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TGoddard/SP333/9617R0

SP333 RS-232/AppleTalk Programmable Transceiver

© Copyright 2000 Sipex Corporation

Shutdown Mode

The SP333 can be put into a low power shut-

down mode by connecting the Shutdown pin

(SD, Pin 26) to a logic HIGH. During Shut-

down, the driver outputs are put into a high

impedance tri-state, and the charge pump is put

into stand-by mode. The supply current drops to

less than 10

µA during shutdown and can be

activated in either RS-232 or AppleTalk mode.

For normal operation, the SD pin should be

connected to a logic LOW.

Receiver Enable

The SP333 has a control line to enable or disable

the receiver outputs. Pin 3 (RXEN) is active

LOW; a logic LOW on Pin 3 will enable the

receiver outputs. A logic HIGH on Pin 3 will

disable the receiver outputs. The receiver en-

able function can be initiated in either RS-232 or

AppleTalk mode.

Wake-Up

The SP333 also features a "wake-up" function.

The wake up function allows the RS-232 receiv-

ers to remain active during Shutdown mode

unless they are disabled by the Receiver Enable

control pin (Pin 3). The wake-up feature allows

users to take advantage of the low power Shut-

down mode and keep the receivers active to

accept an incoming "ring indicator" signal.