MAX5389 Evaluation Kit
Evaluates: MAX5389
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Table 2. MAX5389 VDD Input (JU1) Table 3. Header J1 Pin Assignments
Detailed Description of Hardware
The MAX5389 EV kit is an assembled and tested PCB
that features the MAX5389M 50kI dual digital poten-
tiometer. Each potentiometer has an end-to-end resis-
tance of 50kI. Each 256-tap wiper position can be con-
trolled independently using pushbutton switches. The EV
kit uses a MAX5389M IC in a 14-pin TSSOP package on
a proven two-layer PCB design.
The EV kit supports both mechanical and digital inputs
to control the potentiometer wiper positions using jump-
ers JU2–JU7. Install shunts across jumpers JU2–JU7
to control the MAX5389 logic inputs using pushbutton
switches SW1–SW6, respectively. See the Potentiometer
A Control and Potentiometer B Control sections for addi-
tional information.
The EV kit provides connector J1 to interface the
MAX5389 CSA, CSB, INCA, INCB, UDA, and UDB sig-
nals directly to a user-supplied signal. Connector J1 also
provides a connection to the MAX5389 VDD input.
EV Kit Power Source
The EV kit operates from a 2.8V to 5.5V power supply
applied at the VIN and GND PCB pads. VIN powers the
MAX5389M (U1), two MAX8511 LDO regulators (U2, U3),
and the MAX6818 debouncer switch (U4). Regulators U2
and U3 are used to set the MAX5389 VDD input to 3.3V
or 2.6V, respectively.
Jumper JU1 selects the voltage applied at the MAX5389
VDD input. See Table 2 for proper jumper configuration
for setting the MAX5389 VDD input.
Note that the EV kit VIN input operates down to 2.6V.
However, a minimum 2.7V, 2.8V, and 3.5V is required
when operating debouncer U4, LDO U3, and LDO U2,
respectively.
Digital Interface
Wiper WA positioning can be controlled through
momentary pushbutton switches SW1 (POTA_CSA),
SW2 (POTA_UDA), and SW3 (POTA_INCA) by
installing shunts across jumpers JU2, JU3, and JU4,
respectively. Wiper WB positioning can be controlled
through momentary pushbutton switches SW4 (POTB_
CSB), SW5 (POTB_UDB), and SW6 (POTB_INCB) by
installing shunts across jumpers JU5, JU6, and JU7
respectively. The debouncer (U4) eliminates the “contact
bounce” that SW1–SW6 can exhibit and is not required if
using a digital interface.
The EV kit also provides connector J1 to interface the
MAX5389 CSA, CSB, INCA, INCB, UDA, and UDB inputs
directly to user-supplied digital signals. See Table 3
for header J1 pin assignments. Refer to the Up/Down
Interface section in the MAX5389 IC data sheet for a
more detailed description.
Potentiometer A Control
Jumpers JU2, JU3, and JU4 configure the EV kit opera-
tion for pushbutton control of the MAX5389 CSA, UDA,
and INCA digital inputs, respectively. Install shunts
across jumpers JU2, JU3, and JU4 for wiper WA posi-
tioning using pushbutton switches SW1, SW2, and SW3.
SW1 sets chip-select input CSA low. SW2 configures
the wiper for incrementing or decrementing operation
(UDA). SW3 controls the wiper position (INCA). The
MAX5389 increments or decrements wiper WA position
on a high-to-low transition at INCA.
Remove the shunts at JU2, JU3, and JU4 to position
wiper WA using digital signals at header J1 (pins J1-3,
J1-5, and J1-7). See Table 1 for proper JU2, JU3, and
JU4 jumper configurations.
SHUNT
POSITION
MAX5389 VDD Voltage
1-2 3.3V (LDO U2)
1-3 2.6V (LDO U3)
1-4
Voltage applied at the VIN and GND PCB
pads
Not installed
VDD not powered or power applied at
header J1-1
PIN SIGNAL
J1-1 VDD
J1-2, J1-4, J1-6, J1-8, J1-10,
J1-12, J1-14, J1-16
GND
J1-3
CSA
J1-5 UDA
J1-7
INCA
J1-9
CSB
J1-11 UDB
J1-13
INCB
