IR3503MTRPBF International Rectifier, IR3503MTRPBF Datasheet - Page 30

• Manufacturer Part Number: IR3503MTRPBF
• Description: IC CTRL XPHASE VR11.0/1 32-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase3™r

Specifications of IR3503MTRPBF

• Applications: Processor
• Current - Supply: 8mA
• 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
• Other names: IR3503MTRPBFTR

Droop Resistor
The inductor DC resistance is utilized to sense the inductor current. The copper wire of inductor has a constant
temperature coefficient of 3850 ppm/° C, and therefore the maximum inductor DCR can be calculated from (15),
where R
respectively. After the thermal compensation is achieved using the procedure given above, the droop resistance
can be calculated using the following equation.
Over-current Threshold
No Load Output Voltage Setting Resistor R
A resistor between VSETPT pin and VDAC is used to create output voltage offset V
difference between V
I
Once the current report gain and the thermal compensation are calculated the OCP threshold is calculated using the
following expression.
VSETPT
is the current flowing out of VSETPT pin as shown in Figure 19.
L_tmax
Page 30 of 39
I
OCP
=
and R
1
3
⋅

 

R
L
DAC
_
L_room
room
n
RTHERM
voltage and output voltage at no load condition. R
⋅
G
cs
C
are the inductor DCR at maximum temperature T

⋅  

TH



1
=
+
RTHERM
RTCMP
(
R
R
B
RTCMP
t
t
TH
t
RTCMP
_
_
max
R
t
room
max
DRP
=
R
room
VSETPT
=
RTHERM
. 1
1
=
) 2
=
=
17
=
RTHERM
⋅
II








2
VSETPT
RTHERM
1
3
3
3
(
=
−
RTCMP
⋅
∗
⋅
B




=
K
K
K
R
K
R
RTCMP
TH
R
V
THERM
THERM
t
FB
c
c
o
O
_
,
1
I
_
_
+
t
room
t
VSETPT
max
_
max
t
room
1
∗
max
NLOFST
+

 

_
_
−
room
(
−
3
RTHERM
+
G
B
room
room




 

2
TH
R
RTHERM
CS
RTHERM
t
_
⋅
)
∗
t
−
−
e
2
1
max
R
1
1
β
−
n
R
THERM








L
t
+
4
_
_
_
⋅
⋅
1
1
t
room
⋅
RTCMP
max
RTCMP
ROOM
RTCMP
room
C
⋅
TH

 

t
−
−
273
max
RTHERM
R
)

∗  

t



+
1
_
1
T
×
room
1
max




 

VSETPT
3
3




1
Maximum
−
+
Number
273
t
max
max
RTCMP
+
R
1
T




 

room
t
is determined by (26), where
and room temperature T
_
room
_
_

 

February 12, 2010
of
number
3
O_NLOFST,
_



active
_
IR3503
of
_
_
phases
phases
which is the

 

(17)
(18)
(19)
(20)
(21)
(22)
(23)
room
(24)
(25)
(26)