Datasheet

Switching-Frequency Selection (OSC)
The MAX17061 EV kit is configured to operate at 1MHz,
but provides the option to set the switching frequency
of the step-up DC-DC converter to 500kHz or 750kHz.
The switching frequency is set by configuring JU13 to
the shunt position, as shown in Table 6. Changing the
switching frequency could require different converter
components (refer to the MAX17061 IC data sheet for
proper component selections).
Setting DPWM Frequency (f
DPWM
)
The MAX17061 uses an internal DPWM signal to perform
dimming control. The DPWM frequency is specified by
an external resistor, connected from FSET pin to GND:
where α = 10.638, β = 5.5, γ = 58509.
The adjustable range for the FSET resistor (RFSET) is
from 41kΩ to 465kΩ, corresponding to the DPWM fre-
quency of 2000Hz to 200Hz. RFSET consists of resis-
tors R6 and R7 on the EV kit, where R6 is a 41.2kΩ
resistor and R7 is a 500kΩ potentiometer. If making
adjustments, note that the minimum usable frequency
results from a maximum resistance of 465kΩ.
fHz
RFSET RFSET
DPWM
[]=
×+××
=
×+
10
1000
10
99
ααβαγ
Evaluate: MAX17061
MAX17061 Evaluation Kit/Evaluation System
_______________________________________________________________________________________ 7
Table 5. Jumper JU11 Function
SHUNT
POSITION
ISET PIN I
LED(FS)
1-2 Connected to VCC 25mA
2-3*
Connected to GND
through R4 and R5
Adjustable from
15mA to 30mA
* Default position.
Table 6. Jumper JU13 Function
SHUNT
POSITION
OSC PIN
OPERATING
FREQUENCY
1-2* Connected to VCC 1MHz
2-3 Connected to GND 500kHz
Not
installed
Unconnected 750kHz
* Default position.