R1272 Series

34V Input PWM/VFM Step-down DC/DC Controller with PLL Synchronization

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Description

The R1272 is a step-down DC/DC controller with synchronous rectifier and 34V input voltage. By the adoption of a unique current mode PWM architecture without an external current sense resistor, the R1272 can make up a stable DC/DC converter with high-efficiency even if adding low Ron MOSFETs and a low DCR inductor externally. In PLL_PWM mode, oscillator frequency is synchronized to an external clock frequency using a PLL and is effective for EMI control. For EMI reduction, SSCG (Spread-Spectrum Clock Generation) for diffused oscillation frequency at the PWM operation is optionally available.

Spec

	Consumer	Industrial	Automotive
Input Voltage Range	4.0 V to 34.0 V (36.0 V)
Operating Temperature Range	-40°C to 105°C (125°C)	-40°C to 105°C (125°C)	-40°C to 125°C (150°C)
Supply Current	Typ. 15 µA
Standby Current	Typ. 3 µA
Start-up Voltage	4.5 V
Output Voltage Range	Externally Adjustable: 0.7 V to 5.3 V
Feedback Voltage	0.64 V
Feedback Voltage Accuracy	±1%
Oscillator Frequency	Externally Adjustable: 250 kHz to 1 MHz
Package	HSOP-18

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TSD	ILX	OCP	OVP	UVLO	OVLO	Reverse	Shutdown	Soft Start	SSCG	PGOOD	Auto Discharge	Anti-ringing	Sequencing	Max Duty	Ext. Phase	LED Adjust

Functional Description

Quality &
Packages

Product Name	Package	Marking	Reliability
R1272SxxxA-E2-FE	HSOP-18	See datasheet	R1272S-FE
R1272SxxxA-E2-YE	HSOP-18	See datasheet	R1272S-YE
R1272SxxxA-E2-KE	HSOP-18	See datasheet	R1272S-KE
R1272SxxxA-E2-AE	HSOP-18	See datasheet	R1272S-AE

Refer to the datasheets for the details on the product.
The package file or the datasheet includes package dimensions, taping specifications, taping reels dimensions, power dissipations, and recommended land pattern.

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