15A Highly Integrated SupIRBuck
TM
IR3477
FEATURES
•
Input Voltage Range: 3V to 27V
•
Output Voltage Range: 0.5V to 12V
•
Continuous 15A Load Capability
•
Constant On‐Time Control
•
Compensation Loop not Required
•
Excellent Efficiency at Very Low Output Currents
•
Programmable Switching Frequency and Soft Start
•
Thermally Compensated Over Current Protection
•
Power Good Output
•
Precision Voltage Reference (0.5V, +/‐1%)
•
Enable Input with Voltage Monitoring Capability
•
Pre‐bias Start Up
•
Thermal Shut Down
•
Under/Over Voltage Fault Protection
•
Forced Continuous Conduction Mode Option
•
Small, Low Profile 5mm x 6mm QFN Package
DESCRIPTION
The IR3477 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
IR3477 a space‐efficient solution that delivers up to 15A of
precisely controlled output voltage.
Programmable switching frequency, soft start, and
thermally compensated 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, under/over voltage shutdown, thermal
protection, power good output, and enable input with
voltage monitoring capability.
APPLICATIONS
•
Notebook and Desktop Computers
•
Consumer Electronics – STB, LCD, TV, Printers
•
12V and 24V Distributed Power Systems
•
General Purpose POL DC‐DC Converters
•
Game Consoles and Graphics Cards
BASIC APPLICATION
EFFICIENCY
95%
85%
Efficiency
75%
65%
55%
45%
0.01
19VIN
12VIN
8VIN
0.1
Figure 1: IR3477 Basic Application Circuit
1
10
Load Current (A)
100
Figure 2: IR3477 Efficiency
1
March 27, 2013 | V2.5 | PD97604
15A Highly Integrated SupIRBuck
TM
IR3477
ORDERING INFORMATION
IR3477
―
Package
M
M
PBF – Lead Free
TR – Tape and Reel
M – Package Type
Tape & Reel Qty
750
4000
Part Number
IR3477MTR1PBF
IR3477MTRPBF
MARKING INFORMATION
PIN DIAGRAM
Site/Date/Marking Code
Lot Code
Pin 1 Identifier
3477
?YWW?
xxxxx
θ
JA
=
30
o
C
/
W
θ
J
-
PCB
=
2
o
C
/
W
2
March 27, 2013 | V2.5 | PD97604
15A Highly Integrated SupIRBuck
TM
IR3477
FUNCTIONAL BLOCK DIAGRAM
Figure 3: IR3477 Functional Block Diagram
3
March 27, 2013 | V2.5 | PD97604
15A Highly Integrated SupIRBuck
TM
IR3477
TYPICAL APPLICATION
+3.3V
VCC
R1
10K
R2
10K
TP4
EN
4
3
TP3
FCCM
EN
FCCM
R3
200K
R4
7.50K
VSW
ISET
VSW
1
2
C4
1uF
L1
1.0uH
16
17
14
15
13
U1
IR3477
VOUT
+Vin1s
TP20
+Vin1s
C1
1uF
C2
22uF
+
C3
68uF
VIN
+Vins
TP1
VINS
TP2
VIN
SW1
EN / FCCM
TP5
PGND
-Vins
TP6
PGNDS
TP23
+Vsws
TP7
VOUT
1
2
R6
open
C13
open
C6
open
C7
open
C8
open
C9
330uF
C10
47uF
C11
open
C12
0.1uF
3
4
5
TP8
VOUTS
+3.3V
GND
C5
open
R5
10K
TP11
PGOOD
PGOOD
BOOT
VIN
EN
FF
1
2
3
4
FB
5
6
C20
0.1uF
7
FCCM
ISET
PGOOD
GND1
FB
SS
3
3VCBP
NC1
PGND
4
PHASE
12
IR3477
TP13
SS
SS
2
1
TP22
+Vsws
5
TP12
VSWS
TP21
-Vsws
TP9
+Vout1s
TP24
+Vsws
TP10
PGND
C15
open
C16
open
C17
open
C18
open
C19
open
C26
open
C27
open
8
9
10
VCC
NC2
TP14
+3.3V
+3.3V
+Vdd2s
C21
1uF
11
-Vout1s
TP15
-Vout1s
TP25
-Vin1s
-Vout1s
-Vdd2s
TP26
AGND
+Vdd1s
C25
1uF
C22
open
