MC13146FTA Просмотр технического описания (PDF) - Motorola => Freescale

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MC13146FTA

Low Power Integrated Transmitter for ISM Band Applications

Motorola => Freescale 

Freescale SMeCm1i3c14o6nductor, Inc.

CIRCUIT DESCRIPTION

General

where Cv is the equivalent capacitance of the varactor at the

ARTChHe IMVCE1D31B46YcFonRsiEstEs SofCaAloLwEpSoEweMr IaCmOplNifiDer,UaC5T0OΩR, INCco. n2tr0o0l 5voltage.

linear mixer with linearity control, divide by 64/65 dual

For higher frequency operation, a series tuned oscillator

modulus prescaler and LPA. This device is designated for

configuration is recommended. Table 1 contains the

use as the low power transmitter in analog and digital FM

S–parameters for the VCO transistor in a common collector

systems such as UHF and 800 MHz Special Mobile Radio

(SMR), UHF Family Radio Services, PCS and 902 to 928

MHz cordless telephones. It features a mixer linearity control

to preset or auto program the mixer dynamic range, an

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

enable function and a wideband mixer output so the IC may

be used either as an upconverter or for a direct conversion

source. Additional details are covered in the Pin by Pin

adjusting the value of R5 as illustrated in Figures 3 and 4.

Figure 5 shows the typical operating window for the

prescaler.

Description which shows the equivalent internal circuit and

external circuit requirements.

Figure 2. Typical Tuning

Current Regulation/Enable

935

The device features temperature compensating, voltage

930

independent current regulators which are controlled by the

enable function in which ”high” powers up the IC.

925

920

Mixer: General

915

The mixer is a double–balanced four quadrant multiplier

biased class AB allowing for programmable linearity control

910

via an external current source. An input third order intercept

905

Performance

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

900

VCC = 3.6 V

895

TA = 25 °C

890

880

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

CONTROL VOLTAGE (V)

input of the mixer may be terminated to ground through a 120

to 330 Ω resistor.

Local Oscillator/Voltage Control Oscillator

–10

Figure 3. Mixer/Buffer Output

versus 1st LO Input

The on–chip transistor operates with coaxial transmission

line or LC resonant elements to over 1.8 GHz. Biasing is

–15

done with a temperature/voltage compensated current

source in the emitter. A RFC from VCC to the base is

recommended.

–20

R5 = 120 Ω

R5 = 180 Ω

R5 = 270 Ω

The transistor can be operated in the classic Colpitts,

Clapp, or Hartley configuration. The application circuit

–25

(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

–30

VCC = 3.6 Vdc

TA = 25°C

fLO = 915 MHz

Figure 2). For this configuration, the LO will be driven with

approximately 100 mVrms, and the frequency of oscillation

can be approximated by:

ǒ Ǹǒ Ǔǒ Ǔ Ǔ + Fosc

2p

1

) ) ) ) C1 C2 C3 Cv

C1 C2 C3 Cv

3.6 pF (L1

1.8 nH)

–35

–25

–20

–15

–10

–5.0

0

LO INPUT (dBm)

6

For More Information On This Product, MOTOROLA RF/IF DEVICE DATA

Go to: www.freescale.com

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