MAX038CCP Maxim Integrated Products, MAX038CCP Datasheet - Page 2

• Manufacturer Part Number: MAX038CCP
• Description: Evaluation Kit
• Manufacturer: Maxim Integrated Products

To select the desired output waveform, place shunts
across JU1 and JU2 in the combinations shown in
Table 1. These jumpers set address pins A0 and A1 to
TTL/CMOS-logic levels. External control may be initiat-
ed by connecting an external source to the A0 and
A1 pads and removing the shunts on JU1 and JU2.
Note that there are 10kΩ pull-up resistors to +5V on the
A0 and A1 address lines.
* Note: Frequency pre-set by oscillator capacitor (C1) and input
The output frequency is controlled by the oscillator
capacitor (C1), the current injected into the IIN pin, and
the voltage on the FADJ pin. The EV kit allows indepen-
dent adjustment of both input current (R3) and FADJ
voltage (R2). Refer to the
of the MAX038 data sheet for additional theory of oper-
ation.
4) Verify the shunts on JU1 and JU2 for a square-wave
5) Apply power and verify the output waveform.
MAX038 Evaluation Kit
_______________Detailed Description
Table 1. Waveform Jumper Select
Table 2. Frequency and Duty-Cycle Jumper Select
2
Don't Care
JUMPER
JU3 to allow the frequency to be adjusted. Verify
that there is a shunt on JU5.
output. Refer to Table 1 for alternate waveform
selections.
_______________________________________________________________________________________
Open
Short
JU1
JU3
JU4
current (position of R3) as specified by formula [1].
LOCATION
SHUNT
Open
Short
Short
1 & 2
2 & 3
1 & 2
2 & 3
JU2
Waveform Selection
Detailed Description section
Output Frequency
Sine Wave
Triangle Wave
Square Wave
Adjustable Frequency
Pre-Set Frequency*
Adjustable Duty Cycle
Fixed 50% Duty Cycle
OUTPUT WAVEFORM
MAX038 OUTPUT
The current injected into the IIN pin acts as the primary
frequency-adjustment control. The R3 potentiometer
varies the current to the MAX038’s IIN pin. The input
current can be easily monitored by removing the JU5
shunt and placing a current meter across the JU5 pins.
The components supplied on the EV kit will allow an
input current range of 50µA to 725µA. With the VADJ
pin grounded, the fundamental output frequency (F
as follows:
where: I
To use an external input current, connect the external
current source to the IIN pad and remove the JU5 shunt
completely. Note that there is a 3.3kΩ resistor in series
with the device IIN pin.
Varying the FADJ voltage will also vary the output fre-
quency. With a shunt across pins 1 and 2 of JU3, the
R2 potentiometer will vary the voltage applied to the
FADJ pin. With the JU3 shunt on pins 2 and 3, the FADJ
pin is grounded. Grounding the FADJ pin sets the out-
put to the fundamental output frequency (F
given by equation [1].
To use an external FADJ voltage, connect the external
source to the FADJ pad and remove the JU3 shunt
completely. Limit the external FADJ voltage to ±2.4V.
The voltage on the DADJ pin controls the duty cycle of
the output waveform. With the JU4 shunt on pins 1 and 2,
the R1 potentiometer will vary the voltage applied to the
DADJ pin, thus varying the duty cycle 15% to 85%. With
the JU4 shunt on pins 2 and 3, the DADJ pin is grounded.
Grounding the DADJ pin fixes the duty cycle at 50%.
To use an external DADJ voltage, connect the external
voltage source to the DADJ pad and remove the JU4
shunt completely. Limit the external DADJ voltage to
±2.3V.
C
OSC
IN
F
= current injected into IIN
= V
= 2.5V
o
= external oscillator capacitor (C1)
(MHz) = I
REF
(0kΩ to 50kΩ + 3.3kΩ)
(R3 + R12)
IN
(µA)
Input Current Control
C
Duty-Cycle Control
OSC
(pF)
FADJ Control
o
), as
o
[1]
) is