MC44824/25
Figure 1. HF Sensitivity Test Circuit
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ Bus Controller
I2C Bus
VCC
5.0 V VCC
SDA, SCL
MC44824/25
1.0 nF
HF
HF Gnd
B7 B2
HF Generator
HF Out Gnd
50 Ω Cable
1.0 nF
470 470
50 Ω
Frequency
Counter
In
VCC
Device is in test mode. B2 and B7 are “On”.
Sensitivity is level of HF generator on 50 Ω load.
Figure 2. Typical HF Input Impedance
–j +j
0
0.5
0.5
1.3 GHz
ZO = 50 Ω
1
1
1.0 GHz
2
2
500 MHz
50 MHz
0.5
1
2
Data Format and Bus Receiver
The circuit receives the information for tuning and control
via the I2C bus. The incoming information, consisting of a
chip address byte followed by two or four data bytes, is
treated in the I2C bus receiver. The definition of the
permissible bus protocol is shown below:
1_STA CA CO BA
2_STA CA FM FL
3_STA CA CO BA
STO
STO
FM FL
STO
4_STA CA FM FL CO BA STO
STA = Start Condition
STO = Stop Condition
CA = Chip Address Byte
CO = Data Byte for Control Information
BA = Band Information
FM = Data Byte for Frequency Information (MSB’s)
FL = Data Byte for Frequency Information (LSB’s)
4
MOTOROLA ANALOG IC DEVICE DATA