Control Transmitter. MC14497 Datasheet

MC14497 Transmitter. Datasheet pdf. Equivalent

MC14497 Datasheet
Recommendation MC14497 Datasheet
Part MC14497
Description PCM Remote Control Transmitter
Feature MC14497; MOTOROLA SEMICONDUCTOR TECHNICAL DATA Order this document by MC14497/D PCM Remote Control Transmit.
Manufacture Motorola
Datasheet
Download MC14497 Datasheet




Motorola MC14497
MOTOROLA
SEMICONDUCTOR TECHNICAL DATA
Order this document
by MC14497/D
PCM Remote Control
Transmitter
The MC14497 is a PCM remote control transmitter realized in CMOS
technology. Using a dual–single (FSK/AM) frequency bi–phase modulation, the
transmitter is designed to work with the MC3373 receiver. Information on the
MC3373 can be found in the Motorola Linear and Interface Integrated Circuits
book (DL128/D).
There is not a decoder device which is compatible with the MC14497.
Typically, the decoding resides in MCU software.
Both FSK/AM Modulation Selectable
62 Channels (Up to 62 Keys)
Reference Oscillator Controlled by Inexpensive Ceramic Resonator:
Maximum Frequency = 500 kHz
Very Low Duty Cycle
Very Low Standby Current: 50 µA Maximum
Infrared Transmission
Selectable Start–Bit Polarity (AM Only)
Shifted Key Mode Available
Wide Operating Voltage Range: 4 to 10 V
See Application Notes AN1016 and AN1203
BLOCK DIAGRAM
MC14497
P SUFFIX
PLASTIC DIP
CASE 707
18
1
ORDERING INFORMATION
MC14497P Plastic DIP
PIN ASSIGNMENT
E3 1
E2 2
E9 3
A4 4
A3 5
A2 6
A1 7
SIGNAL OUT 8
VSS 9
18 VDD
17 E1
16 E4
15 E5
14 E6
13 OSCout
12 OSCin
11 E8
10 E7
VDD 18
17
E1
2
E2
1
E3
16
KEYBOARD E4 15
E5
14
E6
10
E7
11
E8
A4 A3 A2 A1
3
E9
7
6
5
4
FK3
FK1
ENCODER
7–BIT
SR
OUTPUT
CONTROL
8
MUX
3–BIT
LATCH
SEQUENCE
CONTROL
STANDBY
SCANNER
DIVIDER
÷ 32
9
DIVIDER
÷ 10/12
DIVIDER
÷ 16
OSC
IN OUT
12 13
500 kHz CERAMIC
RESONATOR
SAME AS IN DL136/D R3
©MOMoTtoOroRla,OInLc.A1995
MC14497
1



Motorola MC14497
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁMAXIMUM RATINGS (Voltages referenced to VSS)
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁParameter
Symbol
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDC Supply Voltage
VDD
Value
– 0.5 to + 18
Unit
V
Input Voltage, All Inputs
Vin
– 0.5 to VDD + 0.5
V
DC Current Drain per Pin
I 10 mA
Operating Temperature Range
TA
– 40 to + 85
°C
Storage Temperature Range
Tstg
– 65 to + 150
°C
This device contains circuitry to protect the
inputs against damage due to high static
voltages or electric fields; however, it is ad-
vised that normal precautions be taken to avoid
application of any voltage higher than maxi-
mum rated voltages to this high–impedance
circuit. For proper operation it is recommended
that Vin and Vout be constrained to the range
VSS (Vin or Vout) VDD.
ELECTRICAL CHARACTERISTICS (TA = 0 to 70°C; all Voltages Referenced to VSS)
Characteristic
Symbol
Supply Voltage
Supply Current
Idle
Operation
VDD
IDD
Output Current — Signal
VOH = 3.0 V
VOL = 0.5 V
Source
Sink
IOH
IOL
Output Current — Scanner
VOH = 3.0 V
VOL = 0.5 V
Output Current — Oscillator
VOH = 3.0 V
VOL = 0.5 V
Input Current — Oscillator
Operation
Idle, VIL = 0.5 V
Input Current — Encoder
VIH = 9.0 V
VIL = 0.5 V
Input Voltage — Encoder
Source
Sink
Source
Sink
IOH
IOL
IOH
IOL
Iin
Iin
VIH
VIL
VIH
VIL
VDD Min Max
— 4.0 10.0
10 — 50
10 —
5
4
– 900
4 120 —
4 – 30 —
4 245 —
4
– 300
4 245 —
10 ± 2 ± 80
4 30 —
10 – 15 —
4 — – 60
10 9 —
10 — 1.2
4 3—
4 — 1.0
Unit
V
µA
mA
µA
µA
µA
µA
µA
V
MC14497
2
MOTOROLA



