Nisshinbo Micro Device Inc. R1245

Description

The R1245 Series are 30V input, CMOS-based PWM step-down DC/DC converters featuring 1.2A*output current. R1245 includes a soft start circuit and latch or fold-back protection circuit. By simply using an inductor, resistors, a diode, and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured. Due to current mode PWM control, the R1245 provides a fast response and high efficiency. Ceramic output capacitors can be used.Compared with R1240, R1245 has a lot of variation of oscillator frequency and can select 330kHz. In case of 330kHz, R1245 can set VOUT lower than R1240. The oscillator maximum duty cycle (Min.) of R1245 is larger than R1240, so it is suitable for low dropout voltage situation. The noise characteristic has been improved rather than R1240, and voltage accuracy is also improved. In addition to HSOP-8E package can be selected, so R1245S is suitable for high power dissipation case.

Features

• Operating Voltage 4.5 V to 30 V
• Internal N-channel MOSFET Driver
• Typ. RON = 0.35Ω
• Adjustable Output Voltage with External Resistor 0.8 V or more
• Feedback Voltage and Tolerance 0.8 V±1.0%
• Peak Current Limit Typ. 2.0 A
• UVLO Function Released Voltage Typ. 4.0 V
• Operating Frequency
  • 330 kHz (Ver. A/B),
  • 500 kHz (Ver. C/D),
  • 1000 kHz (Ver. E/F),
  • 2400 kHz (Ver. G/H)
• Fold-back Protected Frequency
  • 170 kHz (Ver. B/D),
  • 250 kHz (Ver. F),
  • 400 kHz (Ver. H)
• Latch Protection Delay Time Typ. 4ms (Ver. A/C/E/G)
• Ceramic Capacitors Recommended for Input and Output.
• Stand-by Current Typ. 0μA
• Packages SOT-23-6W, DFN(PLP)2020-8, HSOP-8E

Typical applications

• Office Equipment: Printers, Faxes
• 5V PSU or 2-cell or more Li-ion Battery Powered Communication Equipment, Cameras, VCRs, Camcorders
• High Voltage Battery-powered Equipment
• Digital Home Appliances: Digital TVs, DVD Players

More information

• Datasheet
• IC product information