U4285BM Datasheet, PDF (2/10 Pages) TEMIC Semiconductors – AM / FM - PLL

U4285BM
Pin Description
V_DD
1
SCL
2
20 ^GND1
19 OSCOUT
SDA
3
18 OSCIN
AS
4
17 C
SWO 1
SWO 2
5
16 VA
U4285BM
6
15 PDAMO
SWO3 7
14 PDAM
SWO4 8
13 PDFM
FMOSC 9
12 PDFMO
GND 2 10
11 AMOSC
95 10121
Pin Symbol
Function
1
V_DD Supply voltage
2
SCL I²C bus clock
3
SDA I²C bus data
4
AS Address selection
5 SWO 1 Switching output 1
6 SWO 2 Switching output 2
7
SWO3 Switching output 3
8
SWO4 Switching output 4
9 FMOSC FM oscillator input
10 GND 2 Ground 2 (analog)
11 AMOSC AM oscillator input
12 PDFMO FM analogue output
13 PDFM FM current output
14 PDAM AM current output
15 PDAMO AM analogue output
16
VA Analogue supply voltage
17
C Capacitor
18 OSCIN Oscillator input
19 OSCOUT Oscillator output
20 GND1 Ground 1 (digital)
Functional Description
The U4285BM is controlled via the 2-wire I²C bus. For
programming there are one module address byte, two sub-
address bytes and five data bytes.
The module address contains a programmable address bit
A 1 which with address select input AS (Pin 4) makes it
possible to operate two U4285BM in one system. If bit
A 1 is identical with the status of the address select input
AS, the chip is selected .
The subaddress determines which one of the data bytes is
transmitted first. If subaddress of R-divider is trans-
mitted, the sequence of the next data bytes is DB 0
(Status), DB 1 and DB 2.
If subaddress of N-divider is transmitted, the sequence of
the next data bytes is DB 3 and DB 4. The bit organisation
of the module address, subaddress and 5 data bytes are
shown in figure 2.
Each transmission on the I²C bus begins with the
“START”- condition and has to be ended by the “STOP”-
condition (see figure 3).
The integrated circuit U4285BM has two separate inputs
for AM and FM oscillator. Pre-amplified AM and FM
signals are fed to the 16 bit N-divider via AM/FM switch.
AM/FM switch is controlled by software. Tuning steps
can be selected by 16 bit R-divider. Further there is a
digital memory phase detector. There are two separate
current sources for AM and FM amplifier (charge pump)
as given in electrical characterisitics. It allows indepen-
dent adjustment of gain, whereby providing high current
for high speed tuning and low current for stable tuning.
2 (10)
TELEFUNKEN Semiconductors
Rev. A3, 14-May-97