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Número de pieza | XR76116 | |
Descripción | 15A and 20A Synchronous Step-Down COT Regulators | |
Fabricantes | Exar | |
Logotipo | ||
Hay una vista previa y un enlace de descarga de XR76116 (archivo pdf) en la parte inferior de esta página. Total 19 Páginas | ||
No Preview Available ! XR76116/20
PowerBloxTM 15A and 20A Synchronous
Step-Down COT Regulators
Description
The XR76116 and XR76120 are synchronous step-down regulators
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.
FEATURES
■ 15A and 20A step-down regulators
■ 4.5V to 5.5V low VIN operation
■ 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
Typical Application
ENABLE
VIN
POWER GOOD
CIN R
CBST
EN BST
VIN SW
RLIM
PVIN ILIM
PGOOD
XR76116/20
VCC
FB
SS FCCM
CVCC CSS
TON
RON
AGND
VSNS
PGND
L1
CFF
RFF
VOUT
R1
R2
VOUT
R1
COUT
R2
Figure 1. XR76116/20 Typical Application
100
98
96
94
92
90
88
86
84
82
80
78
76
74
72
70
0.1
600kHz
800kHz
5.0V
3.3V
2.5V
1.8V
1.5V
1.2V
1.0V
5.1 10.1 15.1 20.1
IOUT (A)
Figure 2. XR76120 Efficiency
REV1A
1/19
1 page Pin Configuration
PVIN 13
SW
12
11 PGND
XR76116/20
BST 14
EN 15
SS 16
17
AGND
10 VCC
9 VIN
8 VSNS
1234567
Pin Functions
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Pin Name
FB
FCCM
AGND
TON
ILIM
PGOOD
VSNS
VIN
VCC
PGND
SW
PVIN
BST
EN
SS
AGND PAD
Type
Analog
Input
Description
Feedback input to feedback comparator.
Forcing this pin logic level high forces CCM operation.
Analog
Signal ground for control circuitry. Connect to AGND pad with a short trace.
Analog
Analog
Output,
Open Drain
Analog
Analog
Analog
Power
Power
Power
Analog
Input
Analog
Analog
Constant on-time programming pin. Connect with a resistor to AGND.
Overcurrent protection programming. Connect with a resistor to SW.
Power-good output. Open drain to AGND. Low Z when IC unpowered.
Sense pin for output OVP and open FB.
Supply input for the regulator’s LDO. Normally connected to PVIN.
The output of regulators LDO. It requires a 4.7μF VCC bypass capacitor. For operation
using a 5V rail, VCC should be tied to VIN.
Ground of the power stage. Internally connected to source of the low-side MOSFET.
Switch node. Internally it connects source of the high-side MOSFET to drain of the
low-side MOSFET.
Input voltage for power stage. Internally connected to drain of the high-side MOSFET.
High-side driver supply pin. Connect a 0.1μF bootstrap capacitor between BST and SW.
Precision enable pin. Pulling this pin above 2V will enable the regulator.
Soft-start pin. Connect an external capacitor between SS and AGND to program the soft-
start rate based on the 10μA internal source current.
Signal ground for control circuitry.
REV1A
5/19
5 Page XR76116/20
Typical Performance Characteristics (Continued)
All data taken at VIN = 12V, VOUT = 1.8V, f = 800kHz, TA = 25°C, no airflow, forced CCM. (Unless otherwise specified).
Schematic from the Applications Information section of this datasheet.
35 25
30
20
25
20 15
15
10
5 Calculated worst case
Typical
0
1 1.2 1.4 1.6 1.8 2 2.2
RLIM (kΩ)
10
5
0
1.5
Calculated worst case
Typical
2.0 2.5
RLIM (kΩ)
3.0
3.5
Figure 27. XR76120 IOCP vs. RLIM
Figure 28. XR76116 IOCP vs. RLIM
610 300
605 250
600 200
595
590
-40
-20 0
20 40 60 80 100
TJ (°C)
Figure 29. VREF vs. Temperature
120
150
100
-40 -20
0
20 40 60
TJ (˚C)
80 100 120
Figure 30. tON vs. Temperature, RON = 5.9k
REV1A
11/19
11 Page |
Páginas | Total 19 Páginas | |
PDF Descargar | [ Datasheet XR76116.PDF ] |
Número de pieza | Descripción | Fabricantes |
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