MC33411B Motorola, MC33411B Datasheet - Page 33

• Manufacturer Part Number: MC33411B
• Description: (MC33411A/B) ANALOG CORDLESS PHONE BASEBAND
• Manufacturer: Motorola

expressed as T3, can be set to:
pole frequency will be separated from p . Selecting too small
of a K–factor, the equations may provide negative
capacitance or resistor values. Too large of a K–factor may
not provide the maximum attenuation.
and C2 can be solved from the equations. By using equations
(11) and (10), time constants T2 and T1 can be derived by
selecting a phase margin. Finally, R2 follows from T2 and C2.
was constructed with these results:
MOTOROLA RF/IF DEVICE DATA
p , we obtain:
A
T1
T2
C2
C1
C1
Similarly, it can be shown:
In which:
From T1 it can be derived that:
In analogy with (13), by forcing the loopgain to 1 (0 dB) at
Solving for C1:
By selecting
The K–factor shown determines how far the additional
By selecting R3 to be 100 k , C3 becomes known and C1
A test circuit with the following components and conditions
Loop Filter (See Figure 49):
openloop
(
+
+
+
+
T1
C1
R2C2
(
(
T1
T2
(
C1
C1 = 470 pF
R2 = 68 k
C2 = 3.9 nF
R3 = 270 k
C3 = 82 pF
T2
*
)
C2
T2
T1
(
–
T3
C2
)
)
K n 2
C2T3
p via (12), the additional time constant
C3
T3C3
)
*
T2
C3
*
T1
*
T3
(
*
C1 T2
)
C1
T2
(
C1C2
C3T2
(
(21)
+
T3
2 C1T2T3
T3
K p
*
C2
(
*
1
T3
)
+
T3
T1
T3
T1
*
)
K
*
T2C3
C3
K n p 2
K
pd
T1
pd
T1
)
K o
)
T3
T3
–
K o
*
+
2 C1C2C3R2R3
(
T3
2 T1T2T3
R3C3
T2
*
T1
MC33411A/B
1
1
T3
)
(26)
*
K
pd
T1
p
p T2
p T1
K o T1
2 K
(22)
Low Battery/ RSSI Voltage Measurement
5/17–12) measurement circuits have a 6–bit A/D converter
whose value may be read back via the SPI. The A/D’s sample
their voltages at a frequency equal to the internal SCF clock
frequency divided by 128. The Low Battery Measurement A/D
senses and divides by 2.5 the supply voltage (at Pin 23).
Please note that the minimum Low Battery Detect (LBD)
voltage is 2.7 V, since there is no guarantee that the device will
operate below this value. The RSSI Measurement senses the
voltage at Pin 37.
n
1
1
2
2
LO2 Tank:
Both the Low Battery (bits 5/23–18) and RSSI (bits
p
2 T1T2T3 T3
j T2
j T1
Ctotal = 39.3 pF
Lext = 150 nH, Q = 50 @ 250 MHz
Reference Frequency = 10.24 MHz (unadjusted)
R Counter = 205
LO2 Counter = 1266
AC Load = 25
Frequency of LO2 = 63.258 MHz
Phase Noise @ 50 kHz offset = –107 dBc
Sidebands @ 50 kHz & 100 kHz offsets = –69 dBc
1
1
p T2
p T1
2
2
(19)
(20)
(23)
(24)
(25)
33