MC145027DWR2 - Freescale Semiconductor

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 1

   

CMOS

These devices are designed to be used as encoder/decoder pairs in remote

control applications.

The MC145026 encodes nine lines of information and serially sends this

information upon receipt of a transmit enable (TE) signal. The nine lines may be

encoded with trinary data (low, high, or open) or binary data (low or high). The

words are transmitted twice per encoding sequence to increase security.

The MC145027 decoder receives the serial stream and interprets five of the

trinary digits as an address code. Thus, 243 addresses are possible. If binary

data is used at the encoder, 32 addresses are possible. The remaining serial

information is interpreted as four bits of binary data. The valid transmission (VT)

output goes high on the MC145027 when two conditions are met. First, two

addresses must be consecutively received (in one encoding sequence) which

both match the local address. Second, the 4 bits of data must match the last

valid data received. The active VT indicates that the information at the Data

output pins has been updated.

The MC145028 decoder treats all nine trinary digits as an address which

allows 19,683 codes. If binary data is encoded, 512 codes are possible. The VT

output goes high on the MC145028 when two addresses are consecutively

received (in one encoding sequence) which both match the local address.

•Operating Temperature Range: – 40 to + 85°C

•Very–Low Standby Current for the Encoder: 300 nA Maximum @ 25°C

•Interfaces with RF, Ultrasonic, or Infrared Modulators and Demodulators

•RC Oscillator, No Crystal Required

•High External Component Tolerance; Can Use ± 5% Components

•Internal Power–On Reset Forces All Decoder Outputs Low

•Operating Voltage Range: MC145026 = 2.5 to 18 V*

MC145027, MC145028 = 4.5 to 18 V

•Low–Voltage Versions Available:

SC41343 = 2.8 to 10 V Version of the MC145027

SC41344 = 2.8 to 10 V Version of the MC145028

•For Infrared Applications, See Application Note AN1016/D

PIN ASSIGNMENTS

MC145026

ENCODER MC145028/SC41344

DECODERS

MC145027/SC41343

DECODERS

125

CTC

RTC

Dout

VDD

A8/D8

A9/D9

VSS

A7/D7

A6/D6

125

VDD

Din

R2/C2

VSS

125

VDD

Din

R2/C2

VSS

*All MC145026 devices manufactured after date code 9314 or 314 are guaranteed over this wider voltage range. All previous designs using the

low–voltage SC41342 should convert to the MC145026, which is a drop–in replacement. The SC41342 part number has been discontinued.

Order this document

by MC145026/D



SEMICONDUCTOR TECHNICAL DATA

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







P SUFFIX

PLASTIC DIP

CASE 648

ORDERING INFORMATION

MC145026P Plastic DIP

MC145026D SOG Package

MC145027P, SC41343P Plastic DIP

MC145027DW, SC41343DW SOG Package

MC145028P, SC41344P Plastic DIP

MC145028DW, SC41344DW SOG Package

D SUFFIX

SOG PACKAGE

CASE 751B

DW SUFFIX

SOG PACKAGE

CASE 751G

 Motorola, Inc. 1998

REV 2

1/98

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

Figure 1. MC145026 Encoder Block Diagram

RING COUNTER AND 1–OF–9 DECODER

987654321

RSRTC

CTC

1312

14 3–PIN

OSCILLATOR

AND

ENABLE

DIVIDER DATA SELECT

AND

BUFFER Dout

TRINARY

DETECTOR

VDD = PIN 16

VSS = PIN 8

A6/D6

A7/D7

A8/D8

A9/D9

54321

SEQUENCER CIRCUIT

CONTROL

LOGIC

15 D6

LATCH

4–BIT SHIFT REGISTER

9Din

DATA

EXTRACTOR

VDD = PIN 16

VSS = PIN 8

C1C2

Figure 2. MC145027 Decoder Block Diagram

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 3

98 7654321

SEQUENCER CIRCUIT

CONTROL

LOGIC

9–BIT

SHIFT

9Din

11 VT

DATA

EXTRACTOR

Figure 3. MC145028 Decoder Block Diagram

VDD = PIN 16

VSS = PIN 8

C1C2

MAXIMUM RATINGS* (Voltages Referenced to VSS)

Rating Symbol Value Unit

VDD DC Supply Voltage (except SC41343,

SC41344) – 0.5 to + 18 V

VDD DC Supply Voltage (SC41343, SC41344

only) – 0.5 to + 10 V

Vin DC Input Voltage – 0.5 to VDD + 0.5 V

Vout DC Output Voltage – 0.5 to VDD + 0.5 V

Iin DC Input Current, per Pin ± 10 mA

Iout DC Output Current, per Pin ± 10 mA

PDPower Dissipation, per Package 500 mW

Tstg Storage Temperature – 65 to + 150 °C

TLLead Temperature, 1 mm from Case for

10 Seconds 260 °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.

This device contains protection circuitry to

guard against damage due to high static

voltages or electric fields. However, precau-

tions must be taken to avoid applications of any

voltage higher than maximum rated voltages

to this high–impedance circuit. For proper

operation, V in and V out should be constrained

to the range VSS ≤ (Vin or Vout) ≤ VDD.

