TDA7110

Wireless Components
ASK/FSK Transmitter 868/433 MHz
TDA7110 Version 1.0
Data Sheet December 2008
Preliminary
Revision History
Current Version: Version 1.0 as of 10.12.2008
Previous Version: none
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Edition 2008
Published by Infineon Technologies AG,
Am Campeon 1 - 12
85579 Neubiberg, Germany
© 2008 Infineon Technologies AG
All Rights Reserved.
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Due to technical requirements, components may contain dangerous substances. For information on the types in question, please contact the nearest
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Infineon Technologies Components may be used in life-support devices or systems only with the express written approval of Infineon Technologies, if a
failure of such components can reasonably be expected to cause the failure of that life-support device or system, or to affect the safety or effectiveness
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TDA7110
Product Info
Product Info
General Description
Features
Applications
Ordering Information
The TDA7110 is a single chip ASK/FSK Package
transmitter for the frequency bands
868-870 MHz and 433-435 MHz. The
IC offers a high level of integration and
needs only a few external components.
The device contains a fully integrated
PLL synthesizer and a high efficiency
power amplifier to drive a loop antenna.
A special circuit design and an unique
power amplifier design are used to
save current consumption and therefore to save battery life. Additionally
features like a power down mode, a low
power detect, a selectable crystal oscillator frequency and a divided clock output are implemented. The IC can be
used for both ASK and FSK modulation.
■
fully integrated frequency synthesizer
■
voltage supply range 2.1 - 4 V
■
VCO without external components
■
power down mode
■
high efficiency power amplifier
typically 10 dBm @ 3 V
■
low voltage sensor
■
selectable crystal oscillator
6.78 MHz/13.56 MHz
■
switchable frequency range
868-870/433-435 MHz
■
programmable divided clock output
for µC
■
ASK/FSK modulation
■
low supply current typ. 13 mA@3V
■
low external component count
■
Keyless entry systems
■
Alarm systems
■
Remote control systems
■
Communication systems
Type
Ordering Code
Package
TDA7110
SP000524278
PG-TSSOP-16
available on tape and reel
Wireless Components
Product Info
Data Sheet, December 2008
1
Product Description
Contents of this Chapter
1.1
1.2
1.3
1.4
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Package Outlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
TDA7110
Product Description
1.1 Overview
The TDA7110 is a single chip ASK/FSK transmitter for the frequency bands
868-870 MHz and 433-435 MHz. The IC offers a high level of integration and
needs only a few external components. The device contains a fully integrated
PLL synthesizer and a high efficiency power amplifier to drive a loop antenna.
A special circuit design and an unique power amplifier design are used to save
current consumption and therefore to save battery life. Additional features like
a power down mode, a low power detect, a selectable crystal oscillator frequency and a divided clock output are implemented. The IC can be used for
both ASK and FSK modulation.
1.2 Applications
■
Keyless entry systems
■
Remote control systems
■
Alarm systems
■
Communication systems
1.3 Features
Wireless Components
■
fully integrated frequency synthesizer
■
VCO without external components
■
high efficiency power amplifier typ. 10 dBm @ 3 V
■
switchable frequency range 868-870/433-435 MHz
■
ASK/FSK modulation
■
low supply current typ. 13 mA @ 3 V
■
voltage supply range 2.1 - 4 V
■
power down mode
■
low voltage sensor
■
selectable crystal oscillator 6.78 MHz/13.56 MHz
■
programmable divided clock output for µC
■
low external component count
1-2
Data Sheet, December 2008
TDA7110
Product Description
1.4 Package Outlines
Figure 1-1
Wireless Components
PG-TSSOP-16
1-3
Data Sheet, December 2008
2
Functional Description
Contents of this Chapter
2.1
2.2
2.3
2.4
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
2.4.5.1
2.4.5.2
2.4.5.3
2.4.6
Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Pin Definitions and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Functional Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Functional Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
PLL Synthesizer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Crystal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Power Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Low Power Detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Power Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Power Down Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
PLL Enable Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Transmit Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Recommended timing diagrams for ASK- and FSK-Modulation . . 2-12
TDA7110
Functional Description
2.1 Pin Configuration
PDW N
1
16
C S EL
LP D
2
15
FSE L
VS
3
14
PA O U T
LF
4
13
PA G N D
TD A 7110
GND
5
12
FSK G N D
A SK D TA
6
11
FSK O U T
FS KD TA
7
10
COSC
C LKO U T
8
9
C LKD IV
Pin_config.wmf
Figure 2-1
IC Pin Configuration
Table 2-1
Wireless Components
Pin No.
Symbol
Function
1
PDWN
Power Down Mode Control
2
LPD
Low Power Detect Output
3
VS
Voltage Supply
4
LF
Loop Filter
5
GND
6
ASKDTA
Amplitude Shift Keying Data Input
7
FSKDTA
Frequency Shift Keying Data Input
8
CLKOUT
Clock Driver Output
9
CLKDIV
Clock Divider Control
10
COSC
11
FSKOUT
Frequency Shift Keying Switch Output
12
FSKGND
Frequency Shift Keying Ground
13
PAGND
Power Amplifier Ground
14
PAOUT
Power Amplifier Output
15
FSEL
Frequency Range Selection (433 or 868 MHz)
16
CSEL
Crystal Frequency Selection (6.78 or 13.56 MHz)
Ground
Crystal Oscillator Input
2-2
Data Sheet, December 2008
TDA7110
Functional Description
2.2 Pin Definitions and Functions
Table 2-2
Pin
No.
Symbol
1
PDWN
Function
Interface Schematic1)
Disable pin for the complete transmitter circuit.
VS
40 μA ∗ (ASKDTA+FSKDTA)
5 kΩ
A logic low (PDWN < 0.7 V) turns off all
transmitter functions.
A logic high (PDWN > 1.5 V) gives access to
all transmitter functions.
1
"ON"
PDWN input will be pulled up by 40 µA internally by either setting FSKDTA or ASKDTA
to a logic high-state.
150 kΩ
250 kΩ
2
LPD
This pin provides an output indicating the
low-voltage state of the supply voltage VS.
