Pin Assignments and Descriptions
RX V CC
Pin Pin Name
Indicates the state of the internal LED cathode. Normally not connected.
2 Indicates received serial data. It is a push-pull CMOS driver capable of driving a
standard CMOS or TTL load. No external pull-up or pull-down resistor is required. May O
switch indeterminately when the IBM31T1100A is transmitting.
P3 Vcc Connect to +5 V power supply. Place a 1.0-10 F ceramic bypass capacitor as close as
possible to this pin.
Connect to ground of the power supply. A solid ground plane is recommended for proper
5 NC This pin is reserved for special application use only. No signal should be connected to
This CMOS input is used to put the IBM31T1100A in shutdown mode. Nominal supply
Pcurrent draw in this mode is 35 A versus 5 mA in normal mode. Together with the TX
input, this pin also sets the receiver bandwidth. If TX is low when SD/BW transitions
from high to low, the receiver bandwidth is optimized for operation up to 1.2 Mbps. If
TX is high when SD/BW transitions from high to low, the receiver bandwidth is
optimized for operation at 4 Mbps.
7 TX Used to transmit serial data when SD/BW is low. This CMOS input controls the LED
driver. An on-chip protection circuit disables the LED driver if TX is high for more than
P60 sec. This pin is also used to program the bandwidth of the receiver. See SD/BW pin
Connect this input to Vcc through a resistor to set the proper LED current. Add an
external LED in series to increase output intensity if required.
Two through-hole guide pins provide mechanical stability during board mounting. They
(not shown above) also improve heat conduction when the part is in operation.
NOTE: The IBM31T1100A is pin and plug compatible with the Temic TFDS6000D.