STMicroelectronics LF90CPT

Overview

LF90CPT from STMicroelectronics is a very low-dropout linear voltage regulator with logic-controlled electronic shutdown, delivering 500 mA output current at 9.0 V nominal output voltage in PPAK package. It features 0.45 V dropout at 200 mA, 50 µA quiescent current in OFF mode, and ±2% output voltage accuracy (C grade) over -40 °C to 125 °C - designed for automotive power rails requiring AEC-Q100 qualification and standby power management.

For engineers reviewing the LF90CPT datasheet, LF90CPT pinout, LF90CPT application, or LF90CPT equivalent, this device is selected for battery-powered ADAS modules, infotainment domain controllers, and engine control unit (ECU) auxiliary supplies where low-noise, high-temperature stability, and TTL-compatible enable control are critical.

Technical Context

The LF90CPT implements a PNP-based LDO architecture with internal current and thermal limiting, enabling stable operation without external compensation beyond a 2.2 µF output capacitor. Its 5-pin PPAK configuration integrates a dedicated TTL-compatible shutdown input (Pin 2), allowing system-level power gating of downstream circuitry.

Qualified per AEC-Q100 Grade 1 (-40 °C to 125 °C), it supports input voltages from 2.8 V to 16 V and maintains 9.0 V output regulation across load currents up to 500 mA, with supply voltage rejection of 77 dB at 1 kHz and 50 µV RMS output noise (10 Hz–100 kHz).

Key Specifications

Pinout & Package

LF90CPT is housed in a thermally enhanced PPAK (Power Package) with exposed thermal pad electrically connected to GND. This 5-pin surface-mount package enables high-power density and efficient heat dissipation in compact automotive PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 9 V automotive LDO applications.

Compared with NCP1117ST90T3G and TLD1120-1EP, LF90CPT uniquely balances AEC-Q100 Grade 1 compliance, TTL-compatible shutdown, and ultra-low 0.45 V dropout in a space-efficient PPAK package - making it optimal for volume automotive applications demanding both reliability and power-state agility.

Availability

LF90CPT is available at Aetrix Electronics and suitable for automotive ADAS camera modules, infotainment head-units, and engine control units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LF90CPT 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, specializing in automotive, industrial, and power management ICs with broad manufacturing and qualification capabilities.

LF90CPT belongs to the LFXX family of automotive-grade LDOs, engineered specifically for under-hood and cabin electronics requiring AEC-Q100 compliance, low quiescent current, and robust transient response.

FAQ

What is the minimum input voltage required for regulation at 500 mA load?

The LF90CPT maintains regulation down to an input voltage of 9.45 V at 500 mA load, based on its maximum dropout voltage of 0.45 V at 200 mA and typical 0.7 V at 500 mA per datasheet Table 19. At full 500 mA, VI(min) = 9.0 V + 0.7 V = 9.7 V; however, the device remains functional (though not fully regulated) as low as 2.8 V input in shutdown or light-load conditions.

Can the SENSE pin be left unconnected?

No. The SENSE pin must be connected directly to the load-side of the output trace or to the load's VCC pin to enable remote voltage sensing. Leaving it unconnected degrades load regulation to ±15 mV (vs. ±2 mV with sensing) and risks output deviation under high-current PCB trace resistance, especially in automotive harness-fed modules.

Is LF90CPT compatible with ceramic output capacitors only?

Yes - the LF90CPT is optimized for 2.2 µF ceramic capacitors with ESR between 0.1 Ω and 10 Ω. Aluminum or tantalum capacitors are not recommended due to higher ESR and potential instability; using them may cause oscillation or poor transient response, particularly during load steps in CAN or sensor applications.

Does the SHDN pin require a pull-up resistor?

No external pull-up is required. The SHDN pin has an internal weak pull-up to IN voltage, ensuring default ON operation at power-up. However, for deterministic startup in noisy environments, a 100 kΩ pull-up to IN is recommended to guarantee VIH > 2.0 V during brown-out conditions.