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FXL2TD245 Datasheet(PDF) 2 Page - Fairchild Semiconductor |
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FXL2TD245 Datasheet(HTML) 2 Page - Fairchild Semiconductor |
2 / 12 page ![]() ©2005 Fairchild Semiconductor Corporation www.fairchildsemi.com FXL2TD245 Rev. 1.0.4 2 Functional Diagram Connection Diagram (Top View) Pin Assignment Pin Descriptions Truth Table H = HIGH Voltage Level L = LOW Voltage Level X = Don't Care Power-Up/Power-Down Sequencing FXL translators offer an advantage in that either VCC may be powered up first. This benefit derives from the chip design. When either VCC is at 0 volts, outputs are in a HIGH-Impedance state. The control inputs (T/Rn and OE) are designed to track the VCCA supply. A pull-up resistor tying OE to VCCA should be used to ensure that bus contention, excessive currents, or oscillations do not occur during power-up/power-down. The size of the pull- up resistor is based upon the current-sinking capability of the OE driver. The recommended power-up sequence is the following: 1. Apply power to either VCC. 2. Apply power to the T/Rn inputs (Logic HIGH for A-to-B operation; Logic LOW for B-to-A operation) and to the respective data inputs (A Port or B Port). This may occur at the same time as Step 1. 3. Apply power to other VCC. 4. Drive the OE input LOW to enable the device. The recommended power-down sequence is the follow- ing: 1. Drive OE input HIGH to disable the device. 2. Remove power from either VCC. 3. Remove power from other VCC. Pin Number Terminal Name 1VCCA 2A0 3A1 4 T/R0 5 GND 6 T/R1 7OE 8B1 9B0 10 VCCB VCCA A0 A1 T/R0 OE T/R1 VCCB B0 B1 9 8 7 6 2 10 1 VCCA A0 A1 T/R0 B0 VCCB GND B1 OE T/R1 5 3 4 Pin Names Description OE Output Enable Input T/Rn Transmit/Receive Inputs An Side A Inputs or 3-STATE Outputs Bn Side B Inputs or 3-STATE Outputs VCCA Side A Power Supply VCCB Side B Power Supply Inputs Outputs OE T/R0 T/R1 LL X B0 Data to A0 Output LH X A0 Data to B0 Output LXL B1 Data to A1 Output LX H A1 Data to B1 Output HX X 3-STATE |