VS
VS < 2.15 V will set LPD to the low-state.
40 µA
An internal pull-up current of 40 µA gives the
output a high-state at supply voltages above
2.15 V.
2
300 Ω
3
VS
Wireless Components
This pin is the positive supply of the transmitter electronics.
An RF bypass capacitor should be connected directly to this pin and returned to
GND (pin 5) as short as possible.
2-3
Data Sheet, December 2008
TDA7110
Functional Description
4
LF
Output of the charge pump and input of the
VCO control voltage.
The loop bandwidth of the PLL is 150 kHz
when only the internal loop filter is used.
The loop bandwidth may be reduced by
applying an external RC network referencing
to the positive supply VS (pin 3).
VS
140 pF
15 pF
35 kΩ
10 kΩ
4
5
GND
6
ASKDTA
General ground connection.
Digital amplitude modulation can be
imparted to the Power Amplifier through this
pin.
+1.2 V
A logic high (ASKDTA > 1.5 V or open)
enables the Power Amplifier.
60 kΩ
6
+1.1 V
90 kΩ
50 pF
7
30 μA
FSKDTA
A logic low (ASKDTA < 0.5 V)
disables the Power Amplifier.
Digital frequency modulation can be
imparted to the Xtal Oscillator by this pin.
The VCO-frequency varies in accordance to
the frequency of the reference oscillator.
+1.2 V
60 kΩ
7
+1.1 V
90 kΩ
30 μA
A logic high (FSKDTA > 1.5V or open)
sets the FSK switch to a high impedance
state.
A logic low (FSKDTA < 0.5 V)
closes the FSK switch
from FSKOUT (pin 11) to FSKGND (pin 12).
A capacitor can be switched to the reference
crystal network this way. The Xtal Oscillator
frequency will be shifted giving the designed
FSK frequency deviation.
Wireless Components
2-4
Data Sheet, December 2008
TDA7110
Functional Description
8
CLKOUT
Clock output to supply an external device.
An external pull-up resistor has to be added
in accordance to the driving requirements of
the external device.
A clock frequency of 3.39 MHz is selected
by a logic low at CLKDIV input (pin 9).
A clock frequency of 847.5 kHz is selected
by a logic high at CLKDIV input (pin 9).
8
300 Ω
9
CLKDIV
This pin is used to select the desired clock
division rate for the CLKOUT signal.
VS
A logic low (CLKDIV < 0.2 V) applied to this
pin selects the 3.39 MHz output signal at
5 μA
CLKOUT (pin 8).
A logic high (CLKDIV open) applied to this
pin selects the 847.5 kHz output signal at
+0.8 V
CLKOUT (pin 8).
+1.2 V
60 kΩ
9
60 kΩ
10
COSC
This pin is connected to the reference oscillator circuit.
The reference oscillator is working as a negative impedance converter. It presents a
negative resistance in series to an inductance at the COSC pin.
VS
6 kΩ
10
100 μA
11
FSKOUT
This pin is connected to a switch to
FSKGND (pin 12).
VS
The switch is closed when the signal at
FSKDTA (pin 7) is in a logic low state.
200 µA
The switch is open when the signal at
FSKDTA (pin 7) is in a logic high state.
1.5 kΩ
11
FSKOUT can switch an additional capacitor
to the reference crystal network to pull the
crystal frequency by an amount resulting in
the desired FSK frequency shift of the transmitter output frequency.
12
12
FSKGND
Wireless Components
Ground connection for FSK modulation output FSKOUT.
2-5
Data Sheet, December 2008
TDA7110
Functional Description
13
PAGND
Ground connection of the power amplifier.
The RF ground return path of the power
amplifier output PAOUT (pin 14) has to be
concentrated to this pin.
14
PAOUT
RF output pin of the transmitter.
14
A DC path to the positive supply VS has to
be supplied by the antenna matching network.
13
15
FSEL
This pin is used to select the desired transmitter frequency.
+1.2 V
A logic low (FSEL < 0.5 V) applied to this pin
sets the transmitter to the 433 MHz frequency range.
30 kΩ
15
+1.1 V
90 kΩ
30 μA
16
CSEL
+1.2 V
A logic high (FSEL open) applied to this pin
sets the transmitter to the 868 MHz frequency range.
This pin is used to select the desired reference frequency.
VS
5 μA
60 kΩ
16
+0.8 V
60 kΩ
A logic low (CSEL < 0.2 V) applied to this pin
sets the internal frequency divider to accept
a reference frequency of 6.78 MHz.
A logic high (CSEL open) applied to this pin
sets the internal frequency divider to accept
a reference frequency of 13.56 MHz.
1) Indicated voltages and currents apply for PLL Enable Mode and Transmit Mode.
In Power Down Mode, the values are zero or high-ohmic.
Wireless Components
2-6
Data Sheet, December 2008
Wireless Components
Figure 2-2
2-7
Clock Output
Frequency
Select
0.85/3.39 MHz
9
10
11
FSK
Switch
Crystal
6.78/13.56 MHz
12
FSK
Ground
XTAL
Osc
Clock
Output
8
:2/8
:4/16
PFD
7
FSK
Data
Input
OR
1
Power
Down
Control
Crystal
Select
6.78/13.56 MHz
16
:128/64
6
ASK
Data
Input
Loop
Filter
4
LF
VCO
15
:1/2
On
Ground
5
Power
AMP
Low Voltage
Sensor 2.2V
2
Low Power
Detect Output
Frequency
Select
434/868 MHz
Power
Supply
3
Positive
Supply
VS
Power
Amplifier
Output
Power
Amplifier
Ground
14
13
TDA7110
Functional Description
2.3 Functional Block diagram
Block_diagram.wmf
Functional Block diagram
Data Sheet, December 2008
TDA7110
Functional Description
2.4 Functional Blocks
2.4.1 PLL Synthesizer
The Phase Locked Loop synthesizer consists of a Voltage Controlled Oscillator
(VCO), an asynchronous divider chain, a phase detector, a charge pump and a
loop filter. It is fully implemented on chip. The tuning circuit of the VCO consisting of spiral inductors and varactor diodes is on chip, too. Therefore no additional external components are necessary. The nominal center frequency of the
VCO is 869 MHz. The oscillator signal is fed both, to the synthesizer divider
chain and to the power amplifier. The overall division ratio of the asynchronous
divider chain is 128 in case of a 6.78 MHz crystal or 64 in case of a 13.56 MHz
crystal and can be selected via CSEL (pin 16). The phase detector is a Type IV
PD with charge pump. The passive loop filter is realized on chip.
