ATMEL ATA2745 Very high transmitting frequency accuracy compared to saw solution Datasheet

Features
• Very High Transmitting Frequency Accuracy Compared to SAW Solutions
(Enables Receivers at Lower Bandwidth than With SAW Resonators)
• Lower Cost than the Usual Discrete Solutions Using SAW and Transistors
• Supply Voltage 2.2V to 4.0V in the Temperature Range of –40°C to 85°C
• XTO Output for Clocking the Microcontroller, Thereby, Together with the ATAR090 or
ATAR890, Resulting in the Optimum System Cost-effectiveness
• One-chip Solution With Minimum External Circuitry
• Single-ended Open-collector Output (Same Antennas Can Be Used as in Discrete
Solutions, Simpler Matching of Magnetic Loop Antennas)
• ESD Protection According to MIL-STD 883 (4 KV HBM) Except Pins XTO1, XTO2, ANT
and LF
• Very Small SSO16 Package, Pitch 0.635, 150 mil
1. Description
UHF ASK
Transmitter
ATA2745
The ATA2745 is a PLL transmitter IC which has been developed especially for the
demands of RF low-cost data transmission systems at data rates up to 20 kBaud.
The transmitting frequency range is 310 MHz to 440 MHz. It can be used in ASK systems. The main applications of the ATA2745 are in the areas of outside temperature
metering, socket control, garage door openers, consumption metering, light/fan or airconditioning controls, jalousies, wireless keyboards, and various other consumer
market applications.
4898B–RKE–08/06
Figure 1-1.
System Block Diagram
UHF ASK/FSK
Remote control transmitter
UHF ASK/FSK
Remote control receiver
1 Li cell
ATA2745
ATA3745
1 to 3
Demod
Keys
Encoder
ATARx9x
Microcontroller
PLL
Antenna
XTO
IF Amp
Antenna
VCO
PLL
Power
amp.
Figure 1-2.
Control
LNA
XTO
VCO
Block Diagram
ASK
GND
OR
PWRSET
EN
Power
up
VCC
PWRVCC
VCO
PA
CLK
ANT
f
GND
PWRGND1
64
LFVCC
PWRGND2
f
LF
2
XTO
n
LFGND
ATA2745
XTO1
NC
ATA2745
4898B–RKE–08/06
ATA2745
2. Pin Configuration
Figure 2-1.
Pinning SSO16
ASK
1
16
GND
EN
2
15
PWRSET
VCC
3
14
PWRVCC
CLK
4
13
ANT
GND
5
12
PWRGND1
LFVCC
6
11
PWRGND2
LFGND
7
10
XTO1
LF
8
9
NC
ATA2745
Table 2-1.
Pin Description
Pin
Symbol
Function
1
ASK
Modulation input ASK
2
EN
Enable input
3
VCC
Supply voltage
4
CLK
Clock output
5
GND
Ground
6
LFVCC
Supply voltage VCO
7
LFGND
VCO ground
8
LF
Circuit PLL loop
9
NC
Not connected
10
XTO1
11
PWRGND2
Connection for crystal
Power GND2
12
PWRGND1
Power GND1
13
ANT
14
PWRVCC
Supply voltage power amplifier
15
PWRSET
Applied to VCC
16
GND
RF output
Ground
3
4898B–RKE–08/06
3. General Description
The fully integrated VCO and the single-ended open-collector output allow particularly simple,
low-cost RF miniature transmitters to be assembled. The single-ended output enables a considerably simplified adaptation of both a magnetic loop antenna of any form or a  / 4 antenna. This
is because the load impedance must not be balanced as would be the case with a differential
output.
The XTO's frequency can be selected to be either 13.56 MHz or 9.844 MHz (USA). At these frequencies, crystals have a very fast start-up time (< 1.5 ms), whereby a wait time of 5 ms to
10 ms is required until the transmitter IC is locked. This means that the processor does not need
to poll a lock detect output.
