Overview
The CAT4237TDT-MP, manufactured by onsemi, is a DC/DC step-up converter designed to deliver an accurate constant current, making it ideal for driving LEDs. This device operates at a constant switching frequency of 1 MHz, allowing it to be used with small external ceramic capacitors and inductors. It is particularly suited for battery-powered applications, supporting LED currents up to 40 mA over a wide range of input supply voltages from 2.8 V to 5.5 V. The CAT4237 is housed in a low-profile 5-lead thin SOT23 package, making it suitable for space-critical applications.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| VIN, FB voltage | -0.3 | 7 | V | |
| SHDN voltage | -0.3 | 7 | V | |
| SW voltage | -0.3 | 55 | V | |
| Storage Temperature Range | -65 | 160 | °C | |
| Junction Temperature Range | -40 | 150 | °C | |
| Lead Temperature | 300 | °C | ||
| VIN (Recommended Operating Conditions) | 2.8 | 5.5 | V | |
| SW pin voltage (Recommended Operating Conditions) | 0 | 30 | V | |
| Ambient Temperature Range | -40 | 85 | °C | |
| Programmed LED Current | 14.25 | 20 | 31.5 | mA |
| Switching Frequency | 0.8 | 1.0 | 1.3 | MHz |
| Switch Current Limit | 350 | 450 | 600 | mA |
| Thermal Shutdown | 150 | °C | ||
| Undervoltage Lockout (UVLO) Threshold | 1.9 | V |
Key Features
- Drives 6 to 8 white LEDs in series from 3 V
- Up to 87% efficiency
- Low quiescent ground current of 0.6 mA
- Adjustable output current (up to 40 mA)
- High frequency 1 MHz operation
- High voltage power switch
- Shutdown current less than 1 μA
- Open LED low power mode
- Automatic shutdown at 1.9 V (UVLO)
- Thermal shutdown protection
- Thin SOT23 5-lead package (1 mm max height)
- Pb-free, halogen-free/BFR-free, and RoHS compliant
Applications
- Color LCD and keypad backlighting
- Cellular phones
- Handheld devices
- Digital cameras
- PDAs
- Portable game machines
Q & A
- What is the primary function of the CAT4237TDT-MP?
The CAT4237TDT-MP is a DC/DC step-up converter designed to deliver an accurate constant current for driving LEDs.
- What is the operating voltage range of the CAT4237TDT-MP?
The device operates with input supply voltages from 2.8 V to 5.5 V.
- How many LEDs can the CAT4237TDT-MP drive in series?
The device can drive 6 to 8 white LEDs in series.
- What is the maximum LED current supported by the CAT4237TDT-MP?
The device supports LED currents up to 40 mA.
- What is the switching frequency of the CAT4237TDT-MP?
The device operates at a constant switching frequency of 1 MHz.
- What are the thermal protection features of the CAT4237TDT-MP?
The device includes thermal shutdown protection and enters a low power mode during thermal overload conditions.
- How does the CAT4237TDT-MP handle open LED fault conditions?
In the event of an open LED fault, the device enters a very low power mode to prevent overvoltage damage.
- What is the package type and dimensions of the CAT4237TDT-MP?
The device is housed in a thin SOT23 5-lead package with a maximum height of 1 mm.
- Is the CAT4237TDT-MP RoHS compliant?
Yes, the device is Pb-free, halogen-free/BFR-free, and RoHS compliant.
- What are some common applications of the CAT4237TDT-MP?
Common applications include color LCD and keypad backlighting, cellular phones, handheld devices, digital cameras, PDAs, and portable game machines.
- How does the CAT4237TDT-MP support LED dimming?
LED dimming can be achieved using a DC voltage, a logic signal, or a pulse width modulation (PWM) signal.
