STMicroelectronics L4987CPT50

Overview

L4987CPT50 from STMicroelectronics is a 5.0 V, 200 mA very low-dropout linear regulator in PPAK package, featuring 0.3 V typical dropout at 200 mA, open-collector dropout control flag, and logic-controlled shutdown. It delivers stable local regulation for automotive infotainment and battery-powered portable electronics with input dump protection up to 40 V.

For engineers reviewing the L4987CPT50 datasheet, L4987CPT50 pinout, L4987CPT50 application, or L4987CPT50 equivalent, key selection criteria include dropout voltage under load, quiescent current in ON/OFF modes, flag output behavior during saturation, thermal resistance (R_thJA = 100 °C/W), and compatibility with 2.2 µF ceramic output capacitance.

Technical Context

The L4987CPT50 employs a PNP pass transistor architecture enabling ultra-low dropout (0.3 V typ. at 200 mA) and high supply voltage rejection (76 dB at 120 Hz). Its internal current and thermal limiting protect against fault conditions without external circuitry.

The open-collector control flag (pin 3) asserts low when V_IN ≤ V_OUT + V_DROP, during current limit, or thermal shutdown - enabling real-time battery status monitoring and pop-up prevention in car audio systems. Shutdown is TTL-compatible (pin 2, V_IL ≤ 0.8 V, V_IH ≥ 2 V).

Key Specifications

Pinout & Package

Supplied in thermally enhanced PPAK (Power Package) with exposed die pad for improved heat dissipation (R_thJC = 8 °C/W). Package dimensions: 6.0 × 6.4 × 1.0 mm (D × E × A2), 5-pin configuration.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout regulator applications.

Compared with LDL112PU50R and TPS7A2050PDBVR, the L4987CPT50 uniquely combines automotive-grade transient immunity, integrated dropout flag, and PPAK thermal performance - making it the only choice for cost-constrained, safety-aware automotive subsystems requiring deterministic brownout response.

Availability

L4987CPT50 is available at Aetrix Electronics and suitable for automotive infotainment, portable medical instrumentation, and industrial wireless sensor nodes requiring stable component supply with long lifecycle visibility.

Supply support for L4987CPT50 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, and consumer markets since 1987.

The L4987 series belongs to ST's automotive-qualified linear regulator product line, engineered specifically for robust local regulation in harsh environments - emphasizing dropout flag functionality, transient immunity, and thermal resilience in compact packages.

FAQ

What is the minimum input voltage required for regulation at full 200 mA load?

The L4987CPT50 requires a minimum input voltage of 5.7 V to maintain 5.0 V output at 200 mA load, based on its maximum dropout voltage of 0.5 V. At typical 0.3 V dropout, 5.3 V input suffices. Operation below 5.7 V triggers the FLAG output low, indicating impending dropout.

Can the FLAG pin drive a standard CMOS input directly?

Yes, but only with an external pull-up resistor. The FLAG is open-collector and requires a pull-up to either V_OUT or another logic supply. For CMOS inputs, RPULL must be between (V_SUPPLY − 0.5)/10 mA and (V_SUPPLY/3)/10 µA - typically 10 kΩ to 100 kΩ depending on supply and logic family.

Is the L4987CPT50 qualified for automotive applications?

Yes - it is specified for operation from −40 to 125°C junction temperature and withstands 40 V input transients per ISO 7637-2 Pulse 5a. While not AEC-Q100 certified, its electrical and thermal specs meet common automotive subsystem requirements for infotainment and body electronics.

Why does the datasheet specify 2.2 µF output capacitance instead of larger values?

The 2.2 µF value is the minimum ceramic capacitor (ESR 0.5–10 Ω) required for unconditional stability across temperature and load. Larger values do not improve regulation but increase start-up time and physical size. Using lower-ESR capacitors (<0.5 Ω) may cause oscillation unless compensated per Figure 11 in the datasheet.