Datasheet

capacitor and short-circuited load, and thereby cause the
absolute maximum rating of FB/VO (-0.3V) to be exceeded.
This parasitic board or wiring inductance should be mini-
mized and the output voltage waveform under short-cir-
cuit operation should be verified to ensure that the absolute
maximum rating of FB/VO is not exceeded.
Detailed Description of Hardware
The MAX17501B/MAX17501F EV kits provide proven
designs to evaluate the MAX17501B/MAX17501F high-
efficiency, high-voltage, synchronous step-down DC-DC
converters. The EV kits generate a fixed 5V, at load cur-
rents up to 500mA, from a 6V to 60V input supply. The
EV kits feature a 600kHz fixed switching frequency for
optimum efficiency and component size. The MAX17501B
EV kit supports a PFM control scheme with high light-load
efficiency, while the MAX17501F EV kit features a forced-
PWM control scheme that provides constant switching-
frequency operation at all load and line conditions.
The EV kits include an EN/UVLO PCB pad and jumper
JU1 to enable control of the converter output. An
additional RESET PCB pad is available for monitor-
ing the converter output. The VCC PCB pad helps
measure the internal LDO voltage.
Soft-Start Input (SS)
The devices utilize an adjustable soft-start function to
limit inrush current during startup. The soft-start time is
adjusted by the value of C3, the external capacitor from
SS to GND. To adjust the soft-start time, determine C3
using the following formula:
C3 = 5.55 x t
SS
where t
SS
is the required soft-start time in milliseconds
and C3 is in nanofarads.
Regulator Enable/Undervoltage-
Lockout Level (EN/UVLO)
The devices feature an EN/UVLO input. For normal
operation, a shunt should be installed across pins 1-2 on
jumper JU1. To disable the output, install a shunt across
pins 2-3 on JU1 and the EN/UVLO pin is pulled to GND.
See Table 1 for JU1 settings.
Setting the Undervoltage-Lockout Level
The devices offer an adjustable input undervoltage-
lockout level. Set the voltage at which the device turns
on with a resistive voltage-divider connected from VIN
to GND. Connect the center node of the divider to EN/
UVLO.
Choose R1 to be 3.3MI and then calculate R2 as
follows:
INU
R1 1.218
R2
(V 1.218)
×
=
−
where V
INU
is the voltage at which the IC is required to
turn on.
*Default position.
Table 1. Regulator Enable (EN/UVLO) Jumper JU1 Settings
3Maxim Integrated
MAX17501B/MAX17501F Evaluation Kits
Evaluate: MAX17501B/MAX17501F
in TDFN Packages
SHUNT POSITION EN/UVLO PIN MAX17501_ OUTPUT
1-2* Connected to IN Enabled
Not installed
Connected to the center node of
resistor-divider R1 and R2
Enabled, UVLO level set through
the R1 and R2 resistor-divider
2-3 Connected to GND Disabled