PowerBlox

Step-Down COT Regulators

XR

1/19

REV1A

FEATURES

■

15A and 20A step-down regulators

■

■

5V to 22V wide single input voltage

■

3V to 22V operation with external

5V bias

■

≥0.6V adjustable output voltage

■

Proprietary constant on-time control

■

No loop compensation required

■

Ceramic output capacitor stable

operation

■

Programmable 70ns-1μs on-time

■

Constant 200kHz-1MHz frequency

■

Selectable CCM or CCM/DCM

operation

■

Power-good flag with low impedance when

power removed

■

Precision enable

■

Programmable soft-start

■

5mm x 6mm QFN package

APPLICATIONS

■

Servers

■

Distributed power architecture

■

Point-of-load converters

■

FPGA, DSP and processor supplies

■

Base stations, switches/routers

Description

combining the controller, drivers, bootstrap diode and MOSFETs

in a single package for point-of-load supplies. The XR76116 has a

load current rating of 15A and the XR76120 has a load current rating

of 20A. A wide 5V to 22V input voltage range allows for single supply

operation from industry standard 5V, 12V and 19.6V rails.

With a proprietary emulated current mode constant on-time (COT)

control scheme, the XR76116/20 provide extremely fast line and

load transient response using ceramic output capacitors. They

require no loop compensation, simplifying circuit implementation

and reducing overall component count. The control loop also

provides 0.1% load and 0.1% line regulation and maintains constant

operating frequency. A selectable power saving mode, allows the user

to operate in discontinuous mode (DCM) at light current loads thereby

significantly increasing the converter efficiency.

A host of protection features, including overcurrent, over temperature,

overvoltage, short-circuit, open feedback detect and UVLO, helps

achieve safe operation under abnormal operating conditions.

The XR76116/20 are available in a RoHS-compliant, green/halogen-

free space-saving 5mm x 6mm QFN package.

Typical Application

Figure 1. XR76116/20 Typical Application

Figure 2. XR76120 Efficiency

ENABLE

VIN

CIN

POWER GOOD

R

CVCC

CSS

RON

RLIM

RFF

COUT

CFF

VOUT

VOUT

CBST

L1

R1

R2

XR76116/20

EN

VIN

PVIN

PGOOD

VCC

SS

TON

AGND

BST

SW

ILIM

FB

FCCM

VSNS

PGND

R1

R2

70

72

74

76

78

80

82

84

86

88

90

92

94

96

98

100

0.1

5.1

10.1

15.1

5.0V

3.3V

2.5V

1.8V

1.5V

1.2V

1.0V

600kHz

800kHz

IOUT (A)

20.1