UM3750=UM86409=MM53200=, ►Elektronika, ►Aplikacje

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UN13750
Programmable
Encoder/Decoder
Single chip contains both Encoder and Decoder.
3V to 11 V operation.
On chip oscillator uses non-critical RC components.
Cross interference of recetver is virtually eliminated
by circuitry which requires 4 valid words to be received,
each within 64ms of the other.
Schmitt Trigger input provides excellent noise immunity.
Applications. alarm control system, security system
cordless telephone, remote control.
Interfaces with RF, ultrasonic, or infrared modulators
I
and demodulators
General Description
The UM3750 Encoder/Decoder
is a CMOS/LSI digital
code Transmitter-Receiver system. Working in the trans-
mit (encoder) mode, the UM3750 will sequentially encode
and transmit 12 bits of input. Each of the 12 bits may
be 1 or 0 to allow 4096 different codes.
comparison on the next word. If all 12 bits are received
correctly, a “valid” signal is generated. This signal clears a
64ms counter and triggers a 3-stage counter. The 3-stage
counter counts the “valid” pluses and when 4 pulses have
been detected, the TX/RX output pin goes low. After the
TX/RX output pin goes low, the next “valid” must be
received within 128ms, giving a one valid in 6 requirement
to keep the TX/RX output pin.
In the
receive (decoder)
mode, the incoming signal is
compared to the local code In a sequential manner Once
an error
IS
detected the system will reset and beain its
Pin Configurations
“cc
TX/RX OUTPUT
“cc
TX/RX
OUTPUT
RECEIVER INPUT
RECEIVER INPUT
MODE SELECT
MODE SELECT
“SS
“ss
R.C INPUT
A12
R.C. INPUT
A12
All
All
A10
A10
NC
2-3
urn3750
Block Diagram
R.C.INPUT - - - - - - -
RID
COMPARATOR
WD
TIM0
64ms/128ms
TIMER
7
i
ERROR
STATE
VLD
CONTROLLER
CLR
I
INIT
VALID 4
COUNTER
MXCLKR
MXD
Al-Al2
T/R OUT
Block
Diagram Description
CPCLK CLK of Comparator
WXCLKR: CLK of Multiplexer when in Receiver mode
WXCLKT
CLK of Multiplexer when in Transmitter mode
MXD:
Output data of Multiplexer (one of Al, A2 ....
A12)
CLR:
Clear signal of Comparator
ERROR: Error signal from Comparator
TIMO : TIMER time-out signal (64ms or 128ms)
T/R OUT: Transmit/Receiver output pin
INIT:
Reset signal of Valid 4 Counter
RID
Sampled data by Sampling CKT
WD:
Word detected signal
VLD.
“Valid” signal. It is used to trigger Valid 4
Counter and reset 64ms/128ms Timer
TXO:
Transmitter output
PXO:
Receiver output
2-4
CPCLK
UM3750
Absolute Maximum Ratings*
Power Supply Voltage
-0
3v to 11v
*Comments
Stresses
above those ilsted Iunder “Absolute Maximum
Ratings” may cause permanent damage to the dewce.
These are stress ratings only. Functional operation of
this device at these or any other conditions above those
indtcated in the operational sections of this specification
IS not implled and exposure to absolute maximuln rating
conditions for extended pertods may affect device rell-
ability.
Operating Temperature
-20 Deg to 70 Deg C
Storage Temperature (Tstg)
--55 Deg to 150 Deg C
Applied Voltage on any Pin
vss
PO.3 < v,, < v,, +o 3
D.C. Electrical Characteristics
(T, = 25°C. vDD =
9V ilnless otherwise specified)
Input Level
Input Resistor
to Vcc
_
200K
_
1.2M
R
kl5% exclusive
Oscillator Frequency
F
_
100
_
KHz
of external
components
Pin Designation
Pin No.
Designation
Description
l-12
Al - Al2
These data select lines are used to set the addresses of the encoder/decoder
pair They have on-chip pull-up resistors.
13
R.C. INPUT
R.C. input pin for sinqle pin oscillator. A reslstor IS hooked from this
pin to Vcc and a capacttor from this pin to GND The frequency =
2lRC.
14
Vss
The ground pin of the UM3750.
15
MODE SELECT
This pin changes the IC from Receive mode TO Transmit mode, By
grounding this pin the IC IS put Into the Receive mode. By connecting
to VC- the IC IS put into the Transmit mode
16
RECEIVER
INPUT
The receiver input receives the digital PCM waveform from the detect
CIrClllt.
17
TXIRX
OUTPUT
In the transmit mode, this output pin produces the PCM waveform for
transmlttlnq. In the receive mode, this output pin provides the come
partson result and detects low If comparison is ok.
18
Vcc
The positive power
supply
pin of the UM3750.
2-5
B t E
z
F
_____
tiz = =-~
-_ _ _-
UM3750
Connection Diagram for Transmitter/Receiver
Output Waveform (based on 100 KHz)
Typical
2-6
Decoder Flowchart
Stand by Mode
Reset Count
Yes
No
No
+
Data In?
NO
Count - Count +1
R eset 64m s,
128ms, Timer
is
64ms Timer
Overflow
?
Yes
_!:_I-
No
Activates the
TX//RX Output
No
Yes
V
TX,‘RX Output
Ordering Information
I
Part No.
Package
1
2-7
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