-Vdd1s
C24
open
-Vout1s
+Vout1s -Vout1s
10
+Vout2s -Vout2s
9
-Vdd1s
7
-Vdd1s
6
-Vins
TP16
VCC
TP17
PGND
VCC
C23
open
-Vdd2s
C14
open
R7
1.33K
8
-Vdd2s
TP18
VOLTAGE SENSE
+Vdd1s
2
+Vdd1s
+Vdd2s
+Vin1s
R12
open
R8
1.21K
R13
open
R14
open
Vout
TP19
FB
R11
open
1
3
+Vdd2s
+Vins
4
5
Figure 4: Demoboard Schematic for VOUT = 1.05V, F
S
= 300kHz
DEMOBOARD BILL OF MATERIALS
QTY
4
1
2
1
1
1
1
3
1
1
1
1
1
1
REFERENCE DESIGNATOR
C1, C21, C25, C4
C10
C12, C20
C2
C3
C9
L1
R1, R2, R5
R3
R4
R7
R8
SW1
U1
VALUE
1.00uF
47uF
0.100uF
22.0uF
68uF
330uF
1.0uH
10.0K
200K
7.50K
1.33K
1.21K
SPST
IR3477
DESCRIPTION
capacitor, X7R, 1.00uF, 25V, 0.1, 0603
capacitor, 47uF, 6.3V, 805
capacitor, X7R, 0.100uF, 50V, 0.1, 603
capacitor, X5R, 22.0uF, 25V, 20%, 1206
capacitor, electrolytic, 86uF, 25V, 0.2, SMD
capacitor, 330uF, 2.5V, SMD
inductor, ferrite, 1.0uH, 20A, 2.7mOhm, SMT
resistor, thick film, 10.0K, 1/10W, 0.01, 603
resistor, thick film, 200K, 1/10W, 0.01, 603
resistor, thick film, 7.50K, 1/10W, 0.01, 603
resistor, thick film, 1.33K, 1/10W, 0.01, 603
resistor, thick film, 1.21K, 1/10W, 0.01, 603
switch, DIP, SPST, 2 position, SMT
5mm x 6mm QFN
MANUFACTURER
Murata
TDK
TDK
TDK
Panasonic
Sanyo
Cyntec
KOA
KOA
KOA
KOA
KOA
C&K Components
IRF
PART NUMBER
GRM188R71E105KA12D
C2012X5R0J476M
C1608X7R1H104K
C3216X5R1E226M
EEV‐FK1E680P
2R5TPE330M9
PIMB103E‐1R0MS‐39
RK73H1J1002F
RK73H1JLTD2003F
RK73H1JLTD7501F
RK73H1J1331F
RK73H1JLTD1211F
SD02H0SK
IR3477MTRPBF
4
March 27, 2013 | V2.5 | PD97604
15A Highly Integrated SupIRBuck
TM
IR3477
PIN DESCRIPTIONS
PIN #
1
2
3
4, 17
5
6
7
8
9
10
11
12
13
14
15
16
PIN NAME
FCCM
ISET
PGOOD
GND
FB
SS
NC
3VCBP
NC
VCC
PGND
PHASE
VIN
BOOT
FF
EN
I/O LEVEL
3.3V
5V
Reference
3.3V
3.3V
‐
3.3V
‐
5V
Reference
VIN
VIN
VIN + VCC
VIN
5V
PIN DESCRIPTION
Forced Continuous Conduction Mode (CCM). Ground this pin to enable diode
emulation mode or discontinuous conduction mode (DCM). Pull this pin to 3.3V
to operate in CCM under all load conditions.
Connecting resistor to PHASE pin sets over current trip point.
Power good open drain output – pull up with a resistor to 3.3V
Bias return and signal reference.
Inverting input to PWM comparator, OVP / PGOOD sense.
Soft start/shutdown. This pin provides user programmable soft‐start function.
Connect an external capacitor from this pin to GND to set the startup time of the
output voltage. The converter can be shutdown by pulling this pin below 0.3V.
‐
For internal LDO. Bypass with a 1.0µF capacitor to GND.
‐
VCC input. Gate drive supply. A minimum of 1.0µF ceramic capacitor is required.
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 pin to turn on and off the device. Use two external resistors to set the
turn on threshold (see Electrical Specifications) for input voltage monitoring.
5
March 27, 2013 | V2.5 | PD97604
PCB设计
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