FAN5231 Datasheet, PDF (15/17 Pages) Fairchild Semiconductor – Precision Dual PWM Controller And Linear Regulator for Notebook CPUs

FAN5231
FAN5231 DC-DC Converter
Application Circuit
Figure 13 shows an application circuit of a power supply for
a notebook PC microprocessor system. The power supply
provides the microprocessor core voltage (V_core), the I/O
voltage (V_I/O) and the clock generator voltage (V_CLK) from
+5-24V_DC, +5V_DC and +3.3V_DC. For detailed information
on the circuit, including a Bill-of-Materials and circuit board
description, see Application Note ANXXXX.
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www.fairchildsemi.com.
+5V
V_IN
+7.5V-24.0V
GND
C1 ⁺
56µF
CR1
BAT54WT1
C2
0.22 µF
Q1
FDS6612A
V _{I/ O}
(1.5V )
+
1µF
L1
10µH
+ _C3
330µF
Q2
FDS6612A
VR_ON
+3.3VI N
V_{CL K}
(2.5V)
+ _C4
10µF
C4
10µF
C5-6
2x1µF
VBATT
19
BOOT2
3
VCC
28
PGOOD
21
25 ^BOOT1
UGATE2
4
PHASE2 ₅
R1 _ISEN2
6
500
FAN5231
24 ^UGATE1
PHASE1
23
ISEN1 ^R2
22
1k
LG ATE2 ₁
PGND2 ₂
VSEN2
12
EN ₂₀
27 ^{LG ATE1}
26 ^PGND1
17 ^VSEN1
VRTN1
16
CR2
BAT54WT1
Q3
FDS6690A
C7
0.22µF
L2
2µH
Q4
C8 ⁺
Two FDS6670A ^{3x680 µF}
in parallel
V3I N ₁₃
VSEN3
14
11 ^VID0
10 ^VID1
9 ^VID2
8 ^VID3
7 ^VID4
18 ^SOFT
C10
0.22µF
15
GND
VI D0
VI D1
VI D2
VI D3
VI D4
VG AT E
V_core
(0.925 TO 2.0V)
+ _C9
2x1µF
2x10µF
FROM CPU
CORE
Figure 13. Application Circuit
REV. 1.1.1 8/15/01
15