High Efficiency Small Packaged Step-up DC/DC Converter
The RP402x is a CMOS-based high efficiency step-up DC/DC converter with synchronous rectifier. The device can start up with low voltage of typically 0.7V which is ideal for the applications powered by either one-cell or two-cell alkaline, nickel-metal-hydride (NiMH) or one-cell Lithium-ion (Li+) batteries.
Internally, the RP402x consists of an oscillator, a reference voltage unit with soft start, a chip enable circuit, an error amplifier, phase compensation circuits, a slope circuit, a PWM control circuit, a start-up circuit, a PWM/VFM mode control circuit, internal switches and protection circuits.
The RP402x is employing synchronous rectification for improving the efficiency or rectification by replacing diodes with built-in switching transistors. Using synchronous rectification not only increases circuit performance but also allows a design to reduce parts count.
The RP402x is available in either internally fixed output voltage type or adjustable output voltage type. The RP402xxxxx is the internally fixed output voltage type. The RP402x00xx is the adjustable output voltage type, which allows output voltages that range from 1.8V to 5.5V via an external divider resistor.
The RP402x provides the forced PWM control and the PWM/VFM auto switching control. Either one of these can be selected by inputting a signal to the MODE pin. The forced PWM control switches at fixed frequency rate in low output current in order to reduce noise. Likewise, the PWM/VFM auto switching control automatically switches from PWM mode to VFM mode in low output current in order to achieve high efficiency.
The RP402N is available in the PWM/VFM auto switching control. However, the RP402N is also available in the forced PWM control as a custom-designed IC*1.
The RP402x has a soft-start time of typically 0.5 ms.
The RP402x features the complete output disconnect shutdown option and the input-to-output bypass shutdown option. The RP402xxxxA/ B/ E/ F incorporates the complete output disconnect shutdown option, which allows the output to be disconnected from the input. The RP402xxxxC/ D/ G/ H incorporates the input-to-output bypass shutdown option, which allows the output to be connected to the input.
The RP402x is protected against damage by a short-current protection, an over-voltage lockout, an over voltage protection, an anti-ringing switch and a latch-type protection. An anti-ringing switch prevents the occurrence of noise when an inductor current reaches a discontinuous mode. The latch-type protection can be released by switching the CE pin from high to low.
The RP402x is offered in a compact 5-pin SOT23-5*1 package or a 8-pin DFN(PLP)2020-8 package.
- *1As for the custom-designed IC, please contact our sales representatives.
|Low Voltage Start-up||Typ. 0.7V|
|Input Voltage Range||Fixed Output Voltage Type: 0.6V to 4.8V
Adjustable Output Voltage Type: 0.6V to 4.6V
|High Efficiency||94% (100mA/ 5.0V, VIN = 3.6V, 25°C)
90% (1mA/ 5.0V, VIN = 3.6V, 25°C)
|Output Current||800mA: VIN = 3.6V, VOUT = 5.0V|
|Lx Driver ON Resistance
||NMOS/ PMOS: 0.20Ω (VOUT = 5.0V, 25°C)|
|PWM Oscillator Frequency||1.2MHz (Normal PWM), 1.0MHz (Forced PWM)|
|Output Voltage Range||Fixed Output Voltage Type: 1.8V to 5.5V, 0.1V step
Adjustable Output Voltage Type: 1.8V to 5.5V (recommended)
|OVLO Detector Threshold||Typ. 5.1V|
|OVP Detector Threshold||Typ. 6.0V|
|Lx Peak Current Limit||Typ. 1.5A|
|Latch Protection Delay Time||Typ. 3.3ms (RP402Kxx1x, RP402Nxx1x)
Typ. 4.1ms (RP402Kxx2x)
|Soft-start Time||Typ. 0.5ms|
|EMI Suppression (Built-in Anti-ringing Switch) (RP402Kxx1x, RP402Nxx1x)|
|Voltage Regulation at VIN > VOUT|
|Zero Input Complete Shutdown at VIN = 0V|
|Bypass Mode at CE = L (RP402xxxxC/ D/ G/ H)|
|Ceramic Capacitor Capable|
- ・MP3 players, PDA
- ・Digital Still Cameras
- ・LCD Bias Supplies
- ・Portable Blood Pressure Meter
- ・Wireless Handset
|Data Sheet||Flyer||Design Guide||Package Info.||Quality
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