MAX17007GTI+ Maxim Integrated Products, MAX17007GTI+ Datasheet - Page 21

• Manufacturer Part Number: MAX17007GTI+
• Description: IC CTRLR QPWM GRAPHICS 28TQFN
• Manufacturer: Maxim Integrated Products
• Series: Quick-PWM™r

Specifications of MAX17007GTI+

• Applications: Power Supplies
• Current - Supply: 1.7mA
• Voltage - Supply: 4.5 V ~ 26 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Soft-start begins when EN is driven high and REF is in
regulation. During soft-start, the output is ramped up
from 0V to the final set voltage at 1.3mV/µs slew rate for
SMPS1, and 0.65mV/µs for SMPS2, reducing the inrush
current and providing a predictable ramp-up time for
power sequencing:
The soft-start circuitry does not use a variable current
limit, so full output current is available immediately. The
respective PGOOD becomes high impedance approxi-
mately 200µs after the target voltage has been
reached. The MAX17007/MAX17008 automatically use
pulse-skipping mode during soft-start and use forced-
PWM mode during soft-shutdown, regardless of the
SKIP configuration.
For automatic startup, the battery voltage should be
present before V
the output into regulation without the battery voltage
present, the fault latch trips. The controller remains shut
down until the fault latch is cleared by toggling EN or
cycling the V
Soft-shutdown begins when the system pulls EN low,
an output undervoltage fault, or a thermal fault. During
soft-shutdown, the respective PGOOD is pulled low
immediately and the output voltage ramps down with
the same startup slew rate for the respective outputs.
After the controller reaches the 0V target, the drivers
are disabled (DL_ and DH_ pulled low) and the internal
10Ω discharge on CSL_ activated. The MAX17007/
MAX17008 shut down completely when both EN are
low—the reference turns off after both SMPSs have
reached the 0V target, and the supply current drops to
about 1µA (max).
Slowly discharging the output capacitors by slewing
the output over a long period of time (typically 0.5ms to
2ms) keeps the average negative inductor current low
(damped response), thereby preventing the negative
output-voltage excursion that occurs when the con-
troller discharges the output quickly by permanently
turning on the low-side MOSFET (underdamped
t
START
t
START
CC
2
1
Core Controllers for Notebook Computers
=
power supply below 0.5V.
=
CC
t
______________________________________________________________________________________
t
SHDN
SHDN
. If the controller attempts to bring
2
1
Dual and Combinable QPWM Graphics
=
=
V
SR
SR
V
REFIN
FB
SS
SS
2
2
1
1
=
=
0 65
1 3
.
V
.
V
REFIN
Soft-Shutdown
mV s
FB
mV s
2
/µ
/µ
1
Soft-Start
response). This eliminates the need for the Schottky
diode normally connected between the output and
ground to clamp the negative output-voltage excursion.
The low-noise forced-PWM mode (SKIP = 5V) disables
the zero-crossing comparator, which controls the low-
side switch on-time. This forces the low-side gate-drive
waveform to constantly be the complement of the high-
side gate-drive waveform, so the inductor current
reverses at light loads while DH maintains a duty factor
of V
keep the switching frequency fairly constant. However,
forced-PWM operation comes at a cost: the no-load 5V
bias current remains between 2mA to 5mA, depending
on the switching frequency.
The MAX17007/MAX17008 automatically use forced-
PWM operation during shutdown, regardless of the
SKIP configuration.
In skip mode (SKIP = GND or 2V), an inherent automatic
switchover to PFM takes place at light loads. This
switchover is affected by a comparator that truncates
the low-side switch on-time at the inductor current’s
zero crossing. The zero-crossing comparator threshold
is set by the differential across CSL_ and CSH_.
DC output-accuracy specifications refer to the thresh-
old of the error comparator. When the inductor is in con-
tinuous conduction, the MAX17007/MAX17008 regulate
the valley of the output ripple, so the actual DC output
voltage is higher than the trip level by 50% of the output
ripple voltage. In discontinuous conduction (SKIP =
GND or 2V and I
has a DC regulation level higher than the error-com-
parator threshold by approximately 1.5% due to slope
compensation. However, the internal integrator corrects
for most of it, resulting in very little load regulation.
When SKIP = 2V, the MAX17007/MAX17008 use forced-
PWM operation during all dynamic output-voltage transi-
tions until 100µs after the transition has been
completed—REFIN1 and the internal target are within
±50mV (typ) and an error-amplifier transition is detected.
Since SMPS2 does not support dynamic transitions, SKIP
= 2V and SKIP = GND have the same pulse-skipping
behavior without any forced-PWM transitions.
OUT
/V
IN
. The benefit of forced-PWM mode is to
OUT
Automatic Pulse-Skipping Mode
< I
Forced-PWM Mode ( S S K K I I P P = 5V)
LOAD(SKIP)
Modes of Operation
( S S K K I I P P = GND or 2V)
), the output voltage
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