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

ELECTRICAL CHARACTERISTICS — MC145026*, MC145027, and MC145028 (Voltage Referenced to VSS)

Sbl

Ch i i

Guaranteed Limit

Sbl

Ch i i

– 40°C 25°C 85°C

Symbol Characteristic

VDD

VMin Max Min Max Min Max Unit

VOL Low–Level Output Voltage (Vin = VDD or 0) 5.0

—

0.05

—

0.05

—

0.05

VOH High–Level Output Voltage (Vin = 0 or VDD)5.0

4.95

9.95

14.95

—

4.95

9.95

14.95

—

4.95

9.95

14.95

—

VIL Low–Level Input Voltage (Vout = 4.5 or 0.5 V)

(Vout = 9.0 or 1.0 V)

(Vout = 13.5 or 1.5 V)

5.0

—

1.5

3.0

4.0

—

1.5

3.0

4.0

—

1.5

3.0

4.0

VIH High–Level Input Voltage (Vout = 0.5 or 4.5 V)

(Vout = 1.0 or 9.0 V)

(Vout = 1.5 or 13.5 V)

5.0

3.5

7.0

—

3.5

7.0

—

3.5

7.0

—

IOH High–Level Output Current (Vout = 2.5 V)

(Vout = 4.6 V)

(Vout = 9.5 V)

(Vout = 13.5 V)

5.0

– 2.5

– 0.52

– 1.3

– 3.6

—

– 2.1

– 0.44

– 1.1

– 3.0

—

– 1.7

– 0.36

– 0.9

– 2.4

—

IOL Low–Level Output Current (Vout = 0.4 V)

(Vout = 0.5 V)

(Vout = 1.5 V)

5.0

0.52

1.3

3.6

—

0.44

1.1

3.0

—

0.36

0.9

2.4

—

Iin Input Current — TE

(MC145026, Pull–Up Device) 5.0

—

3.0

120

—

µA

Iin Input Current

RS (MC145026), Din (MC145027, MC145028) 15 — ± 0.3 — ± 0.3 — ± 1.0 µA

Iin Input Current

A1 – A5, A6/D6 – A9/D9 (MC145026),

A1 – A5 (MC145027),

A1 – A9 (MC145028)

5.0

—

± 110

± 500

± 1000

—

µA

Cin Input Capacitance (Vin = 0) — — — — 7.5 — — pF

IDD Quiescent Current — MC145026 5.0

—

0.1

0.2

0.3

—

µA

IDD Quiescent Current — MC145027, MC145028 5.0

—

100

150

—

µA

Idd Dynamic Supply Current — MC145026

(fc = 20 kHz) 5.0

—

200

400

600

—

µA

Idd Dynamic Supply Current — MC145027, MC145028

(fc = 20 kHz) 5.0

—

400

800

1200

—

µA

*Also see next Electrical Characteristics table for 2.5 V specifications.

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 5

ELECTRICAL CHARACTERISTICS — MC145026 (Voltage Referenced to VSS)

Sbl

Ch i i

Guaranteed Limit

Sbl

Ch i i

– 40°C 25°C 85°C

Symbol Characteristic

VDD

VMin Max Min Max Min Max Unit

VOL Low–Level Output Voltage (Vin = 0 V or VDD)2.5 — 0.05 — 0.05 — 0.05 V

VOH High–Level Output Voltage (V in = 0 V or VDD)2.5 2.45 — 2.45 — 2.45 — V

VIL Low–Level Input Voltage (Vout = 0.5 V or 2.0 V) 2.5 — 0.3 — 0.3 — 0.3 V

VIH High–Level Input Voltage (Vout = 0.5 V or 2.0 V) 2.5 2.2 — 2.2 — 2.2 — V

IOH High–Level Output Current (Vout = 1.25 V) 2.5 0.28 — 0.25 — 0.2 — mA

IOL Low–Level Output Current (Vout = 0.4 V) 2.5 0.22 — 0.2 — 0.16 — mA

Iin Input Current (TE — Pull–Up Device) 2.5 — — 0.09 1.8 — — µA

Iin Input Current (A1–A5, A6/D6–A9/D9) 2.5 — — — ± 25 — — µA

IDD Quiescent Current 2.5 — — — 0.05 — — µA

Idd Dynamic Supply Current (fc = 20 kHz) 2.5 — — — 40 — — µA

ELECTRICAL CHARACTERISTICS — SC41343 and SC41344 (Voltage Referenced to VSS)

