View AS3901_263931.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

AS3901 ISM 433/315 MHz FSK/ASK Transmitter
Data Sheet Rev. 06, August 2000
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
Key Features
* * * * * * * * * * * Supports the European 433 MHz ISM band. No frequency pulling by (antenna) load variation due to PLL synthesizer. Designed to be conform to EN 300 220-1 requirements. Supports FSK (data rates 0... 32 kb/s) or ASK modulation (data rates 0... 20kb/s) No data synchronization for FSK or ASK needed. Supports clock and reset signals for the external C. Supports different power down modes, one without any running XTAL oscillator. Wide supply range between 2.7 V to 5 V. Only one XTAL and very few external elements required. Wide operating temperature range from -40 C to +85 C. Low TX current, typical 7 mA.
General Description
The AS3901 is a low power FSK/ (ASK) transmitter intended for the European 433 MHz and the US 315 MHz ISM band application. It uses a PLL stabilized oscillator which avoids frequency pulling by approaching the antenna with objects as it occurs at SAW resonator based transmitters. FSK modulation is performed by an I/Q-based continuous phase FSK modulator with a well defined frequency deviation of 16 kHz. The FSK modulator is operating completely asynchronous to the TX data stream and therefore needs no data clock or other possible by switching the driving amplifier and FSK modulator on and off by an applied transmit data stream. The C clock frequency and the FSK frequency deviation can be kept almost constant for both frequency bands by selecting the correct scaling factors by the 433/315 pin. As external components the AS3901 needs only a reference XTAL and 5 capacitors.
STDBY CLK DATA TX GND VDD XTAL2
1 2
14 13
NRES GNDRF ANT1 ANT2 VDDRF 433 XTAL1
AS3901
TSSOP-14
3 4 5 6 7
12 11 10 9 8
Rev. 6, August 2000
Page 2 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
Applications
* * * * * * Short range radio data transmission. Remote keyless entry systems. Security applications and alarm systems. Domestic and consumer remote control units. Remote metering. Low power telemetry.
This document contains information on products under development. Austria Mikro Systeme International AG reserves the right to change or discontinue this product without notice.
Rev. 6, August 2000
Page 3 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
1
Functional Description
The AS3901 consists of a reference XTAL oscillator, a single channel RF- synthesizer, an I/Q based asynchronous continuos phase FSK modulator, a driving amplifier and a C interface, including C clock divider, and a power management circuitry.
XTAL1
XTAL2
8
433 Synthesizer
AS3901
Divider 32:1 LoopFilter Phase Detector XTAL Oscillator
7
VDD
13.560 MHz XTAL
9
VDDRF
6
GND
VCO
10
ANT2 VDD f =433.920 MHz
5
TX Clock
11
ANT1
Driving Amplifier.
SSB signal generation
4
DATA
12
GNDRF
3
CLK
13
NRES
C Interface + Power up/down
2
STDBY
14
1
Figure 1:
Block diagram of the AS3901.
1.1 RF Synthesizer
The RF synthesizer is a fully integrated single channel device with internal loop filter, generating the 433 MHz or 315 MHz transmit carrier frequency fRF by a fix, 32 times, multiplication of the reference XTAL frequency fXTAL.
1.2 Microprocessor Clock
The microprocesor clock frequency fCLK is generated by dividing the XTAL frequency fXTAL by 3 or 4, dependent on the 433/315 MHz selection pin to keep the C clock frequency fCLK almost constant for European and US applications.
1.3 Modulation
The FSK modulator is an I/Q modulator based continuos phase FSK modulator. The modulating NRZ data may be in the range of 0 up to 32 kbit/s. The FSK frequency deviation f is kHz, independent of the data rate. It is also kept almost constant for 16 both transmit frequency bands by selecting proper frequency deviation multiplication factors of the XTAL reference frequency by the 433/315 MHz selection pin. The processing clock of the data source can be different from the AS3901 reference XTAL or C clock fCLK and no data synchronization of the FSK modulator is required.
Rev. 6, August 2000
Page 4 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
1.4 Driving Amplifier
The driving amplifier has a differential open collector output optimized for driving of small, symmetrical high-impedance loop antennas. The amplifier drives a nominal RF current of 0.7 mArms.The maximal differential voltage swing is about 4 VPP. Therefore the output power ist a function of the connected load impedance. With a 2 k differential load a nominal peak output power (to the antenna) of mW is obtained. Please note 1 that the finally radiated power (from antenna) is lower and strongly dependent on the efficiency (function of the size) of the antenna to be used.
1.5 ASK Modulation
ASK modulation with a date rate upt to 20 kbits/s can be achieved by turning the driving amplifier and the FSK modulator by the TX/ASK pin on and off, where a TX/ASK = H" means a turned on state.
