Motorola MC44107P Datasheet
MC44107MOTOROLA
1
Product Preview
CMOS
The MC44107 remote control transmitter converts a keyboard input into a
pulse code modulated signal suitable for infrared transmission to an appropriate
receiver. Its large command capacity, 512 commands, makes it highly suited to
remote control applications in TV, video, hi–fi, etc. The transmitter is an LSI
circuit realized in complementary MOS technology.
• Binary Coded, 9–Bit PCM Data Word
• Simple Modulator Requirements
• One–Pin Reference Oscillator for External Ceramic Resonator
• Very Low (Maximum 1 µA) Standby Current Consumption
• Wide Operating Voltage Range: 4 to 10 V
• Operating Temperature Range: – 40 to 85° C
CB
CC
CD
CE
CF
CG
CH
14
15
19
13
18
16
12
MODULATOR
9–BIT
SHIFT
REG.
COLUMN
DECODER
SCANNER
4
DATA
MUX
÷
2
4
÷
2
5
SUPERVISE
AND
CONTROL
÷
2
2
ROW
ENCODER
TEST
÷
2
5
R1
R2
R3
R4
R5
R6
R7
R8
5
2
9
8
1
6
3
7
OSC
OSC
PAGE
11
V
DD
20
V
SS
BLOCK DIAGRAM
17
10
This document contains information on a product under development. Motorola reserves the right to change or discontinue this product without notice.
Order this document
by MC44107/D
SEMICONDUCTOR TECHNICAL DATA
P SUFFIX
PLASTIC DIP
CASE 738
ORDERING INFORMATION
MC44107P Plastic DIP
PIN ASSIGNMENT
R6
D
out
R7
R2
R5
V
SS
R3
R4
R8
R1 5
4
3
2
1
10
9
8
7
6
14
15
16
17
18
19
20
11
12
13
CG
OSC
CF
CD
MUX
PAGE
CH
CE
CC
CB
20
1
Motorola, Inc. 1995
REV 2
8/95
MC44107 MOTOROLA
2
MAXIMUM RATINGS* (Voltages referenced to V
SS
)
Parameter
Symbol
Value
Unit
DC Supply Voltage
V
DD
– 0.5 to + 12
V
Input Voltage, All Inputs
V
in
– 0.5 to VDD + 0.5
V
DC Current Drain per Pin (Except Signal
Out and VDD)
I
2
mA
DC Current Drain (Signal Out and VDD)
I
10
mA
Storage Temperature Range
T
stg
– 65 to + 150
°C
*Maximum Ratings are those values beyond which damage to the device may occur. Func-
tional operation should be restricted to the limits in the Electrical Characteristics tables or
Pin Descriptions section.
ELECTRICAL CHARACTERISTICS
V
– 40°C 25°C 85°C
Characteristic
Symbol
V
DD
V
dc
Min Max Min Typ Max Min Max
Unit
Inputs R1…R8 and PAGE (with Pull–Up)
Iin at Vin = 1.2 V
Iin at Vin = 3 V
Iin at Vin = 2.8 V
Iin at Vin = 7 V
I
in
4
10
4
10
—
—
5
25
70
350
—
—
—
—
4
20
—
—
—
—
50
250
—
—
—
—
3
15
40
200
—
—
µA
V
IH
V
IH
V
IH
4
10
2.8
7
—
—
2.8
7
—
—
—
—
2.8
7
—
—
V
V
IL
V
IL
V
IL
4
10
—
—
1.2
3
—
—
—
—
1.2
3
—
—
1.2
3
V
Outputs CB…CH (Open Drain)
Ion at Von = 1.2 V
Ion at Von = 3 V
I
on
4
10
270
1350
—
—
200
1000
—
—
—
—
160
800
—
—
µA
I
off
I
off
I
off
4
10
—
—
1
1
—
—
1
1
—
—
—
—
1
1
µA
Output DATA VOH at I
source
= 1.0 mA V
OH
4
10
3.2
9.6
—
—
3.0
9.5
—
—
1
0.5
2.8
9.4
—
—
V
VOL at I
sink
= 1.0 mA V
OL
4
10
—
—
0.8
0.4
—
—
—
—
1
0.5
—
—
1.2
0.6
V
Supply Voltage V
DD
— 4 10 4 — 10 4 10 V
Standby Current I
DDSTB
4
10
—
—
—
—
—
—
0.02
0.02
1
1
—
—
—
—
µA
Active Mode Current I
DDACT
4
10
—
—
—
—
—
—
0.07
0.45
1
2
—
—
—
—
mA
Oscillator Frequency f
osc
— — — 430 — 530 — — kHz
This device contains protection circuitry to
guard against damage due to high static
voltages or electric fields; however, it is advised that precautions be taken to avoid
application of voltage higher than maximum
rated voltages to this high–impedance circuit.
