Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
GPS Receiver RF Front End IC
Preliminary
PT9120
DESCRIPTION
The PT9120 is a single chip Global Positioning System (GPS) receiver front-end IC requiring few
external components and offering extremely low power consumption. The PT9120 employs a
super-heterodyne receiver topology which down-converts the 1575.42MHz L1-band GPS signal to
a 1st IF. The 1st IF is then filtered by an off-chip L-C filter and subsequently sub-sampled by the
2-bit A/D converter to provide both sign and magnitude quantized CMOS level outputs to base band
inputs.
FEATURES
•
•
•
•
•
•
•
•
GPS L1-band (C/A code) receiver
Integrated LNA and antenna detector
Fully-monolithic VCO
Support for several reference frequencies
2-bit ADC output (sign and magnitude)
Extremely low current consumption (7mA at AVDD=TVDD=2.5V)
Multiple power-down modes
Available in 28 pins or 24 pins, QFN package
APPLICATION
•
GPS systems
PT9120 PRE1.0
-1-
August, 2007
Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
GPS Receiver RF Front End IC
Preliminary
PT9120
PIN DESCRIPTION
Pin Name I/O
SGN
MAG
AOK
CP
TVSS
TVDD
XEN
XI
XO
VB
PLL
AON
LNI
ISNS
PVDD
LNO
AVDD
AVSS
RFIN
VBG
IF1P
IF1N
IF2P
IF2N
MODE
AGCCAP
P1
P0
O
O
Description
Quantized 2nd IF “sign” bit
Quantized 2nd IF “magnitude” bit
Active antenna status output (AOK = HIGH = active antenna OK;
O
AOK=LOW=active antenna either open or shorted)
I/O Reference clock input/output
G Ground (digital circuitry)
P Supply voltage (digital circuitry)
Crystal oscillator enable pin
I
(XEN=HIGH=enabled; XEN=LOW=disabled)
I Crystal oscillator input
O Crystal oscillator output
O Regulator (1.9V) output
O Charge pump output
O Antenna switch-controlled supply voltage to active antenna
I LNA input
I Antenna detector current sense input
O Supply voltage (active antenna)
O LNA output
P Supply voltage (analog circuitry)
G Ground (analog circuitry)
I Mixer input
O Band gap reference (1.23V) output
O Differential mixer IF output/differential first-stage IF amplifier
O input
I Differential first-stage IF amplifier output/differential IF AGC
I input
I Reference frequency mode select input
I/O AGC capacitor connection. Sets the AGC time constant.
I
Power-down control pins (see PT9120 operating modes)
I
Pin No.
28-pin 24-pin
1
1
2
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
-
3
4
5
6
7
-
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
-
23
24
-
PT9120 PRE1.0
-5-
August, 2007
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