onsemi CS8140YN14

Overview

CS8140YN14 from ON Semiconductor is a 5.0 V ±4.0%, 500 mA automotive-grade linear regulator with integrated ENABLE, RESET, and watchdog functions. It delivers tightly regulated power to microprocessors in harsh environments while providing fault-protected control logic for safe power-up, supervision, and controlled shutdown. Its 1.25 V dropout at 500 mA enables operation under low-input-voltage conditions typical in vehicle battery systems.

For engineers reviewing the CS8140YN14 datasheet, pinout, applications, or equivalent options, key selection criteria include its programmable watchdog window (64–326 Hz), 47.5 ms power-on reset delay, thermal shutdown at 150°C, 60 V peak transient tolerance, and DIP-14 through-hole package with Kelvin sense capability.

Technical Context

The CS8140YN14 implements a composite PNP-NPN output stage enabling low-dropout regulation with minimal quiescent current (7.0 mA @ 500 mA). Its internal bandgap reference and error amplifier maintain ±4.0% output accuracy across −40°C to +150°C junction temperature and 7.0–26 V input range.

Watchdog supervision uses an external CDELAY capacitor to set both lower (64–96 Hz) and upper (218–326 Hz) frequency thresholds - a feature exclusive to the CS8140 variant. The open-collector RESET output remains functional down to VOUT = 1.0 V and includes hysteresis (150–250 mV) to prevent chatter during undervoltage transitions.

Key Specifications

Pinout & Package

DIP-14 through-hole package (Case 646), lead count 14, tab-free, with GND on pins 8 and 11, and Kelvin sense on pin 5 (Sense).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar linear regulator with watchdog applications.

Compared with CS8141YN14, the CS8140YN14 provides full dual-threshold watchdog supervision essential for safety-critical firmware validation; compared with TL7705ACD, it delivers 5× higher current, automotive-grade transient robustness, and integrated control logic - making CS8140YN14 the only option meeting AEC-Q100 Grade 1 requirements among the three.

Availability

CS8140YN14 is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera ECUs, and infotainment head units requiring stable component supply across extended temperature and high-reliability automotive programs.

Supply support for CS8140YN14 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensor, and connectivity solutions for automotive, industrial, and cloud power applications.

The CS8140 product line was designed specifically for automotive microprocessor power and supervision - integrating linear regulation, reset generation, enable control, and programmable watchdog into a single AEC-Q100 qualified device to simplify ECU design and improve system-level reliability.

FAQ

What is the maximum input voltage the CS8140YN14 can withstand without damage?

The CS8140YN14 supports a continuous input operating range of −0.5 V to 26 V DC and is rated for 60 V peak transient voltage per ISO 7637-2 Pulse 5a (46 V load dump at 14 V nominal). This rating is achieved via internal overvoltage shutdown that activates at 30–38 V, protecting downstream circuitry. Operation above 26 V DC is not permitted; the 60 V rating applies only to short-duration transients.

Does the CS8140YN14 require an external capacitor for stability, and what type is recommended?

Yes, the CS8140YN14 requires an external output capacitor (C2) for loop stability, as specified in Figure 22 of the datasheet. A 10 µF aluminum or tantalum electrolytic capacitor is recommended - ceramic or film capacitors with near-zero ESR may cause oscillation. The capacitor must have ≥1.0 Ω ESR; typical values range from 0.5–5 Ω depending on temperature and construction. Stability testing across −40°C to +125°C is advised per the datasheet's seven-step procedure.

How does the watchdog functionality differ between CS8140YN14 and CS8141YN14?

The CS8140YN14 implements dual-window watchdog supervision: it monitors both lower (64–96 Hz) and upper (218–326 Hz) frequency thresholds using a single CDELAY capacitor. In contrast, the CS8141YN14 only monitors the lower threshold - it ignores fast WDI pulses and triggers RESET only on slow or missing signals. This makes CS8140YN14 suitable for applications requiring detection of both firmware hangs and runaway loops, while CS8141YN14 is optimized for simpler timeout-only supervision.

Can the CS8140YN14 operate with a 5.5 V input during cold-crank conditions?

No - the absolute minimum input voltage for regulation is 7.0 V per the Electrical Characteristics table. At VIN = 5.5 V, the CS8140YN14 cannot maintain 5.0 V output due to its 1.25 V dropout requirement (minimum VIN = 6.25 V at full load). During cold-crank, the device will drop out of regulation. For sub-7 V operation, a buck-boost pre-regulator or alternative low-VIN LDO (e.g., NCV8664) is required upstream of the CS8140YN14.

What is the purpose of the Sense pin on the CS8140YN14, and how should it be connected?

Pin 5 (Sense) is a Kelvin sense input that connects directly to the load-side of the VOUT net - typically at the microcontroller's VCC pin - to compensate for voltage drop across PCB traces. When used, the regulator closes its feedback loop around the remote sense point, maintaining ±4.0% accuracy at the load regardless of trace resistance (up to ~100 mΩ). If unused, Sense must be tied directly to VOUT pin 7; floating the Sense pin will cause regulation failure.