Tel: 886-2-66296288

Fax: 886-2-29174598
URL: http://www.princeton.com.tw

Infrared Remote Control Transmitter PT2248

DESCRIPTION
PT2248 is an infrared remote control transmitter utilizing CMOS Technology. It is capable of 18
functions and a total of 75 commands. Single-shot and continuous keys are available. Furthermore,
multiple keying is possible.

FEATURES
• CMOS Technology
• Low Power Consumption
• Wide Range of Operating Supply Voltage allows Low Voltage Operation (Vcc=2.2 ~ 5.0 V)
• Multiple Keying is Possible (Maximum of 6 Keys)
• Less External Components
• An Oscillator can be constructed by connecting a ceramic resonator at the oscillation circuit

APPLICATIONS
• Television (TV) Remote Control Transmitter
• Video Cassette Recorder (VCR) Remote Control Transmitter

PT2248 V2.7 -1- June, 2005

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Infrared Remote Control Transmitter PT2248

BLOCK DIAGRAM
VS S VCC
1 16

XT 2 O u tput
OSC DIi vi der Sy nthe si zi ng 15 /TX OUT
/XT 3 Ci rc ui t

K1 4
De co der Hol d Si gna l
K2 5 G e ner ato r
14 /TE ST
K3 6
K ey
In put
K4 7 Ci rc ui t
C ode B it
Si gna l
Ti min g Si gna l
K5 8
G e ner ati ng
G e ner ati ng
Ci rc ui t
Ci rc ui t
K6 9

10 11 12 13

T1 T2 T3 CODE

PIN CONFIGURATION

VS S 1 16 VCC
XT 2 15 /TX OUT
/XT 3 14 /TE ST
K1 4 13 CODE
K2 5 12 T3
K3 6 11 T2
K4 7 10 T1
K5 8 9 K6

PT2248

PT2248 V2.7 -2- June, 2005

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Infrared Remote Control Transmitter PT2248

PIN DESCRIPTION
Pin Name Pin No. I/O Description
VSS 1 Negative Supply Voltage Terminal
VCC 16 Positive Supply Voltage Terminal
OSC Input/Output
XT, /XT 2, 3 I, O Terminal for OSC, and used for connecting a 455KHz ceramic
resonator, etc.
Key Code Input. 18 Keys can be connected
K1 ~ K6 4~9 I
Key Input Terminals for Key Matrix at T1 ~ T3 x K1 ~ K6
Scan Key Code Output.
(with a built-in pull-down
T1 ~ T3 10 ~ 12 O Digital Timing Output Terminals for
resistor)
Key Matrix
Tx/Rx matching Code Common.
/CODE 13 I
Terminal for matching code between transmitting and receiving.
Transmitter Key Code Testing Function.
TEST 14 I
Keep this terminal open.
Transmitting Signal Output.
TXOUT 15 O Transmitting signal consists of 12 bits per word and is modulated
by a 38KHz carrier wave.

PT2248 V2.7 -3- June, 2005

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Infrared Remote Control Transmitter PT2248

FUNCTION DESCRIPTION
OSCILLATION CIRCUIT
When the self-bias type amplifier is housed by CMOS inverter method, the oscillation circuit can be
constructed when a ceramic resonator has been connected.

Rf

2 3
Cer am ic Res on ator
45 5K Hz
C1 C2 C1 , C2 = 120 pF ~ 150p F

When the oscillation frequency is set at 455 KHz, the carrier wave of the transmitting signal is set at 38
KHz. Unless the keys are being operated, the oscillation is normally stopped; thereby, reducing power
consumption.

KEY INPUT
18 Keys can be connected by Key Inputs K1 ~ K6 and timing signals T1 ~ T3.
Multiple Keying (maximum of 6 keys) is possible for the keys connected to T1 line (Output becomes
continuous pulses).
The order of priority of the timing signal line is T1, T2, and T3. When 2 or more keys that are connected
to T2 (or T3) line are pressed simultaneously, the single output will have the preferential order of K1 ~
K6.
Furthermore, the keys connected to T2 and T3 lines are for single signals and no second signal is
transmitted unless input is made after the key is released once.

