STMicroelectronics L4987CPT50TR

Overview

L4987CPT50TR 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, logic-controlled shutdown (TTL-compatible pin 2), and open-collector dropout flag output. It delivers stable regulation for automotive infotainment power rails and battery-powered portable electronics where quiescent current (90 µA in OFF mode) and input dump protection to 40 V are critical.

For engineers reviewing the L4987CPT50TR datasheet, L4987CPT50TR pinout, L4987CPT50TR application, or L4987CPT50TR equivalent, key selection criteria include dropout voltage under load, flag output behavior during undervoltage, thermal resistance (R_thJA = 100 °C/W), and compatibility with 2.2 µF ceramic output capacitance for stability.

Technical Context

The L4987CPT50TR employs a PNP pass transistor architecture enabling ultra-low dropout (0.3 V typ. at 200 mA) and high PSRR (76 dB at 120 Hz). Its internal current and thermal limiting protect against fault conditions without external components.

The open-collector flag output asserts low when V_IN ≤ V_OUT + V_DROP, during current limit, or thermal shutdown - with no hysteresis and 0.5 V max low-level voltage at 6 mA sink. Shutdown control is TTL-compatible (V_IL ≤ 0.8 V, V_IH ≥ 2 V) and draws only 10 µA input current.

Key Specifications

Pinout & Package

Supplied in PPAK (Power Package) thermally enhanced surface-mount package (6-pin, 6.0 × 6.6 mm body, 1.27 mm pitch), optimized for high-power density and low thermal impedance (R_thJC = 8 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LDL112PU50R and TLD1120-5V, the L4987CPT50TR uniquely combines 200 mA capability, sub-0.5 V dropout, and a functional flag output in a thermally efficient PPAK package-making it optimal for automotive subsystems requiring both robustness and intelligent power monitoring.

Availability

L4987CPT50TR is available at Aetrix Electronics and suitable for automotive infotainment, portable medical devices, and industrial sensor nodes requiring stable component supply across extended temperature and lifecycle demands.

Supply support for L4987CPT50TR 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-grade linear regulator product line, engineered specifically for 12 V vehicle electrical systems requiring high transient immunity, low quiescent current, and intelligent fault signaling.

FAQ

What is the maximum input voltage the L4987CPT50TR can withstand without damage?

The L4987CPT50TR has an absolute maximum DC input voltage rating of 40 V, verified per STMicroelectronics' datasheet Table 2. This rating covers non-repetitive load-dump transients per ISO 7637-2 Pulse 1 and Pulse 2a, making it suitable for direct connection to automotive 12 V battery rails without external clamping.

How does the FLAG pin behave during thermal shutdown?

During thermal shutdown, the FLAG pin asserts low (≤0.5 V at 6 mA sink), identical to its behavior during input undervoltage or current limiting. This single-fault-signaling behavior allows unified system response-such as disabling downstream loads or logging thermal events-without additional sensing circuitry.

Can the L4987CPT50TR operate with a 2.2 µF output capacitor having 20 mΩ ESR?

Yes. The datasheet specifies stable operation with output capacitance of 2.2 µF and ESR between 0.5 Ω and 10 Ω. A 20 mΩ ESR is well below the minimum specified value and may cause instability or oscillation; a higher-ESR ceramic or polymer capacitor within the 0.5–10 Ω range is required for guaranteed stability.

Is the SHDN pin internally pulled up or down when not driven?

The SHDN pin has no internal pull-up or pull-down resistor. When left floating, leakage current (≤10 µA) and noise susceptibility may cause undefined regulator state. ST recommends actively driving SHDN to either <0.8 V (OFF) or >2 V (ON) using a microcontroller GPIO or dedicated bias network to ensure deterministic operation.