2.4.2 Crystal Oscillator
The crystal oscillator operates either at 6.78 MHz or at 13.56 MHz.
The reference frequency can be chosen by the signal at CSEL (pin 16).
Table 2-3
CSEL (pin 16)
Crystal Frequency
Low1)
6.78 MHz
13.56 MHz
Open2)
1) Low:
2) Open:
Voltage at pin < 0.2 V
Pin open
For both quartz frequency options, 847.5 kHz or 3.39 MHz are available as output frequencies of the clock output CLKOUT (pin 8) to drive the clock input of a
micro controller.
The frequency at CLKOUT (pin 8) is controlled by the signal at CLKDIV (pin 9)
Table 2-4
CLKDIV (pin 9)
CLKOUT Frequency
Low1)
3.39 MHz
847.5 kHz
Open2)
1) Low:
2) Open:
Wireless Components
Voltage at pin < 0.2 V
Pin open
2-8
Data Sheet, December 2008
TDA7110
Functional Description
To achieve FSK transmission, the oscillator frequency can be detuned by a
fixed amount by switching an external capacitor via FSKOUT (pin 11).
The condition of the switch is controlled by the signal at FSKDTA (pin 7).
Table 2-5
FSKDTA (pin7)
FSK Switch
Low1)
CLOSED
OPEN
Open2), High3)
1) Low:
2) Open:
3) High:
Voltage at pin < 0.5 V
Pin open
Voltage at pin > 1.5 V
2.4.3 Power Amplifier
In case of operation in the 868-870 MHz band, the power amplifier is fed directly
from the voltage controlled oscillator. In case of operation in the 433-435 MHz
band, the VCO frequency is divided by 2. This is controlled by FSEL (pin 15) as
described in the table below.
Table 2-6
FSEL (pin 15)
Radiated Frequency Band
Low1)
433 MHz
868 MHz
Open2)
1) Low:
2) Open:
Voltage at pin < 0.5 V
Pin open
The Power Amplifier can be switched on and off
by the signal at ASKDTA (pin 6).
Table 2-7
ASKDTA (pin 6)
Power Amplifier
Low1)
OFF
ON
Open2), High3)
1) Low:
2) Open:
3) High:
Voltage at pin < 0.5 V
Pin open
Voltage at pin > 1.5 V
The Power Amplifier has an Open Collector output at PAOUT (pin 14) and
requires an external pull-up coil to provide bias. The coil is part of the tuning and
matching LC circuitry to get best performance with the external loop antenna.
To achieve the best power amplifier efficiency, the high frequency voltage swing
at PAOUT (pin 14) should be twice the supply voltage.
The power amplifier has its own ground pin PAGND (pin 13) in order to reduce
the amount of coupling to the other circuits.
Wireless Components
2-9
Data Sheet, December 2008
TDA7110
Functional Description
2.4.4 Low Power Detect
The supply voltage is sensed by a low power detector. When the supply voltage
drops below 2.15 V, the output LPD (pin 2) switches to the low-state. To minimize the external component count, an internal pull-up current of 40 µA gives
the output a high-state at supply voltages above 2.15 V.
The output LPD (pin 2) can either be connected to ASKDTA (pin 6) to switch off
the PA as soon as the supply voltage drops below 2.15 V or it can be used to
inform a micro-controller to stop the transmission after the current data packet.
2.4.5 Power Modes
The IC provides three power modes, the POWER DOWN MODE, the PLL
ENABLE MODE and the TRANSMIT MODE.
2.4.5.1 Power Down Mode
In the POWER DOWN MODE the complete chip is switched off.
The current consumption is typically 0.25 nA at 3 V 25°C.
This current doubles every 8°C. The value at +85°C is typically 14 nA.
2.4.5.2 PLL Enable Mode
In the PLL ENABLE MODE the PLL is switched on but the power amplifier is
turned off to avoid undesired power radiation during the time the PLL needs to
settle. The turn on time of the PLL is determined mainly by the turn on time of
the crystal oscillator and is less than 1 msec when the specified crystal is used.
The current consumption is typically 4 mA.
2.4.5.3 Transmit Mode
In the TRANSMIT MODE the PLL is switched on and the power amplifier is
turned on too.
The current consumption of the IC is typically 13 mA when using a proper transforming network at PAOUT, see Figure 3-1.
2.4.5.4 Power mode control
The bias circuitry is powered up via a voltage V > 1.5 V at the pin PDWN (pin 1).
When the bias circuitry is powered up, the pins ASKDTA and FSKDTA are
pulled up internally.
Forcing the voltage at the pins low overrides the internally set state.
Alternatively, if the voltage at ASKDTA or FSKDTA is forced high externally, the
PDWN pin is pulled up internally via a current source. In this case, it is not necessary to connect the PDWN pin, it is recommended to leave it open.
Wireless Components
2 - 10
Data Sheet, December 2008
TDA7110
Functional Description
The principle schematic of the power mode control circuitry is shown in
Figure 2-5.
PDWN
ASKDTA
OR
FSKDTA
On
Bias
Source
Bias Voltage
120 kΩ
120 kΩ
FSKOUT
FSK
On
PLL
868
MHz
PA
PAOUT
IC
Power_Mode.wmf
Figure 2-5
Power mode control circuitry
Table 3-8 provides a listing of how to get into the different power modes
Table 2-8
PDWN
FSKDTA
ASKDTA
Low1)
Low, Open
Low, Open
Open2)
Low
Low
High3)
Low, Open, High
Low
Open
High
Low
High
Low, Open, High
Open, High
Open
High
Open, High
Open
Low, Open, High
High
1) Low:
2) Open:
3) High:
MODE
POWER DOWN
PLL ENABLE
TRANSMIT
Voltage at pin < 0.7 V (PDWN)
Voltage at pin < 0.5 V (FSKDTA, ASKDTA)
Pin open
Voltage at pin > 1.5 V
Other combinations of the control pins PDWN, FSKDTA and ASKDTA are not
recommended.
