IR3856WMTR1PBF International Rectifier, IR3856WMTR1PBF Datasheet - Page 23

• Manufacturer Part Number: IR3856WMTR1PBF
• Description: IC REG SYNC BUCK 6A 17-QFN
• Manufacturer: International Rectifier
• Series: SupIRBuck™r
• Type: Step-Down (Buck)r

Specifications of IR3856WMTR1PBF

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.7 ~ 14.4 V
• Current - Output: 6A
• Frequency - Switching: 225kHz ~ 1.65MHz
• Voltage - Input: 1.5 ~ 16 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 17-PowerVQFN
• Power - Output: 1.3W
• Part Status: Active
• Package: PQFN / 4 x 5
• Circuit: Single Output
• Iout (a): 6
• Switch Freq (khz): 0 - 750
• Input Range (v): 1.5 - 16
• Output Range (v): 0.7 - 0.9*Vin
• Ocp Otp Uvlo Pre-bias Soft Start And: PGOOD + EN + SEQ + OVD
• Server Storage: Yes
• Routers Switches: Yes
• Base Station Telecom: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: IR3856WMTR1PBFTR

Detailed calculation of compensation Type-III
Desired
Select
Select
Calculate
R
Select
C
C
Calculate
R
R
Select
R
F
F
F
Z
P
P
Rev 8.0
3
4
3
10
8
9
2
2
3
=
=
=
=
=
=
=
=
=
V
2
2
2
2
F
F
0.5
2
π
π
π
π
o
:
:
:
:
o
o
V
π
C
R
-
*
*
*
ref
F
R
*
V
*
7
8
*
F
C
1
1
1
1
Z
F
F
3
1
ref
C
Phase
F
1
P
o
Z
1
1
−
+
=
=
+
−
7
s
R
=
R
1
1
C
3
7
=
*
*
sin
sin
sin
sin
2.2
4.02
*
*
10
3
*
*
=
2.55
L
7
0
F
,
R
R
R
o
F
*
.
Z
300
,
5
C
P
V
8
nF
*
3
2
3
Θ
Θ
R
Θ
Θ
*
2
;
3
C
in
;
;
-
k
R
8
C
;
F
k
C
R
o
Ω
=
=
and
Margin
Z
9
Ω
4
kHz
*
3
and
10
R
2
17.63
567.1
V
=
=
=
10
=
;
osc
2.57
8
258.79
R
C
8.82
.
=
84
R
8
4
R ;
128
9
=
:
kHz
kHz
k
Θ
3
nF,
:
3.97
Ω
=
kHz
=
Ω
pF
2.56
70
,
Select
Select
,
k
Select
o
Ω
and
Select
,
k
Ω
:
:
R
C
:
9
R
:
4
C
=
10
=
3
2.55
10
=
=
130
220
nF
k
Ω
Ω
pF
Setting the Power Good Threshold
Power Good threshold is internally set at 88% of
Vref. When the voltage at the FB pin exceeds the
threshold, PGood is asserted.
The PGood is an open drain output. Hence, it is
necessary to use a pull up resistor R
PGood pin to Vcc.
resistor must be chosen such as to limit the
current flowing into the PGood pin, when the
output voltage is not in regulation, to less than
5mA. A typical value used is 10kΩ.
Programming the Current-Limit
The Current-Limit threshold can be set by
connecting a resistor (R
to the OCSet pin. The resistor can be calculated
by using equation (4). This resistor R
be placed close to the IC.
The
coefficient and it should be considered for the
worst case operation.
I
SET
R
I
(50%
I
R
OCSet
SET
DS
OCSet
=
(
R
on
≅
I
DS(on)
L
=
)
I
(
over
=
o
critical
=
59.07
(
LIM
2.694
14.3
)
)
=
nominal
=
has
μA
m
6
R
k
Ω
IR3856WMPbF
Ω
A
OCSet
R
*
*
(at
1.25
1.5
Select
DS
a
The value of the pull-up
∗
F
(
output
on
OCSET
I
s
=
OCSet
)
=
positive
9
=
17.875
A
600
R
) from the SW pin
7
..........
current
kHz)
=
2.67
m
PD-97506
Ω
temperature
..........
OCSET
k
)
Ω
PG
...
must
(32)
23
from