MAX3120EUA+ [MAXIM]
Telecom Circuit, 1-Func, PDSO8, UMAX-8;
| 型号： | MAX3120EUA+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Telecom Circuit, 1-Func, PDSO8, UMAX-8 |
| 文件： | 总8页 (文件大小：153K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1390; Rev 0; 10/98
Lo w -P ro file , 3 V, 1 2 0 µA,
IrDA In fra re d Tra n s c e ive r
MAX3120
Ge n e ra l De s c rip t io n
Fe a t u re s
♦ IrDA 1.2 Compatible: 2.4kbps to 115.2kbps
♦ +3V to +5.5V Single-Supply Operation
♦ Flexible Optics Selection and Layout
♦ 120µA Supply Current
The MAX3120 IrDA 1.2-compatible infrared transceiver
is optimized for battery-powered, space-constrained
applications. It consumes only 120µA while supporting
data rates up to 115kbps over a wide 3V to 5.5V oper-
ating range, and features a 10nA shutdown mode to
further extend battery life.
The MAX3120 reduces the space required for IrDA
applications by requiring a minimum of external compo-
nents: photodiode, infrared LED, and current-setting
resistor. Optical components are external to allow maxi-
mum flexibility in PC board design. The MAX3120 is
available in 8-pin µMAX and SO packages. The µMAX
package consumes half the board space of an 8-pin
SO.
♦ 10nA Shutdown Supply Current
♦ 200mA, High-Current Infrared LED Drive
Ord e rin g In fo rm a t io n
PART
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
8 µMAX
8 SO
MAX3120CUA
MAX3120CSA
MAX3120EUA
MAX3120ESA
0°C to +70°C
Ap p lic a t io n s
IrDA Applications
-40°C to +85°C
-40°C to +85°C
8 µMAX
8 SO
Personal Digital Assistants (PDAs)
Palmtop Computers
Cell Phones
Hand-Held Equipment
Peripherals
Typ ic a l Op e ra t in g Circ u it
+3.3V
P in Co n fig u ra t io n
V
CC
V
SHDN
LEDC
CC
CS
SCLK
DIN
LED
TOP VIEW
TX
RX
TXD
RXD
DOUT
MAX3100
GND
MAX3120
TXD
1
2
3
4
8
7
6
5
RXD
PINC
V
CC
LEDC
PGND
SHDN
MAX3120
GND
PINC
GND
PGND
PIN
DIODE
µMAX/SO
________________________________________________________________ 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.
Lo w -P ro file , 3 V, 1 2 0 µA,
IrDA In fra re d Tra n s c e ive r
ABSOLUTE MAXIMUM RATINGS
(Referred to GND)
Continuous Power Dissipation (T = +70°C)
A
V
...........................................................................-0.3V to +6V
µMAX (derate 4.1mW/°C above +70°C) ....................330mW
SO (derate 5.88mW/°C above +70°C).......................471mW
Operating Temperature Ranges
CC
TXD, SHDN, LEDC ...................................................-0.3V to +6V
RXD ............................................................-0.3V to (V + 0.3V)
CC
PGND ....................................................................-0.1V to +0.1V
PINC....................................................................................10mA
Continuous LEDC Current.................................................200mA
Repetitive Pulsed LEDC Current
MAX3120C_A....................................................0°C to +70°C
MAX3120E_A.................................................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
(<90µs, duty cycle <20%) ..........................................500mA
MAX3120
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.
ELECTRICAL CHARACTERISTICS
(V = +3.0V to +5.5V, T = T
to T , unless otherwise noted. Typical values are at T = +25°C and V = +3.3V.)