Sbl

Ch i i

Guaranteed Limit

Sbl

Ch i i

– 40°C 25°C 85°C

Symbol Characteristic

VDD

VMin Max Min Max Min Max Unit

VOL Low–Level Output Voltage (Vin = 0 V or VDD)2.8

5.0

—

0.05

—

0.05

—

0.05

VOH High–Level Output Voltage (V in = 0 V or VDD)2.8

5.0

2.75

4.95

9.95

—

2.75

4.95

9.95

—

2.75

4.95

9.95

—

VIL Low–Level Input Voltage (Vout = 2.3 V or 0.5 V)

(Vout = 4.5 V or 0.5 V)

(Vout = 9.0 V or 1.0 V)

2.8

5.0

—

0.84

1.5

3.0

—

0.84

1.5

3.0

—

0.84

1.5

3.0

VIH High–Level Input Voltage (Vout = 0.5 V or 2.3 V)

(Vout = 0.5 V or 4.5 V)

(Vout = 1.0 V or 9.0 V)

2.8

5.0

1.96

3.5

7.0

—

1.96

3.5

7.0

—

1.96

3.5

7.0

—

IOH High–Level Output Current (Vout = 1.4 V)

(Vout = 4.5 V)

(Vout = 9.0 V)

2.8

5.0

– 0.73

– 0.59

– 1.3

—

– 0.7

– 0.5

– 1.1

—

– 0.55

– 0.41

– 0.9

—

IOL Low–Level Output Current (Vout = 0.4 V)

(Vout = 0.5 V)

(Vout = 1.0 V)

2.8

5.0

0.35

0.8

3.5

—

0.3

0.6

2.9

—

0.24

0.4

2.3

—

Iin Input Current — Din 10 — ±0.3 — ±0.3 — ± 1.0 µA

Iin Input Current

A1 – A5 (SC41343)

A1 – A9 (SC41344)

2.8

5.0

—

± 30

± 140

± 600

—

µA

Cin Input Capacitance (Vin = 0) — — — — 7.5 — — pF

IDD Quiescent Current 2.8

5.0

—

150

—

µA

Idd Dynamic Supply Current (fc = 20 kHz) 2.8

5.0

—

300

500

1000

—

µA

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

SWITCHING CHARACTERISTICS — MC145026*, MC145027, and MC145028 (CL = 50 pF, TA = 25°C)

Sbl

Ch i i

Figure

Guaranteed Limit

Symbol Characteristic

Figure

No. VDD Min Max Unit

tTLH, tTHL Output T ransition Time 4,8 5.0

—

200

100

trDin Rise Time — Decoders 5 5.0

—

µs

tfDin Fall T ime — Decoders 5 5.0

—

5.0

4.0

µs

fosc Encoder Clock Frequency 6 5.0

0.001

2.0

5.0

MHz

fDecoder Frequency — Referenced to Encoder Clock 12 5.0

1.0

240

410

450

kHz

twTE Pulse Width — Encoders 7 5.0

—

*Also see next Switching Characteristics table for 2.5 V specifications.

SWITCHING CHARACTERISTICS — MC145026 (CL = 50 pF, TA = 25°C)

Sbl

Ch i i

Figure

Guaranteed Limit

Symbol Characteristic

Figure

No. VDD Min Max Unit

tTLH, tTHL Output T ransition Time 4, 8 2.5 — 450 ns

fosc Encoder Clock Frequency 6 2.5 1.0 250 kHz

twTE Pulse Width 7 2.5 1.5 — µs

SWITCHING CHARACTERISTICS — SC41343 and SC41344 (CL = 50 pF, TA = 25°C)

Sbl

Ch i i

Figure

Guaranteed Limit

Symbol Characteristic

Figure

No. VDD Min Max Unit

tTLH, tTHL Output T ransition Time 4, 8 2.8

5.0

—

320

200

100

trDin Rise Time 5 2.8

5.0

—

µs

tfDin Fall Time 5 2.8

5.0

—

5.0

µs

fDecoder Frequency — Referenced to Encoder Clock 12 2.8

5.0

1.0

100

240

410

kHz

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 7

10%

90%

ANY OUTPUT

tTLH tTHL

Figure 4. Figure 5.

Figure 6. Figure 7.

Figure 8. Test Circuit

10%

90%

Din

tftrVDD

VSS

RTC 50%

1/fosc

TE 50% VDD

VSS

DEVICE

UNDER

TEST

*Includes all probe and fixture capacitance.

