DW9255
DW9255
35.42MHz SAW Filter for GPS Receivers
DS3861 - 3.1 November 1997
OUTPUT+
OUTPUT-
The DW9255 is a Surface Acoustic Wave (SAW) bandpass
filter for use with the GP2000 Global Positioning System
(GPS) receiver chip-set, available from Mitel Semiconductor.
It is pre-tuned to the exact 2nd IF filter requirements of the
GP2010 & GP2015 RF front-end devices, with a centre-
frequency of 35.42MHz. The response is tuned for a flat
passband, steep stopband and uniform passband group-delay
with 3 external inductors. The device is realised on a Lithium
Tantalate substrate and housed in a small leadless ceramic
Surface Mount package.
The DW9255 gives significant improvement in correlated
GPS Signal-to-Noise Ratio (SNR) performance compared to
conventional LC bandpass filter schemes. This aids satellite
signal acquisition and tracking capability from the GP2000
GPS chip-set. This device effectively filters out-of-band
(unwanted) noise in the GPS signal. The Automatic Gain
Control (AGC) within the GP2010 and GP2015 RF Front-end
devices will then operate only on in-band noise for optimum
gain and superior correlated GPS signal strength.
INPUT+
2
GND
3
INPUT-
1
12
GND
11
GND
4
GND
DW9255
GND
5
10
GND
GND
6
7
8
9
GND
LCS12/1
FEATURES
INPUT +
s
Insertion Loss of 17dB
鹵1dB
(typical)
s
1dB Bandwidth 1.9MHz (typical)
s
Passband Ripple 0.8dB (typical)
s
Low Profile Ceramic Surface Mount Package
s
Operating Temperature Range -40擄 to +85擄C
GND
3
2
INPUT -
s
Centre Frequency of 35.42MHz
1
12
GND
GND
4
11
GND
DW9255
APPLICATION
s
Commercial Global Positioning
GND
5
10
GND
GND
6
7
OUTPUT +
9
8
OUTPUT -
GND
RELATED PRODUCTS AND PUBLICATIONS
Part
GP2010
GP2015
Description
GPS receiver RF Front-end
Miniature GPS receiver
RF Front-end
Data
Reference
DS4056
DS4374
LCS12/4
Fig.1 Pinout
1
1
2
3
4
5