MAX A CC
CC
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
Supply Current
I
120
200
1.0
µA
µA
T
= +25°C, SHDN = V (Note 1)
CC
A
CC
Shutdown Supply Current
I
0.01
T
A
= +25°C, SHDN = GND (Note 1)
CC(SHDN)
LOGIC INPUTS (TXD, SHDN)
Input Logic Threshold Low
V
0.8
1
V
V
IL
V
= 3.3V
= 5.0V
2.0
2.4
-1
CC
Input Logic Threshold High
V
IH
V
CC
Input Leakage Current
Input Capacitance
I
µA
pF
LEAK
C
2
IN
LOGIC OUTPUT (RXD)
V
OL
I
= 200µA
0.1
0.4
SINK
Output Voltage
V
ns
V
0.5
-
V
0.05
-
CC
CC
V
I
= 100µA
OH
SOURCE
Output Rise and Fall Time
IR RECEIVER
t , t
r
C
= 50pF
LOAD
50
f
Supported Data Rates
Equivalent Input Noise Current
Input Current Sensitivity
2.4
115.2
6
kbps
I
(Note 2)
(Note 3)
10
nA
RMS
NOISE
0.0002
mA
V
= 3.3V
= 5.0V
100
375
10
CC
Ambient DC Current Rejection
Shutdown Time
µA
µs
V
CC
Delay until I < 1µA
CC
Delay until maximum IR receiver data rate is
valid
Shutdown Disable Time
300
µs
Data rate = 2.4kbps
1
1
90
8
IR Receiver Output Pulse Width
µs
Data rate = 115.2kbps
2
_______________________________________________________________________________________
Lo w -P ro file , 3 V, 1 2 0 µA,
IrDA In fra re d Tra n s c e ive r
MAX3120
ELECTRICAL CHARACTERISTICS (continued)
(V = +3.0V to +5.5V, T = T
to T , unless otherwise noted. Typical values are at T = +25°C and V = +3.3V.)
MAX A CC
CC
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
IR TRANSMITTER
Transmitter Rise Time
Transmitter Fall Time
t
10% to 90% of 200mA drive current
90% to 10% of 200mA drive current
20
20
600
600
2.0
1.6
10
ns
ns
r
t
f
V
= 3.3V
= 5.0V
1.15
0.9
CC
Transmitter Output Resistance
Off-Leakage Current
I
= 200mA
Ω
OUT
V
CC
0.01
µA
Note 1: All supply current measurements are made under the following conditions: no load at all outputs, input voltages at GND or
, no PIN diode input current.
V
CC
Note 2: Equivalent input current noise is calculated by dividing the output noise of the transimpedance amplifier by the midband
transimpedance gain.
Note 3: Sensitivity is measured with an IrDA-compliant input signal, where the data rate is within the Supported Data Rate, 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
(T = +25°C, unless otherwise noted.)
A
SUPPLY CURRENT
vs. TEMPERATURE
LED DRIVER
ON-RESISTANCE vs. TEMPERATURE
1.6
1.4
1.2
1.0
0.8
0.6
140
130
120
110
100
90
I
= 100mA
LEDC
V
= 5V
CC
V
CC
= 3.3V
V
= 3V
CC
V
CC
= 5V
60
-40
-15
10
35
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
LEDC VOLTAGE
vs. LEDC CURRENT
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
600
500
400
300
200
100
0
135
130
125
120
115
110
105
PULSED AT
20% DUTY CYCLE
V
CC
= 3.3V
V
CC
= 5V
100
150
200
250
300
350
400
3.0
3.5
4.0
4.5
5.0
5.5
LEDC CURRENT (mA)
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
3
Lo w -P ro file , 3 V, 1 2 0 µA,
IrDA In fra re d Tra n s c e ive r
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 )
(T = +25°C, unless otherwise noted.)
A
RXD OUTPUT PULSE WIDTH
vs. DISTANCE
AMBIENT PHOTODIODE CURRENT REJECTION
RXD OUTPUT PULSE WIDTH
vs. DISTANCE
vs. SUPPLY VOLTAGE
4.0
3.5
3.0
2.5
2.0
1.5
1.0
100
80
60
40
20
0
450
TRANSMITTER POWER = 200mW/sr
INPUT PULSE WIDTH = 78µs
TEMIC BPV22NF
400
350
300
250
200
150
100
50
V
CC
= 3.3V
MAX3120
TRANSMITTER POWER = 200mW/sr
INPUT PULSE WIDTH = 1.63µs
TEMIC BPV22NF
V
CC
= 3.3V
0
0
20
40
60
80
100
0
20
40
60
80
100
3.0
3.5
4.0
4.5
5.0
5.5
DISTANCE (cm)
DISTANCE (cm)
SUPPLY VOLTAGE (V)
RXD OUTPUT
RXD OUTPUT
vs. INFRARED INPUT
vs. INFRARED INPUT
MAX3120 toc08
MAX3120 toc09
RXD
OUTPUT
RXD
OUTPUT
2V/div
2V/div
INFRARED
INPUT
INFRARED
INPUT
2V/div
2V/div
2µs/div
100µs/div
V
CC
= 3.3V, 115.2kbps AT 1cm DISTANCE,
V
CC
= 3.3V, 2400bps AT 1cm DISTANCE,
TERMIC BPV22NF, TRANSMIT POWER 200mW/sr
TERMIC BPV22NF, TRANSMIT POWER 200mW/sr
RXD OUTPUT
RXD OUTPUT
vs. INFRARED INPUT
vs. INFRARED INPUT
MAX3120 toc10
MAX3120 toc11
RXD
RXD
2V/div
2V/div
OUTPUT
OUTPUT
INFRARED
INPUT
INFRARED
INPUT
2V/div
2V/div
2µs/div
100µs/div
V
CC
= 3.3V, 115.2kbps AT 10cm DISTANCE,
V
CC
= 3.3V, 2400bps AT 10cm DISTANCE,
TERMIC BPV22NF, TRANSMIT POWER 200mW/sr
TERMIC BPV22NF, TRANSMIT POWER 200mW/sr
4
_______________________________________________________________________________________
Lo w -P ro file , 3 V, 1 2 0 µA,
IrDA In fra re d Tra n s c e ive r
MAX3120
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 )
(T = +25°C, unless otherwise noted.)