1.6 Power Management and Operation Modes
For normal operation the switching between different operation modes follows a Greycoded scheme to avoid unwanted switching between operation modes due to inaccurate occurrence of edges of STDBY and TX/ASK.
Mode Standby Clock generator operation Transmit operation STDBY 1 1 0 TX/ASK 1 0 1 Function All Off XTAL oscillator on and CLOCK output active. XTAL oscillator, PLL, FSK modulator running, (FSK operation or transmitted H" at ASK). XTAL oscillator and PLL running, output amplifier and FSK modulator off, ( L" transmitted at ASK).
Turned off power
0
0
1.7 C Interface and Timing
The AS3901 contains a direct interface to a microcontroller (C). The C interface of the AS3901 consists of three input and two outputs pins: Standby input"(STDBY). Transmit / ASK input"(TX/ASK). reset output (Active )"(NRES). C L" clock output"(CLK). C FSK data input"(DATA). These lines support the C with the required reset, clock and data signals. Lines 1 to 4 control the AS3901 internal power on/off circuit which wakes up and shuts down the whole transmitter consisting of the AS3901 and the C. Figure 2 shows a typical interconnection of the AS3901 with a typical C. Figure 3 presents a related timing for power up and down of the transmitter.
Rev. 6, August 2000
Page 5 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
AS3901
STDBY DATA TX/ASK NRES CLK
I I I O O O O O I I
uC
STDBY DATA TX/ASK RESET CLK
10k SW Transmit switch
Figure 2:
Note:
Interconnection of the AS3901 with a typical C.
At room temperature, resistor values of k are suggested for the C interface. 10 For other temperatures to be calculated from figure 5.
TX/ASK CLK NRES STDBY
XTon standby reset uC init PLLon TX on transmitting 3 clocks standby
Figure 3:
C interface timing for a transmission cycle.
Note: Activating the transmit switch results in a weak L state" at TX/ASK. It can be overridden by the microcontroller so that the transmission cycle remains unaffected by the duration the switch is pressed. The STDBY and TX/ASK inputs have internal pullup resistors of ~100k
Rev. 6, August 2000
Page 6 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
1.7.1 Interface Description
Wake-up sequence: TX/ASK=H, STDBY=H: Standby. All off low current state. TX/ASK L, STDBY=H; XTAL oscillator starts up. NRES goes L, resetting (starting) the C for tXTON plus 3 clock cycles. NRES returns to H, C initializes. After C is initialized, it sets STDBY L; PLL is turned on, after tPLLon a stable RF carrier is generated. TX/ASK H, STDBY=L; TX is turned on, tTXON later the RF signal is available and data can be transmitted. To switch the AS3901 a on" push button"with series resistance ~10-20 k can be used to make TX/ASK = . The L" push-button"must be pushed long enough (typ. > 3ms) for the C to reset and sustain the TX/ASK state. L" Standby procedure (for sleep-mode ( IDD1 <1A): The C outputs a to TX/ASK and STDBY. After minimal 3 CLK cycles the XTAL H" oscillator will be switched off. The pull-up resistors at the AS3901 TX/ASK and STDBY inputs will sustain the sleep mode. Note: Multiple push buttons"for different functions can be used.
Rev. 6, August 2000
Page 7 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
2
Electrical Characteristics
2.1 Absolute Maximum Ratings ( non operating)
Symbol VDD GND VIN ESD TSTG TLEAD
Note: 1) 2)
Parameter Positive supply voltage Negative supply voltage Voltage on input pins Electrostatic discharge Storage temperature Lead temperature
Min -0.5 0 -0.5
Max 7 0 VDD+0.5 1000
Units V V V V C C
Note
1)
-55
125 260
2)
HBM: R = 1.5 k , C = 100 pF. The pins ANT1, ANT2, XTAL1 and XTAL2 have 500 V ESD protection. 260C for 10 s (reflow and wave soldering), 360 C for 3 s (manual soldering).
2.2 Operating Conditions
Symbol VDD GND IDD1 IDD2 IDD3 IDD4 TAMB
Parameter Positive supply voltage Negative supply voltage Supply current, STDBY = " , TX/ASK = " H" H" Supply current, STDBY = " , TX/ASK = " H" L" Supply current, STDBY = " , TX/ASK = " L" H" Supply current, STDBY = " , TX/ASK = " L" L" Ambient temperature range
Min 2.7 0
Typ 3.0 0
Max 5.0 0 1
Unit V V A A mA mA C
Note
1) 2) 3) 4)
350 7 3.5 -40
850 9 4.5 +85
Note: 1) Standby: 2) Clock generator operation: 3) 4) Transmit operation: Turned off TX power:
TAMB = 23 C, Synthesizer and driving amplifier are turned off. TAMB = 23 C XTAL oscillator and C clock divider on. RF driving amplifier and PLL off, no external load connected to CLK pin. TAMB = 23 C, Synthesizer and driving amplifier are turned on. TAMB = 23 C, XTAL oscillator and C clock divider and PLL on RF driving amplifier off.