Wireless Components
2 - 11
Data Sheet, December 2008
TDA7110
Functional Description
2.4.6 Recommended timing diagrams for ASK- and FSK-Modulation
ASK Modulation using FSKDTA and ASKDTA, PDWN not connected
Modes:
Power Down
PLL Enable
Transmit
High
FSKDTA
Low
to
t
DATA
Open, High
ASKDTA
Low
to
t
min. 1 msec.
ASK_mod.wmf
Figure 2-6
ASK Modulation
FSK Modulation using FSKDTA and ASKDTA, PDWN not connected
Modes:
Power Down
PLL Enable
Transmit
DATA
High
FSKDTA
Low
to
t
to
t
High
ASKDTA
Low
min. 1 msec.
FSK_mod.wmf
Figure 2-7
Wireless Components
FSK Modulation
2 - 12
Data Sheet, December 2008
TDA7110
Functional Description
Alternative ASK Modulation, FSKDTA not connected.
Modes:
Power Down
PLL Enable
Transmit
High
PDWN
Low
to
t
DATA
Open, High
ASKDTA
Low
to
t
min. 1 msec.
Alt_ASK_mod.wmf
Figure 2-8
Alternative ASK Modulation
Alternative FSK Modulation
Modes:
Power Down
PLL Enable
Transmit
High
PDWN
Low
to
t
to
t
Open, High
ASKDTA
Low
DATA
Open, High
FSKDTA
Low
to
t
min. 1 msec.
Alt_FSK_mod.wmf
Figure 2-9
Wireless Components
Alternative FSK Modulation
2 - 13
Data Sheet, December 2008
TDA7110
Functional Description
Wireless Components
2 - 14
Data Sheet, December 2008
3
Applications
Contents of this Chapter
3.1
3.2
3.3
3.4
3.5
3.6
50 Ohm-Output Testboard: Schematic . . . . . . . . . . . . . . . . . . . . . . . . 3-2
50 Ohm-Output Testboard: Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
50 Ohm-Output Testboard: Bill of material . . . . . . . . . . . . . . . . . . . . . 3-4
Application Hints on the Crystal Oscillator . . . . . . . . . . . . . . . . . . . . . 3-5
Design hints on the buffered clock output (CLKOUT). . . . . . . . . . . . . 3-7
Application Hints on the Power-Amplifier . . . . . . . . . . . . . . . . . . . . . . 3-8
TDA7110
Applications
3.1 50 Ohm-Output Testboard: Schematic
X2SMA
C8
C2
C4
L2
L1
VCC
C7
433 (868)
MHz
C3
C6
10
9
8
11
7
12
13
14
15
6.78 (13.56)
MHz
16
Q1
0.85 (3.4)
MHz
6
5
4
3
2
VCC
1
TDA7110
C1
T1
R3A
VCC
R3F
R4
R2
ASK
R1
FSK
C5
X1SMA
50ohm_test_v5.wmf
Figure 3-1
Wireless Components
50Ω-output testboard schematic
3-2
Data Sheet, December 2008
TDA7110
Applications
3.2 50 Ohm-Output Testboard: Layout
pcboben.pdf
Figure 3-2
Top Side of TDA7110-Testboard with 50 Ω-Output
pcbunten.pdf
Figure 3-3
Wireless Components
Bottom Side of TDA7110-Testboard with 50 Ω-Output
3-3
Data Sheet, December 2008
TDA7110
Applications
3.3 50 Ohm-Output Testboard: Bill of material
Table 3-1 Bill of material
Part
R1
Value
434 MHz
869 MHz
ASK
FSK
4.7k
Specification
0805, ± 5%
12k
R2
R3A
15k
R3F
0805, ± 5%
0805, ± 5%
15k
0805, ± 5%
R4
open
0805, ± 5%
C1
47nF
0805, X7R, ± 10%
C2
27pF
27pF
0805, COG, ± 5%
C3
6.8pF
2.7pF
0805, COG, ± 0.1 pF
C4
330pF
100pF
0805, COG, ± 5%
C5
1nF
0805, X7R, ± 10%
C6
6.8pF
C7
0Ω
Jumper
434MHz: 10pF
868MHz: 8.2pF
434MHz: 6.8pF
868MHz: 15pF
0805, COG, ± 0.1 pF
6.8pF: 0805, COG, ± 0.1pF
15pF: 0805, COG, ± 1%
0805, 0Ω Jumper
C8
12pF
5.6pF
5.6pF: 0805, COG, ± 0.1pF
12pF: 0805, COG, ± 1%
L1
68nH
68nH
TOKO LL2012-J
L2
27nH
10nH
27nH: TOKO LL1608-J
10nH: TOKO PTL2012-J
Q1
13.56875 MHz,
CL=20pF
IC1
TDA7110
T1
Push-button
replaced by a short
X1
SMA-S
SMA standing
X2
SMA-S
SMA standing
Wireless Components
Tokyo Denpa TSS-3B
13568.75 kHz
Spec.No. 10-50205
3-4
Data Sheet, December 2008
TDA7110
Applications
3.4 Application Hints on the Crystal Oscillator
The crystal oscillator achieves a turn on time less than 1 msec when the
specified crystal is used. To achieve this, a NIC oscillator type is implemented
in the TDA7110. The input impedance of this oscillator is a negative resistance
in series to an inductance. Therefore the load capacitance of the crystal CL
(specified by the crystal supplier) is transformed to the capacitance Cv.
