IL485-3V Datasheet, PDF (5/8 Pages) List of Unclassifed Manufacturers – Isolated RS485-3V Interface

IL485-3V^ISOLOOP®
Notes:
Application Notes:
1. All Voltage values are with respect to network ground
except differential I/O bus voltages.
2. Differential input/output voltage is measured at the
noninverting terminal A with respect to the inverting
terminal B.
3. Skew limit is the maximum difference in any two channels
in one device.
4. The power-off measurement in ANSI Standard
EIA/TIA-422-B applies to disabled outputs only and is not
applied to combined inputs and outputs.
5. All typical values are at V_DD1,VDD2 = 5V or V_DD1= 3.3 V
and T_A = 25°C.
6. The minimum V_OD2 with a 100Ω load is either ½ V_OD1 or
2V, whichever is greater.
7. ∆|V_OD| and ∆|V_OC| are the changes in magnitude of V_OD
and V_OC, respectively, that occur when the input is changed
form one logic state to the other.
8. This applies for both power on and power off, refer to
ANSI standard RS-485 for exact condition. The
EIA/TIA-422-B limit does not apply for a combined
driver and receiver terminal.
9. Includes 8 ns read enable time. Maximum propagation
delay is 25 ns after read assertion.
10. Pulse skew is defined as the |t_PLH -t_PHL| of each channel.
Power Consumption
Isoloop^ devices achieve their low power consumption from
the manner by which they transmit data across the isolation
barrier. By detecting the edge transitions of the input logic
signal and converting these to narrow current pulses a
magnetic field is created around the GMR Wheatstone
bridge. Depending on the direction of the magnetic field,
the bridge causes the output comparator to switch following
the input logic signal. Since the current pulses are narrow,
about 2.5ns wide, the power consumption is independent of
mark-to-space ratio and solely dependent on frequency. This
has obvious advantages over optocouplers whose power
consumption is heavily dependent on its on-state and
frequency.
The approximate power supply current per channel for
Power Supplies
It is recommended that low ESR ceramic capacitors be
used to decouple the supplies. Both V_DD1 and V_DD2 should
be bypassed with 47 nF capacitors. These should be placed
no further than 1 cm from the device pins for proper
operation. In addition, V_DD2 should have a 10 µF tantalum
capacitor connected in parallel with the 47 nF capacitor.
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NVE Corporation 11409 Valley View Road Eden Prairie, MN 55344-3617 USA Telephone: [phone] Fax: [phone] Internet: www.isoloop.com