CL*

OUTPUT

TEST POINT

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

OPERATING CHARACTERISTICS

MC145026

The encoder serially transmits trinary data as defined by

the state of the A1 – A5 and A6/D6 – A9/D9 input pins. These

pins may be in either of three states (low , high, or open) allow-

ing 19,683 possible codes. The transmit sequence is initiated

by a low level on the TE input pin. Upon power–up, the

MC145026 can continuously transmit as long as TE remains

low (also, the device can transmit two–word sequences by

pulsing TE low). However, no MC145026 application should

be designed to rely upon the first data word transmitted im-

mediately after power–up because this word may be invalid.

Between the two data words, no signal is sent for three data

periods (see Figure 10).

Each transmitted trinary digit is encoded into pulses (see

Figure 11). A logic 0 (low) is encoded as two consecutive

short pulses, a logic 1 (high) as two consecutive long pulses,

and an open (high impedance) as a long pulse followed by a

short pulse. The input state is determined by using a weak

“output” device to try to force each input high then low . If only

a high state results from the two tests, the input is assumed to

be hardwired to VDD. If only a low state is obtained, the input

is assumed to be hardwired to VSS. If both a high and a low

can be forced at an input, an open is assumed and is encoded

as such. The “high” and “low” levels are 70% and 30% of the

supply voltage as shown in the Electrical Characteristics

table. The weak “output” device sinks/sources up to 1 10 µA at

a 5 V supply level, 500 µA at 10 V, and 1 mA at 15 V.

The TE input has an internal pull–up device so that a simple

switch may be used to force the input low. While TE is high

and the second–word transmission has timed out, the encod-

er is completely disabled, the oscillator is inhibited, and the

current drain is reduced to quiescent current. When TE is

brought low, the oscillator is started and the transmit se-

quence begins. The inputs are then sequentially selected,

and determinations are made as to the input logic states. This

information is serially transmitted via the Dout pin.

MC145027

This decoder receives the serial data from the encoder and

outputs the data, if it is valid. The transmitted data, consisting

of two identical words, is examined bit by bit during reception.

The first five trinary digits are assumed to be the address. If

the received address matches the local address, the next four

(data) bits are internally stored, but are not transferred to the

output data latch. As the second encoded word is received,

the address must again match. If a match occurs, the new

data bits are checked against the previously stored data bits.

If the two nibbles of data (four bits each) match, the data is

transferred to the output data latch by VT and remains until

new data replaces it. At the same time, the VT output pin is

brought high and remains high until an error is received or un-

til no input signal is received for four data periods (see Figure

10).

Although the address information may be encoded in tri-

nary, the data information must be either a 1 or 0. A trinary

(open) data line is decoded as a logic 1.

MC145028

This decoder operates in the same manner as the

MC145027 except that nine address lines are used and no

data output is available. The VT output is used to indicate that

a valid address has been received. For transmission security ,

two identical transmitted words must be consecutively re-

ceived before a VT output signal is issued.

The MC145028 allows 19,683 addresses when trinary lev-

els are used. 512 addresses are possible when binary levels

are used.

PIN DESCRIPTIONS

MC145026 ENCODER

A1 – A5, A6/D6 – A9/D9

Address, Address/Data Inputs (Pins 1 – 7, 9, and 10)

These address/data inputs are encoded and the data is

sent serially from the encoder via the Dout pin.

RS, CTC, RTC

(Pins 11, 12, and 13)

These pins are part of the oscillator section of the encoder

(see Figure 9).

If an external signal source is used instead of the internal

oscillator , it should be connected to the RS input and the RTC

and CTC pins should be left open.

Transmit Enable (Pin 14)

This active–low transmit enable input initiates transmission

when forced low. An internal pull–up device keeps this input

normally high. The pull–up current is specified in the Electri-

cal Characteristics table.

Dout

Data Out (Pin 15)

This is the output of the encoder that serially presents the

encoded data word.

VSS

Negative Power Supply (Pin 8)

The most–negative supply potential. This pin is usually

ground.

VDD

Positive Power Supply (Pin 16)

The most–positive power supply pin.

MC145027 AND MC145028 DECODERS

A1 – A5, A1 – A9

Address Inputs (Pins 1 – 5) — MC145027,

Address Inputs (Pins 1 – 5, 15, 14, 13, 12) — MC145028

These are the local address inputs. The states of these

pins must match the appropriate encoder inputs for the VT pin

to go high. The local address may be encoded with trinary or

binary data.

D6 – D9

Data Outputs (Pins 15, 14, 13, 12) — MC145027 Only

These outputs present the binary information that is on

encoder inputs A6/D6 through A9/D9. Only binary data is

acknowledged; a trinary open at the MC145026 encoder is

decoded as a high level (logic 1).

