MAX2620EUA+ Maxim Integrated Products, MAX2620EUA+ Datasheet - Page 10

• Manufacturer Part Number: MAX2620EUA+
• Description: RF Wireless Misc IC RF OSC W/BUFFERED OUT
• Manufacturer: Maxim Integrated Products
• Type: RF Oscillator with Buffered Outputsr

Specifications of MAX2620EUA+

• Package / Case: uMAX-8
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Clock External Input: No
• Supply Voltage Range: 2.7V To 5.25V
• Digital Ic Case Style: µMAX
• No. Of Pins: 8
• Operating Temperature Range: -40°C To +85°C
• Filter Terminals: SMD
• Frequency Max: 1050MHz
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

10MHz to 1050MHz Integrated
RF Oscillator with Buffered Outputs
resonators or high-Q inductors. Also, keep C5 and C17
(see the Typical Operating Circuit) as small a value as
possible while still maintaining desired frequency and
tuning range to maximize loaded Q.
There are many good references on the topic of oscilla-
tor design. An excellent reference is “The Oscillator
as a Reflection Amplifier, an Intuitive Approach to
Oscillator Design,” by John W. Boyles, Microwave
Journal, June 1986, pp. 83–98.
Both of the MAX2620’s outputs (OUT and OUT) are
open collectors. They need to be pulled up to the sup-
ply by external components. An easy approach to this
pull-up is a resistor. A 50
ently match the output to a 50
Operating Circuit shows OUT configured this way.
Alternatively, a choke pullup (Figure 1), yields greater
output power (approximately -8dBm at 900MHz).
When maximum power is required, use an inductor as
the supply pull-up, and match the inductor’s output
impedance to the desired system impedance. Table 1
in the Typical Operating Characteristics shows recom-
mended load impedance presented to OUT and OUT
10
Figure 5. Electrical Model of MAX2620 Circuit
______________________________________________________________________________________
PC BOARD
PARASITICS
Output Matching Configuration
C
STRAY
resistor value would inher-
RESONANT TANK MODEL
VARACTOR+
COUPLING
C17
C
D1
system. The Typical
L1
INDUCTOR
OR
CERAMIC
RESONATOR
R
p
R
C5
C6
S
+ jX
S
for maximum power transfer. Using this data and stan-
dard matching-network synthesis techniques, a match-
ing network can be constructed that will optimize power
output into most load impedances. The value of the
inductor used for pullup should be used in the synthe-
sis of the matching network.
__________________Pin Configuration
TOP VIEW
TEST PORT
MEASUREMENT
(FIGURE 1)
SHDN
TANK
FDBK
V
CC
1
C3
C4
1
2
3
4
MAX2620
MAX2620 PACKAGE MODEL
MAX
C
2.4pF
C
2.4pF
03
04
MAX2620
8
7
6
5
R
OUT
V
GND
n
OUT
CC
2