Laboratory Report
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UAA3201T Demonstration board
with single sided component
placement
Report No:
HAC 95 001
Th. Rudolph
Product Concept & Application Laboratory Hamburg, F. R. Germany
Abstract
The UAA 3201T is a fully integrated single-chip receiver, primarily intended for use in VHF and UHF
systems employing direct return-to-zero (RZ) Amplitude Shift Keying (ASK) modulation. A number of
typical application schematics and the corresponding demonstration board is presented which has been
designed for single sided component placement and compact size. The demonstartion board presented fea-
tures a receiver supply switch in order to allow intermittent receiver operation for use in applications that
target a low avergage supply current. As a function of the receiver On/Off ratio the average receiver supply
current may be as low as 1 mA.
Keywords
UAA 3201T, Amplitude Shift Keying (ASK), single-chip receiver, SAW resonator, superregenerative re-
ceiver, quench frequency, intermittent receiver operation
Date:
Pages:
95-10-04
38
2
Summary:
This Laboratory Note introduces the reader to the fully integrated single-chip receiver UAA 3201T, primarily intended for use in
VHF and UHF systems employing direct return-to-zero (RZ) Amplitude Shift Keying (ASK) modulation. The UAA 3201T fea-
tures a low power and low cost solution for keyless entry, car alarm, remote control, home appliance, security or other telemetry
systems. Data rates up to 10 kbps and more are feasible without a significant reduction in sensitivity. The UAA 3201T has a very
low radiation and is applicable to fulfil the requirements of FTZ 17 TR 2100. Compared with a superregenerative receiver the
UAA 3201T is the superior solution. This note presents a number of application schematics for typical receive frequencies,
together with a complete set of diagrams for the corresponding layout and demonstration board. An intermittent receiver opera-
tion will be presented that allows to reduce the average receiver supply current.
Purchase of Philips I2C Components conveys a license under
the Philips´ I2C patent to use the components in the I2C-system
provided the system conforms to the I2C specification defined
by Philips
Philips Semiconductors
Laboratory Report
HAC/ 95001
3
Table of contents:
1
1.1
1.2
2
2.1
2.1.1
2.1.2
2.1.3
2.2
2.2.1
2.2.2
2.2.3
3
APPENDIX
A.1
A.2
A.3
B
C
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Typical system architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
UAA 3201T Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Application examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
433.92 MHz ASK Receiver with broad band input . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Bill of material for 433.92 MHz application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Component placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Typcial performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
315 MHz ASK Receiver with broad band input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Bill of material for 315 MHz application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Component placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Typical performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Supply current reduction by intermittent receiver operation . . . . . . . . . . . . . . . . . . . . . . . . 16
H5ACS01 demonstration board drawings . . . . . . . . . . . . . . . . . . . . . . . . . . 19
H5ACS01 board assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
H5ACS01 artwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
H5ACS01 board drill holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Product overview SAW devices from RFM . . . . . . . . . . . . . . . . . . . . . . . . . 23
Device specification for the SAW components used . . . . . . . . . . . . . . . . . . . . . 34
Philips Semiconductors
Laboratory Report
HAC/ 95001
4
1
Introduction
Infrared based remote control systems for keyless entry, e.g. automotive, garage door, etc. are more and more replaced by RF
based systems, because RF offers a number of advantages compared to infrared. Some of them are:
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No optical link is required
Almost independent of direction and weather conditions
Larger access range
Today's receiver solutions are mostly based on a so called "superregenerative" architecture. This kind of receiver basically con-
sists of an oscillator, running at or close to the desired receive frequency, which is alternated between oscillation and non-oscil-
lation condition by means of a control signal at a low rate, know as the quench frequency. The quench frequency is typically
below 50 kHz. Since the antenna signal is feed to the oscillator the oscillator rise time varies as a function of the applied signal
strength. The demodulated signal is obtained by simply low pass filtering the oscillator output. Obviously, this receiver is able to
detect amplitude modulated carries only.
Depending on the receive frequency and the spurious radiation limits set by the authorities, a regenerative receiver design may
consist of 30 discrete and inexpensive components with L/C stabilized oscillator or requires twice the amount of components
and a SAW stabilized oscillator. The latter case holds for the UHF range and the stringent radiation limits in Europe.
