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Optical isolator:
To view the description click the following links:
For Further information see ISO100.pdfIso
For Further information see
100
4N35, 4N36, 4N374N.pdf
For Further information see http://www.aeft.co.kr/afl-1000.htmAFL-1000
485OPB
232OPDR
For Further information see HCPL1.pdf & HCPL2.pdfHCPL
ISO422
ISO150
family
ISO 100
The ISO100 is an optically-coupled isolation amplifier.High accuracy, linearity, and time-temperature stability are
achieved by coupling light from an LED back to the input (negative feedback) as well as forward to the output.
Optical components are carefully matched and the amplifier is actively laser-trimmed to assure excellent tracking and
low offset errors.
The circuit acts as a current-to-voltage converter with a minimum of 750V (2500V test) between input and
output terminals. It also effectively breaks the galvanic connection between input and output commons as indicated
by the ultra-low 60Hz leakage current of 0.3mA at 250V. Voltage input operation is easily achieved by using one
external resistor.
Versatility along with outstanding DC and AC performance provide excellent solutions to a variety of challenging
isolation problems. For example, the ISO100 is capable of operating in many modes, including:
noninverting (unipolar and bipolar) and inverting (unipolar and bipolar) configurations. Two precision current
sources are provided to accomplish bipolar operation. Since these are not required for unipolar operation, they are
available for external use.
Designs using the ISO100 are easily accomplished with relatively few external components. Since V OUT of the
ISO100 is simply I IN R F , gains can be changed by altering one resistor value. In addition, the ISO100 has
sufficient bandwidth (DC to 60kHz) to amplify most industrial and test equipment signals.
The ISO100 is fundamentally a unity gain current amplifier intended to transfer small signals between electrical
circuits separated by high voltages or different references. In most applications, an output voltage is obtained by
passing the output current through the feedback resistor (R F ).
The ISO100 uses a single light emitting diode (LED) and a pair of photodiode detectors coupled together to isolate
the output signal from the input.
Figure shows a simplified diagram of the amplifier. I REF1 and I REF2 are required only for bipolar operation to
generate a midscale reference.
The LED and photodiodes (D 1 and D 2 ) are arranged such that the same amount of light falls on each
photodiode. Thus, the currents generated by the diodes match very closely. As a result, the transfer function depends
upon optical match rather than absolute performance. Laser-trimming of the components improves matching and
enhances accuracy, while negative feedback improves linearity. Negative feedback around A 1 occurs through the
optical path formed by the LED and D 1 . The signal is transferred across the isolation barrier by the matched light
path to D 2 .
The overall isolation amplifier is noninverting (a positive going input produces a positive going output).
4N35, 4N36, 4N37
The 4N35, 4N36, 4N37 are optically coupled isolators consisting of a Gallium Arsenide infrared emitting diode and
an NPN silicon phototransistor mounted in a standard 6-pin dual-in-line package.
Features
3500, 2500 or 1500 Volt Isolation.
High DC Current Transfer Ratio (100% min).
Low Cost Dual-In-Line Package.
AFL-1000
The AFL-1000 is a high performance, remote controlled, signal conditioner, built into an optically isolated data
acquisition system, used for acquiring analog data from up to 16 inputs, at a 14 bit resolution, with simultaneous
sampling of up to 16 input channels at up to 90 kHz per channel.
The AFL-1000 is primarily designed for acquiring dynamic and static data from low-level transducers as StrainGages, pressure sensors, and other bridge type sensors as well as voltage producing devices: Piezo sensors,
Temperature sensors, Photo diodes and EEG/DLG inputs. The unit contains a high stability symmetrical excitation
circuit with fixed and variable controls and a high resolution data acquisition system, mainly designed for acquiring
dynamic and static data at 93 kHz per channel, with simultaneous sampling.
The optical isolation between the measuring unit and the host PC is ideal for acquiring low level signal, in industrial
and medical applications, since it eliminates ground-loop problems, and no noise is transferred to the measurement
system caused by long cables or noise generated from the power supply of the PC.
This unit is guaranteed to have noise levels of less than ±1 LSB. By removing a switch on the back panel, you may
switch the channels to a general purpose data acquisition system with an input range of ±3V or ±10V, for connecting
to other analog instruments.
485OPB
The 485OPB optically isolates and protects your RS485 equipment from damaging ground loops and transient spikes
on the data lines. It also acts as a signal repeater to increase the number of possible nodes to more than 32. Works
with either two-wire or four-wire systems. Also, by using one side of the 485OPB in two-wire mode and the other in
four-wire mode, it can convert equipment that is non-tristateable RS422 to a two-wire RS485 device. A set of
jumpers allows the 485OPB to operate in either half-duplex or full-duplex mode for a versatile connection to virtually
any RS422/485 system.
