High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
MAX1710/MAX1711
Pin Description (continued)
PIN
10
11
12
13
14
15
16
(MAX1710)
16
(MAX1711)
17
18
19
20
NAME
GND
GNDS
PGOOD
DL
PGND
V
DD
OVP
D4
D3
D2
D1
D0
Analog Ground
Ground Remote-Sense Input, normally connected to ground directly at the load. GNDS internally con-
nects to the integrator that fine-tunes the ground offset voltage.
Open-Drain Power-Good Output.
Low-Side Gate-Driver Output, swings 0 to V
DD
.
Power Ground. Also used as the inverting input for the current-limit comparator.
Supply Voltage Input for the DL gate driver, 4.5V to 5.5V
Overvoltage-Protection Disable Control Input (Table 3). GND = normal operation and overvoltage
protection active, V
CC
= overvoltage protection disabled.
DAC Code Input, MSB, 5µA internal pull-up to V
CC
(Tables 1 and 2).
DAC Code Input. 5µA internal pull-up to V
CC
.
DAC Code Input. 5µA internal pull-up.
DAC Code Input. 5µA internal pull-up.
DAC Code Input LSB. 5µA internal pull-up.
Low-Noise-Mode Selection Control Input. Low-noise forced-PWM mode causes inductor current
recirculation at light loads and suppresses pulse-skipping operation. Normal operation prevents
current recirculation.
SKIP
can also be used to disable both overvoltage and undervoltage protection
circuits and clear the fault latch (Figure 6). GND = normal operation, V
CC
= low-noise mode.
Do not
leave
SKIP
floating.
Boost Flying-Capacitor Connection. An optional resistor in series with BST allows the DH pull-up
current to be adjusted (Figure 5). This technique of slowing the LX rise time can be used to prevent
accidental turn-on of the low-side MOSFET due to excessive gate-drain capacitance.
Inductor Connection. LX serves as the lower supply rail for the DH high-side gate driver. Also used
for the noninverting input to the current-limit comparator as well as the skip-mode zero-crossing com-
parator.
High-Side Gate-Driver Output. Swings LX to BST.
FUNCTION
21
SKIP
22
BST
23
24
LX
DH
Standard Application Circuit
The standard application circuit (Figure 1) generates a
low-voltage, high-power rail for supplying up to 7A to the
core CPU V
CC
in a notebook computer. This DC-DC
converter steps down a battery or AC adapter voltage to
sub-2V levels with high efficiency and accuracy, and
represents a good compromise between size, efficiency,
and cost.
See the MAX1710 EV kit manual for a list of components
and suppliers.
Detailed Description
The MAX1710/MAX1711 buck controllers are targeted
for low-voltage, high-current CPU power supplies for
notebook computers. CPU cores typically exhibit 0 to
10A or greater load steps when the clock is throttled.
The proprietary QUICK-PWM pulse-width modulator in
the MAX1710/MAX1711 is specifically designed for han-
dling these fast load steps while maintaining a relatively
constant operating frequency and inductor operating
point over a wide range of input voltages. The QUICK-
PWM architecture circumvents the poor load-transient
timing problems of fixed-frequency current-mode PWMs
9
_______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
