6A Highly Integrated SupIRBuck
TM
IR3473
FEATURES
•
Input Voltage Range: 3V to 27V
•
Output Voltage Range: 0.5V to 12V
•
Continuous 6A 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
•
Very Small, Low Profile 4mm x 5mm QFN Package
DESCRIPTION
The IR3473 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
IR3473 a space‐efficient solution that delivers up to 6A 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
90%
85%
80%
Efficiency
75%
70%
65%
60%
55%
50%
45%
0.01
0.1
1
Load Current (A)
10
VIN = 19V
VIN = 12V
VIN = 8V
Figure 1: IR3473 Basic Application Circuit
Figure 2: IR3473 Efficiency
1
March 27, 2013 | V2.2 | PD97601
6A Highly Integrated SupIRBuck
TM
IR3473
ORDERING INFORMATION
IR3473
―
Package
M
M
PBF – Lead Free
TR – Tape and Reel
M – Package Type
Tape & Reel Qty
750
4000
Part Number
IR3473MTR1PBF
IR3473MTRPBF
MARKING INFORMATION
Site/Date/Marking Code
Lot Code
Pin 1 Identifier
3473
?YWW?
xxxxx
PIN DIAGRAM
θ
JA
=
32
o
C
/
W
θ
J
-
PCB
=
2
o
C
/
W
2
March 27, 2013 | V2.2 | PD97601
6A Highly Integrated SupIRBuck
TM
IR3473
FUNCTIONAL BLOCK DIAGRAM
Figure 3: IR3473 Functional Block Diagram
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March 27, 2013 | V2.2 | PD97601
6A Highly Integrated SupIRBuck
TM
IR3473
TYPICAL APPLICATION
+3.3V
VCC
R1
10K
R2
10K
TP4
EN
4
3
EN
FCCM
R3
200K
R4
15.8K
VSW
ISET
VSW
C4
0.22uF
L1
2.2uH
U1
IR3473
VOUT
TP7
VOUT
TP6
PGNDS
TP5
PGND
TP23
VOUTS
VIN
TP1
VINS
TP2
VIN
C1
1uF
C2
22uF
+
C3
68uF
SW1
EN / FCCM
1
2
16
17
14
+3.3V
15
13
GND
BOOT
VIN
R6
open
C13
open
C6
open
R13
open
C7
open
C8
open
C9
150uF
C10
47uF
C11
open
C12
0.1uF
EN
R5
10K
TP11
PGOOD
PGOOD
1
2
3
4
FB
5
6
C20
0.1uF
7
FCCM
ISET
PGOOD
GND1
FB
SS
3VCBP
NC1
PGND
PHASE
12
FF
TP10
PGND
IR3473
TP13
SS
SS
C24
open
C15
open
VCC
NC2
C16
open
C17
open
C18
open
C19
open
C26
open
C27
open
TP24
PGNDS
8
9
10
TP14
+3.3V
+3.3V
C21
1uF
TP26
AGND
R12
4.99
11
C25
1uF
C14
open
-Vdd2s
-Vins
+Vout1s -Vout1s
+Vout2s -Vout2s
-Vdd1s
R7
2.80K
6
7
8
10
9
TP18
VOLTAGE SENSE
+Vdd1s
2
1
3
4
VOUT
VCC
R11
20
R9
open
R8
2.55K
Q1
open
3
2
R10
open
TP28
VID
C22
open
1
+3.3V
VIN
5
TP17
PGND
C23
open
TP27
A
TP25
B
+Vdd2s
+Vins
TP16
VCC
VCC
Figure 4: Demoboard Schematic for VOUT = 1.05V, F
S
= 300kHz
DEMOBOARD BILL OF MATERIALS
QTY
3
1
2
1
1
1
1
1
1
3
1
1
1
1
1
1
1
REFERENCE DESIGNATOR
C1, C21, C25
C10
C12, C20
C2
C3
C4
C9
L1
R4
R1, R2, R5
R11
R12
R3
R7
R8
SW1
U1
VALUE
1.00uF
47uF
0.100uF
22.0uF
68uF
0.22uF
150uF
2.2uH
15.8K
10.0K
20
4.99
200K
2.80K
2.55K
SPST
IR3473
DESCRIPTION
capacitor, X7R, 1.00uF, 25V, 0.1, 0603
capacitor, 47uF, 6.3V, 805
capacitor, X7R, 0.100uF, 25V, 0.1, 603
capacitor, X5R, 22.0uF, 16V, 20%, 1206
capacitor, electrolytic, 68uF, 25V, 0.2, SMD
capacitor, X5R, 0.22uF, 10V, 0.1, 0603
capacitor, tantalum polymer, 150uF, 6.3V, 20%,
7343
inductor, ferrite, 2.2uH, 8.0A, 11.2mOhm, SMT
resistor, thick film, 15.8K, 1/10W, 0.01, 603
resistor, thick film, 10.0K, 1/10W, 0.01, 0603
resistor, thick film, 20, 1/10W, 0.01, 603
resistor, thick film, 4.99, 1/8W, 0.01, 603
resistor, thick film, 200K, 1/10W, 0.01, 603
resistor, thick film, 2.80K, 1/10W, 0.01, 603
resistor, thick film, 2.55K, 1/10W, 0.01, 0603
switch, DIP, SPST, 2 position, SMT
4mm X 5mm QFN
MANUFACTURER
Murata
TDK
TDK
Taiyo Yuden
Panasonic
TDK
Sanyo
Cyntec
KOA
KOA
KOA
KOA
KOA
KOA
KOA
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SD02H0SK
IR3473MTRPBF
4
March 27, 2013 | V2.2 | PD97601
6A Highly Integrated SupIRBuck
TM
IR3473
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. A resistor in series with
the bypass capacitor may be required in single‐ground plane designs. Refer to
Layout Recommendation for details.
‐
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 | V2.2 | PD97601
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