4. Functional Description
4.1
ASK Transmission
The ATA2745 is activated by EN = VS. VASK must remain 0V for 5 ms, then the output power can
be modulated by means of pin ASK. VEN remains equal to VS during the transmission of the
message. The ASK input activates the power amplifier and the PLL.
4.2
Take-over of the Clock Pulse in the Microcontroller
The clock of the crystal oscillator can be used for clocking the microcontroller. The ATAR090
and ATAR890 have the special feature of starting with an integrated RC oscillator to switch on
the ATA2745 with VEN = VS. 5 ms later, the 3.39-MHz clock frequency is present, so that the
message can be sent with crystal accuracy.
5. Application Circuit
The following component values are recommendations for a typical application. C4, C5, and C6
are block capacitors. The values of these capacitors depend on the board layout. C4 = 1 nF,
C5 = 1 nF, and C6 = 22 nF are typically used here. For C5, the impedance between f = 100 MHz
and f = 1 GHz should be as low as possible.
CLoop1 and CLoop2 are selected so that the antenna oscillates in resonance and the matching to
the appropriate impedance transformation is possible.
LFeed is an inductor for the antenna's DC current supply. A typical value is LFeed = 220 nH. LFeed
can be either printed on the PC board or be a discrete component.
4
ATA2745
4898B–RKE–08/06
ATA2745
5.1
Output Power Measurement
The following output network (Figure 5-1 on page 5) can be used for output power evaluation,
the exact values of L10 and C10 are dependent on the layout.
L10 and C10 form the transformation network to adopt the output impedance of the IC to 50. The
following table shows the values for an output power of 2 mW and an RPWRSET = 1.2 k.
Table 5-1.
Transformation Network
f [MHz]
C10 [pF]
L10 [nH]
ZLoad-opt []
315
2.7
56
260 + j330
433.92
1.8
33
185 + j268
Figure 5-1.
Measurement Output Network
VS
PWRVCC
L10
ZLoad-opt
ANT
C10
50Ω
Figure 5-2.
Application Circuit
+VS = 2.2 to 4.0V
GND
ASK
ASK
1
16
OR
2
VCC
CLoop2
PWRSET
EN
EN
15
RPWRSET
Power
up
PWRVCC
3
14
C6
C4
CLK
CLK
VCO
PA
4
LFeed
ANT
13
3.39MHz
f
5
12
64
LFVCC
PWRGND2
6
11
C5
f
XTO
LFGND
n
7
R4
C1
XTO1
13.56MHz
10
C3
NC
LF
8
C2
CLoop1
PWRGND1
GND
ATA2745
9
Antenna
5
4898B–RKE–08/06
6. Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Parameters
Max.
Unit
Supply voltage
Symbol
VS
6
V
Power dissipation
Ptot
250
mW
Tj
150
C
Junction temperature
Min.
Storage temperature
Tstg
–55
125
C
Ambient temperature
Tamb
–40
85
C
Electrostatic sensitive device.
Observe precautions for handling.
7. Thermal Resistance
Parameters
Junction ambient
Symbol
Value
Unit
RthJA
180
K/W
8. Electrical Characteristics
All parameters are refered to GND (pin 5), VS = 3V, Tamb = 25°C, unless otherwise specified
The possible operating ranges refer to different circuit conditions: VS = 2.2V to 4.0V at Tamb = –40°C to +85°C
Parameters
Test Conditions
Supply current (power down)
VASK, VFSK  0.3V, VS < 3.6V
Supply current (power up, output OFF) VASK = GND, VEN = VS, VS = 3V
Supply current (power up, output ON) VASK = VS, VS = 3V, RPWRSET = 1.2 k
Output power
Output power variation for
f = 315 MHz compared to
f = 433.92 MHz
VS = 3V, Tamb = 25C, f = 433.92 MHz
RPWRSET = 1.2 k
f = 315 MHz
Pout = PRef + PRef
Symbol
Typ.
