MAX3130EAI-T [MAXIM]
Interface Circuit, PDSO28, 5.30 MM, 0.65 MM PITCH, SSOP-28;
| 型号： | MAX3130EAI-T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Interface Circuit, PDSO28, 5.30 MM, 0.65 MM PITCH, SSOP-28 光电二极管 接口集成电路 |
| 文件： | 总16页 (文件大小：216K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1402; Rev 0; 11/98
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
0/MAX31
Ge n e ra l De s c rip t io n
Fe a t u re s
The MAX3130/MAX3131 combine an IrDA 1.2 compati-
ble infrared transceiver with an RS-232 interface—all in
a single 3V-powered hybrid microcircuit. The infrared
tra ns c e ive r s up p orts IrDA d a ta ra te s of 2.4kb p s to
115kbps. The infrared receive channel provides a high-
gain/low-noise PIN-diode amplifier with 100µA of ambi-
ent photodiode current rejection at a +3V supply. A
high-power LED driver capable of sinking 200mA is
included in the infrared transmit path. The on-board
encoder/decoder (ENDEC) compresses/stretches sig-
nals to and from the external UART, allowing IrDA com-
munication even with non-IrDA UARTs.
♦ Integrated RS-232 and IrDA in Single 28-Pin SSOP
Package
♦ 370µA Supply Current
♦ IrDA 1.2 Compatible: 2.4kbps to 115kbps
Data Rate
♦ On-Board IR Encoder/Decoder Allows Use of
Non-IrDA UARTs
♦ +3.0V to +5.5V Single-Supply Operation
♦ Meet EIA/TIA-232 Specifications Down to +3V
♦ 200mA, High-Current Infrared LED Drive
A 2-driver/2-receiver RS-232 transceiver supports data
rates up to 120kbps. A proprietary, high-efficiency, dual
charge-pump power supply and a low-dropout trans-
mitter combine to deliver true RS-232 performance from
a single +3.0V to +5.5V supply. Selectable shutdown
for IR and RS-232 circuitry reduces supply current to
1µA.
♦ 1µA Low-Power Shutdown with RS-232
Receivers Active
Ord e rin g In fo rm a t io n
PART
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
28 SSOP
The MAX3130 is optimized for applications using a sin-
gle UART for both infrared and RS-232 communication.
The infrared transmitter input and infrared receiver out-
put are multiplexed with one RS-232 transmitter input
a nd one RS-232 re c e ive r outp ut, re s p e c tive ly. The
MAX3131’s IrDA transceiver and RS-232 transceivers
are separate and have their own data inputs and outputs.
MAX3130CAI
MAX3130EAI
MAX3131CAI
MAX3131EAI
28 SSOP
28 SSOP
28 SSOP
P in Co n fig u ra t io n
Both these devices require a minimum of external com-
ponents: four small 0.1µF capacitors, a photodiode, an
infrared LED, and a current-setting resistor.
TOP VIEW
EDGEDET (RXD)
1
2
28 R2OUT
27 R2IN
26 T2OUT
25 RSSD
24 V-
T1IN
T2IN
Ap p lic a t io n s
3
Personal Digital Assistants (PDAs)
Palmtop Computers
Battery-Powered Systems
Hand-Held Equipment
Peripherals
IRMODE (TXD)
R1OUT
4
5
MAX3130
MAX3131
R1IN
6
23 C2-
T1OUT
7
22 C2+
21 C1-
BAUD16
GND
8
IrDA Applications
9
20 C1+
19 V+
Cellular Phones
V
CC
10
N.C. 11
18 N.C.
17 LEDC
16 PGND
15 IRSD
AV 12
CC
AGND 13
PINC 14
SSOP
( ) ARE FOR MAX3131
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND..............................................................-0.3V to +6V
Output Short-Circuit Duration (to V or GND)
CC
AV to AGND .........................................................-0.3V to +6V
T1OUT, T2OUT.....................................................Continuous
Output Currents
CC
V
to AV .......................................................................±0.3V
CC
CC
AGND, PGND to GND ........................................................±0.1V
V+ to GND................................................................-0.3V to +7V
V- to GND .................................................................+0.3V to -7V
V+ to V-................................................................................+13V
Inputs (referenced to GND)
LEDC Continuous ........................................................200mA
LEDC 20% Duty Cycle t
< 90µs..............................500mA
ON
Input Current
PINC ..............................................................................10mA
Continuous Power Dissipation (T = +70°C)
A
T1IN, T2IN, TXD, RSSD, IRMODE, BAUD16,
SSOP (derate 9.52mW/°C above +70°C)...................762mW
Operating Temperature Ranges
MAX3130/MAX3131CAI ....................................0°C to +70°C
MAX3130/MAX3131EAI..................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
IRSD....................................................................-0.3V to +6V
R1IN, R2IN .....................................................................±25V
Outputs (referenced to GND)
T1OUT, T2OUT............................................................±13.2V
R1OUT, R2OUT, EDGEDET, RXD.........-0.3V to (V + 0.3V)
CC
LEDC...................................................................-0.3V to +6V
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
0/MAX31
ELECTRICAL CHARACTERISTICS
(V = AV = 3.0V to 5.5V, GND = AGND = PGND, C1–C4 = 0.1µF (Note 1), T = T
to T , unless otherwise noted. Typical
MAX
CC
CC
A
MIN
values are at T = +25°C and V = AV = 3.3V.)