-R
L
f, CL Cv
TDA7110
Cv =
1
1
+ ω 2L
CL
(1)
CL:
crystal load capacitance for nominal frequency
ω:
angular frequency
L:
inductance of the crystal oscillator
Example for the ASK-Mode:
Referring to the application circuit, in ASK-Mode the capacitance C7 is replaced
by a short to ground. Assume a crystal frequency of 13.56 MHz and a crystal
load capacitance of CL = 12 pF. The inductance L at 13.5 MHz is about 4.6 μH.
Therefore C6 is calculated to 8.567 pF, but due to parasitic capacitors of the
board C6 usually has to be smaller (e.g. 6.8 pF in the ASK evalboard)
Cv =
Wireless Components
3-5
1
1
+ω 2L
CL
= C6
Data Sheet, December 2008
TDA7110
Applications
Example for the FSK-Mode:
FSK modulation is achieved by switching the load capacitance of the crystal as
shown below.
FSKDTA
FSKOUT
Csw
-R
L
Cv2
f, CL Cv1
COSC
IC
The frequency deviation of the crystal oscillator is multiplied with the divider
factor N of the Phase Locked Loop to the output of the power amplifier. In case
of small frequency deviations (up to +/- 1000 ppm), the two desired load
capacitances can be calculated with the formula below.
CL ± =
C L:
C 0:
f:
ω:
N:
df:
Δf
2(C 0 + CL )
)
(1 +
N * f1
C1
2(C 0 + CL )
Δf
)
1±
(1 +
N * f1
C1
CL m C 0
crystal load capacitance for nominal frequency
shunt capacitance of the crystal
frequency
ω = 2πf: angular frequency
division ratio of the PLL
peak frequency deviation
Because of the inductive part of the TDA7110, these values must be corrected
by Formula 1). The value of Cv± can be calculated.
Cv± =
Wireless Components
3-6
1
1
+ ω 2L
CL ±
Data Sheet, December 2008
TDA7110
Applications
If the FSK switch is closed, Cv_ is equal to Cv1 (C6 in the application diagram).
If the FSK switch is open, Cv2 (C7 in the application diagram) can be calculated.
Cv 2 = C 7 =
Csw ∗ Cv1 − (Cv + ) ∗ (Cv1 + Csw)
(Cv + ) − Cv1
Csw:
parallel capacitance of the FSK switch (3 pF incl. layout parasitics)
Remark:
These calculations are only approximations. The necessary values
depend on the layout also and must be adapted for the specific
application board.
The 434 MHz 50Ω-Output testboard shows an FSK-deviation of +/- 24 kHz, typically.
The 868 MHz 50Ω-Output testboard shows an FSK-deviation of +/- 27 kHz, typically.
3.5 Design hints on the buffered clock output (CLKOUT)
The CLKOUT pin is an open collector output. An external pull up resistor (RL)
should be connected between this pin and the positive supply voltage. The
value of RL is depending on the clock frequency and the load capacitance CLD
(PCB board plus input capacitance of the microcontroller). RL can be calculated
to:
RL =
1
fCLKOUT * 8 * CLD
Table 3-2
fCLKOUT=
847 kHz
CL[pF]
RL[kΩ]
CL[pF]
RL[kΩ]
5
27
5
6.8
10
12
10
3.3
20
6.8
20
1.8
Remark:
Wireless Components
fCLKOUT=
3.39 MHz
To achieve a low current consumption and a low
spurious radiation, the largest possible RL should be chosen.
3-7
Data Sheet, December 2008
TDA7110
Applications
3.6 Application Hints on the Power-Amplifier
The power amplifier operates in a high efficient class C mode. This mode is
characterized by a pulsed operation of the power amplifier transistor at a current
flow angle of θ<<π. A frequency selective network at the amplifier output
passes the fundamental frequency component of the pulse spectrum of the
collector current to the load. The load and its resonance transformation to the
collector of the power amplifier can be generalized by the equivalent circuit of
Figure 3-4. The tank circuit L//C//RL in parallel to the output impedance of the
transistor should be in resonance at the operating frequency of the transmitter.
VS
L
C
RL
Equivalent_power.pdf
Figure 3-4
Equivalent power amplifier tank circuit
The optimum load at the collector of the power amplifier for “critical” operation
under idealized conditions at resonance is:
R LC =
VS 2
2 PO
A typical value of RLC for an RF output power of Po= 10 mW is:
R LC =
32
= 450Ω
2 ∗ 0.01
“Critical” operation is characterized by the RF peak voltage swing at the
collector of the PA transistor to just reach the supply voltage VS.
The high degree of efficiency under “critical” operating conditions can be
explained by the low power losses at the transistor. During the conducting
phase of the transistor, its collector voltage is very small. This way the power
loss of the transistor, equal to iC*uCE , is minimized. This is particularly true for
small current flow angles of θ<<π.
In practice the RF-saturation voltage of the PA transistor and other parasitics
reduce the “critical” RLC.
Wireless Components
3-8
Data Sheet, December 2008
TDA7110
Applications
The output power Po is reduced by operating in an “overcritical” mode
characterised by RL > RLC.
The power efficiency (and the bandwidth) increase when operating at a slightly
higher RL, as shown in Figure 3-5.
The collector efficiency E is defined as
E=
PO
VS I C
The diagram of Figure 3-5 was measured directly at the PA-output at VS = 3 V.
Losses in the matching circuitry decrease the output power by about 1.5 dB. As
can be seen from the diagram, 250 Ω is the optimum impedance for operation
at 3 V. For an approximation of ROPT and POUT at other supply voltages those
two formulas can be used:
ROPT ~ VS
and
POUT ~ ROPT
18
16
14
12
10
Pout [mW]
10*Ec
8
6
4
2
0
0
100
200
300
400
500
RL [Ohm]
Power_E_vs_RL.pdf
Figure 3-5
Output power Po (mW) and collector efficiency E vs. load resistor RL.
The DC collector current Ic of the power amplifier and the RF output power Po
vary with the load resistor RL. This is typical for overcritical operation of class C
amplifiers. The collector current will show a characteristic dip at the resonance
frequency for this type of “overcritical” operation. The depth of this dip will
increase with higher values of RL.