For proper operation it is recommended that
Vin and V
out
be constrained to the range VSS ≤
(Vin or V
out
) ≤VDD.
Unused inputs must always be tied to an
appropriate logic voltage level (e.g., either V
SS
or VDD).
MC44107MOTOROLA
3
CIRCUIT OPERATION
The transmitter emits a 9–bit, labelled A (LSB) to I (MSB),
binary code able to encode 512 commands organized as
8 pages of 64 commands. All of these commands are user
selectable except the last command (511) which is used as
an SST, Start/Stop Transmission code.
Each bit of the transmitted signal is in the form of a biphase
pulse code modulated (PCM) signal, whose coding is shown
in Figure 1.
Figure 1. Signal Coding
BIT–n
‘0’
AM
‘1’
f1*
f1*
*f1 is a train of pulses at the
carrier frequency ÷ 16.
The keyboard can be a simple switch matrix, connected
between the eight row inputs (1 to 8) and the seven column
outputs (B to H). VSS acts as the eight column line to give the
full complement of 64 commands per page. The maximum
“ON” resistance of the keyboard must be limited to 500 Ω.
Page access is accomplished by connecting, by means of
a key, the page input to one of the seven column outputs or
by leaving the input circuit open.
One of the circuit’s major features is its low standby current consumption — typically less than 1 µA. For this reason
the battery may be left continuously in circuit.
As soon as a key is selected, the circuit switches to its active mode and enables the oscillator. To allow for accidental
activation and/or key bounce, the circuit requires that the key
is held for a minimum delay of t
key
, which in the case of a
500 kHz oscillator is 65.6 ms. After this delay the column/
row/page command, consisting of a string of messages (see
Figure 2), appropriate to the key selected will be transmitted
and repeated until the key is released.
Any page key required must be selected before, and held
during, the selection of the column/row matrix key. If this sequence is not followed, the circuit will default to the appropriate command between 0 and 63. If two or more page keys
are accidentally held down, only the first one pressed will be
detected.
A command consists of several messages. Each command starts with the message 511 (SST) followed by the
message appropriate to the key selected. These messages
are repeated until the key is released. The final message is
always followed by the SST message, 511.
Every message consists of a pre–bit, a pre–bit pause, a
start–bit, and nine data bits, where the pre–bit and the start–
bit are always logical “1”. The pre–bit allows for the set up of
the AGC loop in the receiving preamplifier. The truth tables
for data bits are given in Tables 1 and 2, while Figure 2
shows the timing relationships between the commands,
messages, and modulation.
In the event of accidental multi–key operation, the circuit
will react in one of three ways, depending on the combination
of the keys selected.
When two or more keys are connected to the same row input and any column output except A, the command appropriate to the first key selected will be transmitted until that key is
released. After the SST code has been transmitted, assuming another key is still selected, the command appropriate to
that key will be transmitted. If the other key has been released in the meantime, the circuit will revert to standby.
If two keys are selected in the same row with one being
connected to column A, any transmission will terminate with
the SST code and then the circuit will transmit the command
appropriate to the key connected to column A.
In the case where two or more keys connected to the same
column are selected, the circuit reacts in a normal manner to
the first key activated. Upon selection of the second key, the
SST code is transmitted and the circuit will revert to the
standby mode. Only when the multi–key condition is released and a single key is selected will the circuit resume operation, as previously described.
Loading...