Datasheet

Maxim Integrated │ 2
www.maximintegrated.com
Evaluates: MAX17552 (µMAX) in 5V
Output-Voltage Application
MAX17552 5V Output Evaluation Kit
(µMAX)
Detailed Description
The MAX17552 5V EV kit (µMAX) is a fully assembled and
tested circuit board that demonstrates the performance
of the MAX17552 60V, 100mA ultra-small, high-efficiency,
synchronous step-down DC-DC converter in a 10-pin
µMAX package. The EV kit operates over a wide input
voltage range of 6V to 60V and provides up to 100mA
load current at 5V output. It draws only 26µA supply
current under no-load conditions (EN/UVLO
connected to V
IN
) . The EV kit is programmed to
switch at a frequency of 220kHz and delivers a peak
efficiency of 93% with the supplied components. The
device is simple to use and easily configurable with minimal
external components. It features cycle-by-cycle peak
current-limit protection, undervoltage lockout and thermal
shutdown.
The EV kit includes an EN/UVLO PCB pad and jumpers
JU1 and JU2 to enable control of the converter output.
The MODE PCB pad and jumper JU3 are provided for
selecting the mode of operation of the converter. RESET
PCB pad is available for monitoring the RESET output.
The RT/SYNC PCB pad can be used to synchronize the
EV kit switching frequency to an external clock frequency.
Enable Control (JU1, JU2)
The EN/UVLO pin on the EV kit serves as an on/off control
while also allowing the user to program the input under-
voltage lockout (UVLO) threshold. Jumpers JU1 and JU2
configure the EV kit’s output for turn-on/turn-off control.
See Table 1 for proper JU1, JU2 jumper configurations.
Additionally, resistors R1 and R2 are included to set the
UVLO to a desired turn-on voltage. Refer to the Setting
the Input Undervoltage-Lockout Level section in the
MAX17552 IC data sheet for additional information on
setting the UVLO threshold voltage.
RESET Output
The EV kit provides a PCB pad to monitor the status of
the RESET output. RESET goes high when output volt-
age rises above 95% (typ) of its nominal regulated output
voltage. RESET goes low when output voltage falls below
92% (typ) of its nominal regulated voltage.
PFM or Forced-PWM Mode (MODE)
The EV kit includes a jumper (JU3) to select the mode
of operation of the converter. Install a shunt across JU3
before powering up the EV kit to enable the forced-PWM
operation. Keep JU3 open to enable the light-load PFM
operation. See Table 2 for proper JU3 settings.
Soft-Start
The EV kit offers a fixed 5ms soft-start time. Connect the
capacitor C4 to adjust the soft-start time (t
SS
). Use the
following equation to determine the soft-start capacitance
value (C
SS
):
CSS = 6.25 x t
SS
where t
SS
is in milliseconds and C
SS
is in nanofarads.
External Synchronization (RT/SYNC)
The EV kit provides a PCB pad to synchronize the EV
kit switching frequency to an external clock frequency.
Apply the external clock to the RT/SYNC PCB pad
though an AC-coupling capacitor. Refer to the External
Synchronization section in the MAX17552 IC data sheet
for additional information on configuring the external
clock and selecting the AC-coupling capacitor.
Table 1. Enable Control (EN/UVLO) (JU1, JU2)
Table 2. MODE Control (JU3)
*Default position.
*Default position.
SHUNT POSITION
EN/UVLO PIN VOUT OUTPUT
JU1 JU2
1-2 Open Connected to VIN Enabled
Open 1-2 Connected to GND Disabled
1-2* 1-2 Connected to midpoint of R1/R2 resistor-divider Enabled at VIN ≥ 6V
SHUNT POSITION MODE PIN MODE OF OPERATION
1-2 Connected to GND Forced PWM
Open* Unconnected PFM