STMicroelectronics STCS1APHR

Overview

STCS1APHR from STMicroelectronics is a BiCMOS constant current LED driver in PowerSO-8 package, delivering up to 1.5 A output with ±10% current accuracy, <0.5 V dropout voltage at 100 mA, and integrated open-drain LED disconnection diagnostic. It operates from 4.5–40 V input and supports PWM dimming for low-voltage lighting in 5 V/12 V/24 V systems.

For engineers reviewing the STCS1APHR datasheet, STCS1APHR pinout, STCS1APHR application, or STCS1APHR equivalent, key selection criteria include its 100 mV feedback reference, slope-controlled current rise/fall (via external capacitor), shutdown capability (<1 µA quiescent current), and thermal protection at 155 °C - all critical for reliable LED current regulation in space-constrained industrial and appliance designs.

Technical Context

The STCS1APHR integrates a high-voltage preregulator (45 V rating) and precision 100 mV feedback comparator to maintain stable LED current across wide input voltage variations. Its internal N-MOSFET drain supports up to 40 V V_DRAIN, while the dedicated SLOPE pin enables adjustable current slew rate (800 µs to milliseconds) via external capacitor to suppress EMI.

Diagnostic functionality centers on real-time monitoring of V_DRAIN: when voltage drops below 75 mV (indicating LED string open-circuit), the DISC pin pulls low (≤0.5 V at 5 mA sink). The EN pin provides full shutdown with <1 µA supply current, and PWM control operates from DC to 50 kHz with ≤3 µs signal-to-current delay.

Key Specifications

Pinout & Package

STCS1APHR uses the PowerSO-8 package: thermally enhanced surface-mount housing with exposed die pad, 4.8–5.0 mm × 5.8–6.2 mm footprint, 1.7 mm height, and 1.27 mm lead pitch. Designed for high-power dissipation in compact layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar constant current LED driver applications.

Compared with AL8862SP-13 and LM3407MMX/NOPB, STCS1APHR uniquely combines linear simplicity, integrated diagnostics, and slew-rate control in a thermally robust PowerSO-8 package - making it optimal for space-constrained, reliability-critical 5–24 V LED systems where bill-of-materials count and fault visibility matter.

Availability

STCS1APHR is available at Aetrix Electronics and suitable for smart home lighting, industrial control panel indicators, and appliance display backlighting requiring stable component supply and long-term manufacturing continuity.

Supply support for STCS1APHR 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The STCS1A product line delivers highly integrated, thermally robust linear LED drivers targeting low-voltage, high-reliability lighting applications where simplicity, precision, and built-in diagnostics supersede switching efficiency trade-offs.

FAQ

What is the minimum input voltage required for STCS1APHR to regulate 1.5 A LED current?

The STCS1APHR requires a minimum input voltage equal to the sum of LED forward voltage plus dropout voltage. At 1.5 A, typical dropout is 0.58 V; thus, for a 3.6 V white LED, minimum V_IN = 3.6 V + 0.58 V = 4.18 V. The datasheet specifies 4.5 V as the guaranteed operational minimum to accommodate process variation and temperature effects.

Can STCS1APHR drive multiple parallel LED strings reliably?

No - STCS1APHR is designed for single-string operation. Driving parallel LEDs introduces current imbalance due to V_F mismatch, causing thermal runaway. The device's 100 mV FB reference and single-sense node assume one current path; parallel strings require individual current-setting resistors and separate FB connections, which the IC does not support.

How does the SLOPE capacitor affect PWM dimming performance?

The SLOPE capacitor linearly scales current rise/fall time: a 10 nF cap yields ~800 µs transitions, while 1 nF reduces it to ~80 µs. For PWM dimming above 5 kHz, smaller capacitors minimize duty-cycle distortion; however, values below 1 nF risk overshoot and EMI. The datasheet recommends 1–10 nF for most applications balancing speed and noise.

Is reverse polarity protection built into STCS1APHR?

No - STCS1APHR lacks internal reverse-polarity protection. The datasheet explicitly states that external protection (e.g., BAT46 Schottky diode on VCC) is mandatory to prevent damage from negative supply voltage. Without it, reverse bias can exceed absolute maximum ratings on VCC and DRAIN pins, risking permanent failure.