MAX2750AUA+ Maxim Integrated Products, MAX2750AUA+ Datasheet - Page 5

• Manufacturer Part Number: MAX2750AUA+
• Description: Timers & Support Products 2400MHz to 2500MHz M onolithic VCO with I
• Manufacturer: Maxim Integrated Products

Specifications of MAX2750AUA+

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

The MAX2750AUA VCO is implemented as an LC oscil-
lator topology, integrating all of the tank components
on-chip. This fully monolithic approach provides an
extremely easy-to-use VCO, equivalent to a VCO mod-
ule. The frequency is controlled by a voltage applied to
the TUNE pin, which is internally connected to the var-
actor. The VCO core uses a differential topology to pro-
vide a stable frequency versus supply voltage and
improve the immunity to load variations. In addition,
there is a buffer amplifier following the oscillator core to
provide added isolation from load variations and to
boost the output power.
The oscillator signal from the core drives an output
buffer amplifier. The amplifier is internally matched to
50Ω including an on-chip DC-blocking capacitor. No
external DC-blocking capacitor is required, eliminating
the need for any external components. The output
amplifier has its own V
load-pulling effects. The amplifier boosts the oscillator
signal to a level suitable for driving most RF mixers.
The tuning input is typically connected to the output of the
PLL loop filter. The loop filter provides an appropriately
low-impedance source. The input may incorporate an
extra RC filter stage to reduce high-frequency noise and
spurious signals. Any excess noise on the tuning input is
directly translated into FM noise, which can degrade the
phase-noise performance of the oscillator. Therefore, it is
important to minimize the noise introduced on the tuning
input. A simple RC filter with low corner frequency is
needed during testing to filter the noise present on the
voltage source driving the tuning line.
Voltage-Controlled Oscillator for Automotive
Applications Information
_______________________________________________________________________________________
Detailed Description
CC
and GND pins to minimize
Output Buffer
Tune Input
Oscillator
Always use controlled impedance lines (microstrip,
coplanar waveguide, etc.) for high-frequency signals.
Always place decoupling capacitors as close as possi-
ble to the V
sary to add additional decoupling capacitors located
further from the device. Always provide a low-induc-
tance path to ground, and keep GND vias as close as
possible to the device. Thermal reliefs on GND pads
are not recommended.
TOP VIEW
CC
2.4GHz Monolithic
SHDN
TUNE
pins; for long V
GND
BYP
1
2
4
3
+
MAX2750AUA
MAX
Pin Configuration
CC
lines, it may be neces-
6
8
7
5
Layout Issues
GND
OUT
V
V
CC2
CC1
5