Din

Data In (Pin 9)

This pin is the serial data input to the decoder. The input

voltage must be at CMOS logic levels. The signal source driv-

ing this pin must be dc coupled.

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 9

R1, C1

Resistor 1, Capacitor 1 (Pins 6, 7)

As shown in Figures 2 and 3, these pins accept a resistor

and capacitor that are used to determine whether a narrow

pulse or wide pulse has been received. The time constant

R1 x C1 should be set to 1.72 encoder clock periods:

R1 C1 = 3.95 R TC CTC

R2/C2

Resistor 2/Capacitor 2 (Pin 10)

As shown in Figures 2 and 3, this pin accepts a resistor and

capacitor that are used to detect both the end of a received

word and the end of a transmission. The time constant R2 x

C2 should be 33.5 encoder clock periods (four data periods

per Figure 11): R2 C2 = 77 RTC CTC. This time constant is

used to determine whether the Din pin has remained low for

four data periods (end of transmission). A separate on–chip

comparator looks at the voltage–equivalent two data periods

(0.4 R2 C2) to detect the dead time between received words

within a transmission.

Valid Transmission Output (Pin 11)

This valid transmission output goes high after the second

word of an encoding sequence when the following conditions

are satisfied:

1.the received addresses of both words match the local de-

coder address, and

2.the received data bits of both words match.

VT remains high until either a mismatch is received or no

input signal is received for four data periods.

VSS

Negative Power Supply (Pin 8)

The most–negative supply potential. This pin is usually

ground.

VDD

Positive Power Supply (Pin 16)

The most–positive power supply pin.

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

RSCTC RTC

11 12 13

INTERNAL

ENABLE

Figure 9. Encoder Oscillator Information

This oscillator operates at a frequency determined by the

external RC network; i.e.,

f ≈1

2.3 RTC CTC′(Hz)

for 1 kHz ≤ f ≤ 400 kHz

where: CTC′ = CTC + Clayout + 12 pF

RS ≈ 2 RTC

RS ≥ 20 k

RTC ≥ 10 k

400 pF < CTC < 15 µF

The value for RS should be chosen to be ≥ 2 times RTC. This range ensures

that current through RS is insignificant compared to current through RTC. The

upper limit for RS must ensure that RS x 5 pF (input capacitance) is small com-

pared to R TC x CTC.

For frequencies outside the indicated range, the formula is less accurate.

The minimum recommended oscillation frequency of this circuit is 1 kHz. Sus-

ceptibility to externally induced noise signals may occur for frequencies below

1 kHz and/or when resistors utilized are greater than 1 MΩ.

Figure 10. Timing Diagram

PWmin

TE 2 WORD TRANSMISSION

ENCODER

CONTINUOUS TRANSMISSION

ENCODER

OSCILLATOR

(PIN 12)

Dout

(PIN 15)

(PIN 11)

DATA OUTPUTS

1.1 (R2C2)

DECODER

ENCODING SEQUENCE

1ST

DIGIT

HIGH

2ND WORD1ST WORD

OPEN LOW

9TH

DIGIT 9TH

DIGIT

1ST

DIGIT

114

116

118

120

122

178

180

182

184

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 11

DATA PERIOD

ENCODER

OSCILLATOR

(PIN 12)

Dout

(PIN 15)

ENCODED

“ONE”

ENCODED

“ZERO”

ENCODED

“OPEN”

Figure 11. Encoder Data Waveforms

500

400

300

200

100

VDD = 15 V

VDD = 10 V

VDD = 5 V

Figure 12. fmax vs Clayout — Decoders Only

Clayout (pF) ON PINS 1 – 5 (MC145027); PINS 1 – 5 AND 12 – 15 (MC145028)

f (kHz)

(REF. TO ENCODER CLOCK)

max

10 20 30 40 50

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

YES

Figure 13. MC145027 Flowchart

HAS

THE TRANSMISSION

BEGUN?

DOES

THIS DATA

MATCH THE PREVIOUSLY

STORED

DATA?

DISABLE VT

ON THE 1ST

ADDRESS MISMATCH

DISABLE VT

ON THE 1ST

DATA MISMATCH

DISABLE

IS THIS

AT LEAST THE

2ND CONSECUTIVE

MATCH SINCE VT

DISABLE?

DOES

THE 5–BIT

ADDRESS MATCH

THE ADDRESS

PINS?

STORE

THE

4–BIT

DATA

YES

LATCH DATA

ONTO OUTPUT

PINS AND

ACTIVATE VT

HAVE

4–BIT TIMES

PASSED?

HAS

A NEW

TRANSMISSION

BEGUN?

YES

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 13

HAS

THE TRANSMISSION

BEGUN?

YES

DOES

THE ADDRESS

MATCH THE

ADDRESS

PINS?

