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DF2

Enhanced 16 Differential I/O Multi-Mode Transceiver Channels

Function module DF2 (Enhanced Version) multi-mode transceivers with 16 programmable I/O channels. Differential transceivers increase resistance to noise by creating two complementary signals. These complementary signals produced on balanced lines double noise immunity by creating lower power requirements due to lower supply voltages.

When programmed for input, each differential channel has a selectable internal resistor (120 ohm) across its inputs. Each channel also can be programmed for fast or slow slew rates (a slow slew rate may be desirable for certain sensitive EMI-radiated transmission line applications). Status and/or interrupts can be polled/enabled for each channel to indicate transition on rising edge, transition on falling edge, or Background Built-in-Test (BIT) fault. Debounce circuits for each channel offer a programmable time delay to eliminate false signals resulting from contact bounce commonly experienced with mechanical relays and switches. All inputs are continuously scanned.

Continuous Background Built-in-Test (BIT) status provides real-time channel health for mission-critical systems. This feature runs in the background and is transparent in normal operations. When the channels are programmed as inputs, a redundant, read-back circuit continually scans each channel to verify the input. When the channels are programmed as outputs, the read-back circuit is compared with the commanded output logic.

Features
  • 16 channels available as inputs or outputs
  • Programmable Pulse Width Modulation (PWM) output mode
  • Pattern Generator output mode
  • Programmable for fast or slow slew rates
  • Programmable debounce circuitry with selectable time delay eliminates false signals resulting from relay contact bounce.
  • Built-in test runs in background constantly monitoring system health for each channel.

Specifications
  • Operational Mode: RS-433, RS-485
  • Receiver Input Levels: RS-422: -10 V to 10 V, RS-485: -7 V to 12 V
  • Receiver Input Sensitivity: RS-422: +200 mV, RS-485: +200 mV
  • Receiver Input Resistance: RS-422: 120 Ω or 125 kΩ, RS-485: 125 kΩ
  • : Each channel incorporates a 120 Ω termination resistor that can be programmed on a channel by channel basis.
  • Read Delay: RS-422: 300 ns (100 ns w/ low EMI off), RS-485: 300 ns (100 ns w/ low EMI off)
  • Debounce: RS-422: Programmable per bit from 0 to 34.36 sec. (LSB= programmable) (pending characterization), RS-485: Programmable per bit from 0 to 34.36 sec. (LSB= programmable) (pending characterization)
  • Driver Output Voltage: RS-422: -0.25 V to 5 V max., RS-485: -0.25 V to 5 V max.
  • Driver Output Signal Level (Loaded Minimum): RS-422: +2 V, RS-485: +1.5 V
  • Driver Output Signal Level (Unloaded Maximum): RS-422: +5 V, RS-485: +5 V
  • Driver Load Impedance (Maximum Driver Current In): RS-422: 100 Ω, RS-485: 54 Ω
  • Hi Z State (Power-On) (Maximum Driver Current In): RS-422: N/A, Rs-485: +100 µA
  • Hi Z State (Power-Off): RS-422: +10 µA, RS-485: +10 µA
  • Write Delay: RS-422: 100 ns, RS-485: 100 ns (low EMI off)
  • Protection: Short circuit protected, thermal shutdown, built-in current limiting.
  • Rise/Fall Time: 31 ns into a 50 pf load
  • Power (Per 16-Channels): 5 VDC @ 200 mA, 360 mA fully loaded (54Ω load per channel)
  • Ground: All grounds are common and connected to system ground.
  • Weight: 1.5 oz. (42 g)
Block Diagram

(Click diagram to enlarge)

Documentation
5/13/2021 4:03:15 PM
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