IRM1021
1.15 Mb/s Infrared Data Transceiver
Preliminary
Dimensions in inches (mm)
C
L
0.177
(4.50)
Plastic
PCB
Pin 1
0.378 (9.60)
FEATURES
•
•
•
•
Fully Compliant with IrDA Specification
IrDA Data Rates 9.6 Kb/s to 1.152 Mb/s
High Immunity to Fluorescent Light Noise
Battery & Power Management Features:
– Receive – 1.8 mA Typical
– Shutdown – 10 nA Typical
– Independent LED Anode Supply – up to
9.0 V DC
– Wide Operating Voltage Range 2.4 V to 5.5 V
– High
V
CC
Noise Rejection >100 mV
P–P
Shutdown Tri-States Receiver Output and
Disables TxD allowing Bus Interfacing
Integrated Protection for Eye Safety—
AC Coupled Transmit Input
High DC Ambient Rejection—Operates Outdoors
Receiver Latency Less <100
µ
s
Slimline Package:
H 4.0 mm x D 4.5 mm x L 9.6 mm
Pin 1
0.158
(4.00)
•
•
•
•
•
DESCRIPTION
IRM1021 is an IrDA compliant 1.152 Mb/s infrared
data transceiver. The IRM1021 consists of a PIN pho-
todiode, an infrared LED and a custom ASIC, all
attached to a printed circuit board. Its external shut-
down (SD) feature cuts the current consumption to
less that 0.01
µ
A . The transmit pulse is limited to
70
µ
s, extending transmitter life and ensuring eye
safety. The flat top surface is ideal for high speed
pick-and-place manufacturing.
Absolute Maximum Ratings,
T
A
=25°C (except where noted)
Supply Voltage Range, all states,
V
CC
................................–0.5 to +7.0 V
LED Anode Voltage,
V
CC
=0 to 5.5 V, not transmitting, V
LEDA
..........................–0.5 to +9.0 V
LED Anode Voltage,
V
CC
=2.4 to 5.5 V, transmitting, V
LEDA
..................... –0.5 to
V
CC
+4.0 V
Input Current,
I
CC
during transmit,
V
CC
=5.0 V, TxD=
V
CC
(peak) .......................20 mA
Output RxD Current ........................................................................50 mA
Storage Temperature,
storage or reduced performance,
T
S
.............................–40 to +100
°
C
Ambient Temperature, operating,
T
A
..................................... –25 to 85
°
C
Lead Solder Temperature, 230
°
C .................................................... <10 s
IC Junction Temperature,
T
J
........................................................... 125
°
C
Average IR LED Current, LED Anode=3.3 V, I
LED
........................100 mA
Repetitive Pulsed IR LED Current,
<10
µ
s, t
on
<20%, LED Anode=3.3 V, I
LED(RP)
..........................600 mA
Input Voltage: TxD, SD................................................. –0.5 to
V
CC
+0.5 V
RxD Voltage ................................................................ –0.5 to
V
CC
+0.5 V
Table 1. Pin Functions
Pin no.
Function
1
2
3
4
IR LEDA
IR LEDC
TxD
RxD
Pin no.
5
6
7
8
Function
SD
V
CC
GND
GND
Document Number:
82580
Revision: 17-August-01
www.vishay.com
1
Figure 1. Block Diagram
V
CC
Photodiode
Main
AMP
Lowpass
Filter
Preamp
Receive Detector
+
Receiver Output
+
Tri-State
CMOS Buffer
V
CC
500 kΩ
V
CC
Pin 6
RxD
Pin 4
Ambient DC
Cancelling
AGC & Signal
Reference
Processor
Tx
Blanking
Detector
Reference
Tri-State
Control
Regulated
Voltage &
Current
Sources
Power Down
V
CC
SD
Pin 5
AGC
Pin 7
LED Anode
Tx Input
Buffer
TxD
Pin 3
GND
Pin 8
Tx In
Switched
current source
V
CC
Transmit
IR LED
Error
AMP
Pin 1
LED Cathode
Pin 2
Current Limited
Driver
500 kΩ
Theory of Operation
The IRM1021 Cast Slimline Infrared Data Transceiver, IrDT
consists of a detector photodiode, an IR LED transmitter, an IC
containing ambient light suppressor and Automatic Gain con-
trol circuitry (AGC).
The ambient light suppressor can cancel up to 10 mW/cm
2
at
5.0 V. This will typically allow operation in all but direct sunlight.
The receiver automatic gain control (AGC) circuit normalizes
pulse width despite 120 dB signal range. The AGC also
improves noise immunity while receiving a transmission by
reducing gain so that noise less than 1/2 the peak signal
height will not be detected.
Asserting shutdown high powers down the transceiver, and for
bus multiplexing, tri-states the receiver output and disables TxD
input.
