GPS Receiver Overview
BT1575A
June 1, 2000 BTI Proprietary Information 1
Single Chip L1 GPS RF-IF Receiver with Mobile Immunity
TM
Features
Complete L1 band GPS RF-IF receiver
Single supply operation: 2.4 V to 3.0 V
Low current consumption
Optimized for Cellular/PCS embedded applications
Designed to be compatible with the SnapTrack* System
Programmable sleep mode for more standby time in TDMA systems
Integrated LNA
Integrated synthesizer circuitry
4 bit analog-to-digital converter (ADC) with AGC for improved
GPS receiver sensitivity
CDMA/TDMA/GSM system clock compatible synthesizer
Image reject architecture for reduced parts count
Operating temperature range: -40 to +85
C
CMOS compatible inputs/outputs
User selected internal/external sampling clock for ADC
RF BiCMOS technology with ESD Protection
32 Pad Quad Leadless Exposed Pad Package (QLP)
Benefits
Extremely Flexible: Add to ANY existing MPU, DSP or Base-Band (no expensive chip set)
Mobile ImmunityTM architecture will not interfere with RF-IF signals in digital cellular handsets
No special reference frequencies or TCXOs required: Use ANY external source from 10-40MHz
Programmable Serial or Parallel digital outputs increase flexibility & reduce GPS system cost
Very low parts count results in < 1in
2
, 2-layer PCB, with all components mounted on one side!
Enhanced performance GPS receiver provides additional operational margin for higher yields
Very Low power consumption allows adding GPS to existing limited battery power budgets
Total receiver system is programmable for on-demand GPS location fixes with low standby power
Applications
Any Digital Cell Phone handset
PDAs, HPCs, PCMCIA cards, Compact Flash Cards
Notebook PCs, Desktop PCs
Handheld GPS Receivers
Automotive Systems, Marine Systems, Aircraft Systems
Security Systems, Timing Reference Systems
Consumer Appliances, Industrial Process Control Systems
General Description
The BT1575 is a dual down-conversion GPS receiver optimized for operation in CDMA, TDMA, GSM,
and AMPS mobile telephone terminals. The advanced architecture of the BT1575 provides Mobile
ImmunityTM to the complex signals present in digital cellular handsets, as well as notebook PCs, HPCs,
and PDAs. The external signals of the BT1575 also have been carefully designed to prevent interference
with the operation of digital cellular handsets. The BT1575 includes an integrated low-noise amplifier,
programmable synthesizer and a four-bit analog-to-digital converter (ADC) for use in GPS applications
requiring exceptional sensitivity, such as SnapTrack compatible E-911. The BT1575 can also be used
with more conventional base-band processors that may require only single bit resolution.
* SnapTrack is a registered mark of the SnapTrack Corp.
QLP 32L
(Top View)
BT1575
1
2
3
4
5
6
7
8
24
23
22
21
20
19
18
17
32
31
30
29
28
27
26
25
9
10
11
12
13
14
15
16
GPS Receiver Overview
BT1575A
June 1, 2000 BTI Proprietary Information 2
Operating Modes Description
Two non-reset operating modes exist in the BT1575. Normal mode (GPS RECEIVER ENABLED)
powers up the entire receive chain to allow immediate processing of down converted GPS signals.
Sleep mode (also known as blanking mode) is programmable via the three-wire interface to allow
maximum flexibility.
Block Diagram
As illustrated below, the BT1575 is a dual down conversion receiver optimized for operation in the
presence of strong CDMA, TDMA, GSM, and AMPS mobile telephone interferers. An external or internal
sampling clock can be selected for operation of the BT1575.
GPS L1 Rx
(1575.42 MHz)
Loop Filter
IF1 Filter
LNA
IF1
amp
Loo
Reference
Divider
Programming
Interface
4 bit A-D
Converter
VCO
Sampling
CLK to/from
Baseband
Serial
interface
Lock Detect
Vdd / GND
4
A/D data to
Baseband
N
Prescaler
IF2
amp
GPS Receiver Overview
BT1575A
June 1, 2000 BTI Proprietary Information 3
System Diagram
The receiver architecture below shows a typical low power integration of the GPS BT1575 with a GPS
Baseband to provide a complete solution for integration into a single mode, multi-mode, or multi-band
multi-mode cellular/PCS mobile handset.
Ordering Information
Part No. / Description
For:
Contact:
BT1575
GPS Receiver
!
Pricing Information
!
Application Assistance
!
Samples & Eval Boards
!
Other RFIC products
USA:
BTI
Tel: (562) 407-0500
Fax: (562) 407-0510
sales@betheltronix.com
BTI
BT1575
GPS Receiver
GPS, PDA or
Digital Cell
Phone
Baseband
Mobile Reference (or external)
Crystal Oscillator (TCVCXO)
Mobile Handset
4
GPS A/D Data Out
GPS L1 Rx (1575.42 MHz)
Ceramic Filter
3
Serial Interface
Voltage
Regulator
Enable
Sampling Clock
SAW IF Filter
Tunable Tank
Loop Filter
IF1
Antenna
The information provided herein is believed to be accurate and correct. BethelTronix, Inc. assumes no responsibility for
the inaccuracies or use of the information or the use of the described product. BethelTronix, Inc. reserves the right to
make changes in circuit design and/or specifications at any time without further notice. No patent rights or licenses to
any of the circuits described herein are implied or granted to any third parties.
BethelTronix, Inc.
Copyright
2000 BethelTronix, Inc. All Rights Reserved
13825 Cerritos Corporate Dr., Cerritos, CA 90703, USA
Phone: 562-407-0500
Fax: 562-407-0510
http://www.betheltronix.com
PDF 
ZIP