Wireless Components
3-9
Data Sheet, December 2008
TDA7110
Applications
As Figure 3-6 shows, detuning beyond the bandwidth of the matching circuit
results in an increase of the collector current of the power amplifier and in some
loss of output power. This diagram shows the data for the circuit of the test
board at the frequency of 434 MHz. The behaviour at 868 MHz is similar. The
effective load resistance of this circuit is RL = 250 Ω, which is the optimum
impedance for operation at 3 V. This will lead to a dip of the collector current of
approx. 10%.
16
TDA7110
14
434 MHz / 3V
12
10
8
Is [mA]
Pout [dBm]
6
4
2
0
375
400
425
450
475
500
f [MHz]
pout_vs_frequ.wmf
Figure 3-6
Output power and collector current vs. frequency
C3, L2-C2 and C8 are the main matching components which are used to
transform the 50 Ω load at the SMA-RF-connector to a higher impedance at the
PA-output (250 Ω @ 3 V). L1 can be used for some finetuning of the resonant
frequency but should not become too small in order to keep its losses low.
The transformed impedance of 250+j0 Ω at the PA-output-pin can be verified
with a network analyzer using the following measurement procedure:
1. Calibrate your network analyzer.
2. Connect some short, low-loss 50 Ω cable to your network analyzer with an
open end on one side. Semirigid cable works best.
3. Use the „Port Extension“ feature of your network analyzer to shift the reference plane of your network analyzer to the open end of the cable.
4. Connect the center-conductor of the cable to the solder pad of the pin „PA“
of the IC. The outer conductor has to be grounded. Very short connections
have to be used. Do not remove the IC or any part of the matching-components!
5. Screw a 50 Ω dummy-load on the RF-I/O-SMA-connector
6. Be sure that your network analyzer is AC-coupled and turn on the power
supply of the IC. The TDA7110 has to be in PLL-Enable-Mode.
7. Measure the S-parameter S11
Wireless Components
3 - 10
Data Sheet, December 2008
TDA7110
Applications
Plot0.pdf
Figure 3-7
Sparam_measured_200M
Above you can see the measurement of the evalboard with a span of 200 MHz.
The evalboard has been optimized for 3 V. The load is about 250+j0 Ω at
the transmit frequency.
A tuning-free realization requires a careful design of the components within the
matching network. A simple linear CAE-tool will help to see the influence of
tolerances of matching components.
Suppression of spurious harmonics may require some additional filtering within
the antenna matching circuit. The total spectrum of the 50 Ω-Output testboard
can be summarized as:
Table 3-3
Frequency
Output Power
434 MHz Testboard
Output Power
868 MHz Testboard
Fundamental
+10 dBm
+10 dBm
Fund − 13.56 MHz
−75 dBc
−61 dBc
Fund + 13.56 MHz
−69 dBc
−63 dBc
harmonic
−45 dBc
−54 dBc
3rd harmonic
−77 dBc
−56 dBc
2
Wireless Components
nd
3 - 11
Data Sheet, December 2008
4
Reference
Contents of this Chapter
4.1
4.2
4.3.1
4.3.2
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Operating Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
AC/DC Characteristics at 3V, 25°C . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
AC/DC Characteristics at 2.1 V ... 4.0 V, -40°C ... +85°C. . . . . . . . . . 4-6
TDA7110
Reference
4.1 Absolute Maximum Ratings
The AC / DC characteristic limits are not guaranteed. The maximum ratings
must not be exceeded under any circumstances, not even momentarily and
individually, as permanent damage to the IC may result.
Table 4-1
Symbol
Parameter
Limit Values
Unit
Min
Max
Junction Temperature
TJ
-40
150
°C
Storage Temperature
Ts
-40
125
°C
230
K/W
Remarks
Thermal Resistance
RthJA
Voltage at any pin
excluding pin 14
Vpins
-0.3
VS + 0.3
V
Voltage at pin 14
Vpin14
-0.3
2 * VS
V
Current into pin 11
Ipin11
-10
10
mA
ESD integrity, all pins
VESD
-1
+1
kV
JEDEC Standard
JESD22-A114-B
ESD integrity, all pins
excluding pin 11 and pin 14
VESD
-2.5
+2.5
kV
JEDEC Standard
JESD22-A114-B
No ESD-Diode to VS
Ambient Temperature under bias: TA = -40°C to +85°C
Note: All voltages referred to ground (pins) unless stated otherwise.
Pins 5, 12 and 13 are grounded.
4.2 Operating Range
Within the operating range the IC operates as described in the circuit description.