In receive mode, the receiver output (RxD) which normally
stays high, will go low for duration of the receive pulses. It is a
push-pull CMOS driver capable of driving a standard CMOS or
TTL load. No external pull-up or pull-down resistor is required.
In transmit mode, by asserting the TxD pin above 1.4 V will turn
on IR LED transmitter. This pin has a 500 k
Ω
pulldown. At the
LED Anode (pin 1) connect this pin to
V
CC
or unregulated
power supply (not to exceed
V
CC
+4.0 V), through a resistor to
set the proper LED current to reduce the thermal dissipation
and to lower LED current.
Table 2. Slimline Truth Table
Inputs
SD
High
Low
TxD
X=don’t
care state
High
Low
<0.4
µ
W/cm
2
(115 Kb/s)
<1
µ
W/cm
2
(1 Mb/s)
>4
µ
W/cm
2
(115 Kb/s)
>10
µ
W/cm
2
(1 Mb/s)
detector
X=don’t care state
Outputs
RxD
500 k
Ω
pull-up
Undefined
High
Low
LED
Off
On
Off
Document Number:
82580
Revision: 17-August-01
www.vishay.com
2
Electrical Characteristics
Table 3. Basic Operating Parameters,
T
A
=25
°
C (except where noted)
Parameter
Sym-
Min.
Typ.
Max.
Supported IrDA Data Rate
V
CC
Voltage
Maximum LED Anode Voltage
I
CC
Shut Down Current
(Note 1)
I
CC
Standby Current
I
CC
Receiving Current
I
CC
Transmitting Current, Saturated
Driver (Average)
V
CC
V
LEDA
I
CC1
I
CC2
I
CC3
I
CC4
0.01
1.4
1.8
3.0
4.5
9.6 K
2.4
1152
5.5
V
CC
+4
1.0
2.5
µ
A
mA
Unit
Kb/s
V
Conditions
3/16 clock period or 1/4 clock >115 Kb/s
0 to 70
°
C
V
CC
to V
SS
V
CC
=1.5 V to 5.5 V
SD=
V
CC
V
CC
=2.4 V to 5.5 V
SD=0
V
CC
=2.4 V to 5.0 V no signal
SD=0, Vcc=5.0V, 1Mbps, 50% pulses 1
µ
A
V
CC
=5.0, LED I=400 mA
Table 4. I/O Parameters
Parameter
TxD, SD input capacitance
TxD Resistance
TxD, SD Input Threshold
(Note 1)
SD to RxD Tri-State
SD to RxD Enable
RxD Output High
RxD Output High
RxD Output Low
RxD Output Low
RxD Short Circuit
RxD Short Circuit
RxD to
V
CC
Tri-State Impedance
RxD Rise/Fall Time
350
V
OL
V
OH
350
1.0
50
20
3.5
2.0
4.0
2.1
0.7
0.2
48
10
500
7
18
12
30
650
kΩ
ns
1.2
0.4
mA
V
Sym-
Min.
Typ.
3.0
500
1.4
Max.
700
1.8
Unit
pF
k
Ω
V
ns
Conditions
V
CC
=2.4 V to 5.5 V
TxD=
V
CC
V
CC
=5.0 V
V
CC
=5.0 V
V
CC
=2.4 V to 5.0 V
V
CC
=2.4 V to 5.0 V
V
CC
=5.0 V I
oh
=20 mA
V
CC
=2.4 V I
oh
=3.0 mA
V
CC
=5.0 V I
ol
=20 mA
V
CC
=2.4 V I
ol
=3.0 mA
V
CC
=5.0 V RxD=0 RxD=V
CC
V
CC
=2.4 V RxD=0 RxD=V
CC
SD=V
CC
V
CC
=5.0 V between RxD to
V
CC
V
CC
=5.0 V Load=15 pF
V
CC
=5.0 V Load=100 pF
V
CC
=2.4 V Load=15 pF
V
CC
=2.4 V Load=50 pF
Table 5. Receiver Parameters,
T
A
=25°C (except where noted)
Parameter
Maximum Data Rate
Receive 1/2 Angle
Minimum Signal Detect Irradiance
Maximum Signal Detect Irradiance
Maximum Signal Irradiance No detect
Maximum DC Ambient Irradiance 5.0 V
Maximum DC Ambient Irradiance 2.7 V
AGC Attack Time
(Note 2)
AGC Settling
(Note 3)
AGC Decay Rate
(Note 5)
Transmit Receiver Latency
(Note 4)
Document Number:
82580
Revision: 17-August-01
Sym-
Min.
15
Typ.
1.15
Max.