PT2248 V2.7 -4- June, 2005

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Infrared Remote Control Transmitter PT2248

KEY MATRIX
KEY NO. 1~ 6
These are continuous keys. Multiple Keying is possible.

KEY NO. 7 ~ 18
These are single-shot keys. When an input is made, there is only one signal output.

T1 T2 T3

K1 1 7 13
K2 2 8 14
K3 3 9 15

K4 4 10 16
K5 5 11 17
K6 6 12 18

(H) (S1) (S2)

TRANSMISSION COMMAND
The Transmission Command consists of one Command Word. One Command Word is composed of
Code Bits (3 bits), Continuous Code (1 Bit), Single-Shot Code (2 bits) and the Key Input Code (6 bits).
Thus, one Command Word has 12 bits. C1 ~ C3 are code bits that are adaptable to many models. “H”
indicates the continuous signal code while “S1” and “S2” are single-shot signal codes. D1 ~ D6 are key
input data codes in 6 bits.

C1 C2 C3 H S1 S2 D1 D2 D3 D4 D5 D6

C o d e B it s C o n t inu o u s K e y I n pu t C o d e
S in g le -S h o t
C o de

PT2248 V2.7 -5- June, 2005

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Infrared Remote Control Transmitter PT2248

DATA CODE
Key Data Output Key Data Output
No. H S1 S2 D1 D2 D3 D4 D5 D6 Form No. H S1 S2 D1 D2 D3 D4 D5 D6 Form
1 1 0 0 1 0 0 0 0 0 Continuous 10 0 1 0 0 0 0 1 0 0 Single-Shot
2 1 0 0 0 1 0 0 0 0 Continuous 11 0 1 0 0 0 0 0 1 0 Single-Shot
3 1 0 0 0 0 1 0 0 0 Continuous 12 0 1 0 0 0 0 0 0 1 Single-Shot
4 1 0 0 0 0 0 1 0 0 Continuous 13 0 0 1 1 0 0 0 0 0 Single-Shot
5 1 0 0 0 0 0 0 1 0 Continuous 14 0 0 1 0 1 0 00 0 0 Single-Shot
6 1 0 0 0 0 0 0 0 1 Continuous 15 0 0 1 0 0 1 0 0 0 Single-Shot
7 0 1 0 1 0 0 0 0 0 Single-Shot 16 0 0 1 0 0 0 1 0 0 Single-Shot
8 0 1 0 0 1 0 0 0 0 Single-Shot 17 0 0 1 0 0 0 0 1 0 Single-Shot
9 0 1 0 0 0 1 0 0 0 Single-Shot 18 0 0 1 0 0 0 0 0 2 Single-Shot

Since multiple keying is possible, Key No. 1 ~ 6 (in combination with D1 ~ D6 data) are capable of
sending out 63 commands. Key No. 7 ~ 18 are single-shot keys capable of sending out 12 commands.
Thus, a total of 75 commands can result from a combination of continuous keys (multiple keying) and
single-shot keys.

CODE BITS (C1, C2 AND C3)

Code bits can be made at one terminal with diodes connected through T1 ~ T3 timing terminals.

Data of C1, C2 and C3 Code Bits become “1” when diodes are connected to CODE Terminal through
the timing signal terminals -- T1 ~ T3, and “0” when diodes are not connected.

CO D E T3 T2 T1
( C3 ) ( C2 ) ( C1 )

In the diagram above: C1, C2 and C3 are 1, 1, and 1 data respectively.

PT2248 has three (3) Code Bits. The receiving IC -- PT 2249A Series (DIP 16 Pins) can only use C2
and C3 Code Bits, while PT 2250A Series (DIP 24 Pins) are able to use only C1 and C2 Code Bits.
Therefore, diodes must be connected so that PT2248 Code Bits Data match with that of the receiving
IC.

