R1270 Series
3A 34V Input PWM/VFM Step-down DC/DC Converter with PLL Synchronization
Download Datasheet
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Description
The R1270 Series are 34V input (Absolute maximum rating: 36V), CMOS-based PWM/VFM step-down DC/DC converters capable of outputting the maximum 3A* current. The R1270 is selectable from two control types - PWM control or PWM/VFM auto switching control in which mode automatically switches to high-efficiency VFM mode in low output current. The R1270 includes a soft start circuit, a fold-back protection circuit and a latch protection circuit (only A Version). By simply using an inductor, resistors, and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured. The R1270 can be synchronized externally by PLL.
*) This is an approximate value, because output current depending on conditions and external parts.
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Spec
Consumer Industrial Automotive Input Voltage Range 3.6 V to 34.0 V (36.0 V) Operating Temperature Range -40°C to 105°C (125°C) -40°C to 125°C (150°C) -40°C to 125°C (150°C) Supply Current Typ. 18 µA Standby Current Typ. 0 µA Output Voltage Range Externally Adjustable: 0.8 V to 31.6 V Feedback Voltage 0.8 V Feedback Voltage Accuracy ±8 mV Feedback Voltage Temperature Coefficient Typ. ±100 ppm/°C (−40°C ≤ Ta ≤ 125°C) Output Current 3 A Oscillator Frequency Externally Adjustable: 300 kHz to 2.4 MHz Maximum Duty Cycle Min. 93% (fosc = 300 kHz), Min. 67% (fosc = 2.4 MHz) Package HSOP-18 Protections / Functions
TSD ILX OCP OVP UVLO OVLO Reverse Shutdown Soft Start SSCG PGOOD Auto Discharge Anti-ringing Sequencing Max Duty Ext. Phase LED Adjust 
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Technical
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Typical Application
* PLLREF pin must not be “OPEN”. When using the Nisshinbo Micro Devices' evaluation board, a pull-down resistor (RPLLREF2: 100 kΩ) is contained on the evaluation board.
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Efficiency vs. Output Current
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Quality &
Packages- Refer to the datasheets for the details on the product.
- The package file includes package dimensions, taping specifications, taping reels dimensions, power dissipations, and recommended land pattern.
- Please contact us or our distributors for unpublished reliability information.
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Sample / Buy
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Buy Online
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Buy, Request for Samples, Request for Information Materials
Authorized Distributors
Please contact your local distributors for any sales-related inquiry such as price, stock, delivery, etc.
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Download Datasheet
Functional Description
| TSD | Thermal Shutdown Function |
|---|---|
| ILX | LX Current Limit Function |
| OCP | Overcurrent Protection |
| OVP | Overvoltage Protection |
| UVLO | Undervoltage Lockout Protection |
| OVLO | Overvoltage Lockout Protection |
| Reverse | Reverse Current Protection Circuit |
| Shutdown | Shutdown Function |
| Soft Start | Soft Start Function |
| SSCG | Spread Spectrum Clock Generator Function |
| PGOOD | Power Good Output |
| Auto Discharge | Auto Discharge Function |
| Anti-ringing | Anti-ringing Switch Function |
| Sequencing | Start-up Sequencing Control |
| Max Duty | Maximum Duty Cycle |
| Ext. Phase | Externally Adjustable Phase Compensation |
| LED Adjust | LED High-speed Dimming Control |