Product Overview
The Vishay BAT85S-TR is a small signal Schottky diode designed for applications requiring precise low forward voltage performance and fast switching capabilities. This axial-leaded component serves as an efficient barrier diode in compact electronic circuits, delivering reliable rectification and signal handling with minimal power dissipation. Its construction incorporates advanced semiconductor technology to balance low voltage drop with controlled leakage and capacitance characteristics, making it a standard choice for through-hole designs where space and efficiency matter.

Key Features
The BAT85S-TR includes an integrated protection ring that guards against electrostatic discharge, enhancing device robustness during manufacturing, assembly, and field operation. It provides a very low forward voltage across its operating current range, which directly contributes to reduced conduction losses. The diode also supports material categorization aligned with industry compliance definitions, ensuring suitability for diverse production and environmental standards. These attributes combine to deliver high reliability in sensitive low-power environments.

Applications
The BAT85S-TR is specifically intended for circuits where achieving a very low forward voltage drop is critical. Typical uses include signal detection and clamping in analog and digital interfaces, low-power rectification in portable devices, protection networks in sensitive electronics, and general-purpose switching tasks that benefit from its rapid recovery and minimal voltage requirements. Its fast switching profile supports high-frequency signal processing, while the low capacitance aids in preserving signal integrity in RF and mixed-signal designs.

Mechanical Data and Packaging
The diode is housed in a DO-35 (DO-204AH) glass case, offering a compact axial form factor optimized for through-hole mounting on printed circuit boards. The component weighs approximately 125 mg, with a black cathode band providing clear visual polarity identification during inspection and assembly. Available packaging formats include tape and reel with 10,000 units per 14-inch reel utilizing 52 mm tape width, supplied in boxes containing 50,000 units total, as well as ammopack options for high-volume automated insertion processes. These configurations facilitate efficient logistics and compatibility with standard pick-and-place equipment.

Ordering Information
The BAT85S-TR ordering code corresponds to the single-diode configuration supplied in tape and reel packaging. The device marking on the package is BAT85S, enabling straightforward traceability and verification in inventory and production workflows. This variant is part of a family that also includes an ammopack alternative under the BAT85S-TAP code, both sharing identical electrical and mechanical performance.

Absolute Maximum Ratings
Rated at an ambient temperature of 25 °C unless otherwise specified, the BAT85S-TR supports a reverse voltage of 30 V. The peak forward surge current reaches 5 A for pulse durations up to 10 ms. Repetitive peak forward current is limited to 300 mA for pulses shorter than 1 s. Continuous forward current is rated at 200 mA, and average forward current maintains the same 200 mA level under PCB mounting conditions with 4 mm lead length, repetitive peak reverse voltage of 25 V, and ambient temperature of 50 °C. These limits establish safe operating boundaries to prevent thermal runaway, avalanche breakdown, or mechanical stress under transient and steady-state conditions.

Thermal Characteristics
With an ambient temperature of 25 °C unless otherwise noted, the junction-to-ambient thermal resistance measures 350 K/W when leads are 4 mm long and lead temperature is held constant. Maximum junction temperature is 125 °C, while the storage temperature range extends from -65 °C to +150 °C. These thermal parameters guide heatsinking decisions and derating calculations in high-density board layouts, ensuring junction temperatures remain below the specified limit to preserve long-term parameter stability and prevent accelerated degradation.

Electrical Characteristics
Evaluated at an ambient temperature of 25 °C unless otherwise specified, forward voltage values are 240 mV at 0.1 mA forward current, 320 mV at 1 mA, 400 mV at 10 mA, 500 mV at 30 mA, and 800 mV at 100 mA. Reverse current measures 2 μA at 25 V reverse voltage. Diode capacitance is 10 pF at 1 V reverse bias and 1 MHz test frequency. Reverse recovery time equals 5 ns when tested with a forward current of 10 mA transitioning to a reverse current of 10 mA and then to 1 mA. These precise measurements confirm the diode’s low-loss forward conduction, tightly controlled leakage in the reverse state, low parasitic capacitance for AC applications, and ultra-fast recovery that minimizes switching losses in high-speed circuits.

Typical Performance Characteristics
Performance curves illustrate forward current versus forward voltage at junction temperatures of -50 °C, 25 °C, 75 °C, and 125 °C, demonstrating how forward voltage decreases with rising temperature for any given current level while maintaining predictable conduction behavior across the operating range. Reverse leakage current versus reverse voltage is plotted at junction temperatures of 25 °C, 50 °C, 75 °C, 100 °C, and 125 °C, showing the expected exponential rise in leakage with both voltage and temperature to inform bias design margins. Reverse current versus junction temperature at the rated repetitive reverse voltage further quantifies thermal effects on off-state leakage. Capacitance versus reverse voltage at 1 MHz reveals a gradual decrease in capacitance as reverse bias increases, providing data for impedance and frequency response calculations in tuned or filtering applications. These graphical representations enable engineers to model temperature-dependent variations, predict worst-case scenarios, and optimize circuit performance under real operating conditions.

Package Dimensions
The DO-35 package dimensions are specified in millimeters with corresponding inch equivalents for global compatibility. The glass body length is 3.9 mm maximum, with lead extensions each measuring at least 26 mm. Lead diameter ranges from 0.4 mm minimum to 0.6 mm maximum. The body diameter measures between 1.3 mm and 1.7 mm in relevant sections, with a minimum overall lead span of 3.1 mm from the body edge and cathode identification clearly marked. These standardized dimensions ensure precise fitment in PCB holes, reliable soldering, and mechanical stability during vibration or thermal cycling in finished assemblies.