A
CC
CC
PARAMETER
DC CHARACTERISTICS
Power-Supply Current
CONDITIONS
MIN
TYP
MAX
UNITS
V
= 3.3V or 5V, T = +25°C (Note 2)
A
0.25
120
1.0
mA
µA
CC
Analog Power-Supply Current
T
A
= +25°C (Note 2)
200
RSSD = low or IRMODE = low,
= +25°C (Note 2)
Shutdown Supply Current
1.0
10
µA
µA
T
A
Shutdown Analog Supply Current
0.01
1.0
IRSD = low, T = +25°C (Note 2)
A
LOGIC INPUTS (T1IN, T2IN, TXD, IRMODE, BAUD16, IRSD, RSSD)
Input Logic Threshold Low
0.8
V
V
V
= AV = 3.3V
2.0
2.4
CC
CC
Input Logic Threshold High
Input Leakage Current
V
CC
= AV = 5V
CC
V
IN
= 0 to V
±0.01
0.1
±1.0
0.4
µA
CC
LOGIC OUTPUTS (R1OUT, R2OUT, RXD, EDGEDET)
Output Voltage Low
I
= 1.6mA
V
V
SINK
V
-
V
-
CC
CC
Output Voltage High
I
= 1.0mA
SOURCE
0.6
0.05
IR RECEIVER
Data Rate
(Note 3)
(Note 3)
2.4
115.2
6
kbps
Equivalent Input Noise Current
Input Current Sensitivity
10
nA
RMS
0.0002
mA
AV = 3.3V
100
375
CC
Ambient Photodiode Current
Rejection
µA
AV = 5V
CC
2
_______________________________________________________________________________________
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
0/MAX31
ELECTRICAL CHARACTERISTICS (continued)
(V = AV = 3.0V to 5.5V, GND = AGND = PGND, C1–C4 = 0.1µF (Note 1), T = T
to T , unless otherwise noted. Typical
MAX
CC
CC
A
MIN
values are at T = +25°C and V = AV = 3.3V.)
A
CC
CC
PARAMETER
CONDITIONS
MIN
TYP
10
MAX
UNITS
µs
IR Receiver Disable Time
IR Receiver Enable Time
Delay until I
< 1µA
AVCC
Delay until maximum IR receive data rate is valid
300
µs
Data rate = 2.4kbps
Data rate = 115kbps
1
1
90
8
BAUD16 = static
(Note 3)
IR Receiver Output Pulse Width
µs
1.6
IR TRANSMITTER
Transmitter Rise Time
Transmitter Fall Time
10% to 90% of 200mA drive current
90% to 10% of 200mA drive current
20
20
600
600
2
ns
ns
AV = 3.3V
1.15
0.9
CC
Transmitter Output Resistance
I
= 200mA
Ω
OUT
AV = 5V
1.6
10.0
CC
Off-Leakage Current
V
LEDC
= 5.5V
0.01
µA
IrDA ENCODER/DECODER (ENDEC)
Maximum Operating Frequency
IR Output Pulse Width
Maximum frequency at BAUD16
= 1.8432MHz, measured at V
2
MHz
µs
f
1.43
34.6
2.23
2000
BAUD16
LEDC
BAUD16 Operating Frequency Range
RS-232 RECEIVER
f
required to enable ENDEC
kHz
BAUD16
Input Voltage Range
-25
0.6
0.8
25
V
V
V
= 3.3V
1.2
1.5
1.5
1.8
0.3
5
CC
Input Threshold Low
Input Threshold High
V
CC
= 5V
V
CC
= 3.3V
= 5V
2.4
2.4
V
V
CC
Input Hysteresis
Input Resistance
V
T
A
= +25°C
3
7
kΩ
t
t
300
300
300
PHL
R_IN to R_OUT,
Receiver Propagation Delay
ns
ns
C
= 150pF
L
PLH
t
- t
, C = 150pF
L
Receiver Skew
PHL PLH
RS-232 TRANSMITTER OUTPUTS
Output Voltage Swing
Output Resistance
T1OUT, T2OUT, loaded with 3kΩ to GND
= V+ = V- = 0, T_OUT = ±2V
±5
±5.4
10M
±35
V
Ω
V
CC
300
Output Short-Circuit Current
V
T_OUT
= 0
±60
±25
mA
V
T_OUT
= ±12V, V = 0 to 5.5V,
CC
Output Leakage Current
µA
RS-232 transceiver shutdown
Maximum Data Rate
Transmitter Skew
R
= 3kΩ, CL = 1000pF, one transmitter switching
120
235
300
kbps
ns
L
t
- t
PHL PLH
_______________________________________________________________________________________
3
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
ELECTRICAL CHARACTERISTICS (continued)
(V = AV = 3.0V to 5.5V, GND = AGND = PGND, C1–C4 = 0.1µF (Note 1), T = T
to T , unless otherwise noted. Typical
MAX
CC
CC
A
MIN
values are at T = +25°C and V = AV = 3.3V.)