PT2248 V2.7 -6- June, 2005

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Infrared Remote Control Transmitter PT2248

The PT2248 Code Bits Connection Table for PT 2249A / PT 2250A Series Application is given below:

Rx
PT2249A PT2250A
PT2248 Code Pin
T1 (C1 Code) Diode C1
T2 (C2 Code) C2 C2
T3 (C3 Code) C3 Diode

Note: where C1, C2, C3 will be “1” if one diode is connected between CODE and Tn pins; n=1 to 3 in
PT2248; otherwise, it will be set to “0”.

Note: When communicating with any of the PT2249A Series Receivers, C1 Code Bit Data is not used.
Therefore, it is necessary to connect diodes to the Code terminal corresponding to C1 Code Bit
of PT2248. (In this way, the C1 Code Bit of PT2248 transmits “1”. Likewise, when
communicating with any of the PT2250A Series Receivers, C3 Code Bit is not used. Therefore,
it is necessary to connect diodes to the Code Terminal corresponding to the C3 Code Bit of
PT2248.)

TRANSMITTING WAVEFORM
a 3a

Con tinu ous /

Co de Bi t S ingl e- Sh ot Code K ey Inp ut Cod e

48 a

The diagram above shows the basic transmitting waveform. A basic transmitting waveform consists of
12-bits serial data.

The time of bit “a” is dependent on the oscillation frequency (fosc) and is given by the following formula:

1
a= x 192
fosc

PT2248 V2.7 -7- June, 2005

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Infrared Remote Control Transmitter PT2248

DISTINCTION OD BIT “1” AND “0”

a 3a

B it "0 "

B it "1 "

3a a

0 1 0 1 1 0 0 1 0 0 0 1

One word of the transmission command is in the configuration of (010110010001).

SINGLE-SHOT SIGNAL
P T 2248 K ey O n Com ma nd Dupl ic ate of
Cod e Com ma nd Cod e

/T X OU T 60 a 48 a 80 a 48 a

2 Co mm and W or ds

When any one of the single-shot keys is depressed, the above single-shot transmits only 2 command
words and then the transmitting output ends.

PT2248 V2.7 -8- June, 2005

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Infrared Remote Control Transmitter PT2248

CONTINUOUS SIGNAL
P T 2248 K ey O n

/T X OU T 48 a 80 a 48 a 20 8a 48 a 80 a 48 a

2 Co mm and W or ds P aus e

When any of the continuous keys is depressed, the above continuous signal transmits a repetitive
cycle of 2 command words and then a pause (with a pause duration of 208a) until the key is released.

If the key is released during code transmission, PT2248 will still continue to send out the last set of 2
command words and then the transmitting output stops. Please refer to the diagram below:

P T 2248 K ey O n

/T X O UT 48a 80a 48a 208a 48a 80a 48a 48a 80a 48a

2 Co mm and W or ds P aus e 2 Co mm and W or ds

CARRIER WAVE
About 50 ~ 100mA current is normally applied through an infrared LED in order to extend the infrared
reaching distance. Therefore, reducing the time when the LED is ON leads to the reduction of power
consumption. On PT2248, when the signal is transmitting, each bit is switching by a carrier wave of 1/3
duty. Carrier frequency (fc) is dependent on the oscillation frequency (fosc) and is given by the
following formula:

fosc
a= (Hz)
12

where: fc = 38KHz at fosc = 455KHz

Tr an s m it tin g S ig n a l

P u ls e M od u la te d
Tra n s mit t in g S ig na l

PT2248 V2.7 -9- June, 2005

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Infrared Remote Control Transmitter PT2248

ABSOLUTE MAXIMUM RATINGS

(Ta=25℃)

Parameter Symbol Ratings Unit

Supply Voltage Vcc 5.5 V
Input/Output Voltage VIN Vss-0.5 to Vcc+0.5 V
Power Dissipation Pd 200 mV
Operating Temperature Topr -40 ~ +85 ℃
Storage Temperature Tstg -65~+150 ℃
Txout Output Current Iout -5 mA

ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, Vcc=3V and Ta=25 ℃)

