SP3244E datasheet(13/22 Pages) SIPEX

13 / 22 page

Rev M 10/9/06

SP3244E-SP3245E, 3.0V to 5.5V RS-232 Transceivers with Auto On-Line® Plus

DESCRIPTION

±15KV ESD PROTECTION

ESD-protection structures are incorporated

on all pins to protect against electrostatic

discharges encountered during handling and

assembly. The driver output and receiver inputs

of the SP3244E/3245E have extra protection

against static electricity. Sipex uses state-of-

the-art structures to protect these pins against

ESD of ±15kV without damage. The ESD struc-

tures withstand high ESD in all states: normal

operation, shutdown, and powered down. After

an ESD event, the SP3244E/3245E keep work-

ing without latch-up or damage.

ESD protection can be tested in various ways.

The transmitter outputs and receiver inputs

of the SP3244E/3245E are characterized for

protection to the following limits:

• ±15kV using the Human Body Model

• ±8kV using the Contact Discharge

method speciﬁed in IEC 1000-4-2

• ±15kV using the Air-Gap Discharge method

speciﬁed in IEC 1000-4-2

Auto On-line® Plus provides greater power

savings in typical operation because the trans-

ceiver will go into low power standby mode

unless a communication link is in use. Signals

such as CTS, RTS, DTR, DSR, or RI will typi-

cally change signal-state to establish hand-

shaking before any actual data-communication

takes place. Transitions on these handshake

signals will wake up the Auto On-line® Plus

transceiver to prepare it for sending data

(tONLINE 100µs typical).

Receivers remain active to detect incoming

signals in Auto On-line® Plus standby mode.

Receiver outputs may be disabled by enter-

ing manual shutdown by driving SHUTDOWN

pin to logic 0. A special non-inverted receiver

output R2OUT remains active in all modes,

including SHUTDOWN pin at logic 0.

In some applications if there is a signiﬁcant

delay (greater than tOFFLINE) between the

handshaking transitions and the start of data

communication the transceiver may enter

Auto On-Line® Plus standby mode before data

communication begins. The tOFFLINE interval

is at least 15 seconds and no longer than 60

seconds.

In applications where the transceiver needs to

remain active anytime it is connected to live

RS-232 signals, even if those signals remain

idle for longer than tOFFLINE, then the STATUS

output may be used to drive the ONLINE pin.

The STATUS output pin functions the same in

both Auto On-line® and Auto On-line® Plus de-

vices. STATUS will output logic 1 if any of the

receiver inputs are driven greater than ±2.7V

magnitude by incoming RS-232 signals and

drives logic 0 if receiver inputs are ﬂoating or

driven to ground. Driving the ONLINE pin with

the STATUS output disables Auto On-line® Plus

(Forced On-Line) whenever RS-232 voltages

are seen on any receiver inputs. If no RS-232

voltages are seen on the receiver inputs the

Auto On-line® Plus transceiver will still activate

its charge pump and driver outputs when the

driver inputs are active. This allows the trans-

ceiver to signal a remote Auto On-Line® or Auto

On-Line® Plus, on the other end of the data

cable, to wake up.

The STATUS output pin remains active in all

modes, including SHUTDOWN pin at logic 0.

Connecting STATUS output to drive both

ONLINE and SHUTDOWN will wake the trans-

ceiver if any receiver inputs are driven greater

than ±2.7V magnitude and put the transceiver

into Forced Shutdown mode if all receiver

inputs are ﬂoating or driven to ground.

SP3244E Datasheet(PDF) 13 Page - Sipex Corporation

SP3244E Datasheet(HTML) 13 Page - Sipex Corporation

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