A
CC
CC
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V/µs
µs
V
= 3.3V, R = 3kΩ to
L
7kΩ, measured from
+3V to -3V or -3V to +3V,
CC
C
C
= 150pF to 1000pF
= 150pF to 2500pF
6
4
30
L
L
Transition-Region Slew Rate
Transmitter Enable Time
30
T
A
= +25°C
Delay until transmitter outputs are valid
100
Note 1: C1–C4 = 0.1µF, tested at +3.3V ±10%. C1 = 0.047µF, C2–C4 = 0.33µF, tested at +5.0V ±10%.
Note 2: All supply current measurements are made under no-load condition on all outputs, and all input voltages are at V or GND.
CC
Note 3: For a compliant IrDA input signal where the data rate is within the supported data rate for the IR receive mode: rise/fall
times are less than 600ns and pulse widths are between 1.41µs and 3/16 of the baud rate.
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(V = AV = 3.3V, GND = AGND = PGND, C1–C4 = 0.1µF, R = 3kΩ, T = +25°C, unless otherwise noted.)
CC
CC
L
A
0/MAX31
ANALOG SUPPLY CURRENT
vs. TEMPERATURE
AMBIENT PHOTODIODE CURRENT
REJECTION vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. TEMPERATURE
150
140
130
120
110
100
90
500
400
300
200
100
0
380
360
340
320
300
280
260
240
220
200
V
= 3.3V or 5V
AV = 5V
CC
CC
AV = 3.3V
CC
-40 -20
0
20
40
60
80 100
3.0
3.5
4.0
4.5
5.0
5.5
-40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
RXD OUTPUT PULSE WIDTH
vs. DISTANCE (2400bps)
LED DRIVER ON-RESISTANCE
vs. TEMPERATURE
LEDC VOLTAGE vs. LEDC CURRENT
600
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
100
80
60
40
20
0
TRANSMITTER POWER = 200mW/sr
INPUT PULSE WIDTH = 78µs
TEMIC BPV22NF
V
CC
= 3.3V
500
400
300
200
100
0
V
CC
= 3.3V
V
CC
= 3.3V
V
CC
= 5V
V
CC
= 5V
PULSED AT
20% DUTY CYCLE
I
= 200mA
LEDC
100
150
200
250
300
350
400
-40
-20
0
20
40
80
100
0
20
40
60
80
100
LEDC CURRENT (mA)
TEMPERATURE (°C)
DISTANCE (cm)
4
_______________________________________________________________________________________
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
0/MAX31
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(V = AV = 3.3V, GND = AGND = PGND, C1–C4 = 0.1µF, R = 3kΩ, T = +25°C, unless otherwise noted.)
CC
CC
L
A
RXD OUTPUT PULSE WIDTH vs. DISTANCE
(115.2 kbps)
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
4.0
3.5
3.0
2.5
2.0
1.5
1.0
6
5
TRANSMITTER POWER = 200mW/sr
INPUT PULSE WIDTH = 1.63µs
TEMIC BPV22NF
V
+
OUT
4
1 TRANSMITTER AT 235kbps
1 TRANSMITTER AT 15kbps
V
CC
= 3.3V
3
2
1
0
-1
-2
-3
-4
-5
-6
V
OUT
-
0
20
40
60
80
100
0
1000
2000
3000
4000
5000
DISTANCE (cm)
LOAD CAPACITANCE (pF)
RS-232 TRANSMITTER SLEW RATE
vs. LOAD CAPACITANCE
SUPPLY CURRENT vs. LOAD CAPACITANCE
(RS-232 TRANSMITTING)
18
16
14
12
10
8
40
35
1 TRANSMITTER DRIVEN ONLY
235kbps
30
25
-SLEW
120kbps
20kbps
20
15
+SLEW
6
10
5
4
2
0
0
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
RXD OUTPUT
vs. INFRARED INPUT
RXD OUTPUT
vs. INFRARED INPUT
MAX3130 toc12
MAX3130 toc11
RXD
OUTPUT
2V/div
RXD
OUTPUT
2V/div
2V/div
INFRARED
INPUT
INFRARED
INPUT
2V/div
100µs/div
V = 3.3V, 2400bps AT 1cm DISTANCE
CC
TEMIC BPV22NF
2µs/div
V
= 3.3V, 115.2kbps AT 1cm DISTANCE
CC
TEMIC BPV22NF
TRANSMIT POWER 200mW/sr
TRANSMIT POWER 200mW/sr
_______________________________________________________________________________________
5
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(V = AV = 3.3V, GND = AGND = PGND, C1–C4 = 0.1µF, R = 3kΩ, T = +25°C, unless otherwise noted.)