Rev. 6, August 2000
Page 8 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
2.3 Transmit Operation
TAMB = 23 C, VDD = 3.0 V, unless specified otherwise. Symbol fRF, EU fRF, US foffset fCLK, EU fCLK, US tTXon tPLLon TXTon Parameter Conditions Min Typ 433.920 315.000 2 3.390 3.28125 20 t.b.d. 5 Max Units MHz MHz kHz MHz MHz s ms ms Note 1) 1)
Transmit frequency (Europe) fXTAL = 13.560 MHz Transmit frequency (US) Frequency tolerance fXTAL = 9.84375 MHz After tTXON, no XTAL tolerance.
C clock frequency (Europe) fXTAL = 13.560 MHz C clock frequency (US) Transmitter turn on time PLL turn on time XTAL oscillator turn on time fXTAL = 9.84375 MHz FSK modulator and driver amplifier
Note: 1) XTAL tolerances will slightly change the typical transmit frequency.
2.3.1 ASK Operation
TAMB = 23 C, VDD = 3.0 V, unless specified otherwise. Symbol POUT,H POUT,L POUT 3rd PSP Parameter Available peak output power Leakage peak output power Radiated third harmonic output power Spurious power Conditions In 2 k , STDBY = " , L" TX/ASK = " H" In 2 k , STDBY = " , L" TX/ASK = " L" Antenna attenuation> 20 dB In distance of fCLK or fXTAL from carrier. No antenna selectivity assumed. For a RF packet duty cycle 25 %. 0 -45 Min -1.5 Typ 0 Max 1.5 -50 -39 -25 Units dBm dBm dBm dBC 2) 2) 3) Note 1) 3)
RASK
ASK data rate range
20
Kb/s
Note: 1) Output power depends on load impedance, differential output current is typical 0.7 mArms. Maximum differential voltage swing is typical 4 VPP. 2) Measurement bandwidth (close to EN 300 220-1) see also figure 10. 3) Actual E.R.P. depends on antenna efficiency
Rev. 6, August 2000
Page 9 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
2.3.2 FSK Operation
TAMB = 23 C, VDD = 3.0 V, unless specified otherwise. Symbol Parameter Conditions In 2 k , STDBY = " , L" TX/ASK = " H" Antenna and band pass filter attenuation> 20 dB In distance of fCLK or fXTAL from carrier. No antenna selectivity assumed. 0 16 -45 Min -1.5 Typ 0 Max 1.5 -36 -25 Units dBm dBm dBC Note 1) 3) 2) 2) 3)
POUT,FSK Available peak output power POUT 3rd PSP Radiated third harmonic output power Spurious power
RFSK f
Note: 1) 2) 3) 4)
FSK data rate range FSK frequency deviation
32
kb/s kHz
4)
Output power depends on load impedance, differential output current is typical 0.7 mAms. Maximum differential voltage swing is typical 4 VPP. Measurement bandwidth (close to EN 300 220-1) see also figure 10. Actual E.R.P. depends on antenna efficiency Guaranteed by design
Rev. 6, August 2000
Page 10 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
2.4 Digital Pin Characteristics
TAMB = 23 C, VDD = 3.0 V, unless specified otherwise. GND is the 0 V reference. Symbol Parameter CLK (C clock output) VOH VOL tr td jcc High level output voltage IOH = -1 mA Low level output voltage Rise time Fall time Cycle to cycle jitter IOL = 1 mA CLoad = 10 pF CLoad = 10 pF VDD-0.7 GND 20 20 +/-5 VDD 1.2 V V ns ns % 1) Conditions Min Typ Max Units Note
NRES (Inverted reset output) VOH VOL tr td High level output voltage IOH = -1 mA Low level output voltage Rise time Fall time IOL = 1 mA CLoad = 10 pF CLoad = 10 pF VDD-0.3 GND 20 20 VDD 0.2 V V ns ns
TX/ASK (Driving amplifier and FSK modulator on/off (ASK) input) VIH VIL IIH IIL High level input voltage Low level input voltage High level input current Low level input current VIH = VDD VIL = 0 V. internal pull-up DATA (FSK data input) VIH VIL IIH IIL High level input voltage Low level input voltage High level input current Low level input current VIH = VDD VIL = 0 V -1 VDD-0.5 GND VDD 0.3 1 V V A A -40 VDD-0.5 GND VDD 0.3 1 A V V
Rev. 6, August 2000
Page 11 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
433/315 (Band selection (division ratio)) VIH VIL IIH IIL High level input voltage Low level input voltage High level input current Low level input current VIH = VDD VIL = 0 V. -1 VDD-0.5 GND VDD 0.3 1 V V A A
STANDBY (Standby input) VIH VIL IIH 1IIL High level input voltage Low level input voltage High level input current Low level input current VIH = VDD VIL = 0 V. internal pull-up
Notes 1)
VDD-0.5 GND -
VDD 0.3 1
