ir3086a International Rectifier Corp., ir3086a Datasheet - Page 26

• Manufacturer Part Number: ir3086a
• Description: Xphasetm Phase Ic With Ovp, Fault And Overtemp Detect
• Manufacturer: International Rectifier Corp.

Calculate the programming resistor.
From Figure 15 of IR3081A Data Sheet, the source current of VDAC pin is 250uA. The VDAC up-slope slew rate is
Over Current Setting Resistor R
The room temperature is 25ºC and the target PCB temperature is 100 ºC. The phase IC die temperature is about 1
ºC higher than that of phase IC, and the inductor temperature is close to PCB temperature.
Calculate Inductor DC resistance at 100 ºC,
The current sense amplifier gain is 34 at 25ºC, and its gain at 101ºC is calculated as,
Set the over current limit at 135A. From Figure 14 of IR3081A Data Sheet, the bias current of OCSET pin (I
is 90uA with R
offset created by the current sense amplifier input resistor mismatch.
Calculate constant K
No Load Output Voltage Setting Resistor R
From Figure 14 of IR3081A Data Sheet, the bias current of FB pin is 90uA with R
Body Braking
N/A. The body braking during Dynamic VID is disabled.
C
G
R
SR
R
K
R
R
R
L
OCSET
VDAC
VDAC
FB
DRP
CS
P
(
UP
_
135
MAX
_
6
MIN
(
V
R
I
R
I
L
Page 26 of 33
. 0
0
C
SR
SOURCE

[
_
FB
R
5 .
VDAC
64
R
I
MAX
V
L
G
SINK
DOWN
LIMIT

O
_
n
*
CS
R
ROOM
)
3
10
L
TM
2 .
C
_
OSC
V
V
_
I
n
ROOM

VDAC
O
*
O
MAX
LIMIT
3
Related Resistors R
R
10
250
_
/(
68
R
1 [
=13.3k . The total current sense amplifier input offset voltage is 0.55mV, which includes the
L
I
NLOFST
2
. 1
L
FB

O
_
5 .
P,
2

*
15
32
/
MAX
170
*
G
10
*
3850
V
10
the ratio of inductor peak current over average current in each phase,
n
1 [
CS
10
I
R




*
L
9
0
. 0

_

6
1470
_
10
5 .
*
MIN
3
f
1 (
V
55
MAX
SW
10
/
CS



10
3
6

*
K
_
(
7 .
6
*
10

3
68
TOFST
10
) 2
P
6
mV
2 .
162
(
)

T
*
OCSET

*

3
L
10
6
* )
10
V
68
_
/
(
6
MAX
12
CS
uS

. 0
(
30

nF
n
9
BBFB
T
15
64
_
. 0
)

IC
2 .
2
TOFST

91
. 1
R
*
_
T
/(
O
28
10
MAX
*
ROOM
90
1
and R
10
)
2 .

]
FB
3
*
. 0
:

*
. 1

10
G
3
)]
64
30
and Adaptive Voltage Positioning Resistor R
T
28
CS

ROOM
BBDRP
*
2 .
6
0
/(
_
10
)
5 .
100
MIN

*
135
576
3
)]
. 6
10
*
/
34
10
I

20
6 /
:
3
OCSET
34
90
k

*
:
9
1 [
10
*

10
1 [
12

3850
3



6
1470
800
*
. 0
*
. 0
55
10
64
*
*
*

10
10
6
10
*
10
3

(

6
100
3

) 2
3
(
6
101

25
OSC
. 0
. 0

)]
32
91
25
=13.3k .
*
. 0
)]
10
64

3
m
30
:
2 .
162
IR3086A
:
DRP
1/31
/05
OCSET
)