LANSDALE ML13146-9P Low power dc â 1.8 ghz transmitter Datasheet

ML13146
Low Power DC – 1.8 GHz
Transmitter
LOW POWER INTEGRATED TRANSMITTER FOR ISM BAND APPLICATIONS
SEMICONDUCTOR TECHNICAL DATA
Legacy Device: Motorola MC13146
The ML13146 is an integrated RF transmitter targeted at ISM band
applications. It features a 50 Ω linear Mixer with linearity control, voltage
controlled oscillator, divide by 64/65 dual modulus Prescaler and Low
Power Amplifier (LPA). Together with the receiver chip (ML13145) and
either baseband chip (MC33410 or MC33411A/B), a complete 900 MHz
cordless phone system can be implemented. This device may be used in
applications up to 1.8 GHz.
• Low Distortion LPA: Pout_1dB Compression Point 10 dBm
• High Mixer Linearity: IIP3 = 10 dBm
• 50Ω Mixer Input Impedance
• Differential Open Collector Mixer Output
• Low Power 64/65 Dual Modulus Prescaler (ML12054 type)
• 2.7 to 6.5 V Operation, Low Current Drain (25 mA @ 2.0 GHz)
• Powerdown Mode: <60 µA
• Usable up to 1.8 GHz
• Operating Temperature Range TA = –20° to 70°C
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Note: Lansdale lead free (Pb) product, as it
becomes available, will be identified by a part
number prefix change from ML to MLE.
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Low Power Amplifier
Power Gain @ 950 mA (matching required)
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CIRCUIT DESCRIPTION
General
The ML13146 consists of a low power amplifier, a 50 Ω linear mixer with linearity control, divide by 64/65 dual modulus
prescaler and LPA. This device is designated for use as the low
power transmitter in analog and digital FM systems such as
UHF and 800 MHz Special Mobile Radio (SMR), UHF Family
Radio Services, PCS and 902 to 928MHz cordless telephones.
It features a mixer linearity control to preset or auto program
the mixer dynamic range, an enable function and a wideband
mixer output so the IC may be used either as an up converter
or for a direct conversion source. Additional details are covered
in the Pin by Pin Description which shows the equivalent internal circuit and external circuit requirements.
where Cv is the equivalent capacitance of the varactor at the
control voltage.
For higher frequency operation, a series tuned oscillator configuration is recommended. Table 1 contains the S–parameters
for the VCO transistor in a common collector configuration.
This information is useful for designing a VCO at other operating frequencies or for various other oscillator topologies.
The output power (at Mix/Buf Out) can be varied by adjusting the value of R5 as illustrated in Figures 3 and 4. Figure 5
shows the typical operating window for the prescaler.
Current Regulation/Enable
The device features temperature compensating, voltage independent current regulators which are controlled by the enable
function in which “high” powers up the IC.
Mixer: General
The mixer is a double–balanced four quadrant multiplier
biased class AB allowing for programmable linearity control
via an external current source. An input third order intercept
point of 20 dBm has been achieved. The mixer has a 50 Ω single–ended RF input and open collector differential outputs. An
onboard Local Oscillator transistor has the emitter, base and
collector pinned out to implement a low phase noise VCO in
various configurations. Additionally, a buffered prescaler output is provided for operation with a low frequency synthesizer.
For direct conversion applications the input of the mixer may
be terminated to ground through a 120 to 330 Ω resistor.
Local Oscillator/Voltage Control Oscillator
The on–chip transistor operates with coaxial transmission
line or LC resonant elements to over 1.8 GHz. Biasing is done
with a temperature/voltage compensated current source in the
emitter. A RFC from VCC to the base is recommended.The
transistor can be operated in the classic Colpitts, Clapp, or
Hartley configuration. The application circuit (Figure 8)
depicts a parallel resonant VCO which can cover the entire 902
to 928 MHz frequency band with phase noise of approximately
–80 dBc/Hz at a 10 kHz offset (see Figure 2). For this configuration, the LO will be driven with approximately 100 mVrms,
and the frequency of oscillation can be approximated by:
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The linear gain of the Mixer/Buf when used as a buffer is
approximately –5.0 to –8.0 dB.
Mixer/Buffer Outputs
The mixer outputs (Mixer/Buf Out + and Mixer/Buf Out –)
are balanced, open collector. A shunt resistor of 200 Ω minimum to VCC is recommended for stability.
The outputs can be used as a single–ended driver or connected in a balanced–to–unbalanced configuration. If the single–ended driver configuration is used, the unused output must
be tied directly to VCC. For the balanced–to–unbalanced configuration, an additional 3.0 to 6.0 dB of power gain can be
achieved. Conjugate matching is easily accomplished to the
desired load by the addition of a shunt and series element (see
Table 2, S22 parameters).
Mixer/Buffer Input
The Mixer/Buf In pin is a broadband, 50 Ω input used to
drive the IF port of the mixer (see Table 2, S11parameters).
The Mixer/Buf In pin can be used in one of three modes:
1. A IF signal can be applied to this pin and up–converted
to the desired RF frequency.
2. A resistor can be connected to ground, controlling the
RF output power.
3. A resistor can be connected to VCC, disabling the entire
mixer.
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Low Power Amplifier (LPA)
The LPA is internally biased at low supply current (approximately 2.0 mA emitter current) for optimal low power operation, yielding a 10 dBm 1.0 dB output power compression
point. Input and output matching may be achieved at various
frequencies using few external components (see Table 3
S–parameters). Typical power gain is 16 dB with the input/output conjugately matched to the source/load impedance. A minimum 200 Ω shunt resistor from the output to VCC is recommended for stability.
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Legacy Applications Information
Evaluation PCB
The evaluation PCB is a versatile board which allows the
ML13146 to be configured as a basic transmitter, or to characterize individual operating parameters.
The general purpose schematic and associated parts list for
the PCB is given in Figure 9. This parts list build–up is identi-
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cal to the Test Circuit illustrated in Figure 1, although parameters can very significantly due to differences in PCB parasitics.
Figures 10, 11, and 12 show the actual PCB component,
ground and solder sides, respectively.
Please refer to AN1687/D and AN1691/D for additional
details and applications for the device.
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Legacy Applications Information
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Legacy Applications Information
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Lansdale Semiconductor reserves the right to make changes without further notice to any products herein to improve reliability, function or design. Lansdale does not assume any liability arising out of the application or use of any product or circuit
described herein; neither does it convey any license under its patent rights nor the rights of others. “Typical” parameters which
may be provided in Lansdale data sheets and/or specifications can vary in different applications, and actual performance may
vary over time. All operating parameters, including “Typicals” must be validated for each customer application by the customer’s
technical experts. Lansdale Semiconductor is a registered trademark of Lansdale Semiconductor, Inc.
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