Rainbow Electronics MAX17008 - Manual (Page 15)

MAX17007A/MAX17008
Dual and Combinable QPWM Graphics
Core Controllers for Notebook Computers
______________________________________________________________________________________ 15
V OUT1 = 1.0V/1.2V AT 12A
(FIGURE 1)
V OUT = 1.5V AT 12A
(FIGURE 1)
COMPONENT
V IN = 7V to 20V
TON1 = 220k
(270kHz)
V IN = 7V to 20V
TON2 = 180k
(330kHz)
Input Capacitor
(per Phase)
(2x) 10μF, 25V
Taiyo Yuden TMK432BJ106KM (2x) 10μF, 25V
Taiyo Yuden TMK432BJ106KM
Output Capacitor
(2x) 330μF, 2.5V, 12m
, C case
SANYO 2R5TPE330MCC2
(2x) 330μF, 2.5V, 12m
, C case
SANYO 2R5TPE330MCC2
Inductor
1μH, 3.25m
, 16A
Würth Electronics 7443552100
1μH, 3.25m
, 16A
Würth Electronics 7443552100
Schottky Diode
2A, 30V Schottky diode (SMA)
Nihon EC21QS03L
Central Semiconductor
CMSH2-40M 2A, 30V Schottky diode (SMA)
Nihon EC21QS03L
Central Semiconductor
CMSH2-40M
High-Side MOSFET
Fairchild Semiconductor
(1x) FDS8690
8.6m

/11.4m
(typ/max)
Fairchild Semiconductor
(1x) FDS8690
8.6m

/11.4m
(typ/max)
Low-Side MOSFET
Fairchild Semiconductor
(1x) FDS8670
4.2m

/5m
(typ/max)
Fairchild Semiconductor
(1x) FDS8670
4.2m

/5m
(typ/max)
Table 1. Component Selection for Standard Applications
MANUFACTURER WEBSITE MANUFACTURER WEBSITE
AVX Corp. www.avxcorp.com Pulse Engineering www.pulseeng.com
BI Technologies www.bitechnologies.com Renesas Technology Corp. www.renesas.com
Central Semiconductor Corp. www.centralsemi.com SANYO Electric Company, Ltd. www.sanyodevice.com
Fairchild Semiconductor www.fairchildsemi.com Siliconix (Vishay) www.vishay.com
International Rectifier www.irf.com Sumida Corp. www.sumida.com
KEMET Corp. www.kemet.com Taiyo Yuden www.t-yuden.com
NEC TOKIN America, Inc. www.nec-tokinamerica.com TDK Corp. www.component.tdk.com
Panasonic Corp. www.panasonic.com TOKO America, Inc. www.tokoam.com
Table 2. Component Suppliers
Detailed Description
The MAX17007A/MAX17008 standard application circuit
(Figure 1) generates the 1V to 1.2V/12A and 1.5V/12A
chipset voltages in a notebook computer. The input sup-
ply range is 7V to 20V for the specific application. Table 1
lists component selections, while Table 2 lists the com-
ponent manufacturers. Figure 2 shows the combined-
mode standard application circuit and Figure 3 is the
MAX17007A/MAX17008 functional diagram.
The MAX17007A/MAX17008 contain two constant on-
time step-down controllers designed for low-voltage
power supplies. The two SMPSs can also be combined
to operate as a two-phase high-current single-output
regulator. Constant on-time Quick-PWM operation pro-
vides fast response to load transients and handles wide
I/O voltage ratios with ease, while maintaining a relatively
constant switching frequency. The switching frequency
can be adjusted between 200kHz and 600kHz with
external resistors. Differential output current sensing
allows output sense-resistor sensing for an accurate cur-
rent-limit, lossless inductor DCR current sensing for lower
power dissipation while maintaining 0.7% output accura-
cy. Overvoltage (MAX17007A) and undervoltage protec-
tion and accurate user-selectable current limits (four
different levels) ensure robust operations.
The MAX17007A/MAX17008 feature a special com-
bined-mode configuration that allows higher current
outputs to be supported. A current-balance integrator
maintains equal currents in the two phases, improving
efficiency and power distribution.