IR3840MTR1PBF International Rectifier, IR3840MTR1PBF Datasheet - Page 22

• Manufacturer Part Number: IR3840MTR1PBF
• Description: IC REG SYNC SUPIRBUCK 12A 5X6QFN
• Manufacturer: International Rectifier
• Series: SupIRBuck™r
• Type: Step-Down (Buck)r

Specifications of IR3840MTR1PBF

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.7 ~ 14.4 V
• Current - Output: 12A
• Frequency - Switching: 250kHz ~ 1.5MHz
• Voltage - Input: 1.5 ~ 16 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 15-PowerVQFN
• Power - Output: 2.6W
• Part Status: Active
• Package: PQFN / 5 x 6
• Circuit: Single Output
• Iout (a): 12
• Switch Freq (khz): 250 - 1500
• 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
• Server Storage: Yes
• Routers Switches: Yes
• Base Station Telecom: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: IR3840MTR1PBFTR

Detailed calculation of compensation TypeIII
06/18/09
C
C
Desired
F
F
Select
F
Select
Calculate
R
Select
Calculate
R
R
Select
R
Z
P
P
4
3
10
8
3
9
2
3
2
=
=
=
=
=
=
=
=
=
V
2
2
2
2
F
F
0.5
2
π
:
:
π
:
π
π
:
o
π
o
o
V
C
R
F
R
*
*
*
-
*
ref
*
7
Z
8
V
*
3
F
C
F
F
Phase
1
1
1
1
1
C
1
F
1
P
ref
=
o
Z
1
=
R
=
R
7
−
+
+
−
1
=
s
1
3
7
C
*
10
2.2
3
3.92
sin
sin
1.87
*
sin
sin
*
*
*
0
=
,
*
L
7
F
,
R
.
R
F
C
o
R
5
Z
300
*
R
nF
P
3
2
Θ
Θ
Θ
3
V
3
8
Θ
*
*
2
8
;
k
;
kΩ
F
C
in
;
-
R
Margin
and
C
;
C
Ω
=
R
=
Z
and
o
3
9
2
4
kHz
R
10
17.63
567.1
*
=
=
=
=
10
V
;
C
2.49
osc
283.7
9.65
R
8.82
R
=
4
8
9
128
:
;
kHz
kHz
Θ
=
R
:
kΩ
nF,
3.97
3
=
kHz
pF
, Ω
70
=
,
1.85
Select
o
Select
kΩ
Select
Select
and
,
kΩ
:
:
R
:
:
C
C
R
9
4
3
10
=
=
=
2.49
=
10
220
130
nF
kΩ
pF
Ω
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 5
mA. A typical value used is 4.7kΩ.
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
I
(50%
I
R
R
OCSet
SET
DS
OCSet
=
R
(
I
on
≅
L
DS(on)
(
=
)
critical
I
over
=
o
=
59.07
(
LIM
2.696
5
9 .
)
)
=
=
mΩ
nominal
has
μA
R
12
kΩ
OCSet
*
R
A
1.5
(at
DS
*
Select
IR3840MPbF
a
The value of the pull-up
1.5
∗
(
on
=
F
I
OCSET
OCSet
s
)
8.85
output
=
positive
=
18
600
R
) from the SW pin
A
mΩ
..........
7
kHz)
=
current
2.8
..........
temperature
OCSET
kΩ
)
PG
...
(32)
must
from
22