CC
CC
L
A
RXD OUTPUT
RXD OUTPUT
vs. INFRARED INPUT
vs. INFRARED INPUT
MAX3130 toc14
MAX3130 toc13
RXD
OUTPUT
RXD
OUTPUT
2V/div
2V/div
2V/div
INFRARED
INPUT
INFRARED
INPUT
2V/div
100µs/div
2µs/div
0/MAX31
V
CC
= 3.3V, 2400bps AT 10cm DISTANCE
V
CC
= 3.3V, 115.2kbps AT 10cm DISTANCE
TEMIC BPV22NF
TRANSMIT POWER 200mW/sr
TEMIC BPV22NF
TRANSMIT POWER 200mW/sr
RXD OUTPUT
RXD OUTPUT
vs. INFRARED INPUT
vs. INFRARED INPUT
MAX3130 toc15
MAX3130 toc16
RXD
OUTPUT
RXD
OUTPUT
2V/div
2V/div
2V/div
2V/div
INFRARED
INPUT
INFRARED
INPUT
2µs/div
100µs/div
V
CC
= 3.3V, 115.2kbps AT 1m DISTANCE
V
CC
= 3.3V, 2400bps AT 1m DISTANCE
TEMIC BPV22NF
TEMIC BPV22NF
TRANSMIT POWER 200mW/sr
TRANSMIT POWER 200mW/sr
P in De s c rip t io n
PIN
NAME
FUNCTION
MAX3130
MAX3131
Edge Detector Output. EDGEDET goes low if activity is sensed on either the RS-232
receiver or the IrDA receiver, depending on the state of IRMODE. See EDGEDET: Edge-
Detection Circuitry section.
1
—
EDGEDET
—
2
1
2
RXD
T1IN
IR Receiver TTL/CMOS Data Output
TTL/CMOS RS-232 Transmitter Input
6
_______________________________________________________________________________________
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
0/MAX31
P in De s c rip t io n (c o n t in u e d )
PIN
NAME
FUNCTION
MAX3130
MAX3131
TTL/CMOS RS-232 Transmitter Input. For the MAX3130, drive IRMODE low to connect
T2IN to the IR transmitter input, and drive IRMODE high to connect T2IN to the RS-232
transmitter input. For the MAX3131, T2IN is always connected to the RS-232 transmitter
input.
3
3
T2IN
IR Mode Control. Drive IRMODE low to connect R2OUT to the IR receiver output and
T2IN to the IR transmitter input. Driving IRMODE low also shuts down the RS-232
charge pump and puts the RS-232 transmitter outputs in a high-impedance state. Drive
IRMODE high to connect R2OUT to the RS-232 receiver output and connect T2IN to the
RS-232 transmitter input.
4
—
IRMODE
—
5
4
5
6
7
TXD
R1OUT
R1IN
IR Transmitter TTL/CMOS Data Input
TTL/CMOS RS-232 Receiver Output
RS-232 Receiver Input
6
7
T1OUT
RS-232 Transmitter Output
16-Times Baud-Rate Input. To use the ENDEC, apply a signal that is 16 times the baud
rate into BAUD16. Connect BAUD16 to GND or V to disable the ENDEC.
CC
8
8
BAUD16
GND
9
10
9
10
Ground
V
CC
3.0V to 5.5V Supply Voltage
11, 18
12
11, 18
12
N.C.
AV
No Connection. Do not make connections to these pins.
Analog Supply Voltage V for IR Signal Processing. AV range is 3.0V to 5.5V.
CC
CC
CC
13
13
AGND
Analog Ground for IR Signal Processing. Connect to GND.
Silicon PIN Photodiode Input. Connect PINC to the cathode of the PIN photodiode.
Connect the anode of the PIN photodiode to GND.
14
14
PINC
15
16
17
19
20
21
22
23
24
25
26
27
15
16
17
19
20
21
22
23
24
25
26
27
Shutdown Input for the IrDA Transceiver Circuitry
Power Ground for IR LED Driver. Connect to GND.
Open-Drain Output for Driving the IR LED. Connect LEDC to the cathode of the IR LED.
+5.5V Generated by the Internal Charge Pump
IRSD
PGND
LEDC
V+
C1+
Positive Terminal of the Voltage-Doubling Charge-Pump Capacitor
Negative Terminal of the Voltage-Doubling Charge-Pump Capacitor
Positive Terminal of the Inverting Charge-Pump Capacitor
Negative Terminal of the Inverting Charge-Pump Capacitor
-5.5V Generated by the Internal Charge Pump
C1-
C2+
C2-
V-
Shutdown Input for the RS-232 Transmitters and Charge Pump
RS-232 Transmitter Output
RSSD
T2OUT
R2IN
RS-232 Receiver Input
TTL/CMOS RS-232 Receiver Output. For the MAX3130, drive IRMODE low to connect
R2OUT to the IR receiver output, and drive IRMODE high to connect R2OUT to the
RS-232 receiver output. For the MAX3131, R2OUT is always internally connected to the
RS-232 receiver output.
