Datasheet

3
Evaluate: MAX17501A/MAX17501E
in TDFN Packages
MAX17501A/MAX17501E Evaluation Kits
Detailed Description of Hardware
The MAX17501A/MAX17501E EV kits provide proven
designs to evaluate the MAX17501A/MAX17501E high-
efficiency, high-voltage, synchronous step-down DC-DC
converters. The EV kits generate a fixed 3.3V, at load
currents up to 500mA, from a 4.5V to 60V input sup-
ply. The EV kits feature a 600kHz fixed switching fre-
quency for optimum efficiency and component size. The
MAX17501A EV kit supports a PFM control scheme with
high light-load efficiency, while the MAX17501E 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 device is required
to turn on.
Table 1. Regulator Enable (EN/UVLO) Jumper JU1 Settings
*Default position.
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