ISL6532CR Intersil, ISL6532CR Datasheet - Page 13

• Manufacturer Part Number: ISL6532CR
• Description: IC REG/CTRLR ACPI DUAL DDR 20QFN
• Manufacturer: Intersil

Specifications of ISL6532CR

• Applications: Memory, DDR/DDR2 Regulator
• Current - Supply: 5.25mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 20-QFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Supply: -

from the switching losses seen when sinking current. When
sourcing current, the upper MOSFET realizes most of the
switching losses. The lower switch realizes most of the
switching losses when the converter is sinking current (see
the equations below). These equations assume linear voltage-
current transitions and do not adequately model power loss
due the reverse-recovery of the upper and lower MOSFET’s
body diode. The gate-charge losses are dissipated in part by
the ISL6532 and do not significantly heat the MOSFETs.
However, large gate-charge increases the switching interval,
t
that both MOSFETs are within their maximum junction
temperature at high ambient temperature by calculating the
temperature rise according to package thermal-resistance
specifications. A separate heatsink may be necessary
depending upon MOSFET power, package type, ambient
temperature and air flow.
SW
1.25V
V
TT
which increases the MOSFET switching losses. Ensure
V
REF
PGOOD
220µF
V
C
DDQ
20
0.1µF
V
C
+
DDQ
26
0.1µF
C
+
27
220µF
C
21
10.0kΩ
R
FIGURE 7. DDR SDRAM AND AGP VOLTAGE REGULATOR USING THE ISL6532
0.47µF
2
13
C
19
+3.3V
S5
S3
C
1µF
17,18
PGOOD
SLP_S5#
SLP_S3#
VREF_OUT
VREF_IN
VTT
VTT
VTTSNS
5VSBY
ISL6532
ISL6532
VCC12
UGATE
LGATE
COMP
VDDQ
VDDQ
NCH
ISL6532 Application Circuit
Figure 7 shows an application circuit utilizing the ISL6532.
Detailed information on the circuit, including a complete Bill-
of-Materials and circuit board description, can be found in
Application Note AN1055.
Approximate Losses while Sinking current
FB
Approximate Losses while Sourcing current
C
1µF
16
P
P
P
P
LOWER
UPPER
UPPER
LOWER
Where: D is the duty cycle = V
4.99kΩ
= Io
= Io
R
=
=
t
f
1
SW
s
6.8nF
C
Io
2
Io
is the switching frequency.
2
14
2
x r
x r
2
is the combined switch ON and OFF time, and
1000pF
×
×
C
DS(ON)
DS(ON)
r
15
r
DS ON
19.1kΩ
DS ON
R
(
3
(
VCC5
x D
x (1 - D)
)
)
Q
×
Q
Q
×
L
2.1µH
5
1,3
56nF
D
2,4
825Ω
C
(
1
R
1 D
13
+
6
2.1µH
–
1.74kΩ
1
-- - Io
2
OUT
L
R
2
⋅
4
)
22.6Ω
C
1µF
+
R
4,5
/ V
5
×
1
-- - Io
2
V
⋅
IN
IN
,
+
×
×
V
+
t
2200µF
SW
IN
C
1-3
1800µF
×
C
×
6-8
t
f
SW
s
V
2.5V
DDQ
×
C
22µF
f
9-12
s