Overview
The NCP1421DMR2, produced by onsemi, is a monolithic micropower high-frequency step-up switching converter IC. It is specifically designed for battery-operated handheld electronic products, capable of handling loads up to 600 mA. This IC integrates synchronous rectification (Sync-Rect) to improve efficiency and eliminate the need for an external Schottky diode. The high switching frequency of up to 1.2 MHz allows for the use of small-sized inductors and output capacitors, making it ideal for low-profile designs.
Key Specifications
| Characteristic | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Operating Voltage (VIN) | 1.0 | - | 5.0 | V |
| Output Voltage Range (VOUT) | 1.5 | - | 5.0 | V |
| Reference Voltage (VREF_NL) at 25°C | 1.183 | 1.200 | 1.217 | V |
| Reference Voltage Temperature Coefficient (TCVREF) | -0.03 | - | - | mV/°C |
| Cycle-by-Cycle Current Limit | - | - | 1.5 A | - |
| Thermal Shutdown Temperature (TSHDN) | - | - | 145 °C | - |
| Thermal Shutdown Hysteresis (TSDHYS) | - | - | 30 °C | - |
| Shutdown Current | - | - | 50 nA | - |
Key Features
- Synchronous Rectification (Sync-Rect): Eliminates the need for an external Schottky diode, reducing conduction losses.
- High Switching Frequency: Up to 1.2 MHz, allowing for small-sized inductors and output capacitors.
- True-Cutoff Function: Isolates the output from the battery during shutdown, reducing leakage current to 50 nA.
- Logic-Controlled Shutdown Pin: Multi-function pin for shutdown control.
- On-Chip Thermal Shutdown with Hysteresis: Protects against overheating with a hysteresis of 30°C.
- Low-Battery Detector: Adjustable low-battery detect voltage using external resistors.
- Ring-Killer Function: Eliminates high-frequency ringing in discontinuous conduction mode.
Applications
- Personal Digital Assistants (PDA)
- Handheld Digital Audio Products
- Camcorders and Digital Still Cameras
- Handheld Instruments
- Conversion from one to two Alkaline, NiMH, NiCd battery cells to 3.0-5.0 V or one Lithium-ion cell to 5.0 V
- White LED Flash for Digital Cameras
Q & A
- What is the operating voltage range of the NCP1421DMR2?
The operating voltage range is from 1.0 V to 5.0 V.
- What is the output voltage range of the NCP1421DMR2?
The output voltage range is from 1.5 V to 5.0 V.
- What is the typical reference voltage of the NCP1421DMR2?
The typical reference voltage is 1.200 V.
- What is the cycle-by-cycle current limit of the NCP1421DMR2?
The cycle-by-cycle current limit is 1.5 A.
- How does the True-Cutoff function work in the NCP1421DMR2?
The True-Cutoff function isolates the output from the battery during shutdown, reducing leakage current to 50 nA.
- What is the thermal shutdown temperature of the NCP1421DMR2?
The thermal shutdown temperature is 145°C.
- What is the purpose of the Ring-Killer function in the NCP1421DMR2?
The Ring-Killer function eliminates high-frequency ringing in discontinuous conduction mode.
- How is the low-battery detect voltage set in the NCP1421DMR2?
The low-battery detect voltage is set using an external divider network.
- What is the recommended inductance range for the NCP1421DMR2?
The recommended inductance range is from 3 μH to 10 μH, depending on the application.
- What are some typical applications of the NCP1421DMR2?
Typical applications include personal digital assistants, handheld digital audio products, camcorders, and digital still cameras.
