MAX15112EVKIT# Maxim Integrated, MAX15112EVKIT# Datasheet - Page 13

• Manufacturer Part Number: MAX15112EVKIT#
• Description: Power Management IC Development Tools MAX15112 Eval Kit
• Manufacturer: Maxim Integrated
• Type: Power Switchesr
• Series: MAX15112r

Specifications of MAX15112EVKIT#

• Rohs: yes
• Product: Evaluation Kits
• Tool Is For Evaluation Of: MAX15112
• Input Voltage: 2.7 V to 5.5 V
• Output Voltage: 0.6 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Output Current: 12 A
• For Use With: MAX15112

A high-gain transconductance error amplifier provides
accuracy for the voltage-feedback loop regulation.
Connect the neces sary compensation network between
COMP and GND (see the
Guidelines
tance is 1.1mS (typ). COMP clamp low is set to 0.91V
(typ), just below the slope ramp compensation valley,
helping COMP to rapidly return to the correct set point
during load and line transients.
The MAX15112 features a ground-sense amplifier to pre-
vent output voltage droop under heavy load conditions.
Connect GSNS to the negative terminal of the load output
capacitor to properly Kelvin-sense the output ground.
Route the GSNS trace away from the switching nodes.
The PWM comparator compares the COMP voltage to
the current-derived ramp waveform (COMP voltage to LX
current transconductance value is 80A/V, typ). To avoid
instability due to subharmonic oscillations when the duty
cycle is around 50% or higher, a slope compensation
ramp is added to the current-derived ramp waveform.
The compensation ramp slope is designed to ensure
stable operation at any duty cycle up to 94%.
When the converter output is shorted or the device is
overloaded, each high-side MOSFET current-limit event
turns off the high-side MOSFET and turns on the low-side
MOSFET. On each current-limit event (either high-side
or low-side) a 3-bit counter is incremented. The counter
is reset after three consecutive switching cycles that do
not reach the current limit. If the current-limit condition
persists, the counter fills up reaching eight events. The
control logic then keeps the low-side MOSFET turned on
until the inductor current is fully discharged to avoid high
currents circulating through the low-side body diode.
Overcurrent Protection and Hiccup Mode
High-Efficiency, 12A, Current-Mode Synchronous
Step-Down Regulator with Integrated Switches
section). The error-amplifier transconduc-
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Ground-Sense Amplifier
Compensation Design
PWM Comparator
Error Amplifier
The control logic turns off both high-side and low-side
MOSFETs and waits for the hiccup period (1024 clock
cycles, typ) before attempting a new soft-start sequence.
The hiccup mode is also enabled during soft-start time.
The MAX15112 contains an internal thermal sensor that
limits the total power dissipation to protect the device in
the event of an extended thermal fault condition. When
the die temperature exceeds +150NC (typ), the thermal
sensor shuts down the device, turning off the DC-DC
converter to allow the die to cool. After the die tempera-
ture falls by 20NC (typ), the device restarts.
The MAX15112 features selectable skip mode operation
when SKIP is con nected to EN. When in skip mode, the
LX output becomes high impedance when the inductor
current falls below 0.5A (typ). The inductor current does
not become negative. If during a clock cycle the inductor
current falls below the 0.5A threshold (during off-time),
the low-side turns off. At the next clock cycle, if the
output voltage is above set point, the PWM logic keeps
both high-side and low-side MOSFETs off. If instead the
output voltage is below the set point, the PWM logic
drives the high-side on until a reduced current limit
threshold (3A, typ) is reached. In this way the system can
skip cycles, reducing the frequency of operation, and
switches only as needed to service load at the cost of
an increase in output voltage ripple (see the
Frequency and Output Ripple
power dissipation is reduced and efficiency is improved
at light loads because power MOSFETs do not switch at
every clock cycle.
The MAX15112 automatically enters continuous mode
regardless of the state of SKIP when the load current
increases beyond the skip mode current limit.
Do not change the state of SKIP when EN is high.
Thermal Shutdown Protection
Skip Mode Operation
MAX15112
section). In skip mode,
Skip Mode