A receiver design that offers lower component count, better sensitivity, easy application and very low radiation is the
UAA 3201 T, manufactured by Philips Semiconductors.
The UAA 3201T is a fully integrated single-chip receiver, primarily intended for use in VHF and UHF systems employing direct
return-to-zero (RZ) Amplitude Shift Keying (ASK) modulation. The UAA 3201 T is based on a superhet architecture and
requires 25 external low cost components only. Using the same pcb board layout the receiver may be adapted to other receive
frequencies by changing values of 7 components. Due to the use of a SAW stabilized local oscillator, which requires no adjust-
ment, very good long term and temperature stability is achieved. The UAA 3201 T may operate with data rates up to some
10 kbit/sec without a significant reduction of sensitivity.
As a result of the high integration level the whole receiver occupies 5 cm2 (0.8 square inch) of pcb with single side component
placement only. The UAA 3201T features a low power and low cost solution for keyless entry, car alarm, remote control, home
appliance, security or other telemetry systems.
1.1
Typical system architecture
Like in figure 1, a typical system architecture consists of a ASK modulated transmitter with the data to be send generated by a
microcontroller or an encoder ASIC. ASK modulation is preferred compared to FSK due to power consumption reasons, since
the transmitter is usually battery powered. In addition ASK is easier to design, providing lower transmitter costs. The carrier is
generated by means of an oscillator build around a single transistor. L/C stabilized oscillators are used for VHF and low end
applications. SAW stabilized oscillators are used at UHF frequencies or when good frequency stability is required and oscillator
alignment has to be avoided. Usually the antenna is part of the oscillator coil in order to minimize component count. Depending
on the design some filtering has to be provided in order to suppress harmonics of the carrier frequency. Instead of a discrete
solution, a complete ASK transmitter module may be used. Such transmitter modules are available from RFM and include the
carrier filtering, e.g. HX 1000. Suitable SAW resonators for a discrete solution are available from RFM, Siemens and others.
It is recommended to use a SAW stabilized transmitter, in order to make use of the relative small system bandwidth of 800 kHz
provided by the UAA 3201T on the receive side. Larger or smaller receive bandwidths are feasible when the IF filter design is
modified accordingly.
Philips Semiconductors
Laboratory Report
HAC/ 95001
5
Fig.1 Typical system architecture
On the receive side all necessary functions are provided by means of the UAA 3201T from Philips Semiconductors. The
UAA 3201 T is based on the superhet architecture and incorporates a local oscillator stabilized by an external SAW resonator
(e.g. RFM RO 2112, Siemens R647), thus no alignment is necessary. After filtering the received signal is feed to the mixer and
down converted to the IF band. The UAA 3201T uses an IF frequency of 500 kHz which allows to use low cost L and C compo-
nents for IF filtering. After amplification and filtering the signal is demodulated by a limiter amplifier that rectifies the incoming
IF. The RSSI (receive signal strength indicator) derived contains the demodulated data and unwanted frequencies which are
removed by low pass filtering in the following. This signal is feed to the positive input of a data slicer (data comparator). The
slice reference is derived from the same signal by means of a separate low pass filter. This low pass filter is designed for a long
time constant, in order to derive the average RSSI value as an adaptive reference for the data slicer. The adaptive reference
enables the receiver to detect a modulated carrier over a input signal dynamic range of more than 75 dB. By means of an exter-
nal resistor a data slicer threshold may be set, which inhibits noise coming out of the data output, when no RF carrier is present.
Due to the relative low IF frequency of typically 500 kHz and the high receive frequency of up to 434 MHz, the receiver image
rejection is limited. With a SAW filter in front of the mixer input (e.g RFM RF 1172, Siemens B 3530), about 10 dB of image
rejection could be obtained. With a simple L/C circuit or a helical filter (e.g. double tuned) almost no image rejection is
achieved. However, since the UAA 3201T targets a low cost solution a lack of image rejection can be accepted.
Philips Semiconductors
Laboratory Report
HAC/ 95001
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