include its ±5% Zener tolerance, -65°C to +175°C operating temperature range, 500 mW power dissipation at 125°C, low-leakage performance (≤0.01 µA at 66.12 V), and hermetic glass construction for long-term stability under thermal cycling.

Technical Context

The CDLL4133 operates as a two-terminal voltage reference device with cathode-banded polarity, requiring reverse-bias connection. Its Zener breakdown mechanism delivers stable regulation at 87 V with 1000 Ω dynamic impedance measured at 250 µA DC test current and 60 Hz AC perturbation.

Thermal design must account for 100 °C/W junction-to-case thermal resistance at zero lead length and a +6 ppm/°C axial coefficient of expansion, mandating matched COE mounting surfaces to prevent mechanical stress-induced parameter drift or hermetic seal failure.

Key Specifications

Pinout & Package

Package: DO-213AA (MELF/LL34), hermetically sealed glass case with tin/lead lead finish; axial symmetry requires orientation verification via cathode band marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CDLL4133, 1N4133UR-1 offers identical electrical specs with enhanced screening for defense use, while BZX85C82 trades hermetic reliability and low leakage for higher power and lower cost in non-critical applications.

Availability

CDLL4133 is available at Aetrix Electronics and suitable for aerospace power conditioning, downhole instrumentation, military avionics reference, and high-reliability test equipment requiring stable component supply across extended temperature ranges and long service lifetimes.

Supply support for CDLL4133 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 and mixed-signal components for aerospace, defense, and industrial markets.

The CDLL4099–CDLL4135 series was designed specifically for precision voltage reference and regulation in mission-critical systems where hermeticity, wide temperature operation, and long-term parametric stability are mandatory.

FAQ

What is the Zener voltage tolerance for CDLL4133?

The CDLL4133 has a nominal Zener voltage of 87 V with a tolerance of ±5%, measured at 250 µA test current and 25°C ambient temperature. This tolerance is specified per Note 1 in the official Microsemi datasheet and applies to all CDLL4099–CDLL4135 devices unless modified by a "C" (+2%) or "D" (+1%) suffix, which CDLL4133 does not carry. The CDLL4133 maintains this tolerance across its full operating temperature range.

Does CDLL4133 require heatsinking in typical applications?

No, CDLL4133 does not require external heatsinking in standard operation because its maximum power dissipation is 500 mW at 125°C end-cap temperature, and its thermal resistance is 100 °C/W at zero lead length. At 4.4 mA maximum Zener current and 87 V, power dissipation remains below 383 mW, well within derated limits. The CDLL4133 relies on PCB copper area and ambient airflow for thermal management.

Can CDLL4133 be used in place of CDLL4132 or CDLL4134?

CDLL4133 is not a direct replacement for CDLL4132 (82 V) or CDLL4134 (91 V) due to its specific 87 V Zener voltage. Substituting alters regulation setpoints by ±5 V, potentially violating system voltage margins. The CDLL4133 must be selected only when 87 V is explicitly required; voltage-sensitive circuits like feedback dividers or overvoltage clamps will malfunction if replaced with adjacent family members.

What is the meaning of the "CDLL" prefix in CDLL4133?

The "CDLL" prefix identifies Microsemi's commercial-grade, hermetically sealed Zener diode series in DO-213AA (LL34) package, distinguishing it from military variants (e.g., 1N4133UR-1) and other package types. CDLL4133 belongs to the CDLL4099–CDLL4135 family, all sharing identical construction, thermal characteristics, and test conditions, with differentiation solely by Zener voltage rating.

Is CDLL4133 RoHS compliant?

CDLL4133 is not RoHS compliant due to its tin/lead lead finish and hermetic glass construction, which predate RoHS requirements and are retained for reliability in high-reliability applications. It complies with MIL-PRF-19500/435 for JANTX-level screening but contains lead per exemption 7a. For RoHS-compliant alternatives, consult Microchip's current-generation Zener offerings, as CDLL4133 remains a legacy high-reliability part.