MAX8643EVKIT+ Maxim Integrated Products, MAX8643EVKIT+ Datasheet - Page 3

• Manufacturer Part Number: MAX8643EVKIT+
• Description: Power Management Modules & Development Tools MAX8643 KIT MAX8643 KIT
• Manufacturer: Maxim Integrated Products

Specifications of MAX8643EVKIT+

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

When externally programming the MAX8643 (Figure
1a), install an 8.06kΩ resistor at R8. The output voltage
is then determined by:
For an output voltage of 0.6V, install an 8.06kΩ resistor
at R8 and do not install R9. Refer to the MAX8643 data
sheet for information on selecting output inductor,
capacitor, and compensation components to optimize
the circuit for different output voltages.
The MAX8643 EV kit comes preset with a 1MHz switch-
ing frequency. Replace R7 to change the switching fre-
quency. R7 is calculated as:
where the switching frequency is in megahertz and
must be between 500kHz and 2MHz. Refer to the
MAX8643 data sheet for information on selecting output
inductor, capacitor, and compensation components to
optimize the circuit for different switching frequencies.
Figure 1. Preset and Adjustable Output Configuration
1a
CTL1
CTL2
R
MAX8643
7 52 63
R
=
9
_______________________________________________________________________________________
Evaluating Other Switching
=
.
V
COMP
OUT
OUT
FB
LX
4836
x
⎛
⎜
⎝
− .
f
1
S
Frequencies (FREQ)
0 6
−
0 05
L
C12
.
R4
⎞
⎟
⎠
k
C11
Ω
8.06kΩ
C2
R8
R9
V
OUT
R6
C10
MAX8643 Evaluation Kit
VOLTAGE
The MAX8643 features an external reference input
(REFIN). The IC regulates FB to the voltage applied to
REFIN. The internal soft-start is not available when
using an external reference. A method of soft-start
when using an external reference is shown by the use
of R3 and C7 in Figure 2. To use the REFIN input of the
EV kit, remove the shunt on jumper JU2. Connect an
external reference to the REFIN pad on the EV kit. If the
external reference produces step-voltage changes,
install C7. Refer to the MAX8643 data sheet for more
details.
PWRGD is an open-drain output that goes high im-
pedance when V
when V
PWRGD is low during shutdown. PWRGD is pulled up
to V
The MAX8643 features a shutdown mode to minimize
the IC quiescent current. To shut down the IC, place a
shunt between pins 1-2 of JU1. For normal operation,
remove the shunt from JU1.
SELECT
DD
Jumper JU1 Function (Shutdown Mode)
through R5.
FB
is below 0.54V for at least 48 clock cycles.
1b
CTL1
CTL2
MAX8643
FB
8kΩ
is above 0.54V. PWRGD pulls low
Ri
COMP
OUT
FB
Using the REFIN Input
LX
Power Good (PWRGD)
L
C12
R4
C2
C11
C10
V
OUT
R6
3