28
28
R2OUT
_______________________________________________________________________________________
7
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
MAX3 1 3 0 Fu n c t io n Ta b le
MAX3130
CONTROL INPUTS
IrDA
OUTPUT
IrDA
INPUT
LOGIC INPUTS
RS-232 I/O
LOGIC OUTPUTS
T1IN
T2IN
T1OUT T2OUT
R1IN
RS-232 RS-232 RS-232
Input Input Output
RS-232 RS-232 RS-232
Input Input Output
RS-232 RS-232 RS-232
Input Input Output
RS-232 RS-232 RS-232
Input Input Output
R2IN
R1OUT
R2OUT
LEDC
PINC
RSSD IRMODE IRSD
RS-232
Input
IrDA
Input
IrDA
Output
X
X
0
0
0
1
1
1
1
0
1
0
1
0
1
High-Z High-Z
Enabled
Disabled
RS-232
Input
IrDA
Input
IrDA
Output
High-Z High-Z
High-Z High-Z
High-Z High-Z
Enabled
Disabled
Disabled
Disabled
Disabled
Enabled
Disabled
Enabled
Disabled
Enabled
RS-232 RS-232
Input Input
RS-232
Output
RS-232 RS-232
Input Input
RS-232
Output
0
RS-232 RS-232 RS-232 RS-232 RS-232 RS-232 RS-232
Input Input Output Output Input Input Output
RS-232
Output
1
RS-232 RS-232 RS-232 RS-232 RS-232 RS-232 RS-232
Input
RS-232
Output
1
Input
Output Output
Input
Input
Output
0/MAX31
X = Don’t care
MAX3 1 3 1 Op e ra t io n a l Mo d e s Ta b le
T_OUT
High-Z
R_IN
LEDC
Enabled
Enabled
Enabled
Enabled
RXD
RSSD
IRSD
0
0
1
1
0
1
0
1
Enabled
Enabled
Enabled
Enabled
Logic High
IrDA Output
Logic High
IrDA Output
High-Z
Enabled
Enabled
IR Re c e ive rs
De t a ile d De s c rip t io n
The receiver amplifier reverse biases the PIN diode
with approximately 1.2V, and the PIN diode converts
pulses of IR light into pulses of current. The input trans-
impedance (current-to-voltage) amplifier converts and
amplifies these current pulses into voltage pulses. The
MAX3130/MAX3131 incorporate filters that remove low-
frequency ambient light interference and high-frequency
circuit noise from these voltage pulses. A high-speed
comparator then translates these voltage pulses into
CMOS output levels. Figures 1 and 2 show system
functional diagrams.
The MAX3130/MAX3131 a re IrDA 1.2 c omp a tib le ,
infrared transceivers with an integrated RS-232 inter-
face. By selecting appropriate external optical compo-
nents, these devices support IrDA 1.2 data rates from
2.4kbps to 115kbps at distances from 1cm to 1m. A
low-noise design allows them to achieve a bit-error rate
-8
below 10 at maximum data rates. On-chip filtering
rejects out-of-band ambient light signals that interfere
with infrared communication. Both devices include a
high-power LED driver capable of sinking 200mA.
The MAX3130 and MAX3131 contain two RS-232 drivers
and two RS-232 receivers that support data rates up to
120kbps. The RS-232 transceiver is powered by a high-
efficiency, dual charge-pump power supply that oper-
ates with input supply voltages from +3.0V to +5.5V.
The RXD pin is the output of the infrared receiver for
the MAX3131. The R2OUT p in is the outp ut of the
infrared receiver for the MAX3130 (IRMODE = low).
With the ENDEC disabled, the infrared receiver output
pulses low upon each incoming infrared pulse. The
pulse width of the receiver output depends on many
factors, including transmitter distance and power, PIN
photodiode efficiency and area, and incoming data
rate. Under all circumstances the output pulse is less
than one baud period. To communicate with UARTs
that are not IrDA compatible, enable the ENDEC (see
the IrDA Encoder/Decoder (ENDEC) section).
The MAX3130 is optimized for applications using a sin-
gle UART for both infrared and RS-232 communication.
The infrared transmitter input and infrared receiver out-
put are multiplexed with one RS-232 transmitter input
a nd one RS-232 re c e ive r output, re spe c tive ly. The
MAX3131 IrDA and RS-232 transceivers are indepen-
dent of each other for use in simultaneous multiprotocol
transceiver applications.
8
_______________________________________________________________________________________
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
0/MAX31
ON
RSSD
OFF
C1+
SHDN
C1
C2
C1-
V+
V-
CHARGE PUMP
C2+
C3
C4
C2-
R1OUT
R1IN
5k
5k
RECEIVE
LOGIC
OUTPUTS
RS-232
INPUTS
R2IN
R2OUT
T1IN
EDGE
T1OUT
T2OUT
TRANSMIT
LOGIC
INPUTS
RS-232
OUTPUTS
T2IN
232
IRMODE
IR
Rx
TxIN
Tx
BAUD16
EDGEDET
ENDEC
EDGE
RxIN
f
BAUD16
V
CC
GND
1µF
R
SET
MAX3130
LEDC
PGND
PINC
ON
IRSD
AV
CC
1.2V
BIAS
OFF
AGND
1µF
Figure 1. MAX3130 Functional Diagram
_______________________________________________________________________________________
9
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
ON
C1+
RSSD
OFF
SHDN
C1
C2
C1-
V+
V-
CHARGE PUMP
C2+
C3
C4
C2-
R1OUT
R1IN
RS-232
RECEIVE
LOGIC
RS-232
INPUTS
5k
5k
R2IN
R2OUT
T1IN
OUTPUTS
T1OUT
T2OUT
RS-232
TRANSMIT
LOGIC
0/MAX31
RS-232
OUTPUTS
T2IN
TXD
INPUTS
IrDA TRANSMIT
LOGIC INPUT
RXD
IrDA RECEIVE
LOGIC
MAX3131
Rx
TxIN
ENDEC
V
CC
BAUD16
OUTPUT
Tx
RxIN
GND
R
SET
1µF
f
BAUD16
LEDC
PGND
PINC
ON
IRSD
AV
CC
1.2V
BIAS
OFF
AGND
1µF
Figure 2. MAX3131 Functional Diagram
10 ______________________________________________________________________________________
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
0/MAX31
IR Tra n s m it t e r
The infrared transmitter consists of an internal high-
power, open-drain MOSFET switch. This switch has an
on-resistance of less than 2Ω and is capable of switch-
ing 200mA of current. Internal buffering keeps the input
capacitance of the TXD pin extremely low to ease user
drive requirements. Connect an IR LED in series with a
current-setting resistor to select the appropriate IR out-
put power (see the Powering the IR LED section). The
transmitter is not current limited so do not exceed the
power dissipation of the external components during
high duty-cycle transmit schemes.
