Manual

MAX8775
Detailed Description
The MAX8775 is a dual fixed-frequency step-down con-
troller for low-voltage I/O and graphics core (GPU) sup-
plies. It can be configured as two separate regulators
generating two independent outputs. Alternatively, the
MAX8775 can be configured in combined mode as a
two-phase, single-output, high-current regulator, pow-
ering the high-performance graphics cores used in
game machines and media center notebooks.
The standard applications circuit (Figure 1) generates
dynamically adjustable output voltages on both out-
puts. REFIN voltage setting allows for multiple dynamic
Dual and Combinable Graphics Core
Controller for Notebook Computers
12 ______________________________________________________________________________________
V
DD
V
CC
C4
1μF
OSC
R
OSC
154kΩ
CCI2
REF
R7
10Ω
PGOOD1
+5V
R8
100kΩ
PGOOD2
GND
SKIP1
SKIP2
ON1
ON2
SLEW1
C
REF
0.1μF
SLEW2
NOT USED
DTRANS
C
BST1
0.1μF
+5V
LX1
DH1
BST1
DL1
CSL1
CSH1
C3
2.2μF
INPUT V
IN
7V TO 20V
L1
0.88μH
D
L1
C
IN1
N
H1
N
L1
V
OUT1
1.5V/1.2V 15A
CSL2
CSH2
LX2
DH2
BST2
DL2
ANALOG GROUND
POWER GROUND
R
SENSE1
1.5mΩ
R10
150Ω
R11
10Ω
C1
2.2nF
C2
4.7nF
R1
100kΩ
OVP1
REFIN1
REF
V
OUT1(L)
V
OUT2(L)
V
OUT1(H)
V
OUT2(H)
SEE TABLE 1 FOR COMPONENT
SPECIFICATIONS.
R3
249kΩ
R2
150kΩ
OVP2
REFIN2
REF
R9
100kΩ
C
OUT1
(2) 330μF
PGND
MAX8775
C
SLEW1
470pF
C
SLEW2
470pF
R4
100kΩ
R6
249kΩ
R5
150kΩ
C
BST2
0.1μF
INPUT V
IN
7V TO 20V
L2
0.88μH
D
L2
C
IN2
N
H2
N
L2
V
OUT2
1.5V/1.2V 15A
R
SENSE2
1.5mΩ
R12
150Ω
R13
10Ω
C5
2.2nF
C6
4.7nF
C
OUT2
(2) 330μF
EP
Figure 1. MAX8775 Separate Output Typical Operating Circuit