A
RXD OUTPUT
RXD OUTPUT
vs. INFRARED INPUT
vs. INFRARED INPUT
MAX3120 toc13
MAX3120 toc12
RXD
RXD
2V/div
2V/div
OUTPUT
OUTPUT
INFRARED
INPUT
INFRARED
INPUT
2V/div
2V/div
100µs/div
2µs/div
V
= 3.3V, 115.2kbps AT 1m DISTANCE,
V
= 3.3V, 2400bps AT 1m DISTANCE,
CC
CC
TERMIC BPV22NF, TRANSMIT POWER 200mW/sr
TERMIC BPV22NF, TRANSMIT POWER 200mW/sr
P in De s c rip t io n
PIN
1
NAME
FUNCTION
TXD
IR Transmitter TTL/CMOS Data Input. High = LED on.
Supply Voltage
2
V
CC
3
GND
PINC
SHDN
PGND
LEDC
RXD
Ground. Connect anode of PIN diode to GND. Connect GND to PGND.
PIN Diode Cathode Input. Connect cathode of PIN diode to PINC.
Shutdown Input. Active low.
4
5
6
Power Ground. Ground for IR LED driver. Connect PGND to GND.
LED Driver Output. Connect cathode of IR-emitting LED to LEDC.
IR Receiver TTL/CMOS Data Output. Pulses low for IR input pulse.
7
8
Re c e ive r
De t a ile d De s c rip t io n
The MAX3120’s IR receiver amplifier reverse biases the
PIN diode by approximately 1.2V, and the PIN diode
converts pulses of IR light into pulses of current. The
input transimpedance (current-to-voltage) amplifier
then converts these current pulses into voltage pulses
of a useful magnitude. The MAX3120 filters the result-
ing output voltage pulses to remove low-frequency
ambient light interference and high-frequency circuit
nois e . Fina lly, a hig h-s p e e d c omp a ra tor tra ns la te s
these voltage pulses into usable CMOS output levels
(Figure 1).
The MAX3120 is an IrDA 1.2-compatible infrared (IR)
transceiver. By selecting appropriate external optical
components (see IR LED and PIN Photodiode Selection
section), the MAX3120 will operate at data rates of
2.4kb p s to 115kb p s a t d is ta nc e s from 1c m to 1m.
Be c a us e of its low-nois e d e s ig n, the MAX3120
achieves a bit error rate (BER) below 10-8 at maximum
data rates when used with the appropriate external
c omp one nts . On-c hip filte ring re je c ts out-of-b a nd
ambient light signals that would otherwise interfere with
IR communication. Also included in the MAX3120 is
a high-power LED driver capable of sinking 200mA. It
can drive most available IR LEDs at IrDA speeds of
2.4kbps to 115kbps.
_______________________________________________________________________________________
5
Lo w -P ro file , 3 V, 1 2 0 µA,
IrDA In fra re d Tra n s c e ive r
2
2
2
I
= (4µW/cm )(0.075cm )(1.8)(0.95) (0.6A/W)
= 291nA
RXD
TXD
LEDC
PIN
The first term (4µW/cm2) is the minimum guaranteed
irradiance in the ±15° angular range. The second term
(0.075cm2) is the effective sensitive area of the PIN
diode. The factor of 1.8 accounts for the efficiency
increase due to the spherical lens. The first 0.95 factor
normalizes the sensitivity to the 875nm wavelength,
while the second 0.95 factor adjusts for decreased
re c e ive r e ffic ie nc y a t ± 15° off-a xis . The la s t te rm,
0.6A/W, is the sensitivity of the PIN diode. In this exam-
ple, the Temic BPV22NF is an appropriate selection.