Parameter Symbol Conditions Min. Typ. Max. Unit

Operating Supply Voltage Vcc All Function Operations 2.2 - 5.0 V
Operating Supply Voltage Icc Key On Without Load - - 1.0 mA
All Keys Off,
Stand-by Current ISTB - 1.0 10 µA
Stops oscillation
“H”
K1~K6 Voltage VIH - 0.8Vcc - Vcc V
Level
“L”
CODE VIL - 0 - 0.5 V
Level
Input
“H”
IIH VI=3.0V 20 40 60 µA
Level
K1~K6 Current
“L”
IIL VI=0V -1.0 - 1.0 µA
Level
“H”
IOH Vo=2.0V -500 - - µA
Level
T1~T3 Current
“L”
IOL Vo=2.0V 30 - - µA
Level
Output
“H”
IOH Vo=2.0V -0.1 - - mA
Level
/TXOUT Current
‘L”
IOL Vo=2.0V 1.0 - - mA
Level
OSC Feedback Resistor Rf - - 500 - KΩ
Oscillation Frequency fosc - 400 455 600 KHz

PT2248 V2.7 - 10 - June, 2005

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Infrared Remote Control Transmitter PT2248

APPLICATION CIRCUIT

3V
IR LED
PNP

IN4148 2Ω

+
47 µf
- 16 15 14 13 12 11 10 9
Vcc /T XOUT /T EST CO DE T3 T2 T1 K6

P T22 48

Vss XT /XT K1 K2 K3 K4 K5
1 2 3 4 5 6 7 8

120p 455K 120p

1 2 3 4 5 6

7 8 9 10 11 12

Pin No. 4 ~ 9
13 14 15 16 17 18

Pin No. 10 ~ 12

Notes:
1. R = 200Ω to 3.9 KΩ
2. It is highly recommended that the 47µf capacitor be situated near the Vcc.

PT2248 V2.7 - 11 - June, 2005

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Infrared Remote Control Transmitter PT2248

ORDER INFORMATION
Valid Part Number Package Type Top Code
PT2248 16 Pins, DIP, 300mil PT2248
PT2248-S 16 Pins, SOP, 300mil PT2248-S
PT2248-SN 16 Pins, SOP, 150mil PT2248-SN
PT2248 (L) 16 Pins, DIP, 300mil PT2248
PT2248-S (L) 16 Pins, SOP, 300mil PT2248-S
PT2248-SN (L) 16 Pins, SOP, 150mil PT2248-SN

Notes:
1. (L), (C) or (S) = Lead Free
2. The Lead Free mark is put in front of the date code.

PT2248 V2.7 - 12 - June, 2005

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Infrared Remote Control Transmitter PT2248

PACKAGE INFORMATION

16 PINS, DIP, 300 MIL

PT2248 V2.7 - 13 - June, 2005

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Infrared Remote Control Transmitter PT2248

Symbol Min. Nom. Max.

A - - 0.210
A1 0.015 - -
A2 0.115 0.130 0.195
b 0.014 0.018 0.022
b1 0.014 0.018 0.020
b2 0.045 0.060 0.070
b3 0.030 0.039 0.045
c 0.008 0.010 0.014
c1 0.008 0.010 0.011
D 0.780 0.790 0.800
D1 0.005 - -
E 0.300 0.310 0.325
E1 0.240 0.250 0.280
e 0.100 BSC.
eA 0.300 BSC.
eB - - 0.430
eC 0.000 - 0.060
L 0.115 0.130 0.150
Notes:
1. All dimensions are in INCHES.
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimensions “A”, “A1” and “L” are measured with the package seated in JEDEC Seating Plane
Gauge GS-3.
4. “D”, “D1” and “E1” dimensions do not include mold flash or protrusions. Mold flash or
protrusions shall not exceed 0.010 inch.
5. “E” and “eA” measured with the leads constrained to be perpendicular to datum -c-.
“eB” and “eC” are measured at the lead tips with the loads unconstrained.
6. “N” is the number of terminal positions. (N=16)
7. Pointed or rounded lead tips are preferred to ease insertion.
8. “b2” and “b3” maximum dimensions are not include dambar protrusions. Dambar protrusions
shall not exceed 0.010 inch (0.25 mm).
9. Distance between leads including Dambar protrusions to be 0.005 inch minimum.
10. Datum plane -H- coincident with the bottom of lead, where lead exits body.
11. Refer to JEDEC MS-001 Variation AB.
JEDEC is the trademark of JEDEC SOLID STATE TECHNOLOGY ASSOCIATION.