Max.
Unit
ISoff
2
10
µA
ISon
4.7
6.2
mA
IStransmit
10
12.5
mA
3
5
dBm
PRef
1
PRef
1.5
dB
Voutmax
VS – 0.7V
V(peak)
Maximum peak output
antenna voltage
At Pout = 2.0 mW,
the load impedance must be selected
to meet the Vout maximum
requirement, the supply current is not
dependent on the load impedance
tolerance
Spurious emission
fo ±(n  fPC) where fPC = 6.78 MHz
Load capacitance at CLK  3 pF
f = 230 MHz to 470 MHz
f < 230 MHz, f > 470 MHz
Em
Em
Oscillator frequency XTO
Crystal frequency = 13.56 MHz
fXTO
6
Min.
13.56 –
30 ppm
13.56
–40
–58
dBC
dBC
13.56 +
30 ppm
MHz
ATA2745
4898B–RKE–08/06
ATA2745
8. Electrical Characteristics (Continued)
All parameters are refered to GND (pin 5), VS = 3V, Tamb = 25°C, unless otherwise specified
The possible operating ranges refer to different circuit conditions: VS = 2.2V to 4.0V at Tamb = –40°C to +85°C
Parameters
Test Conditions
Loop bandwidth
For best LO noise
Loop filter components:
C2 = 3.9 nF, C1 = 15 nF, R4 = 220
BLoop
100
Phase noise PLL
Referring to the phase comparator
fPC = 6.78 MHz
PNPLL
–111
Phase noise VCO
At 1 MHz
At 36 MHz
PNVCO
PNVCO
–90
–122
Frequency range of the VCO
Symbol
fVCO
Min.
Typ.
310
Max.
Unit
kHz
–105
dBC/Hz
dBC/Hz
440
MHz
Clock output
(CMOS microcontroller compatible)
Clkout
Load capacitance at CLK
CCLK
10
pF
Rs
Rs
80
100

20
kHz
100
µA
µA
µA
µA
Series resonance R of the crystal
fXTO = 13.56 MHz
fXTO = 9.84 MHz
ASK modulation frequency rate
Duty cycle of the
modulation signal = 50%
fout / 128
fmodASK
0
Iol
Iol
Ioh
Ioh
150
200
–150
–200
ASK input
- Low level input voltage
- High level input voltage
- Input current High
VASKl
VASKh
IASKh
1.7
Enable ASK
- Low level input voltage
- High level input voltage
- Input current High
VEN
VFSKl
VFSKh
IFSKh
CLK output
- Output current Low
- Output current Low
- Output current High
- Output current High
VCLK = 0.2  VS
VCLK = 0.3  VS
VCLK = 0.8  VS
VCLK = 0.7  VS
MHz
0.3
140
0.3
1.7
140
V
V
µA
V
V
µA
7
4898B–RKE–08/06
9. Ordering Information
Extended Type Number
Package
ATA2745M-TCQY
SSO16
Remarks
Taped and reeled, Pb-free
10. Package Information
5 max.
0.6
1.4
1.7 max.
4.9±0.1
0.1+0.15
0.2
0.25
3.95 max.
0.635 nom.
5±0.2
7 x 0.635 = 4.445 nom.
6±0.2
16
9
technical drawings
according to DIN
specifications
1
8
Dimensions in mm
Package acc. JEDEC MO 137 AB
02/05/99
TITLE
Package Drawing Contact:
[email protected]
8
Package: SSO16
GPC
DRAWING NO.
REV.
6.543-5060.01-4
2
ATA2745
4898B–RKE–08/06
ATA2745
11. Revision History
Please note that the following page numbers referred to in this section refer to the specific revision
mentioned, not to this document.
Revision No.
History
4898B-RKE-08/06
Put datasheet in a new template
Section 9 “Ordering Information” on page 8 changed
9
4898B–RKE–08/06
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