Be sure to observe frequency and amplitude limits for

the MAX110. The recommended frequency of operation

is 512kHz for XCLK÷1 mode, 1024kHz for XCLK÷2

mode, or 2048kHz for XCLK÷4 mode. The conversion

clock must have a constant, low-jitter frequency, other-

wise the MAX110’s linearity will suffer. Refer to the

MAX110 data sheet for additional information.

Using the Internal RC Oscillator

To use the MAX110’s internal RC oscillator, remove the

shunt from J5 and move the J1 shunt to pins 2-3. Make

sure that the XCLK÷4 mode is selected in the MAX110

program. The XCLK÷4 mode must be used when the

RC oscillator is enabled, since the RC oscillator fre-

quency is approximately 2MHz. To switch back to the

on-board crystal clock oscillator U3, move the J1 shunt

to pins 1-2 and put a shunt across J5 pins 1-2.

Crystal clock oscillators can introduce noise into the

system. For applications that demand reduced noise

and do not require either precisely controlled conver-

sion timing or 60Hz rejection, the MAX110’s internal RC

oscillator is recommended.

Changing the Reference Voltage

The default reference voltage for the MAX110 EV kit is

2V. When a different reference voltage is selected, for

proper scaling of the displayed output, specify the volt-

age in the command-line option when starting the pro-

gram (see Table 3).

To use the 2.5V MAX873 reference directly, carefully

cut the printed circuit trace at J3 between pins 2 and 3,

and then install a 3-pin header. Next, select the 2.5V

reference by installing a shunt at J3 between pins 1

and 2. Start the MAX110 program with the “-V2.5” com-

mand-line option, to tell the program that the

reference is now 2.5V. Be sure to observe absolute

maximum ratings for the device being evaluated. An

optional 100k

Ω trim pot may be added at site R12 to

trim the MAX873 voltage, if desired.

To supply an external voltage reference, carefully cut

the printed circuit trace at J3, between pins 2 and 3,

and at J2. Connect the reference voltage between the

VREF+ and VREF- pads. Run the MAX110 program,

and use the “-V” command-line option to specify the

reference voltage. Be sure to observe absolute maximum

ratings for the device being evaluated.

Activating Shutdown Mode

The MAX110 EV kit software can be used to measure

the supply current of the MAX110 in shutdown mode.

To evaluate shutdown mode, use the following

procedure:

MAX110 Evaluation System/Evaluation Kit

4

_______________________________________________________________________________________

JUMPER SETTING

FUNCTION

1-2

2-3

XCLK is the output from the MAX110’s

internal RC oscillator.

J1

open

Do not operate the EV kit with J1 open.

closed

VREF- connects to ground.

J2

open

VREF- does not connect to ground.

2-3

VREF+ connects to the on-board 2V

reference.

1-2

VREF+ connects to the on-board 2.5V

reference.

J3

open

VREF+ connects to a user-supplied

reference.

1-2

2-3

J4

open

1-2

XCLK is driven by the crystal oscillator

U3 (note that when J5 is in 1-2

position, J1 must be in 1-2 position).

2-3

XCLK connects to EXTCLK edge pad.

J5

open

XCLK is isolated.

J6

—

None

closed

IN1- connects to ground.

J7

open

IN1- does not connect to ground.

closed

IN2- connects to ground.

J8

open

IN2- does not connect to ground.

closed

through this jumper. Use this site to

measure the supply current drawn by

the MAX110.

J9

open

Do not operate the EV kit with J9 open.

Table 2. Jumper Settings on MAX110 EV Kit

XCLK is the clock input to the MAX110.