DISABLE VT ON THE 1ST

ADDRESS MISMATCH

AND IGNORE THE REST

OF THIS WORD

DISABLE VT

THIS AT LEAST

THE 2ND CONSECUTIVE

MATCH SINCE VT

DISABLE?

ACTIVATE VT

HAVE

4–BIT TIMES

PASSED?

HAS A

NEW TRANSMISSION

BEGUN?

YES

Figure 14. MC145028 Flowchart

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

MC145027 AND MC145028 TIMING

To verify the MC145027 or MC145028 timing, check the

waveforms on C1 (Pin 7) and R2/C2 (Pin 10) as compared to

the incoming data waveform on Din (Pin 9).

The R–C decay seen on C1 discharges down to 1/3 VDD

before being reset to VDD. This point of reset (labelled “DOS”

in Figure 15) is the point in time where the decision is made

whether the data seen on Din is a 1 or 0. DOS should not be

too close to the Din data edges or intermittent operation may

occur.

The other timing to be checked on the MC145027 and

MC145028 is on R2/C2 (see Figure 16). The R–C decay is

continually reset to VDD as data is being transmitted. Only

between words and after the end–of–transmission (EOT)

does R2/C2 decay significantly from VDD. R2/C2 can be used

to identify the internal end–of–word (EOW) timing edge which

is generated when R2/C2 decays to 2/3 VDD. The internal

EOT timing edge occurs when R2/C2 decays to 1/3 VDD.

When the waveform is being observed, the R–C decay

should go down between the 2/3 and 1/3 VDD levels, but not

too close to either level before data transmission on Din re-

sumes.

Verification of the timing described above should ensure a

good match between the MC145026 transmitter and the

MC145027 and MC145028 receivers.

VDD

0 V

Din

VDD

2/3

1/3

0 V

DOS DOS

Figure 15. R–C Decay on Pin 7 (C1)

VDD

2/3

1/3

0 V

R2/C2

EOT

Figure 16. R–C Decay on Pin 10 (R2/C2)

EOW

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 15

VDD TE

TRINARY

ADDRESSES

4–BIT

BINARY

DATA

14 16 15 Dout

0.1

MC145026

RTC

VDD

CTC

REPEAT OF ABOVE

MC145027

SC41343

VDD

0.1

Din 9

R2 C2

D9 VT

VDD

TRINARY

ADDRESSES

Figure 17. Typical Application

CTC′ = CTC + Clayout + 12 pF

100 pF ≤ CTC ≤ 15 µF

RTC ≥ 10 kΩ; RS ≈ 2 RTC

R1 ≥ 10 kΩ

C1 ≥ 400 pF

R2 ≥ 100 kΩ

C2 ≥ 700 pF

fosc = 1

2.3 RTCCTC′

R1C1 = 3.95 RTCCTC

R2C2 = 77 RTCCTC

Example R/C Values (All Resistors and Capacitors are ±5%)

(CTC′ = CTC + 20 pF)

fosc (kHz) RTC CTC′RSR1C1R2C2

362

181

88.7

42.6

21.5

8.53

1.71

10 k

50 k

20 k

100 k

120 pF

240 pF

490 pF

1020 pF

2020 pF

5100 pF

10 k

50 k

100 k

200 k

910 pF

1800 pF

3900 pF

7500 pF

0.015 µF

0.02 µF

0.1 µF

470 pF

910 pF

2000 pF

3900 pF

8200 pF

0.02 µF

REPEAT OF ABOVE

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

APPLICATIONS INFORMATION

INFRARED TRANSMITTER

In Figure 18, the MC145026 encoder is set to run at an os-

cillator frequency of about 4 to 9 kHz. Thus, the time required

for a complete two–word encoding sequence is about 20 to

40 ms. The data output from the encoder gates an RC oscilla-

tor running at 50 kHz; the oscillator shown starts rapidly

enough to be used in this application. When the “send” button

is not depressed, both the MC145026 and oscillator are in a

low–power standby state. The RC oscillator has to be

trimmed for 50 kHz and has some drawbacks for frequency

stability. A superior system uses a ceramic resonator oscilla-

tor running at 400 kHz. This oscillator feeds a divider as

shown in Figure 19. The unused inputs of the MC14011UB

must be grounded.

The MLED81 IRED is driven with the 50 kHz square wave

at about 200 to 300 mA to generate the carrier . If desired, two

IREDs wired in series can be used (see Application Note

AN1016 for more information). The bipolar IRED switch,

shown in Figure 18, offers two advantages over a FET. First,

a logic FET has too much gate capacitance for the

MC14011UB to drive without waveform distortion. Second,

the bipolar drive permits lower supply voltages, which are an

advantage in portable battery–powered applications.

