RP600x Series

RP600xseries are high efficiency, current mode step-up DC-DC converter ICs with a voltage regulator and a voltage detector. This converter starts up of low voltage (typ. 0.8V) operation from one or two alkaline or nickel-metal-hydride (NiMH) batteries, or a single Li+ battery.
This IC consists of a reference voltage unit with soft start, error amplifiers, PWM comparator, protection circuits such as a current limit circuit, an internal switch transistor, an oscillator, and PWM/VFM mode control circuit. A low ripple high efficiency step-up DC/DC converter can be composed of RP600x series with only an inductor, a diode, divider resistors and capacitors. In terms of output voltage setting, fixed type and adjustable with external divider resisters type are available. Output voltage is from 2.3V to 5.5V.

The built-in LDO Regulator(VR) consists of a reference voltage unit, an error amplifier, output voltage setting resister net, a short current limit circuit, an output transistor, and so on. To prevent the inrush current at start-up, soft-start function is included. The Soft-start time is typically 200μs. The output voltage is fixed internally and the output range is from 1.5V to 5.0V.
This IC has an MODE pin. When the MODE pin is set as "H", the DC/DC converter control becomes fixed PWM control, and the LDO becomes the fast mode. When the MODE pin is set as "L", the DC/DC converter is automatic PWM/VFM control and the LDO becomes low power mode.*
The voltage detector always turns on. The output is Nch open drain type. Since the package is DFN(PLP)2527-10, so high density mounting on board is possible. If the internal chip temperature is beyond the certain level, system reset will work, or thermal shutdown circuit is included in the IC.

• *The switch-over point is fixed internally. As for A/D version, regardless the MODE pin signal, LDO mode is always set at fast mode. As for B/C version, regardless the MODE pin signal, when the DC/DC converter is active, LDO becomes fast mode.

Functions

A version:	The input power supply of the built-in voltage regulator (LDO) is the output of the built-in DC/DC converter. After the soft-start function of the DC/DC converter, the LDO starts up. The built-in voltage detector outputs "L" when the supervised level becomes lower than the set detector threshold level. The output delay circuit for release the voltage detector is also built-in and the delay time is set at typically 10ms.
B version:	The input power supply of the built-in voltage regulator (LDO) and the DC/DC converter is VDD pin. Each channel is individual. The minimum operating voltage of the LDO is 2.0V. The output of the DC/DC converter is fixed internally. If the DC/DC is active, the LDO mode becomes fixed fast mode. The built-in voltage detector outputs "L" when the supervised level becomes lower than the set detector threshold level. The output delay circuit for release the voltage detector is also built-in and the delay time is set at typically 10ms.
C_version: (Under Development):	The input power supply of the built-in voltage regulator (LDO) is the output of the built-in DC/DC converter. The voltage regulator is always active. The output of the DC/DC converter is fixed internally. The built-in voltage detector outputs "L" when the supervised level becomes lower than the set detector threshold level. The output delay circuit for release the voltage detector is not included. The hysteresis range can be selected from 30% of the set voltage detector threshold to 80% of the detector threshold.
D version:	The input power supply of the built-in voltage regulator (LDO) and the DC/DC converter is VDD pin. The output of the DC/DC converter is adjustable with external divider resisters. The built-in voltage detector outputs "L" when the supervised level becomes lower than the set detector threshold level. The output delay circuit for release the voltage detector is also built-in and the delay time is set at typically 10ms.