IR3521MTRPBF International Rectifier, IR3521MTRPBF Datasheet - Page 38

• Manufacturer Part Number: IR3521MTRPBF
• Description: IC CTRL XPHASE3 SVID 32-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase3™r

Specifications of IR3521MTRPBF

• Applications: Processor
• Current - Supply: 10mA
• Voltage - Supply: 4.75 V ~ 7.5 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: *
• Package: 32-Lead MLPQ
• Circuit: X-Phase Control IC
• Switch Freq (khz): 250kHz to 1.5MHz
• Pbf: PbF Option Available
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

VDAC Slew Rate Programming Capacitor C
Over Current Setting Resistor R
The output1 over current limit is 115A and the output2 over current limit is 25A. From the electrical characteristics
table can get the bias current of OCSET pin (I
amplifier input offset voltage is around 0mV, Calculate constant K
current in each phase,
VCCL Programming Resistor R
Choose VCCL=7V to maximize the converter efficiency. Pre-select R
No Load Offset Setting Resistor RFB11, RFB13, RTHERM1 and Adaptive Voltage Positioning Resistor
RDRP11 for Output1
Define R
offset voltage V
the equation in the ELECTRICAL CHARACTERISTICS Table, then the effective offset resistor value R
be determined by:
Adaptive voltage positioning lowers the converter voltage by R
the converter. Pre-select feedback resistor R
K
K
R

R

R
R
C
R
OCSET
OCSET
FB
P
P
(
(
VCCLFB
VDAC
VDAC
115
1
25
2
1
_
5


R

1
(
2
(
1

V
. 0
12



2
. 0

I

FB_R
47
0

SR

V
[
52

[
5 .
I
O
I
V
I
. 1
*
R
SINK
LIMIT
LIMIT
DOWN
O
VCCL
*
_

10
VCCLFB
I
) 2
n
n
)
10
NLOFST
FB
is the effective offset resistor at room temperature equals to R
3



2 .
C
O_NLOFST
1
V

3
I
1
3

VDAC

O
LIMIT

2 .




R
1
R
. 1
10
/(
/(
. 1
*
. 1
L
45
L
L
19

. 1
3

220

2
38
23

15

2 .
2 .
/
23
1 (
15
26
* )
1 (
V
n
* )
*



I
*

*
34
*
10

10

10
25
34
above the DAC voltage, calculate the sink current from the FB1 pin I
10
10
K
7
K
20
1 .
3
f
/(

P

SW
P


6
/(
Ohm
9
)
26
3
6
)
*
7

26



10

12


V
*
14
V
) 2
*
CS
10
. 1
VCCLFB1
577
3
CS
10
OCSET

1 .
*
23

520
_

. 1
nF
_
TOFST

6
Ohm
TOFST
(
6
23
)
12
)
*
, Choose C


10


18
]
21
. 1
and R
. 4
3
]

.


k 4
) 2
G
26
.
G
k 6
FB,
) 2
CS


k
VDAC
CS

1


/
and calculate the droop resistor RDRP,
2 .
VCCLFB2
/
I
. 0
OCSET
OCSET
I
/(
VDAC
19
OCSET
120
and Resistor R
Page 38
115
*
=22nF
) is 26uA with R
10
5 /

9

12
O
*I

P,
O,
520
the ratio of inductor peak current over average
where R
VDAC
VCCLFB1
*
10
3
OSC

) 2
O
=20kΩ, and calculate R
=23.2 kΩ. The total current sense

is the required output impedance of
FB11
. 0
38
//(R
FB13
+R
THERM1
FB1
IR3521
V3.03
VCCLFB2.
= 26uA using
). Given the
FB_R
1 can