3A, 18V, 700kHz ACOT® Synchronous Step-Down Converter

RT7275/RT7276

The RT7275/76 are high-performance 700kHz 3A step-down regulators with internal power switches and synchronous rectifiers. They feature quick transient response using their Advanced Constant On-Time (ACOT^TM) control architecture that provides stable operation with small ceramic output capacitors and without complicated external compensation, among other benefits. The input voltage range is from 4.5V to 18V and the output is adjustable from 0.765V to 8V.

The proprietary ACOT^TM control improves upon other fast-response constant on-time architectures, achieving nearly constant switching frequency over line, load, and output voltage ranges. Since there is no internal clock, response to transients is nearly instantaneous and inductor current can ramp quickly to maintain output regulation without large bulk output capacitance. The RT7275/76 are stable with and optimized for ceramic output capacitors.

With internal 90mΩ switches and 60mΩ synchronous rectifiers, the RT7275/76 display excellent efficiency and good behavior across a range of applications, especially for low output voltages and low duty cycles. Cycle-by-cycle current limit, input under-voltage lock-out, externally-adjustable soft-start, output under- and over-voltage protection, and thermal shutdown provide safe and smooth operation in all operating conditions.

The RT7275 and RT7276 are each available in WDFN-10L 3x3 and PTSSOP-14 packages, with exposed thermal pads.

應用

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
Not Recommended for Sink/Source Applications

主要規格

	RT7275	RT7276
Status	Active	Active
Vin (min) (V)	4.5	4.5
Vin (max) (V)	18	18
Number of Outputs	1	1
Vout (min) (V)	0.765	0.765
Vout (max) (V)	8	8
Output Adj. Method	Resistor	Resistor
Iout (max) (A)	3	3
Current Limit (typ) (A)	4.5	4.5
Freq (typ) (kHz)	700	700
Ext Sync	No	No
Ron_HS (typ) (mOhm)	100;90	100;90
Ron_LS (typ) (mOhm)	60	60
Iq (typ) (mA)	0.7	0.7
Features	ACOT Control;Adjustable Soft-Start;Cycle-by-Cycle Current Limit;Enable Input;Fast Transient Response;Force PWM;OCP;OTP;OVP;Power Good;Stable with Ceramic Capacitor;UVP	ACOT Control;Adjustable Soft-Start;Cycle-by-Cycle Current Limit;Enable Input;Fast Transient Response;OCP;OTP;OVP;PSM;Power Good;Stable with Ceramic Capacitor;UVP
Package Type	WDFN3x3-10;TSSOP-14(PP)	WDFN3x3-10;TSSOP-14(PP)

關鍵特性

Fast Transient Response
Steady 700kHz Switching Frequency
► At all Load Currents (RT7275)
► Discontinuous Operating Mode at Light Load (RT7276)
3A Output Current
Advanced Constant On-Time (ACOT^TM) Control
Optimized for Ceramic Output Capacitors
4.5V to 18V Input Voltage Range
Internal 90mΩ Switch and 60mΩ Synchronous Rectifier
0.765V to 8V Adjustable Output Voltage
Externally-Adjustable, Pre-Biased Compatible Soft-Start
Cycle-by-Cycle Current Limit
Optional Output Discharge Function (PTSSOP-14 Only)
Output Over- and Under-Voltage Shut-Down