PGND
PINC
BANDPASS
FILTER
-
MAX3120
+
BIAS
GND
MAX3120
1.2V
SHDN
V
CC
The final important factor in selecting a PIN diode is
effective diode capacitance. It is important to keep this
capacitance below 70pF at 1.2V reverse bias. Higher
input capacitance can compromise system noise per-
formance by increasing the noise gain of the input tran-
simpedance amplifier.
Figure 1. Functional Diagram
Tra n s m it t e r
The MAX3120’s IR transmitter consists of a high-power
MOS switch, capable of quickly switching 200mA with
less than 2Ω of on-resistance. Internal buffering keeps
the input capacitance of the TXD pin extremely low to
ease the input drive requirement. Connect an IR LED in
series with a current-setting resistor to select the appro-
priate IR output power (see the Powering the IR LED
section). Note that the transmitter does not have an
automatic shutoff circuit, so pay special attention to com-
ponent power dissipation in high-duty-cycle transmit
schemes.
P o w e rin g t h e IR LED
Set the current in the IR LED using an external resistor.
Consult the IR LED manufacturer’s data sheet to select
a forward current that will meet IrDA specifications dis-
cussed in the IR LED and PIN Photodiode Selection
section. Look up the drop across the LED (V
) and
LED
the drop across the MAX3120 LED driver (see Typical
Operating Characteristics - V ) and choose the cur-
LEDC
rent-setting resistor based on the following equation:
Ap p lic a t io n s In fo rm a t io n
V
-V -V
CC LED LEDC
R
=
IR LED a n d P IN P h o t o d io d e 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. The optical rise and fall times
of the IR LED must be less than 600ns. Based on these
system requirements, the Hewlett Packard HSDL-4220
or the Temic TSHF5400 IR LEDs are two appropriate
choices.
SET
I
SET
Using the Hewlett Packard HSDL-4220 IR LED as an
example, V = 5V, I
CC
= 100mA, and V
= 1.67V,
SET
LED
therefore:
V
= 0.08V
LEDC
R
SET
= 32.5Ω
Ap p rop ria te PIN p hotod iod e s e le c tion is e xtre me ly
important to system performance. The PIN diode must
generate at least 200nA (minimum sensitivity of the
MAX3120) of current when aimed ±15° off-axis with an
incident irradiance of 4µW/cm2. Use the following equa-
tion to determine if the Temic BPV22NF meets these
requirements:
6
_______________________________________________________________________________________
Lo w -P ro file , 3 V, 1 2 0 µA,
IrDA In fra re d Tra n s c e ive r
MAX3120
Power-dissipation requirements of the MAX3120, IR
LED, and R must be met based on maximum duty
cycle and output current requirements.
La yo u t Co n s id e ra t io n s
The MAX3120 requires careful layout techniques to mini-
mize parasitic signal coupling to the PINC input. Keep
the lead length between the photodiode and PINC as
short as possible. Be sure to keep PC board traces to
the PIN diode separate from other noisy traces. To mini-
mize coupling, run the AGND trace adjacent to the PINC
trace on both sides. To prevent oscillation, avoid routing
the RXD signal near the PINC signal. Connect the anode
of the PIN diode, the GND pin, and the supply bypass
capacitor pin in a star-ground connection. Connect
PGND and GND together. Reduce the output trace
length from RXD as much as possible to minimize cou-
pling back to the input via parasitic capacitance.
SET
MAX3120 Power Dissipation = ISET · VLEDC · Duty Cycle
IR LED Power Dissipation = ISET · VLED · Duty Cycle
R
Power Dissipation = I 2 · RSET · Duty Cycle
SET
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 quiet supply
voltage. Use a separate analog supply voltage where
possible. Place a 1µF ceramic bypass capacitor as
close to the V
pin as possible. In especially noisy
CC
systems, connect a small (10Ω) resistor in series with
, in addition to the normal bypass capacitor.
Ch ip In fo rm a t io n
V
CC
TRANSISTOR COUNT: 256
P a c k a g e In fo rm a t io n
_______________________________________________________________________________________
7
Lo w -P ro file , 3 V, 1 2 0 µA,
IrDA In fra re d Tra n s c e ive r
P a c k a g e In fo rm a t io n (c o n t in u e d )
MAX3120
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.
8
_____________________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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