EDGEDET: Ed g e -De t e c t io n Circ u it ry
(MAX3 1 3 0 )
The MAX3130 has internal edge-detection circuitry that
monitors the RS-232 R2OUT line when IRMODE is low
and monitors the IrDA receive channel when IRMODE
is high. EDGEDET goes low when a positive or negative
edge is detected on either the RS-232 R2OUT line or
the IrDA receive channel (depending on the IRMODE
pin). This edge-detection feature is useful for initiating
an interrupt when data is received on the deselected
line. The EDGEDET signal is cleared when IRMODE is
toggled. Table 1 shows EDGEDET operation.
The TXD input controls the IR LED for the MAX3131.
The T2IN input controls the IR LED for the MAX3130
(IRMODE = low). With the ENDEC disabled (see IrDA
Enc od e r/De c od e r (ENDEC) s e c tion), the IR LED is
turned on by a logic-high signal at the TXD or T2IN
input, for the MAX3131 and MAX3130 respectively.
IrDA En c o d e r/De c o d e r (ENDEC)
The MAX3130 a nd MAX3131 p rovid e a n on-b oa rd
ENDEC to communicate with UARTs that are not IrDA
compatible. The ENDEC is enabled by applying a clock
with a frequency 16 times the baud rate to the BAUD16
input. This BAUD16 clock is commonly provided on
UARTs that do not have IrDA ENDEC capability. Figure
3 illustrates the operation of the ENDEC. The ENDEC
stretches the incoming infrared pulse (a pulse between
IRMODE: Mu lt ip le x e d RS -2 3 2 Op e ra t io n
a n d IrDA Op e ra t io n (MAX3 1 3 0 )
The MAX3130 has the capability to multiplex R2OUT and
T2IN between the IrDA infrared interface and the RS-232
electrical interface. The state of the IRMODE input deter-
mines which interface (infrared or RS-232) is multiplexed
to R2OUT and T2IN. When IRMODE is low, R2OUT acts
as the infrared receiver output and T2IN acts as the
infrared transmitter input. Also, while IRMODE is low, the
RS-232 charge pumps are shut down and the RS-232
transmitters are disabled (see Shutdown section). When
IRMODE is high, R2OUT and T2IN assume their func-
tions as the RS-232 data receive output and transmit
input, respectively. Also, while IRMODE is high, the IR
transmitter is disabled (turned off).
Table 1. EDGEDET Operation
R2IN IrDA RxIN
IRSD RSSD IRMODE
EDGEDET*
X
X
X
X
X
X
X
X
0
0
1
1
X
X
X
X
X = Don’t care
* EDGEDET is cleared by any transition on IRMODE.
INFRARED
PHOTODIODE INPUT *
1.41µs < t < 3CS
16CS
R2OUT (RXD)
WITH ENDEC DISABLED
R2OUT (RXD)
WITH ENDEC ENABLED
16CS
32CS
CS = BAUD16 CLOCK CYCLES
* HIGH = INFRARED LIGHT PULSE
( ) ARE FOR MAX3131
Figure 3a. ENDEC Operation, Receiving Infrared
______________________________________________________________________________________ 11
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
T2IN (TXD)
7CS
INFRARED LED
OUTPUT *
3CS
16CS
CS = BAUD16 CLOCK CYCLES
* HIGH = INFRARED LIGHT PULSE
( ) ARE FOR MAX3131
Figure 3b. ENDEC Operation, Transmitting Infrared
1µs and three BAUD16 clock cycles) into a full baud
period (Figure 3a). Signals applied to TXD are inverted
and compressed to three BAUD16 clock cycles by the
ENDEC b e fore b e ing tra ns mitte d (Fig ure 3b ). The
ENDEC is disabled by connecting the BAUD16 input to
__________ Ap p lic a t io n s In fo rm a t io n
S h u t d o w n
The MAX3130/MAX3131 have split analog and digital
s up p lie s (V
a nd AV ) with s e p a ra te s hutd own
CC
CC
0/MAX31
modes. When IRSD is pulled low, the IR receiver is dis-
V
CC
or GND.
abled and AV current reduces to <1µA. When RSSD
CC
Du a l Ch a rg e -P u m p Vo lt a g e Co n ve rt e r
or IRMODE is pulled low, the RS-232 charge pumps
The MAX3130/MAX3131’s internal power supply con-
sists of a regulated dual charge pump that provides
output voltages of +5.5V (doubling charge pump) and
-5.5V (inverting charge pump) for supply voltages from
+3.0V to +5.5V. The charge pump operates in a dis-
continuous mode: if the output voltages are less than
5.5V, the charge pumps are enabled; if the output volt-
ages exceed 5.5V, the charge pumps stop switching.
