IR3502MTRPBF International Rectifier, IR3502MTRPBF Datasheet - Page 28

• Manufacturer Part Number: IR3502MTRPBF
• Description: IC XPHASE3 CONTROLLER 32-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase3™r

Specifications of IR3502MTRPBF

• Applications: Processor
• Current - Supply: 8mA
• Voltage - Supply: 8 V ~ 16 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 32-MLPQ
• 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: IR3502MTRPBFTR

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 28 of 39
and R
DAC
L_room
voltage and output voltage at no load condition. R
C
TH
I
are the inductor DCR at maximum temperature T
OCP
=
=
RTHERM
1
3
RTCMP
R
R
⋅
B
RTHERM




t
t
TH
RTCMP
R
_
_
R
t
room
L
max
DRP
_
=
room
R
room
VSETPT
n
RTHERM
1
=
=
=
⋅
=
G








2
⋅
VSETPT
t
RTHERM
1
3
3
3
max
cs
−
=
⋅
∗
⋅

⋅  

B




=
K
K
K
=
R
K
TH
R



R
V
1
THERM
THERM
t
FB
c
RTHERM
c
o
+
O
_
,
1
I
+
_
_
t
room
VSETPT
max
_
(
t
room
∗
RTCMP
max
NLOFST
t
max

 

(
_
_
−
+
B
G
room
room
TH
2
−
R
CS
RTHERM
t




 

_
)
. 1
RTHERM
∗
) 2
room
2
t
−
−
1
max
17
−
R
1
II
1
n








4
L
(
⋅
+
RTCMP
_
⋅
⋅
e
1
⋅
RTCMP
RTCMP
ROOM
RTCMP
β
R
C
THERM
RTCMP
t
TH
_
t
1
t
max
room
max
⋅





∗  

1
273
+
−
−
1
+



RTHERM
3
VSETPT
3
3
1
RTHERM




T
R
1
max
t
+
_
1
−
room
max
273
RTCMP
R
+
1
T
t
and room temperature T
is determined by (26), where
room
_
room
_
t
max
room




3




 

O_NLOFST,



)
July 28, 2009



IR3502
which is the
(17)
(18)
(19)
(20)
(21)
(22)
(23)
room
.
(24)
(25)
(26)