Specifications
-directional over voltage suppressor
600 W peak power dissipation
3000pF maximum capacitance
8K baud
-14 VDC @ 60 mA (idle state)
170 mA (full-duplex data with 62 Ohm load)
Dimensions: 9.7 x 6.1 x 2.5 cm
232OPDR
Optically isolate and protect your equipment from damaging ground loops and transient spikes on the data lines. The
232OPDR isolates four channels, TD, RD, RTS and CTS. LEDs indicate transmission and power. All four channels
have a maximum baud rate of 115.2K baud. Protects the transmit and receive lines of your RS-232 port from ground
loops and power surges up to 2,000 Volts. 3" x 4" x 1" thick.
HCPL family
Agilent Technologies offers a wide array of Optoisolators for noise rejection,ground loop current elimination,and
high voltage isolation for digital data transmission and communication applications.The product offering includes
low speed (100 kbit/s to 1 M bit/s)split Darlington or single transistor type optoisolators to high speed 25 M bit/s
cascaded amplifier stage optoisolators with Schottky transistor or CMOS output stage.
Description
Figure 1 shows a Photodiode/Transistor Optoisolator where a PIN photodiode detector is coupled to a single
transistor amplifier output stage (e.g.HCPL-4504).
Compared to a typical phototransistor optoisolator,a PIN photodetector diode reduces the base-collector “Miller ”
capacitance and allows operability at a much higher speed.
Figure 2 shows a Split Darlington Output Stage,where an emitter-follower stage is added between a PIN photodiode
and the output amplifier.This allows the optoisolator to be driven at a much lower input drive current, as low as 40
mA for the HCPL-4701/HCPL-4731 family or 0.5 mA for the 6N139 family.This allows much higher current transfer
ratio (CTR)or current gain at the output,and TTL/CMOS gates can be easily driven.
Figure 3 shows a photodiode cascaded amplifier,coupled to a Schottky transistor,open collector output stage.In order
for an open collector output stage to function,a pull-up resistor is required at the output of the Optoisolator.
Figure 4 shows a photodiode and cascaded amplifier,coupled to a totem pole output stage.This type of output stage
eliminates the necessity of using a pull-up resistor at the output.The outputs can sink or source current allowing
higher output power drive capability.
Figure 5showsapush-pullCMOS output stage.These types of optoisolators are designed to achieve highest speed
performance (up to 25 M bit/s for HCPL-7721/7720).Theamplifier stage presents very low input impedance to the
photodiode, and does not become saturated, while allowing the signal to be amplified several olds through the
amplifier stages,allowing operation at relatively low LED drive currents (2 to 5 mA).
ISO422 & ISO150:Isolating Serial Data Streams
When isolating a digital signal, you have a great range of options. If the data stream is bit serial, candidate solutions
range from a simple optical coupler to an isolated transceiver IC. Major design considerations include:
• Required data rate
• Power supply requirements on the isolated side of the system
• Whether the data channel must be bidirectional
LED-based optical couplers were one of the first techniques
applied to the isolation design problem. Several LED-based
ICs are now available and can supply data speeds of 10 Mbps
and beyond. An important design consideration is an LED’s
decreased light output with age. You must therefore supply
excess current to the LED during its early life so it will
output sufficient light as it ages. Because power can be in
short supply on the isolated side, this need to supply excess
current may pose a significant problem. Because an LED
could require drive currents higher than those available from
simple logic output stages, special drive circuits are often
required.
Figure 1.The ISO150 isolates serial data. In this
configuration, the direction of transmission is
reversible under control of the signal labeled DIR.
For high-speed applications and instances where the direction
of data flow must be reversed under control of a logic signal,
Burr-Brown’s ISO150 digital coupler can be used. Figure1
shows this IC in a bidirectional application. Channel 1
controls the direction of transmission for channel 2 and is
configured for transmission from side A to side B. The signal
applied to the D1A pin determines the direction of signal
flow. A high level sent to the B side sets that side of channel
2 into the receive mode and the inverse (a low) is applied to
Figure2.The ISO422 can be connected for either half
the Mode pin for channel 2, side A, to set it into the send
duplex
or full duplex. Termination resistors reduce
mode. The state of the direction signal is available on both
reflections
and ringing for maximum distance.
sides of the isolation barrier. This circuit will function at data
rates to 80 MHz.
A second variation on bit-serial communication is the growing set of differential bus systems. These systems are
described by the RS-422, RS-485, and CANbus standards. While some systems have the luxury of a common ground,
many have nodes at different potentials. This is particularly true when the nodes are separated by even modest
distances. The Burr-Brown ISO422 is a highly integrated, full-duplex isolated transceiver designed for service to all
of these specifications. This transceiver can be configured for half-duplex or full-duplex service (see Figure2).
Service at transmission rates of 2.5 Mbps is possible. This device even contains a loop-back test facility so that each
node can perform self-test operations. During this mode, data on the bus are ignored.