The configuration shown in Figure 18 operates over a

supply range of 4.5 to 18 V. A low–voltage system which

operates down to 2.5 V could be realized if the oscillator sec-

tion of a MC74HC4060 is used in place of the MC14011UB.

The data output of the MC145026 is inverted and fed to the

RESET pin of the MC74HC4060. Alternately, the

MC74HCU04 could be used for the oscillator.

Information on the MC14011UB is in book number

DL131/D. The MC74HCU04 and MC74HC4060 are found in

book number DL129/D.

INFRARED RECEIVER

The receiver in Figure 20 couples an IR–sensitive diode to

input preamp A1, followed by band–pass amplifier A2 with a

gain of about 10. Limiting stage A3 follows, with an output of

about 800 mV p–p. The limited 50 kHz burst is detected by

comparator A4 that passes only positive pulses, and peak–

detected and filtered by a diode/RC network to extract the

data envelope from the burst. Comparator A5 boosts the sig-

nal to logic levels compatible with the MC145027/28 data

input. The Din pin of these decoders is a standard CMOS

high–impedance input which must

not

be allowed to float.

Therefore, direct coupling from A5 to the decoder input is

utilized.

Shielding should be used on at least A1 and A2, with good

ground and high–sensitivity circuit layout techniques applied.

For operation with supplies higher than + 5 V, limiter A4’s

positive output swing needs to be limited to 3 to 5 V. This is

accomplished via adding a zener diode in the negative feed-

back path, thus avoiding excessive system noise. The bias-

ing resistor stack should be adjusted such that V3 is 1.25 to

1.5 V.

This system works up to a range of about 10 meters. The

gains of the system may be adjusted to suit the individual

design needs. The 100 Ω resistor in the emitter of the first

2N5088 and the 1 kΩ resistor feeding A2 may be altered if

different gain is required. In general, more gain does not nec-

essarily result in increased range. This is due to noise floor

limitations. The designer should increase transmitter power

and/or increase receiver aperature with Fresnal lensing to

greatly improve range. See Application Note AN1016 for

additional information.

Information on the MC34074 is in data book DL128/D.

TRINARY SWITCH MANUFACTURERS

Midland Ross–Electronic Connector Div.

Greyhill

Augat/Alcoswitch

Aries Electronics

The above companies may not have the switches in a DIP.

For more information, call them or consult

eem Electronic En-

gineers Master Catalog

or the

Gold Book

Ask for SPDT with

center OFF.

Alternative: An SPST can be placed in series between a

SPDT and the Encoder or Decoder to achieve trinary action.

Motorola cannot recommend one supplier over another

and in no way suggests that this is a complete listing of trinary

switch manufacturers.

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 17

10 k

Ω

220 k

Ω

SEND

RSCTC RTC

MC145026

SWITCHES 100 k

Ω

FOR APPROX. 4 kHz

47 k

Ω

FOR APPROX. 9 kHz

1000 pF

Dout

MC14011UB

220 k

Ω

0.01

SELECT FOR

200 mA TO 300 mA

MLED81 USE OF 2 MLED81s

IS OPTIONAL

MPSA13

MPSW13

ADJUST/SELECT FOR

f = 50 kHz (APPROX. 100 k

Ω

)

Figure 18. IRED Transmitter Using RC Oscillator to Generate Carrier Frequency

V+

50 kHZ TO

DRIVER

TRANSISTOR

X1 = 400 kHz CERAMIC RESONATOR

P ANASONIC EFD–A400K04B

OR EQUIVALENT

MC14024

CLK

470 pF

MC14011UB

Dout

FROM MC145026

Ω

470 pF

Figure 19. Using a Ceramic Resonator to Generate Carrier Frequency

RESET

V+ MC14011UB

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

ÉÉ

Figure 20. Infrared Receiver

22 k

Ω

OPTICAL

FILTER

10 k

Ω

10 k

Ω

10 k

Ω

100

Ω

6.8 k

Ω

2.2 k

Ω

1N914

100 k

Ω

–+

–

+5 V

0.01

F1 k

Ω

1 mH — TOKO TYPE 7PA OR 10PA

OR EQUIVALENT

0.01

F4.7 k

Ω

A3 A4 A5

10 k

Ω

V1 V2

1 M

Ω

1N914 1 k

Ω

1000 pF 47 k

Ω

22 k

Ω

1 M

Ω

1000 pF 390 k

Ω

FOR APPROX. 4 kHz

180 k

Ω

FOR APPROX. 9 kHz 750 k

Ω

FOR APPROX. 4 kHz

360 k

Ω

FOR APPROX. 9 kHz

0.01

C1 R1 R2/C2

VSS

VDD 4

9 FOR MC145027

5 FOR MC145028

ADDRESS

SWITCHES

DATA OUT

MC145027 ONLY

+5 V

F10

4.7 k

Ω

2.2 k

Ω

390

Ω

2.7 k

Ω

≈

2.7 V

Din

0.01

1/4 MC34074

+5 V

2N5088 2N5086 2N5088

1/4 MC34074 1/4 MC34074 1/4 MC34074

≈

1.3 V

≈

2.5 V

MC145027/28

MC145026•MC145027•MC145028•SC41343•SC41344MOTOROLA 19

PACKAGE DIMENSIONS

P SUFFIX

PLASTIC DIP (DUAL IN–LINE PACKAGE)

