The STB5610, using ST Microelectronics RF Bipolar
technology, implements a Global Positioning System
RF front-end. The chip provides down conversion
from the 1575.42 MHz GPS (L1) signal to 4.092 MHz
Output signal. The integrated PLL with on-chip
reference oscillator uses a low cost 16.368 MHz
crystal. No TCXO is required.
25GCLNA Gain control
26AS_OutAntenna sensor output
27AS2Antenna sensor input
28AS1Vcc Antenna Supply
29Vc c_Lo gicP ower suppl y
30Gnd_LogicGround
31Vcc_DriverSupply Voltage
32Gnd_DriverGround
33CLKClock
34DATAData
35GndGround
36Vcc_Logic2Supply Voltage
37CE2Chip Enable (no data)
38CEChip Enable
39FselectFrequency Selector
40Gnd_IFGround
41IF2-Lim. Amp. Output
42IF2+Lim. Amp. Output
43Gnd_IFGround
44Vcc_IFSupply Voltage
45Gnd_XTALGround
46XTAL_inCrystal Input
47XTAL_outCrystal Output
48Gnd_XTALGround
STB5610
3/11
Page 4
STB5610
BLOCK DIAGRAM (GPS L1)
SAW F ilt e r
Passive
Antenna
Two gain
LNA
Gain
Select.
16.368 MHz
Quartz
1.57 GHz
PLL
LC Filter
RF Amp.MixerD Latc h Output buffer
1.55 GHz
VCO
~
LC Filter
1ST Lim. amp.2NDLim. amp.
20 MHz
20 MHz
D
Q
CK
4 MHz
16 MHz
Data @ 4 MHz
CMOS levels
CLK @ 16MHz
CMOS levels
Loop
Freq.
Filter
select
ExternalTank
FUNCTIONAL DESCRIPTION
LNA section
The RF input signal is amplified by two gain levels
LNA. Using gain control pin the LNA gain is set to
19 dB to support passive antenna or 10 dB to support active antenna. The LNA ou tput signal i s filtered by 1575.42 MHz SAW filter.
RF Amplifier plus mixer section
The 1575.42 MHz input signal, amplified by RF
amp., is mixed with the VCO signal to generate a
differential 20.46MHz IF signal
IF section
Two LC filters at mixer output and at first limiting
output are used to s uppress undesirab le signals
and mixer products. The second stage limiting
amplifier is connected to a D-Type latch clocked
by 16.368MHz crystal oscillator signal. The effect
of sampling the 20.46MHz signal at 16.368MHz is
to create sub-sampling alias at 4.092MHz. This is
fed to the output level converter.
Output section
The output buffers perform level translation from
the internal ECL levels to CMOS output levels referred to ground. The Data signal changes during
the clock signal negative edge.
CE
ASout
CE2
VCO and PLL
Using external tank the VCO is able to provide
very low phase noise signal. Through the freq. selector pin the VC O signal is set at 1554.96 M Hz
and at 1571.328 MHz. The on-chip ref erence oscillator uses a low cost 16.368 MHz crystal.
Antenna sensor circuitry
Integrated sensor circuitry is ab le to eval uate th e
antenna current consum ption; the As out pin output provides this info externally. Using external
sensing resistor of 10 Ohm if the antenna current
consumption is inside the range 10mA…40mA
(active antennas typical current consumption) the
Asout output logic level is High, if the antenna current consumption is outside the ab ove reported
range (passive anten na or problem on antenna
connection) the Asout output logic level is low.
Chip enable
Using the CE pin it is possible to switch off all the
chip ( neither data nor clock available).
Using CE2 pin it is possible to disable the analog
portion of the chip (no data available) maintaining
the digital portion active (Clock available) optimizing the chip current consumption.
Power supplies
The STB5610, has been designed to support
from 2.7 V to 3.6 V supply voltage.
The Asout pin output provides information on Antenna current consumption
ASout Pi n (A nt enna sensor pi n)
*
Logic levelV alue
Low**Iant<10mA
Iant.>40mA
High**10mA<Iant<40mA
* It is referred to external sensing resistor of 10 O Hm
Application requiring higher or lower current threshold should adjust the resistor value appropiately
** The logic levels are referred to STB5610 Supply Voltage
6/11
Page 7
APPLICATION BOARD SCHEMATIC (ACTIVE ANTENNA)
STB5610
T
S
QUE
A
V
A
I
L
A
B
L
E
ON
RE
7/11
Page 8
STB5610
APPLICATION BOARD LAYOUT (ACTIVE ANTENNA)
T
S
QUE
A
V
A
I
L
A
B
L
E
ON
RE
8/11
Page 9
BILL OF MATERIALS
STB5610
T
S
QUE
A
V
A
I
L
A
B
L
E
ON
RE
9/11
Page 10
STB5610
MECHANICAL DATA
mm
DIM.
A1.60
A10.050.15
A21.351.401.45
D8.759.009.25
D16.97.007.1
E8.759.009.25
E16.97.007.1
L0.50.600.75
e0.5
b0.170.220.27
ccc0.08
ddd0.08
TETA
Note: L is measured at gage plane (at 0.25 above the seating plane)
MIN.TYP.MAX
o
0
o
7
10/11
Page 11
STB5610
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implic ation or otherwise under any patent or pat ent rights of STMicroelectronics. Specifications mentioned in thi s publicati on are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as cri tical comp onents in life support dev i ces or systems wi thout express written approval of STM i croelect ronics.
The ST logo is registered trademark of STMicroelectronics
2002 STMicroelectroni cs - All Righ ts Reserved
All other na m es are the prop erty of their respectiv e owners.
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Malaysi a - M alta - Moroc co - Singapore - Spain - Sw eden - Switz erland - Unit ed Kingdo m - U. S. A.
STMicroelectroni cs GROUP OF COMPANIES
http://www.st.co m
11/11
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