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18V, 1.5A, 500kHz ACOTTM Step-down Converter in 8 Pin TSOT-23

RT7255

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The RT7255 is a simple, easy-to-use, 1.5A synchronous step-down DC-DC converter with an input supply voltage range of 4.3V to 18V. The device build-in an accurate 0.6V reference voltage and integrates low RDS(ON) power MOSFETs to achieve high efficiency in a TSOT-23-8 package.

The RT7255 adopts Advanced Constant On-Time (ACOTTM) control architecture to provide an ultrafast transient response with few external components and to operate in nearly constant switching frequency over the line, load, and output voltage range. The RT7255A operates in automatic PSM that maintains high efficiency during light load operation. The RT7255C operates in Forced PWM that helps meet tight voltage regulation accuracy requirements.

The RT7255 senses low-side FETs current for a robust over-current protection. It features cycle-by-cycle current limit protection and prevent the device from the catastrophic damage in output short circuit, over current or inductor saturation. An externally adjustable soft-start function prevents inrush current during start-up. The device also includes input under-voltage lockout, output under-voltage protection, and over-temperature protection (thermal shutdown) to provide safe and smooth operation in all operating conditions. The RT7255 is offered in a TSOT-23-8 package.

Applications

  • Industrial and Commercial Low Power Systems
  • Computer Peripherals
  • LCD Monitors and TVs
  • Green Electronics/Appliances
  • Point of Load Regulation for High-Performance DSPs, FPGAs, and ASICs
Key Spec.
RT7255A RT7255C
Status Preview Preview
Vin (min) (V) 4.3 4.3
Vin (max) (V) 18 18
Number of Outputs 1 1
Vout (min) (V) 0.6 0.6
Vout (max) (V) 8 8
Preset Vout (V)
Output Adj. Method Resistor Resistor
Iout (max) (A) 1.5 1.5
Current Limit (typ) (A) 2.2 2.2
Freq (typ) (kHz) 500 500
Freq (min) (kHz)
Freq (max) (kHz)
Ext Sync No No
Ron_HS (typ) (mOhm) 230 230
Ron_LS (typ) (mOhm) 130 130
Iq (typ) (mA) 0.5 0.5
Features ACOT Control;Adjustable Soft-Start;Built-in Bootstrap Switch;Cycle-by-Cycle Current Limit;Fast Transient Response;PSM;Stable with Ceramic Capacitor;UVP ACOT Control;Adjustable Soft-Start;Built-in Bootstrap Switch;Cycle-by-Cycle Current Limit;Fast Transient Response;Force PWM;Stable with Ceramic Capacitor;UVP
Package Type TSOT-28 TSOT-28
Features
  • 1.5A Converter With Built-In 230mΩ/130mΩ Low RDS(ON) Power FETs
  • Input Supply Voltage Range : 4.3V to 18V
  • Output Voltage Range : 0.6 to 8V
  • Advanced Constant On-Time (ACOTTM) Control
  • Ultrafast Transient Response
  • No Needs For External Compensations
  • Optimized for Low-ESR Ceramic Output Capacitors
  • 0.6V ±1.5% High-Accuracy Feedback Reference Voltage
  • Low Quiescent Current (500μA typ.)
  • Optional for Operation Modes :
    ► Power Saving Mode (PSM) at Light Load (RT7255A)
    ► Forced PWM Mode (RT7255C)
  • Light-load VOUT Ripple Reduction Technology in PSM
  • Fixed Switching Frequency : 500kHz
  • Externally Adjustable Soft-Start
  • Monotonic Start-Up for Pre-Biased Output
  • Input Under-Voltage Lockout (UVLO)
  • Output Under-Voltage Protection (UVP) with Hiccup Mode
  • Power Good Indication
  • Enable Control
  • Available In TSOT-23-8 Package
Datasheet
TitleLast UpdateShareDownload
18V, 1.5A, 500kHz ACOTTM Step-down Converter in 8 Pin TSOT-232018/01/25
Technical Documents
TitleLast UpdateShareDownload
ACOT™ Stability Testing2019/03/18
ACOT™ (Advanced Constant-On Time) Synchronous Step-Down Converters2018/11/15
Comparing Buck Converter Topologies2018/09/20
Buck Converter Selection Criteria2016/08/04
The Calculation of Output DC Offset for ACOT™ Control Buck Converter with Feed-forward Compensator2016/07/07
Videos
TitleLast UpdateShareViews
How to estimate control loop bandwidth from the transient response time?2017/03/30 522
How to Select a Power Management Component for Your Application2014/10/28 168
Evaluation Boards
TitleLast UpdateShareDownload
1.5A, 18V, 500kHz ACOT™ Synchronous Step-down Converter2018/11/01
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