CASE 648–08

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

3. DIMENSION L TO CENTER OF LEADS WHEN

FORMED PARALLEL.

4. DIMENSION B DOES NOT INCLUDE MOLD FLASH.

5. ROUNDED CORNERS OPTIONAL.

–A–

HGD

16 PL

SEATING

916

PLANE

–T–

0.25 (0.010) T

DIM MIN MAX MIN MAX

MILLIMETERSINCHES

A0.740 0.770 18.80 19.55

B0.250 0.270 6.35 6.85

C0.145 0.175 3.69 4.44

D0.015 0.021 0.39 0.53

F0.040 0.70 1.02 1.77

G0.100 BSC 2.54 BSC

H0.050 BSC 1.27 BSC

J0.008 0.015 0.21 0.38

K0.110 0.130 2.80 3.30

L0.295 0.305 7.50 7.74

M0 10 0 10

S0.020 0.040 0.51 1.01

____

D SUFFIX

SOG (SMALL OUTLINE GULL–WING) PACKAGE

CASE 751B–05

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

2. CONTROLLING DIMENSION: MILLIMETER.

3. DIMENSIONS A AND B DO NOT INCLUDE

MOLD PROTRUSION.

4. MAXIMUM MOLD PROTRUSION 0.15 (0.006)

PER SIDE.

5. DIMENSION D DOES NOT INCLUDE DAMBAR

PROTRUSION. ALLOWABLE DAMBAR

PROTRUSION SHALL BE 0.127 (0.005) TOTAL

IN EXCESS OF THE D DIMENSION AT

MAXIMUM MATERIAL CONDITION.

16 9

SEATING

PLANE

RX 45

8 PLP

–B–

–A–

0.25 (0.010) B S

–T–

16 PL

0.25 (0.010) A S

DIM MIN MAX MIN MAX

INCHESMILLIMETERS

A9.80 10.00 0.386 0.393

B3.80 4.00 0.150 0.157

C1.35 1.75 0.054 0.068

D0.35 0.49 0.014 0.019

F0.40 1.25 0.016 0.049

G1.27 BSC 0.050 BSC

J0.19 0.25 0.008 0.009

K0.10 0.25 0.004 0.009

M0 7 0 7

P5.80 6.20 0.229 0.244

R0.25 0.50 0.010 0.019

____

MC145026•MC145027•MC145028•SC41343•SC41344 MOTOROLA

DW SUFFIX

SOG (SMALL OUTLINE GULL–WING) PACKAGE

CASE 751G–02

DIM MIN MAX MIN MAX

INCHESMILLIMETERS

A10.15 10.45 0.400 0.411

B7.40 7.60 0.292 0.299

C2.35 2.65 0.093 0.104

D0.35 0.49 0.014 0.019

F0.50 0.90 0.020 0.035

G1.27 BSC 0.050 BSC

J0.25 0.32 0.010 0.012

K0.10 0.25 0.004 0.009

M0 7 0 7

P10.05 10.55 0.395 0.415

R0.25 0.75 0.010 0.029

0.010 (0.25)

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

2. CONTROLLING DIMENSION: MILLIMETER.

3. DIMENSIONS A AND B DO NOT INCLUDE MOLD

PROTRUSION.

4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER

SIDE.

5. DIMENSION D DOES NOT INCLUDE DAMBAR

PROTRUSION. ALLOWABLE DAMBAR

PROTRUSION SHALL BE 0.13 (0.005) TOTAL IN

EXCESS OF D DIMENSION AT MAXIMUM

MATERIAL CONDITION.

–A–

–B– P8X

G14X

D16X

SEATING

PLANE

–T–

0.010 (0.25) B S

16 9

RX 45

____

Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding

the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and

specifically disclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters which may be provided in Motorola

data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals”

must be validated for each customer application by customer’s technical experts. Motorola does not convey any license under its patent rights nor the rights of

others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other

applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury

or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola

and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees

arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that

Motorola was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal

Opportunity/Af firmative Action Employer .

MC145026/D

◊

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