Motorola MC14497
CIRCUIT OPERATION
The transmitter sends a 6–bit, labelled A (LSB) to F (MSB),
binary code giving a total of 64 possible combinations or
code words. All of these channels are user selectable, ex-
cept the last two (where channel 63 is not sent while channel
62 is automatically sent by the transmitter at the end of each
transmission as an “End of Transmission” code).
In either mode, FSK or AM, the transmitted signal is in the
form of a bi–phase pulse code modulation (PCM) signal. The
AM coding is shown in Figure 1.
BIT–n
“0”
AM
“1”
f1
f1
Figure 1. AM Coding
In the AM mode, f1 is a train of pulses at the modulating
frequency of 31.25 kHz for a reference frequency of 500 kHz.
In the FSK mode, two modulating frequencies are used as
shown in Figure 2.
BIT–n
“0”
FSK
“1”
f2 f3
f3 f2
Figure 2. FSK Coding
In this mode, f3 is 50 kHz and f2 is 41.66 kHz for a refer-
ence frequency of 500 kHz.
The keyboard can be a simple switch matrix using no ex-
ternal diodes, connected to the four scanner inputs (A1 – A4)
and the eight row input (E1 – E8). Under these conditions,
only the first 32 code words are available since bit–F is al-
ways at logical 0. However, a simple 2–pole changeover
switch, in the manner of a typewriter “shift” key (switch FK3 in
the Block Diagram) can be used to change the polarity of
bit–F to give access to the next full set of 32 instructions.
An alternative method of accessing more than 32 instruc-
tions is by the use of external diodes between the address
inputs (see Figure 3). These have the effect of producing
“phantom” address inputs by pulling two inputs low at the
same time, which causes bit–F to go high (i.e., to logical 1).
By interconnecting only certain address inputs it is possible
to make an intermediate keyboard with between 32 and 64
keys.
The other two switches in the Block Diagram (FK1 and
FK2) change the modulation mode. Closing FK1 changes
the modulation from FSK to AM and the start–bit polarity.
Closing FK2 changes the start–bit to a logical 0.
The full range of options available is illustrated in Table 1.
E9 = Open
E9 = A1 (FK1)
E9 = A2 (FK2)
E9 = A3 (FK3)
E9 = A1 A2
E9 = A1 A3
E9 = A2 A3
E9 = A1 A2 A3
* Not allowed.
Table 1.
Start
Bit Modulation Bit–F Channels
1 FSK 0 0 – 31
1 AM 0 0 – 31
0 FSK 0 0 – 31*
1 FSK 1 32 – 61
0 AM 0 0 – 31
1 AM 1 32 – 61
0 FSK 1 32 – 61*
0 AM 1 32 – 61
One of the transmitter’s major features is its low power
consumption (in the order of 10 µA in the idle state). For this
reason, the battery is perpetually in circuit. It has in fact been
found that a light discharge current is beneficial to battery
life.
In its active state, the transmitter efficiency is increased by
the use of a low duty cycle which is less than 2.5% for the
modulating pulse trains.
While no key is pressed, the circuit is in its idle state and
the reference oscillator is stopped. Also, the eight address in-
put lines are held high through internal pull–up resistors.
As soon as a key is pressed, this takes the appropriate ad-
dress line low, signaling to the circuit that a key has been se-
lected. The oscillator is now enabled. If the key is released
before the code word has been sent, the circuit returns to its
idle state. To account for accidental activation of the transmit-
ter, the circuit has a built–in reactive time of approximately
20 ms, which also overcomes contact bounce. After this
delay, the code word will be sent and repeated at 90 ms inter-
vals for as long as the key is pressed. As soon as the key is
released, the circuit automatically sends channel 62, the
“End of Transmission” (EOT) code. The transmitter then re-
turns to its idle state.
The differences between the two modulation modes are il-
lustrated in Figure 4. However, it should be noted that in the
AM mode, each transmitted word is preceded by a burst of
pulses lasting 512 µs. This is used to set up the AGC loop in
the receiver’s preamp. In the FSK mode, the first frequency
of the first bit is extended by 1.5 ms and the AGC burst is
suppressed. In either mode, it is assumed that the normal
start–bit is present.
MOTOROLA
MC14497
3







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