IR3522 International Rectifier, IR3522 Datasheet - Page 24

• Manufacturer Part Number: IR3522
• Description: DDR & VTT CONTROL IC
• Manufacturer: International Rectifier

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The soft start delay time TD1, power good time TD3, and soft stop time are determined by equation (2), (3) and
(4) respectively.
VDAC Slew Rate Programming Capacitor C
The slew rate of VREF1 down-slope SR
(5), where I
determined by (6)
Over Current Setting Resistor R
The total input offset voltage (V
(V
sense resistor R
The inductor DC resistance is utilized to sense the inductor current. R
The over-current limit is set by the external resistor, R
limit. I
CHARACTERISTICS Table. G
of inductor peak current over average current in each phase and can be calculated from (10).
CS_OFST)
OCSET
Page 24
SINK
of the amplifier itself and that created by the amplifier input bias current flowing through the current
is the bias current of OCSET pin and can be calculated with the equation in the ELECTRICAL
is the sink current of VREF1 pin. The resistor R
CS
TD
TD
C
.
SS
TD
1
3
/
DEL
=
=
4
C
C
V
R
K
=
=
SS
CS
OCSET
SS
P
C
/
_
=
TD
/
DEL
I
TOFST
DEL
SS
CHG
(
CS
V
SVID
/
2
=
( *
I
DEL
1 *
I
*
CS_TOFST
−
[
is the gain of the current sense amplifier of the IR3506 phase IC. K
CHG
R
OCSET
. 3
C
I
V
=
I
VDAC
LIMIT
4 .
*
VDAC
O
92
I
CHG
V
n
CHG
)
SVIS
CS
∗
=
−
V
_
DOWN
=
∗
O
=
C
=
OFST
SVIC
I
0
R
O
/(
) of current sense amplifier in phase ICs is the sum of input offset
SS
45
5 .
TD
SR
L
=
L
/
I
/
∗
+
n
SINK
DEL
DOWN
+
∗
*
VDAC
C
1 (
can be programmed by the external capacitor C
2
V
3
−
10
I
SVID
2 .
I
SS
C
CSIN
*
+
. 1
1 *
∗
55
VDAC
45
−
/
∗
K
) 4
6
DEL
f
10
and Resistor R
+
P
SW
4 .
*
*
)
=
∗
−
10
2
+
OCSET,
10
*
15
∗
R
C
V
) 2
CS
SVID
−
CS
−
SS
6
6
/
_
DEL
TOFST
as defined in (9). I
( *
VDAC
]
45
. 3
∗
VDAC
92
G
*
L
CS
10
is used to compensate VDAC circuit and is
is the inductor DCR.
−
/
−
SVID
I
6
OCSET
−
. 1
LIMIT
(2)
(9)
) 4
(4)
is the required over current
(1)
(5)
(6)
(7)
(10)
VDAC
(3)
V3.01
IR3522
as defined in
P
is the ratio