V V A A
-40
Guaranteed by design
Rev. 6, August 2000
Page 12 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
3
Pin-out Information
Pin Name STDBY CLK DATA TX/ASK on/off ASK GND VDD XTAL2 XTAL1 433/315 VDDRF ANT2 ANT1 GNDRF NRESET Input / Output Dig. Input, 100 k pull up Dig. Output Dig. Input Dig. Input, 100 k pull up Power Power Analog Analog Dig. Input Power Analog open collector output Analog open collector output Power Dig. Output Description Power down for all functions Clock output (CMOS level) Transmit data input (CMOS level) Power off for TX (PLL and XTAL working) ASK modulation Ground Positive supply (2.7 V-5.0 V) XTAL pin2 XTAL pin1 Selects division factors for constant C Clock frequency and deviation Positive supply (2.7 V-5.0 V) To loop antenna To loop antenna Ground Reset, state resets a microcontroller L"
Pin # 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Rev. 6, August 2000
Page 13 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
4
Application Schematic
VDD C3 100N VDD STDBY U1 CLK DATA TX 1 2 3 4 5 6 7 STDBY CLK DATA TX/ASK GND VDD XTAL2 NRESET GNDRF ANT1 ANT2 VDDRF 433 XTAL1 14 13 12 11 10 9 8 NRES A1 C5 3P 443_315 LOOP ANTENNA C4 100P C1 10P
AS3901 U2 13.56MHZ C2 10P
Figure 4:
Basic application schematic of the AS3901.
Figure 5:
Pull Up characteristics for the TX/ASK pin.
Page 14 of 18
Rev. 6, August 2000
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
5
Typical Measurements
Figure 6:
Narrow band output spectrum of the AS3901 FSK modulated with pseudo random data at 32 kbit/s.
Figure 7:
Modulation bandwidth of the AS3901 in FSK operation at 32.6 kbit/s, measured close to the EN 300-220-1 recommendation for wide-band equipment, clause 8.6. Instead of 5 kHz video bandwidth (VBW) 10 kHz was used. The markers were set up to the band edges. (433.050 MHz, 434.790 MHz) The recommendation says that the spectrum should be observed at least 1MHz form the ISM band edges, but it was measured with larger frequency span.
Rev. 6, August 2000
Page 15 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
Figure 8:
Modulation bandwidth of the AS3901 in AKS operation at 9.2 kbit/s, measured close to the EN 300-220-1 recommendatio for wide-band equipment, clause 8.6. Instead of 5 kHz video bandwidth (VBW) 10 kHz was used. The markers were set up to the band edges. (433.050 MHz, 434.790 MHz) The recommendation says that the spectrum should be observed at least 1 MHz from the ISM band edges, but it was measured with larger frequency span.
Figure 9: Spurious emissions of the AS3901 in FSK operation, measured close to the EN 300-2201Recommendation for wide-band equipment, clause 8.7, without modulation. (Only difference: 100 kHz RBW was used instead of 120 kHz). From the measurement it can be seen that the main critical spurious emission is generated by the 13.56 MHz clock frequency. The level of CLK spurious is near -48 dBM so the suppression is 45 dB for this component.
Rev. 6, August 2000
Page 16 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
Figure 10:
Typical out spectrum in ASK 9.2 kb/s PRN modulation.
Figure 11:
Transmission power as function of time at ASK modulation with an 9.2 kbit/s 0101.. data pattern.
Rev. 6, August 2000
Page 17 of 18
ISM 433/315 MHz FSK/ASK Transmitter - Data Sheet
AS3901
6
Package Information
Figure 12:
Physical dimensions of TSSOP-14.
Common Dimensions Symbol Minimal (mm) A A1 b D e E E1 L 4.30 0.45 0 0.05 0.19 4.90 Nominal (mm) 0.65 BSC 6.40 4.50 0.75 8 Maximal (mm) 1.20 0.15 0.30 5.10
Copyright (c) 2000, Austria Mikro Systeme International AG, Schlo Premstatten, 8141 Unterpremstatten, Austria. Tel.: +43-(0)3136-500-0, Fax: +43-(0)3136-52501, E-Mail: info@amsint.com
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing by the copyright holder. To the best of its knowledge, Austria Mikro Systeme International asserts that the information contained in this publication is accurate and correct.
Rev. 6, August 2000
Page 18 of 18

▲Up To Search▲

Price & Availability of AS3901

	To Download AS3901 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .