MAX1856EVKIT Maxim Integrated, MAX1856EVKIT Datasheet - Page 3

• Manufacturer Part Number: MAX1856EVKIT
• Description: Power Management IC Development Tools Evaluation Kit for the MAX1856
• Manufacturer: Maxim Integrated
• Series: MAX1856r

When the input voltage drops to +5V, the total output
power will fall to about 7.2W.
The MAX1856 EV kit switches at 250kHz but can be var-
ied from 100kHz to 500kHz by the internal oscillator in
combination with resistor R8 (R
quency may also be controlled by an external clock at
the SYNC/SHDN pad. The external source must be a
TTL level, and its maximum duty cycle may not exceed
45% for the 100kHz to 500kHz frequency range.
The MAX1856 EV kit features a shutdown mode that
reduces the MAX1856 quiescent current. The 2-pin
jumper (JU1) selects the shutdown mode for the
MAX1856. Table 1 lists the selectable jumper options.
The MAX1856 EV kit features a synchronous mode that
enables the operating frequency to be controlled by an
external clock. To utilize the sync mode, remove the
shunt on jumper JU1, and connect an external frequen-
cy source to the SYNC/SHDN pad. Select R8 as:
The external frequency source must be a TTL level and
have a 20% to 45% duty cycle.
R (R
8
OSC
_______________________________________________________________________________________
)
=
1.15 50M
ƒ
CLOCK
×
OSC
Jumper Selection
Ω
(kHz)
×
). The operating fre-
kHz
Shutdown Mode
Sync Mode
MAX1856 Evaluation Kit
The MAX1856 EV kit’s -72V (VOUT1) output may be
reconfigured for -48V and supply up to 200mA of cur-
rent. To configure the -72V (VOUT1) output to -48V,
remove diode D1 and install diode D2 (Central
Semiconductor CMR1U-02 recommended). Remove
capacitor C5 and install capacitor C6 (100pF, 200V).
Remove resistor R1 and install resistor R2 (470Ω,
0.5W). Replace resistor R10 with a 196kΩ ±1%, sur-
face-mount (0805) resistor. Remove D3 and R11.
*External frequency source must have a duty cycle within the
20% to 45% range.
Table 1. Jumper JU1 Functions
LOCATION
SHUNT
None
None
1-2
SLIC Power Supply
SYNC/SHDN PIN
Connected to VIN
No external
frequency source
connected to
SYNC/SHDN pad
External frequency
source* connected
to SYNC/SHDN
pad
Evaluating -48V Output
MAX1856 enabled,
VOUT1 = -72V,
VOUT2 = -24V
Shutdown mode,
VOUT1 = VOUT2 = 0
MAX1856 enabled,
VOUT1 = -72V,
VOUT2 = -24V
MAX1856 OUTPUT
3