Each charge pump requires a flying capacitor (C1, C2)
and a reservoir capacitor (C3, C4) to generate the V+
and V- supplies (Figures 1 and 2). If RSSD (or IRMODE
for MAX3130) is low, both charge pumps shut down.
a re d is a b le d a nd the RS-232 tra ns mitte r outp uts
become high impedance. In this mode, the V current
CC
reduces to <10µA.
IR LED S e le c t io n
The IrDA specification calls for an IR transmitter with a
peak wavelength between 850nm and 900nm. Within a
±15° half-cone angle, the output intensity of the IR LED
must be between 40mW/sr and 500mW/sr. Outside a
±30° half-cone angle, the output intensity of the IR LED
must fall below 40mW/sr. Within these cases, the opti-
cal rise and fall times of the IR LED must be less than
600ns. Based on these system requirements the HP
HSDL-4220, the Temic TSHF5400, or equivalent IR
LEDs are appropriate choices.
RS -2 3 2 Tra n s m it t e rs
The RS-232 transmitters are inverting level translators
that convert CMOS-logic levels to ±5.0V EIA/TIA-232
levels. The MAX3130/MAX3131 transmitters are guar-
anteed for data rates of 120kbps, providing compatibili-
ty with PC-to-PC c ommunic a tion softwa re , suc h a s
LapLink™. These RS-232 transmitters typically operate
at data rates of 235kbps. The RS-232 transmitter out-
puts are high impedance when either IRMODE or RSSD
are low.
P o w e rin g t h e IR LED
Set the current in the IR LED with an external resistor.
Using the IR LED manufacturer’s data sheet, select a
forward current that meets the IrDA specifications dis-
cussed in the IR LED Selection section. Determine the
forward bias voltage of the IR LED (V
) and the
IRLED
voltage drop across the MAX3130/MAX3131 LED driver
(s e e LEDC Volta g e vs . LEDC Curre nt g ra p h in the
Typical Operating Characteristics) and choose the cur-
rent-setting resistor based on the following equation:
The MAX3130/MAX3131 RS-232 receivers translate RS-
232 signa l le ve ls to CMOS-le ve l log ic . The RS-232
receivers also perform a logic inversion from input to
output. The receivers are always active and are not
affected by the RS-232 shutdown input (RSSD).
R
= (V - V
- V
) / I
SET
CC
IRLED
LEDC
SET
Using the HP HSDL-4220 IR LED as an example:
= 5V, I = 100mA, V = 1.67V
V
CC
IRLED
SET
V
= 90mV
LEDC
LapLink is a trademark of Traveling Software.
R
SET
= (5V - 1.67V - 90mV) / 0.1A = 32.4Ω
12 ______________________________________________________________________________________
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
0/MAX31
Power dissipation of the MAX3130/MAX3131, IR LED,
and R are based on the maximum LED current and
duty cycle.
When using the minimum required capacitor values,
ma ke s ure the c a p a c itor va lue d oe s not d e g ra d e
excessively with temperature. If in doubt, use capaci-
tors with a larger nominal value. The capacitor’s equiv-
a le nt s e rie s re s is ta nc e (ESR) us ua lly ris e s a t low
temperatures and increases the amount of ripple on V+
and V-.
SET
Use the following equations to calculate the power dis-
sipation in each component:
MAX3130 power dissipation = I
· V
· duty cycle
SET
DRV
IR LED power dissipation = I
· V
· duty cycle
SET IRLED
2
· duty cycle
SET
P o w e r-S u p p ly No is e Re je c t io n
Because of the extremely sensitive nature of photodi-
ode amplifiers, it is important to maintain a low-noise
supply voltage. Use a separate analog supply voltage
where possible. Place a 1µF ceramic bypass capacitor
R
power dissipation = I
· R
SET
SET
For reliable operation, do not exceed maximum power
dissipation of the components.
as close as possible to the AV
especially noisy systems, connect a small (10Ω) resis-
and V
pins. In
P IN P h o t o d io d e S e le c t io n
PIN photodiode selection is extremely important to sys-
tem performance. The PIN diode must generate at least
200nA (minimum sensitivity of the MAX3130/MAX3131)
of current when aimed ±15° off-axis with an incident
CC
CC
tor in series with V , in addition to the normal bypass
CC
capacitors.