Unit
Mb/s
degrees
µW/cm
2
Conditions
200 ns 4.0
µW/cm
2
to 500 mW/cm
2
IrDA
Physical Layer
specification
Bit error Rate=10
–8
217 ns pulse
E
IHmin
E
Emax
1.0
3.0
500
0.7
30
10
1.0
5.0
44
2.0
10.0
mW/cm
2
Bit error Rate=10
–8
217 ns pulse
µW/cm
2
< 0.1 pulse per second detect, 20 kHz to
200 kHz square wave <100 ns rise/fall
mW/cm
2
V
CC
=5.0 V
V
CC
=2.4 V
µs
pulse
dB/ms
150
µs
4.0
µW/cm
2
to 500 mW/cm
2
4.0
µW/cm
2
to 500 mW/cm
2
217ns pulse
Following AGC settling at 500 mW/cm
2
0 to 3.0 mW/cm
2
DC ambient input
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3
t
L
100
Table 5. Receiver Parameters,
T
A
=25°C (except where noted) (continued)
Parameter
RxD Suppression Duration
(Note 6)
Powerup Receiver Latency
RxD pulse width
150
1.2
Sym-
Min.
Typ.
50
100
Max.
100
150
450
5
30
Unit
µs
Conditions
Following end of TxD pulse
0 to 2.5 mW/cm
2
DC ambient input
ns
µs
1.162 Mbps
115 kbps
9.6 kbps
RxD Jitter, Leading edge
120
ns
Between two pulse@1.152 Mbps
Table 6. Transmitter Output
Parameter
Maximum Data Rate
TxD Radiant Intensity, Tx Mode High
Symbol
Min.
Typ.
1.1
Max.
Unit
Mb/s
Conditions
TxD pulse width=125 ns
V
CC
=5.0 V LEDA=3.3 V Tx High 10% duty
cycle
V
CC
=2.7 V LEDA=3.3 V Tx High 10% duty
cycle
LEDA=1.8 V 10% duty cycle
LEDA=3.3 V Tx Low 10% duty cycle
LEDA=2.7 V Tx Low 10% duty cycle
100
170
150
50
500
mW/Sr
TxD Radiant Intensity, Tx Mode Low
18
16
TxD 1/2 Angle
TxD Peak Wavelength
I
LED
Limit, Tx High
I
LED
Limit, Tx Low
TxD
V
CC
dV/dt Rejection
15
850
385
40
20
870
500
50
5.0
30
900
650
70
degrees
nm
mA
IrDA
Physical Layer
specification
I
F
=500 mA
TxD=V
CC
LED anode=3.3 V
V
CC
=2.7 to 5.0 V
TxD=V
CC
LED anode=3.3 V
V
CC
=2.7 to 5.0 V
V/µs
dV/dt for less than 20% change in TxD output
Note 1:
For Shut Down (SD) current to fall below 1.0
µA
requires driving
Shut Down (SD) to within 0.5 V of
V
CC
to ensure cutoff of the PMOS
transistor of the input CMOS totem pole. In most applications this is
not an issue if Shut Down (SD) is driven from a CMOS driver sup-
plied from the same voltage supply.
Note 2:
“AGC Attack Time” is the time required for internal AGC (Automatic
Gain Control) attenuation to rise to within 10% of final value.
Note 3:
“AGC Settling” is the number of pulses within 100
µs
required for
the output pulse width to settle to 90% of its final value.
Note 4:
“Near-far Receiver Latency” is the time required for the AGC and
ambient correction circuits to return to maximum sensitivity (Far) fol-
lowing reception of a maximum (Near) signal or a change in ambi-
ent. “Transmit Receiver Latency” is commonly called “Receiver
Latency” or “Transmitter Turnaround Time”.
Note 5:
“AGC Decay Rate” is the rate at which the receiver gain increases
following the cessation of signal input.
Note 6:
RxD is active while (TxD) transmit pulse is active.
Table 7. External Component
Parameter
Values
V
LED
2
power supply
Resistor (R
0
)
0
2.7
0
3.0
0
3.5
1.5
4.0
2.7
4.5
3.9
5.0
5.1
Unit
V
Ω
Document Number:
82580
Revision: 17-August-01
www.vishay.com
4
Figure 2. Input Schematics
V
CC
TxD
Figure 3. Output Schematics
V
CC
500 k
Ω
pullup
V
CC
V
CC
V
CC
V
CC
V
CC
RxD
V
CC
SD
A current limiting resistor should be used between the LED
anode and
V
CC
(see Table 7 for recommended values).
Figure 4. Infrared Reflow Soldering Profile
300
Maximum 240(+5/– 0)
°C
210
°C
Temperature
(°C)
200
250
150
100
50
60 s minimum
30 s minimum
30 s maximum
0
0
50
100
Time (sec)
150
Figure 5. Super I/O (PC87108AVJE) to IRM1021
V
CC
0.1
µF
22
µF
R0
1
6
V
CC
LED
Anode
50
V
CC
IR TxD
PC87338VLJ
IR RxD
67
4
65
3
TxD
IRM1020
RxD
SD GND
5
8
GND
V
SS
IR SLO
42
68
Document Number:
82580
Revision: 17-August-01
www.vishay.com
5
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