Table 4-2
Parameter
Symbol
Limit Values
Min
Max
Unit
Supply voltage
VS
2.1
4.0
V
Ambient temperature
TA
-40
85
°C
Wireless Components
4-2
Test Conditions
Data Sheet, December 2008
TDA7110
Reference
4.3 AC/DC Characteristics
4.3.1
AC/DC Characteristics at 3V, 25°C
Table 4-3 Supply Voltage VS = 3 V, Ambient temperature Tamb = 25°C
Parameter
Symbol
Limit Values
Min
Unit
Typ
Max
Test Conditions
Current consumption
Power-Down mode
IS PDWN
0.25
100
nA
V (Pins 1, 6 and 7)
< 0.2 V
PLL-Enable mode
IS PLL_EN
4
5
mA
Transmit mode
IS TRANSM
13.8
16.5
mA
Load tank see
Figure 3-1 and 3-2
Power Down Mode Control (Pin 1)
Stand-by mode
V PDWN
0
0.7
V
VASKDTA < 0.2 V
VFSKDTA < 0.2 V
PLL enable mode
V PDWN
1.5
VS
V
VASKDTA < 0.5 V
Transmit mode
V PDWN
1.5
VS
V
VASKDTA > 1.5 V
Input bias current PDWN
IPDWN
30
µA
VPDWN = VS
Low Power Detect Output (Pin 2)
Internal pull up current
I LPD1
30
µA
VS = 2.3 V ... VS
Input current low voltage
I LPD2
1
mA
VS = 1.9 V ... 2.1 V
V
fVCO = 867.84 MHz
Loop Filter (Pin 4)
VCO tuning voltage
VLF
Output frequency range
868 MHz-band
fOUT, 868
854
869
884
MHz
VFSEL = VS
fOUT = fVCO
Output frequency range
433 MHz-band
fOUT, 433
427
434.5
442
MHz
VFSEL = 0 V
fOUT = fVCO / 2
VS - 1.5
VS - 0.7
ASK Modulation Data Input (Pin 6)
ASK Transmit disabled
VASKDTA
0
0.5
V
ASK Transmit enabled
VASKDTA
1.5
VS
V
Input bias current ASKDTA
IASKDTA
30
µA
VASKDTA = VS
Input bias current ASKDTA
IASKDTA
µA
VASKDTA = 0 V
ASK data rate
fASKDTA
Wireless Components
-20
20
4-3
kHz
Data Sheet, December 2008
TDA7110
Reference
Table 4-3 Supply Voltage VS = 3 V, Ambient temperature Tamb = 25°C
Parameter
Symbol
Limit Values
Min
Typ
Unit
Test Conditions
Max
FSK Modulation Data Input (Pin 7)
FSK Switch on
VFSKDTA
0
0.5
V
FSK Switch off
VFSKDTA
1.5
VS
V
Input bias current FSKDTA
IFSKDTA
30
µA
VFSKDTA = VS
Input bias current FSKDTA
IFSKDTA
µA
VFSKDTA = 0 V
FSK data rate
fFSKDTA
20
kHz
Output current (High)
ICLKOUT
5
µA
VCLKOUT = VS
Saturation Voltage (Low)1)
VSATL
0.56
V
ICLKOUT = 1 mA
0.2
V
-20
Clock Driver Output (Pin 8)
Clock Divider Control (Pin 9)
Setting Clock Driver output
frequency fCLKOUT=3.39 MHz
VCLKDIV
Setting Clock Driver output
frequency fCLKOUT=847.5kHz
VCLKDIV
Input bias current CLKDIV
ICLKDIV
Input bias current CLKDIV
ICLKDIV
0
30
-20
V
pin open
µA
VCLKDIV = VS
µA
VCLKDIV = 0 V
Crystal Oscillator Input (Pin 10)
Load capacitance
CCOSCmax
Serial Resistance of the crystal
Input inductance of the
COSC pin
3.25
4.25
Serial Resistance of the crystal
Input inductance of the
COSC pin
3.6
4.6
5
pF
100
Ω
f = 6.78 MHz
5.25
µH
f = 6.78 MHz
100
Ω
f = 13.56 MHz
5.6
µH
f = 13.56 MHz
FSK Switch Output (Pin 11)
On resistance
RFSKOUT
250
Ω
VFSKDTA = 0 V
On capacitance
CFSKOUT
6
pF
VFSKDTA = 0 V
Off resistance
RFSKOUT
kΩ
VFSKDTA = VS
Off capacitance
CFSKOUT
pF
VFSKDTA = VS
Wireless Components
10
1.5
4-4
Data Sheet, December 2008
TDA7110
Reference
Table 4-3 Supply Voltage VS = 3 V, Ambient temperature Tamb = 25°C
Parameter
Symbol
Limit Values
Unit
Test Conditions
Min
Typ
Max
POUT433
8
10
12
dBm
fOUT = 433 MHz
VFSEL = 0 V
POUT868
8
10
12
dBm
fOUT = 868 MHz
VFSEL = VS
0.5
V
Power Amplifier Output (Pin 14)
Output Power2)
transformed to 50 Ohm
Frequency Range Selection (Pin 15)
Transmit frequency 433 MHz
VFSEL
Transmit frequency 868 MHz
VFSEL
Input bias current FSEL
IFSEL
Input bias current FSEL
IFSEL
0
25
-20
V
pin open
µA
VFSEL = VS
µA
VFSEL = 0 V
Crystal Frequency Selection (Pin 16)
Crystal frequency 6.78 MHz
VCSEL
Crystal frequency 13.56 MHz
VCSEL
Input bias current CSEL
ICSEL
Input bias current CSEL
ICSEL
1)
2)
0
0.2
50
-20
V
V
pin open
µA
VCSEL = VS
µA
VCSEL = 0 V
Derating linearly to a saturation voltage of max. 140 mV at ICLKOUT = 0 mA
Power amplifier in overcritical C-operation
Matching circuitry as used in the 50 Ohm-Output Testboard at the specified frequency.
Tolerances of the passive elements not taken into account.