PT2248 V2.7 - 14 - June, 2005

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Infrared Remote Control Transmitter PT2248

16 PINS, SOP, 300 MIL

Symbol Min. Max

A 2.35 2.65
A1 0.10 0.30
B 0.33 0.51
C 0.23 0.32
D 10.10 10.50
E 7.40 7.60
e 1.27 BSC.
H 10.00 10.65
h 0.25 0.75
L 0.40 1.27
o
α 0 8o

PT2248 V2.7 - 15 - June, 2005

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Infrared Remote Control Transmitter PT2248

Notes:
1. Dimensioning and tolerancing per ANSI Y14.5M-1982.
2. Dimension “D” does not include mold flash, protrusions or gate burrs. Mold Flash, protrusion
or gate burrs shall not exceed 0.15 mm (0.006 in) per side.
3. Dimension “E” does not include interlead flash or protrusions. Interlead flash or protrusions
shall not exceed 0.25 mm (0.010 in) per side.
4. The chamfer on the body is optional. It is not present, a visual index feature must be located
within the crosshatched area.
5. “L” is the length of the terminal for soldering to a substrate.
6. N is the number of the terminal positions (N=16)
7. The lead width “B” as measured 0.36 mm (0.014 in) or greater above the seating plane, shall
not exceed a maximum value of 0.61 mm (0.24 in).
8. Controlling dimension : MILLIMETER.
9. Refer to JEDEC MS-013, Variation AA.
JEDEC is the trademark of JEDEC SOLID STATE TECHNOLOGY ASSOCIATION.

PT2248 V2.7 - 16 - June, 2005

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Infrared Remote Control Transmitter PT2248

16 PINS, SOP, 150MIL

PT2248 V2.7 - 17 - June, 2005

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Infrared Remote Control Transmitter PT2248

PT2248 V2.7 - 18 - June, 2005

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Infrared Remote Control Transmitter PT2248

Symbol Min. Typ. Max.

A 1.35 - 1.75
A1 0.10 - 0.25
A2 1.25 - 1.65
b 0.31 - 0.51
b1 0.28 - 0.48
c 0.17 - 0.25
c1 0.17 - 0.23
D 9.90 BSC.
E 6.00 BSC.
E1 3.90 BSC.
e 1.27 BSC.
L 0.40 - 1.27
L1 1.04 REF.
L2 0.25 BSC.
R 0.07 - -
R1 0.07 -
h 0.25 - 0.50
θ 0° - 8°
θ1 5° - 15°
θ2 0° - -

Note:
1. Dimensioning and tolerancing per ANSI Y 14.5M-1994
2. Controlling Dimension: MILLIMETERS.
3. Dimension D does not include mold flash protrusions or gate burrs. Mold flash, protrusions or
gate burrs shall not exceed 0.15 mm (0.006 in) per end. Dimension E1 does not include
interlead flash or protrusion. Interlead flash or protrusion shall not exceed 0.25mm per side. D
and E1 dimensions are determined at datum H.
4. The package top may be smaller than the package bottom. Dimensions D and E1 are
determined at the outermost extremes of the plastic body exclusive of mold flash, tie bar burrs,
gate burrs and interlead flash, but including any mismatch between the top and bottom of the
plastic body.
5. Datums A & B to be determined at datum H.
6. N is the number of terminal positions. (N=8)
7. The dimensions apply to the flat section of the lead between 0.10 to 0.25mm from the lead tip.
8. Dimension “b” does not include dambar protrusion. Allowable dambar protrusion shall be
0.10mm total in excess of the “b” dimension at maximum material condition. The dambar cannot
be located on the lower radius of the foot.
9. This chamfer feature is optional. If it is not present, then a pin 1 identifier must be located within
the index area indicated.
10. Refer to JEDEC MS-012, Variation AC.
JEDEC is the registered trademark of JEDEC SOLID STATE TECHNOLOGY ASSOCIATION.

PT2248 V2.7 - 19 - June, 2005