Overview
The STCS05A, produced by STMicroelectronics, is a BiCMOS constant current source designed to provide a precise constant current from a varying input voltage source. This component is particularly useful for driving LEDs in low voltage applications, offering benefits in terms of precision, integration, and reliability. It is aimed at replacing discrete component solutions for LED driving in applications such as 5 V, 12 V, or 24 V systems.
Key Specifications
| Parameter | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|
| Supply Voltage Range (VCC) | 4.5 | - | 40 | V |
| Output Current Range (IO) | 1 | - | 500 | mA |
| Feedback Voltage (VFB) | 90 | 100 | 110 | mV |
| Quiescent Current (ICC) - On Mode | 450 | 750 | - | µA |
| Quiescent Current (ICC) - Shutdown Mode (VCC = 5 to 12 V) | - | 1 | - | µA |
| Quiescent Current (ICC) - Shutdown Mode (VCC = 12 to 40 V) | - | 3 | - | µA |
| Dropout Voltage (VDROP) | 0.12 | 0.16 | 0.9 | V |
| Drain Leakage Current (LEAKDRAIN) | - | - | 10 | µA |
| Rise/Fall Time of the Current on PWM Transition | - | - | 800 | µs |
| Load Disconnection Threshold (VDRAIN-GND) | 75 | - | 110 | mV |
| Thermal Shutdown Temperature | - | - | 155 | °C |
Key Features
- Up to 40 V input voltage and less than 0.5 V voltage overhead.
- Up to 0.5 A output current with ±10% precision set by an external resistor.
- PWM dimming pin for controlling the brightness of LEDs.
- Shutdown pin for turning the device on or off.
- LED disconnection diagnostic feature using an open-drain output pin.
- External capacitor for slope control to reduce EMI and avoid current spikes.
- Thermal shutdown protection to prevent overheating.
Applications
The STCS05A is suitable for various LED lighting applications, including:
- LED constant current supplying for varying input voltages.
- Low voltage lighting systems.
- Small appliances LED lighting.
Q & A
- What is the maximum input voltage for the STCS05A?
The maximum input voltage for the STCS05A is 40 V. - What is the maximum output current of the STCS05A?
The maximum output current of the STCS05A is 0.5 A. - How is the output current set in the STCS05A?
The output current is set using an external sensing resistor connected to the FB pin, with a feedback voltage of 100 mV. - Does the STCS05A support PWM dimming?
Yes, the STCS05A has a PWM dimming pin for controlling the brightness of LEDs. - What is the purpose of the SLOPE pin in the STCS05A?
The SLOPE pin is used to connect an external capacitor for controlling the rise and fall slope of the current, reducing EMI and avoiding current spikes. - How does the STCS05A detect LED disconnection?
The STCS05A detects LED disconnection by monitoring the VDRAIN pin; if VDRAIN is lower than 75 mV, the DISC pin is pulled low. - What is the thermal shutdown temperature of the STCS05A?
The thermal shutdown temperature of the STCS05A is 155 °C. - What package type is the STCS05A available in?
The STCS05A is available in an SO-8 package. - What are the key benefits of using the STCS05A over discrete components?
The key benefits include precision, integration, and reliability in driving LEDs in low voltage applications. - How can I protect the STCS05A from reverse polarity connection?
The STCS05A must be protected from reverse connection of the supply voltage, which can be achieved by using a small diode connected to VCC.
