mc13176d ETC-unknow, mc13176d Datasheet - Page 4
Manufacturer Part Number
13 & 14
Out 1 and
PIN FUNCTION DESCRIPTIONS
Crystal Oscillator Inputs
The internal reference oscillator is configured as a common
emitter Colpitts. It may be operated with either a fundamental
or overtone crystal depending on the carrier frequency and the
internal prescaler. Crystal oscillator circuits and specifications
of crystals are discussed in detail in the applications section.
Wi h V
With V CC = 3.0 Vdc, the voltage at Pin 8 is approximately 1.8
Vdc and at Pin 9 is approximately 2.3 Vdc. 500 to 1000 mVp–p
should be present at Pin 9. The Colpitts is biased at 200 A;
additional drive may be acquired by increasing the bias to
approximately 500 A. Use 6.2 k from Pin 8 to ground.
An additional ground pin is provided to enhance the stability of
the system. Decoupling to the V CC (RF ground) is essential; it
should be done at the ground return for Pin 10.
The potential at Pin 11 is approximately 1.25 Vdc. When Pin 11
is open, the transmitter is disabled in a power down mode and
draws less than 1.0 A I CC if the MOD at Pin 16 is also open
(i.e., it has no current driving it). To enable the transmitter a
current source of 10 A to 90 A is provided. Figures 3 and 4
show the relationship between I CC , V CC and I reg. enable . Note
that I CC is flat at approximately 10 mA for I reg . enable = 5.0 to
100 A (I mod = 0).
Supply Voltage (V CC )
The output is configured differentially to easily drive a loop
antenna. By using a transformer or balun, as shown in the
application schematic, the device may then drive an unbalanced
low impedance load. Figure 6 shows how much the Output
Power and Free–Running Oscillator Frequency change with
temperature at 3.0 Vdc; I mod = 2.0 mA.
This additional ground pin provides direct access for the output
ground to the circuit board V EE .
AM Modulation/Power Output Level
The DC voltage at this pin is 0.8 Vdc with the current source
active. An external resistor is chosen to provide a source
current of 1.0 to 3.0 mA, depending on the desired output power
level at a given V CC . Figure 28 shows the relationship of Power
The operating supply voltage range is from 1.8 Vdc to 5.0 Vdc.
In the PCB layout, the V CC trace must be kept as wide as
possible to minimize inductive reactances along the trace; it is
best to have it completely fill around the surface mount
components and traces on the circuit side of the PCB.
Output to Modulation Current, I mod . At V CC = 3.0 Vdc, 3.5 dBm
power output can be acquired with about 35 mA I CC .
For FM modulation, Pin 16 is used to set the desired output
power level as described above.
For AM modulation, the modulation signal must ride on a
positive DC bias offset which sets a static (modulation off)
modulation current. External circuitry for various schemes is
further discussed in the Applications Information section.
MOTOROLA RF/IF DEVICE DATA