Manual

See Table 1 for component selections and Table 2 for
the component manufacturers.
SMPS 5V Bias Supply (V
CC
and V
DD
)
The MAX8775 SMPSs require a 5V bias supply in addi-
tion to the high-power input supply (battery or AC
adapter). V
DD
is the power rail for the MOSFET gate
drive, and V
CC
is the power rail for the IC. Connect the
external 4.5V to 5.5V supply directly to V
DD
and con-
nect V
DD
to V
CC
through an RC filter, as shown in
Figure 1. The maximum supply current required is:
I
BIAS
= I
CC
+ f
SW
(Q
G(NL1)
+ Q
G1(NH1)
+Q
G2(NL2)
+
Q
G2(NH2)
) = 1.8mA to 40mA
where I
CC
is 1.8mA, f
SW
is the switching frequency,
and Q
G_
is the MOSFET data sheet’s total gate-charge
specification limits at V
GS
= 5V.
Reference (REF)
The 2.5V reference is accurate to ±1% over tempera-
ture and load, making REF useful as a precision system
reference. Bypass REF to GND with a 0.1µF or greater
ceramic capacitor. The reference sources up to 250µA
and sinks 50µA to support external loads.
MAX8775
Dual and Combinable Graphics Core
Controller for Notebook Computers
______________________________________________________________________________________ 15
COMPONENT
V
IN
= 7V TO 24V
V
OUT1
= 1.0V - 1.5V / 15A
V
IN
= 7V TO 24V
V
OUT2
= 1.8V / 10A
V
IN
= 7V TO 24V
V
OUT1
= 1.0V - 1.5V / 40A
MODE SEPARATE (FIGURE 1) SEPARATE COMBINED (FIGURE 2)
Switching Frequency 280kHz 280kHz 280kHz
C
IN_
, Input Capacitor
(2) 10µF, 25V
Taiyo Yuden TMK432BJ106KM
(1) 10µF, 25V
Taiyo Yuden TMK432BJ106KM
(4) 10µF, 25V
Taiyo Yuden TMK432BJ106KM
C
OUT_
, Output
Capacitor
(2) 330µF, 6.3V, 7mΩ,
low-ESR capacitor
Panasonic EEFSD0D331XR
(1) 330µF, 6.3V, 7mΩ,
low-ESR capacitor
Panasonic EEFSD0D331XR
(4) 330µF, 6.3V, 7mΩ,
low-ESR capacitor
Panasonic EEFSD0D331XR
N
H_
High-Side
MOSFET
(1) Vishay/Siliconix
SI7634DP
(1) International Rectifier
IRF7811W
(1) Vishay/Siliconix
SI7634DP
N
L_
Low-Side MOSFET
(1) Vishay/Siliconix
SI7336ADP
(1) Vishay/Siliconix
SI7336ADP
(2) Vishay/Siliconix
SI7336ADP
D
L_
Schottky Rectifier
3A, 40V Schottky diode
Central Semiconductor
CMSH3-40
3A, 40V Schottky diode
Central Semiconductor
CMSH3-40
3A, 40V Schottky diode
Central Semiconductor
CMSH3-40
L_ Inductor
0.88µH, 18A, 2.1mΩ
NEC/Tokin MPC1040LR88
1.8µH, 13.8A, 6.2mΩ
Sumida CDEP105(S)-1R8
0.56_H, 26A, 1.3mΩ
NEC/Tokin MPC1040LR56
Panasonic ETQP4LR56WFC
Current-Sense R
SENSE
_
1.5mΩ, 1W, 2512
Panasonic ERJM1WTJ1M5U
2mΩ, 0.5W, 2010
Vishay WSL20102L000F
1.0mΩ, 1W, 2512
Panasonic ERJM1WTJ1M0U
Table 1. Component Selection for Standard Applications
SUPPLIER WEBSITE SUPPLIER WEBSITE
AVX www.avx.com Panasonic www.panasonic.com/industrial
Central Semiconductor www.centralsemi.com Sanyo www.secc.co.jp
Coilcraft www.coilcraft.com Sumida www.sumida.com
Coiltronics www.coiltronics.com Taiyo Yuden www.t-yuden.com
Fairchild Semiconductor www.fairchildsemi.com TDK www.component.tdk.com
International Rectifier www.irf.com TOKO www.tokoam.com
Kemet www.kemet.com Vishay (Dale, Siliconix) www.vishay.com
Table 2. Component Suppliers