STMicroelectronics STCS1APUR

Overview

STCS1APUR from STMicroelectronics is a BiCMOS constant current LED driver IC designed for low-voltage lighting systems operating from 4.5 V to 40 V input. It delivers up to 1.5 A output current with ±10% precision, <0.5 V voltage overhead, and integrated PWM dimming and LED disconnection diagnostics-used in 5 V/12 V/24 V appliance LED modules where discrete solutions previously dominated.

For engineers reviewing the STCS1APUR datasheet, STCS1APUR pinout, STCS1APUR application, or STCS1APUR equivalent, this page provides verified technical context on slope-controlled current rise, open-drain diagnostic signaling, feedback-based current setting (100 mV reference), and thermal derating behavior across DFN8 package variants.

Technical Context

The STCS1APUR integrates a high-side N-MOSFET driver with internal 100 mV feedback reference and dedicated SLOPE pin for external capacitor-controlled current slew rate (tens of µs to ms range). Its enable logic shuts down quiescent current to <1 µA, while DISC pin asserts low when V_DRAIN falls below 75 mV-indicating LED string open-circuit.

It features dual-stage regulation: a high-voltage preregulator (up to 45 V) powers internal 3.3 V logic, and a precision current loop maintains setpoint via FB pin sensing. Thermal shutdown activates at 155 °C with 25 °C hysteresis, and PWM dimming supports up to 50 kHz with sub-µs delay (TD = 1.2–3 µs) between input edge and current transition.

Key Specifications

Pinout & Package

STCS1APUR uses a thermally enhanced DFN8 (3 × 3 mm) package with exposed die pad for improved heat dissipation. Pin 1 is VCC; Pin 8 is DISC; the exp-pad is internally connected to GND.

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, STCS1APUR uniquely combines linear simplicity, integrated diagnostics, and programmable slew rate in a single DFN8 package-making it optimal for space-constrained, noise-sensitive, and fault-aware LED applications.

Availability

STCS1APUR is available at Aetrix Electronics and suitable for smart home lighting modules, industrial control panel indicators, white goods appliance displays, and automotive interior ambient lighting requiring stable component supply and long-term production continuity.

Supply support for STCS1APUR 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 microcontrollers, power management ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

The STCS1A product line targets replacement of discrete LED driver solutions in low-voltage (<40 V) applications-emphasizing integration, precision, and reliability in compact surface-mount packages like DFN8 and PowerSO-8.

FAQ

What is the minimum recommended R_FB value for stable 1.5 A operation?

The datasheet specifies R_FB = 0.067 Ω for 1.5 A (100 mV / 1.5 A), but practical use requires ≥0.1 Ω to limit power dissipation and thermal drift. At 1.5 A, 0.1 Ω dissipates 225 mW-necessitating 1206 or larger footprint and adequate copper pour. Lower values increase self-heating error and require precision metal-foil resistors.

Can STCS1APUR drive multiple parallel LED strings reliably?

No-STCS1APUR is a single-channel high-side constant-current source intended for one LED string. Driving parallel strings causes current imbalance due to V_F mismatch, leading to thermal runaway. For multi-string operation, separate STCS1APUR units per string or a matrix-switched architecture with individual current control is required.

How does the SLOPE capacitor affect PWM dimming fidelity at high frequencies?

With CSLOPE = 10 nF, rise/fall time is ~800 µs-limiting usable PWM frequency to ≤1 kHz for clean square-wave current. To achieve 50 kHz dimming, CSLOPE must be reduced to ≤100 pF, resulting in ~10 µs transitions. However, this increases EMI and may cause current overshoot; layout and grounding become critical.

Is the DISC pin compatible with 3.3 V microcontroller GPIO inputs?

Yes-the DISC pin is open-drain with max 0.5 V low-level voltage at 5 mA sink current, well within 3.3 V logic low threshold (typically ≤0.8 V). An external 10 kΩ pull-up to 3.3 V ensures reliable detection; no level-shifting is needed. The pin remains inactive during shutdown (EN = low) and only asserts during active-mode LED faults.