MAX1474AXT+T Maxim Integrated Products, MAX1474AXT+T Datasheet - Page 4

• Manufacturer Part Number: MAX1474AXT+T
• Description: IC CAP ELEC TRIM SC70-6
• Manufacturer: Maxim Integrated Products
• Type: Electronically Trimmable Capacitorr

Specifications of MAX1474AXT+T

• Applications: Keyless Entery, Home Automation, Wireless Audio/Video
• Mounting Type: Surface Mount
• Package / Case: SC-70-6, SC-88, SOT-363
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MAX1474AXT+T; MAX1474AXT+TTR

The MAX1474 consists of a binary-weighted array of
capacitors that can be switched in and out of parallel to
provide 32 monotonic steps. The switches implement-
ed allow the DC bias of either terminal of the capacitor
to be anywhere from ground to the supply voltage.
There is no inherent polarity. The signal swing range is
limited to 300mV above V
Therefore, if a large-signal swing range is desired, care
must be taken to bias the terminal(s) requiring high
swing capability near midsupply.
If the capacitance is measured differentially from one
terminal to the other, the greatest min/max ratio of the
binary array can be realized, allowing tuning from
Miniature Electronically Trimmable Capacitor
(V
4
DD
_______________________________________________________________________________________
= +5V, V
PIN
1
2
3
4
5
6
SS
= 0, T
NAME
DAT
V
V
CM
CP
EN
DD
SS
A
f
1
= +25°C, unless otherwise noted.)
Detailed Description
DD
15 DAT PULSES
SMITH CHART:
Capacitor Pin Connected to High-Impedance Node. See Detailed Description.
Positive Supply Pin. Connect a 0.01µF capacitor to V
Programming Enable Pin. Has an internal 50kΩ pulldown resistor to V
Programming Data Pin. Has an internal 50kΩ pulldown resistor to V
Negative Supply Pin
Capacitor Pin Connected to Low-Impedance Node. See Detailed Description.
f
1
and 300mV below V
= 962MHz
Typical Operating Characteristics (continued)
SS
.
0.42pF to 10.9pF in 0.34pF steps. If one terminal is
grounded, and the capacitance is measured to ground,
the parasitics inherent in the package will become
lumped with the switched array, allowing tuning from
6.4pF to 13.3pF in 0.22pF steps. When using the
MAX1474, it is recommended for optimal performance
to connect the CM terminal to the lowest impedance
node (i.e., ground or supply if possible) and CP to the
higher impedance node (i.e., the resonant node in a
ground-referenced LC tank circuit).
The digital interface sets the desired capacitance
value. There are only two pins, EN and DAT, required
for this operation. EN is an active-high control signal.
FUNCTION
f
1
SS
.
31 DAT PULSES
SMITH CHART:
f
1
= 848MHz
SS
SS
.
.
Pin Description
Digital Interface