Wireless Components
4-5
Data Sheet, December 2008
TDA7110
Reference
4.3.2
AC/DC Characteristics at 2.1 V ... 4.0 V, -40°C ... +85°C
Table 4-4 Supply Voltage VS = 2.1 V ... 4.0 V, Ambient temperature Tamb = -40°C ... +85°C
Parameter
Symbol
Limit Values
Min
Typ
Unit
Test Conditions
Max
Current consumption
Power-Down mode
IS PDWN
4
µA
PLL-Enable mode
IS PLL_EN
4
5.5
mA
Transmit mode
Load tank see
Figure 3-1 and 3-2
IS TRANSM
10.8
14.5
mA
VS = 2.1 V
IS TRANSM
13.8
17
mA
VS = 3.0 V
IS TRANSM
15.7
19
mA
VS = 4.0 V
2.8
V (Pins 1, 6 and 7)
< 0.2 V
Power Down Mode Control (Pin 1)
Stand-by mode
V PDWN
0
0.5
V
VASKDTA < 0.2 V
VFSKDTA < 0.2 V
PLL enable mode
V PDWN
1.5
VS
V
VASKDTA < 0.5 V
Transmit mode
V PDWN
1.5
VS
V
VASKDTA > 1.5 V
Input bias current PDWN
IPDWN
38
µA
VPDWN = VS
Low Power Detect Output (Pin 2)
Internal pull up current
I LPD1
30
µA
VS = 2.3 V ... VS
Input current low voltage
I LPD2
0.5
mA
VS = 1.9 V ... 2.1 V
V
fVCO = 867.84 MHz
Loop Filter (Pin 4)
VCO tuning voltage
VLF
VS - 1.8
VS - 0.5
Output frequency range 1)
868 MHz-band
fOUT, 868
864
869
874
MHz
VFSEL = VS
fOUT = fVCO
Output frequency range
433 MHz-band
fOUT, 433
432
434.5
437
MHz
VFSEL = 0 V
fOUT = fVCO / 2
ASK Modulation Data Input (Pin 6)
ASK Transmit disabled
VASKDTA
0
0.5
V
ASK Transmit enabled
VASKDTA
1.5
VS
V
Input bias current ASKDTA
IASKDTA
33
µA
VASKDTA = VS
Input bias current ASKDTA
IASKDTA
µA
VASKDTA = 0 V
ASK data rate
fASKDTA
Wireless Components
-20
20
4-6
kHz
Data Sheet, December 2008
TDA7110
Reference
Table 4-4 Supply Voltage VS = 2.1 V ... 4.0 V, Ambient temperature Tamb = -40°C ... +85°C
Parameter
Symbol
Limit Values
Min
Typ
Unit
Test Conditions
Max
FSK Modulation Data Input (Pin 7)
FSK Switch on
VFSKDTA
0
0.5
V
FSK Switch off
VFSKDTA
1.5
VS
V
Input bias current FSKDTA
IFSKDTA
35
µA
VFSKDTA = VS
Input bias current FSKDTA
IFSKDTA
µA
VFSKDTA = 0 V
FSK data rate
fFSKDTA
20
kHz
Output current (High)
ICLKOUT
5
µA
VCLKOUT = VS
Saturation Voltage (Low)2)
VSATL
0.5
V
ICLKOUT = 0.6 mA
0.2
V
-20
Clock Driver Output (Pin 8)
Clock Divider Control (Pin 9)
Setting Clock Driver output
frequency fCLKOUT=3.39 MHz
VCLKDIV
Setting Clock Driver output
frequency fCLKOUT=847.5kHz
VCLKDIV
Input bias current CLKDIV
ICLKDIV
Input bias current CLKDIV
ICLKDIV
0
30
-20
V
pin open
µA
VCLKDIV = VS
µA
VCLKDIV = 0 V
Crystal Oscillator Input (Pin 10)
Load capacitance
CCOSCmax
Serial Resistance of the crystal
Input inductance of the
COSC pin
2.9
4.25
Serial Resistance of the crystal
Input inductance of the
COSC pin
3.2
4.6
5
pF
100
Ω
f = 6.78 MHz
6
µH
f = 6.78 MHz
100
Ω
f = 13.56 MHz
6.3
µH
f = 13.56 MHz
FSK Switch Output (Pin 11)
On resistance
RFSKOUT
280
Ω
VFSKDTA = 0 V
On capacitance
CFSKOUT
6
pF
VFSKDTA = 0 V
Off resistance
RFSKOUT
kΩ
VFSKDTA = VS
Off capacitance
CFSKOUT
pF
VFSKDTA = VS
Wireless Components
10
1.5
4-7
Data Sheet, December 2008
TDA7110
Reference
Table 4-4 Supply Voltage VS = 2.1 V ... 4.0 V, Ambient temperature Tamb = -40°C ... +85°C
Parameter
Symbol
Limit Values
Min
Typ
Max
Unit
Test Conditions
Power Amplifier Output (Pin 14)
Output Power3) at 433 MHz
transformed to 50 Ohm.
POUT, 433
5
6.5
8.5
dBm
VS = 2.1 V
POUT, 433
7
10
12
dBm
VS = 3.0 V
VFSEL = 0 V
POUT, 433
7.5
11.5
13.5
dBm
VS = 4.0 V
Output Power4) at 868 MHz
transformed to 50 Ohm.
POUT, 868
5.8
7.5
8.5
dBm
VS = 2.1 V
POUT, 868
7.1
10.2
12.2
dBm
VS = 3.0 V
VFSEL = VS
POUT, 868
7.5
11
12.5
dBm
VS = 4.0 V
0.5
V
Frequency Range Selection (Pin 15)
Transmit frequency 433 MHz
VFSEL
Transmit frequency 868 MHz
VFSEL
Input bias current FSEL
IFSEL
Input bias current FSEL
IFSEL
0
35
-20
V
pin open
µA
VFSEL = VS
µA
VFSEL = 0 V
Crystal Frequency Selection (Pin 16)
Crystal frequency 6.78 MHz
VCSEL
Crystal frequency 13.56 MHz
VCSEL
Input bias current CSEL
ICSEL
Input bias current CSEL
ICSEL
0
0.2
55
-25
V
V
pin open
µA
VCSEL = VS
µA
VCSEL = 0 V
1) The output-frequency range can be increased by limiting the temperature and supply voltage
range.
Minimum fVCO − 1 MHz => Minimum Tamb + 5°C
Maximum fVCO + 1 MHz => Maximum Tamb − 5°C
Maximum fVCO + 1 MHz => Minimum VS + 25 mV, max. + 40 MHz.
2) Derating linearly to a saturation voltage of max. 140 mV at ICLKOUT = 0 mA
3) Matching circuitry as used in the 50 Ohm-Output Testboard for 434 MHz operation.
Tolerances of the passive elements not taken into account.
Range @ 2.1 V, +25°C: 6.5 dBm +/- 1 dBm
Range @ 3.0 V, +25°C: 10 dBm +/- 2.0 dBm
Range @ 4.0 V, +25°C: 11.5 dBm +/- 2.5 dBm
4) Matching circuitry as used in the 50 Ohm-Output Testboard for 868 MHz operation.
Tolerances of the passive elements not taken into account.
Range @ 2.1 V, +25°C: 7.5 dBm +/- 1.0 dBm
Range @ 3.0 V, +25°C: 10.2 dBm +/- 2.0 dBm
Range @ 4.0 V, +25°C: 11 dBm +/- 2.5 dBm
A smaller load impedance reduces the supply-voltage dependency.
A higher load impedance reduces the temperature dependency.
Wireless Components
4-8
Data Sheet, December 2008