PD-97763
IR3876MPBF
SupIRBuck
Features
TM
12A HIGHLY INTEGRATED
WIDE-INPUT VOLTAGE, SYNCHRONOUS BUCK REGULATOR
Description
The IR3876
SupIRBuck
TM
is an easy-to-use,
fully integrated and highly efficient DC/DC
voltage regulator. The onboard constant on time
hysteretic controller and MOSFETs make
IR3876 a space-efficient solution that delivers up
to 12A of precisely controlled output voltage in
o
60 C ambient temperature applications without
airflow.
Programmable switching frequency, soft start,
and over current protection allows for a very
flexible solution suitable for many different
applications and an ideal choice for battery
powered applications.
Additional features include pre-bias startup, very
precise 0.5V reference, over/under voltage shut
down, power good output, and enable input with
voltage monitoring capability.
Input Voltage Range: 3V to 21V
Output Voltage Range: 0.5V to 12V
Continuous 12A Load Capability
Constant On-Time control
Excellent Efficiency at very low output current levels
Compensation Loop not Required
Programmable switching frequency, soft start, and
over current protection
Power Good Output
Precision Voltage Reference (0.5V, +/-1%)
Pre-bias Start Up
Under/Over Voltage Fault Protection
Ultra small, low profile 5mm x 6mm QFN Package
Applications
Notebook and desktop computers
Game consoles
Consumer electronics – STB, LCD, TV, printers
General purpose POL DC-DC converters
V5
(4.5V-7.5V)
R
FF
VIN
(3V-21V)
VCC
3VCBP
FF
VIN BOOT
C
BOOT
C
LDO
PHASE
L
VOUT
(0.5V-12V)
EN
IR3876
PGND
R
ISET
C0
PGOOD
ISET
FB
GND
R
1
SS
C
SS
R
2
1
IR3876MPBF
ABSOLUTE MAXIMUM RATINGS
(Voltages referenced to GND unless otherwise specified)
•
•
•
•
•
•
•
•
•
•
•
•
VIN. FF .………………………………………………. -0.3V to 25V
VCC, PGood, EN ………………….…....……..….… -0.3V to 8.0V
Boot ……………………………………..………….…. -0.3V to 33V
PHASE ……………………………………………....... -0.3V to 25V(DC), -5V(100ns)
Boot to PHASE …..…………………………….…….. -0.3V to 8V
ISET …..…………………………………………..……. -0.3V to 30V
PGND to GND ……………...……………………….... -0.3V to +0.3V
All other pins ……………...……………………….….. -0.3V to 3.9V
Storage Temperature Range .................................... -65°C To 150°C
Junction Temperature Range ................................... -10°C To 150°C
ESD Classification …………………………….……… JEDEC Class 1C
Moisture sensitivity level ..……………...…………….. JEDEC Level 2 @ 260°C (Note 2)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. These are stress ratings only and functional operation of the device at these or any other
conditions beyond those indicated in the operational sections of the specifications are not implied.
PACKAGE INFORMATION
5mm x 6mm POWER QFN
PHASE
12
VIN 13
11
PGND
θ
JA
=
35
o
C / W
θ
J
-
PCB
=
2
o
C / W
BOOT 14
FF 15
EN 16
1
2
3
4
5
6
SS
7
NC
17
GND
10
9
VCC
NC
8 3VCBP
NC ISET PGOOD GND FB
ORDERING INFORMATION
PKG DESIG
M
M
PACKAGE
DESCRIPTION
IR3876MTRPbF
IR3876MTR1PbF
PIN COUNT
17
17
PARTS PER
REEL
4000
750
2
IR3876MPBF
Block Diagram
VCC
3VCBP
FF
VBG
VCC
-
VCC
GND
SS
FB
x0.8
GND V
REF
GND
x1.2
EN
+
LDO
3VCBP
BOOT
PWM
COMP
+
+
-
+
-
SET
Run
VIN
PWM
ON-TIME
UV#
Run
3VCBP VCC
Run
GATE
DRIVE
LOGIC
PHASE
VCC
SOFT
START
FF
SSDelay
CONTROL
LOGIC
POR
Zcross
PGND
DCM
OVER
CURRENT
OC#
PGOOD
ISET
3
IR3876MPBF
Pin Description
NAME
NC
ISET
PGOOD
GND
FB
SS
NC
3VCBP
NC
VCC
PGND
PHASE
VIN
BOOT
FF
EN
NUMBER
1
2
3
4,17
5
6
7
8
9
10
11
12
13
14
15
16
5V
Reference
3.3V
3.3V
-----
3.3V
-----
5V
Reference
VIN
VIN
VIN +VCC
VIN
5V
I/O
LEVEL
-----
DESCRIPTION
No connection
Connecting resistor to PHASE pin sets over current trip point
Power good – pull up to 3.3V
Bias return and signal reference
Inverting input to PWM comparator, OVP / PGood sense
Set soft start slew-rate with a capacitor to GND
No connection
LDO output. A minimum of 1.0 µF ceramic capacitor is required
No connection
Gate drive supply
Power return
Phase node (or switching node) of MOSFET half bridge
Input voltage for the system.
Bootstrapped gate drive supply – connect a capacitor to PHASE
Input voltage feed forward – sets on-time with a resistor to VIN
Enable
4
IR3876MPBF
Recommended Operating Conditions
Symbol
VIN
VCC
V
OUT
I
OUT
Fs
T
J
Definition
Input Voltage
Supply Voltage
Output Voltage
Output Current
Switching Frequency
Junction Temperature
Min
3
4.5
0.5
0
N/A
0
Max
21*
7.5
12
12
1000
125
Unit
V
A
kHz
o
C
*
Note: PHASE pin must not exceed 25V.
Electrical Specifications
Unless otherwise specified, these specification apply over VIN = 12V, VCC = 5V, 0
o
C ≤ T
J
≤ 125
o
C.
PARAMETER
BIAS SUPPLIES
VCC Turn-on Threshold
VCC Turn-off Threshold
VCC Threshold Hysteresis
VCC Operating Current
VCC Shutdown Current
FF Shutdown Current
VIN Shutdown Current
INTERNAL LDO OUTPUT
LDO Output Voltage Range
Output Current
CONTROL LOOP
Reference Accuracy, V
REF
On-Time Accuracy
Min Off Time
Soft-Start Current
Zero Current Threshold
FAULT PROTECTION
ISET Pin Output Current
Under Voltage Threshold
Under Voltage Hysteresis
Over Voltage Threshold
Over Voltage Hysteresis
PGOOD Delay Threshold
(V
SS
)
1
1
1
1
EN = HIGH
Measure at V
PHASE
8
-5
18
0.37
0.58
NOTE
TEST CONDITION
MIN
3.9
3.6
R
FF
= 200K,
EN = HIGH, Fs = 300kHz
EN = LOW
EN = LOW
EN = LOW
C
LDO
= 1µF
3.1
TYP
4.2
3.9
150
9.2
35
2
1
3.3
MAX
4.5
4.2
UNIT
V
V
mV
mA
µA
µA
µA
V
mA
V
ns
ns
µA
mV
µA
V
mV
0.66
V
mV
V
50
3.5
8
V
REF
R
FF
= 180K, T
J
= 65
o
C
0.495
280
0.5
300
400
10
-2.4
20
0.4
10
0.62
10
1
0.505
320
12
0
22
0.43
Falling V
FB
& Monitor PGOOD
Rising V
FB
Rising V
FB
& Monitor PGOOD
Falling V
FB
5
单片机
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