Nexperia USA Inc. BZX585-C51,115

Overview

BZX585-C51,115 from Nexperia is a ±5 % tolerance Zener diode in SOD523 (SC-79) package, rated for 51 V nominal Zener voltage at 2 mA test current, 300 mW total power dissipation, and 40 W non-repetitive peak reverse power handling - used for precision voltage reference and overvoltage protection in low-power sensor interfaces and microcontroller I/O rail clamping.

For engineers reviewing the BZX585-C51,115 datasheet, BZX585-C51,115 pinout, BZX585-C51,115 application, or BZX585-C51,115 equivalent, this device serves as a compact, thermally efficient voltage regulation solution where tight voltage tolerance, low differential resistance (≤90 Ω at I_Z = 2 mA), and stable temperature coefficient (+51.0 mV/K typical) are critical for analog signal conditioning and ESD-robust power rail stabilization.

Technical Context

This Zener diode operates in reverse breakdown mode with a specified Zener voltage of 48.45 V to 53.55 V at I_Z = 2 mA, exhibiting a typical temperature coefficient of +51.0 mV/K and differential resistance of 90 Ω (max) under same conditions. Its SC-79 package enables high-density PCB layouts while maintaining thermal resistance of 65 K/W from junction to solder point.

The device supports non-repetitive surge events up to 100 µs square-wave pulses at 40 W, with maximum reverse current I_ZSM of 0.4 A under those conditions. It maintains <0.05 µA reverse leakage at VR = 38.2 V and operates across −65 °C to +150 °C junction temperature range.

Key Specifications

Pinout & Package

SOD523 (SC-79) ultra-small flat-lead surface-mount plastic package with cathode band marking; dimensions: 1.25 mm × 0.85 mm × 0.65 mm (L × W × H), 2-terminal configuration.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX585-B51,115, the C-grade offers relaxed tolerance at lower cost and identical surge capability; versus MMSZ5257B-7-F, it trades off power headroom for 60 % smaller area - making it optimal for space-constrained, cost-sensitive 51 V reference nodes.

Availability

BZX585-C51,115 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, microcontroller I/O protection, low-power battery monitor reference, and optocoupler feedback regulation requiring stable component supply, consistent parametric performance, and long-term obsolescence management.

Supply support for BZX585-C51,115 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

Nexperia is a global semiconductor expert focused on high-volume, high-reliability discrete and logic devices, with leadership in advanced packaging and automotive-qualified components.

The BZX585 series belongs to Nexperia's general-purpose Zener diode product line, engineered for compact, thermally efficient voltage regulation and transient suppression in consumer, industrial, and communications equipment.

FAQ

What is the maximum continuous forward current for BZX585-C51,115?

The absolute maximum forward current is 200 mA per limiting values table. However, forward conduction is not its intended operating mode; the device is designed for reverse-bias Zener operation. Forward voltage is specified at 100 mA (≤1.1 V), but sustained forward bias above 10 mA risks thermal overstress due to low thermal mass in SOD523.

Can BZX585-C51,115 be used in place of a 50 V Zener diode?

No - its nominal Zener voltage is 51 V with a guaranteed range of 48.45 V to 53.55 V at 2 mA. Substituting for a true 50 V part introduces up to +3.55 V offset, potentially violating downstream circuit thresholds. For 50 V applications, BZX585-C50 does not exist; BZX585-C47 (44.65–49.35 V) or BZX585-C51 must be validated against system-level tolerance budgets.

How does the temperature coefficient affect regulation accuracy over −40 °C to +85 °C?

With a typical S_Z of +51.0 mV/K, V_Z shifts approximately +6.4 V across 125 K ΔT. At 25 °C, V_Z = 51.0 V; at 85 °C, it rises to ~54.2 V. This drift must be accommodated in reference designs - e.g., by pairing with negative-TC components or implementing software calibration based on temperature sensor readings.

Is the SOD523 package compatible with standard reflow profiles for lead-free assembly?

Yes - Nexperia specifies compatibility with JEDEC J-STD-020D.2 lead-free reflow profile: peak temperature 260 °C, time above liquidus 60–150 s, ramp-up rate ≤3 °C/s. The recommended solder land pattern (Fig. 12) uses 0.5 mm pad width and 1.4 mm center-to-center spacing to ensure reliable wetting and mechanical strength without tombstoning.