IrDA o r RS -2 3 2 Ap p lic a t io n Circ u it
Figure 4 shows how the MAX3130 is used to multiplex
between RS-232 and IrDA communication while using
only one UART. By using the IRMODE input, the type of
communication (infrared or RS-232) is controlled by the
I/O of a µP. The internal MAX3130 ENDEC is used to
tra ns la te b e twe e n UART-typ e a nd IrDA-typ e b it-
s tre a ms . If the UART ha s this c a p a b ility, c onne c t
BAUD16 of the MAX3130 to GND.
2
irradiance of 4µW/cm . The following equation deter-
mines if the Temic BPV22NF meets these requirements:
2
2
I
= (4µW/cm ) (0.075cm ) (0.95) (0.95) (1.8) (0.6A/W)
= 292nA
PIN
The first term (4mW/cm2) is the minimum guaranteed
irradiance in the ±15° angular range. The second term
(0.075cm2) is the sensitive area of the PIN diode. The
first 0.95 factor normalizes the sensitivity to the 875nm
wavelength and the second 0.95 factor adjusts for the
decreased receiver efficiency at ±15° off-axis. The 1.8
factor accounts for the round lens which increases the
effective PIN diode area. The last term (0.6A/W) is the
sensitivity of the PIN diode. Based on this example, the
Temic BPV22NF is an appropriate selection.
Figure 5 shows the MAX3131 used with two UARTs to
perform simultaneous IrDA and RS-232 communication.
UART1 is a software UART used to perform infrared
IrDA c ommunic a tion. The inte rna l ENDEC on the
MAX3131 translates between UART-type and IrDA-type
bit-streams. The MAX3100 is implemented as UART2
a nd c ommunic a te s via the RS-232 inte rfa c e . The
MAX3100 interfaces to the µP using a SPI interface.
The final important factor in selecting a PIN diode is the
effective diode capacitance. It is important to keep this
capacitance below 70pF at 1.2V reverse bias. Higher
input capacitance compromises the noise performance
of the system by increasing the noise gain of the input
transimpedance amplifier.
La yo u t Co n s id e ra t io n s
The MAX3130/MAX3131 require careful layout tech-
niques to minimize parasitic signals coupling to the
PINC input. Keep the lead length between the photodi-
ode and PINC as short as possible. Keep PC board
traces to the PIN diode away from other noisy traces.
To minimize coupling, run the AGND trace adjacent to
the PINC trace on both sides. To prevent oscillation,
a void routing the RXD tra c e ne a r the PINC tra c e .
Connect the anode of the PIN diode, GND, and the
Ca p a c it o r S e le c t io n
The capacitor type used for C1–C4 is not critical for
p rop e r op e ra tion; e ithe r p ola rize d or nonp ola rize d
c a p a c itors a re g ood c hoic e s . The c ha rg e p ump
requires 0.1µF capacitors for 3.3V operation. For other
supply voltages, refer to Table 2 for suggested capaci-
tor values. Do not use values smaller than those listed
in Table 2. Increasing the capacitor values (e.g., by a
factor of 2) reduces ripple on the transmitter outputs
and slightly reduces power consumption. C2, C3, and
C4 can be increased without changing C1’s value.
However, do not increase C1 without also increas-
ing the values of C2, C3, and C4.
ground lead of the AV
bypass capacitor in a star-
CC
connection. Keep the output pins RXD and TXD as
short as possible to minimize coupling back to the input
via parasitic capacitance.
______________________________________________________________________________________ 13
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
Table 2. Required Capacitor Values
V
(V)
C1 (µF)
0.1
C2, C3, C4 (µF)
CC
3.0 to 3.6
4.5 to 5.5
3.0 to 5.5
0.1
0.047
0.1
0.33
0.47
STANDARD
MAX3130
NON-IrDA
UART
RTS
CTS
T1IN
DB-9
T1OUT
R1OUT
1 2 3 4 5
6 7 8 9
R1IN
RS-232
IrDA
µP
T2OUT
R2IN
Tx
Rx
T2IN
0/MAX31
R2OUT
LEDC
PINC
BAUD16
BAUD16
IRMODE
232
IrDA
I/O
Figure 4. Using the MAX3130 and a Single UART to Perform Both IrDA and RS-232 Communication
SPI
MAX3131
MAX3100
UART2
DIN
RTS
CTS
T1IN
DB-9
T1OUT
DOUT
SCLK
CS
µP
R1OUT
1 2 3 4 5
6 7 8 9
R1IN
RS-232
IrDA
Tx
Rx
T2IN
T2OUT
R2IN
R2OUT
NON-IrDA UART
LEDC
PINC
TX
TXD
RX
RXD
BAUD16
BAUD16
(UART1)
Figure 5. Using the MAX3131 and Two UARTs to Perform Simultaneous IrDA and RS-232 Communication
14 ______________________________________________________________________________________
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
0/MAX31
Ch ip In fo rm a t io n
TRANSISTOR COUNT: 1039
________________________________________________________P a c k a g e In fo rm a t io n
______________________________________________________________________________________ 15
3 V t o 5 .5 V, IrDA In fra re d Tra n s c e ive r w it h
In t e g ra t e d RS -2 3 2 In t e rfa c e
NOTES
0/MAX31
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
16 ____________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 4 0 8 -7 3 7 -7 6 0 0
© 1998 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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