SP3220EUEA View Datasheet(PDF) - Signal Processing Technologies
Part Name
Description
Manufacturer
SP3220EUEA Datasheet PDF : 21 Pages
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DESCRIPTION
The SP3220E/EB/EU devices meet the EIA/TIA-
232 and V.28/V.24 communication protocols and
can be implemented in battery-powered, portable,
or hand-held applications such as notebook or
palmtop computers. The SP3220E/EB/EU de-
vices feature Sipex's proprietary on-board charge
pump circuitry that generates 2 x VCC for RS-232
voltage levels from a single +3.0V to +5.5V power
supply. This series is ideal for +3.3V-only systems,
mixed +3.0V to +5.5V systems, or +5.0V-only
systems that require true RS-232 performance.
The SP3220EB device has a driver that can oper-
ate at a data rate of 250Kbps fully loaded. The
SP3220EU can operate at 1000Kbps; the SP3220E
operates at a typical data rate of 235Kbps fully
loaded.
The SP3220E/EB/EU is a 1-driver/1-receiver de-
vice ideal for portable or hand-held applications.
The SP3220E/EB/EU features a 1µA shutdown
mode that reduces power consumption and ex-
tends battery life in portable systems. Its receivers
remains active in shutdown mode, allowing exter-
nal devices to be monitored using only 1µA supply
current.
PC-to-PC communication software. The
SP3220EU driver can guarantee a data rate of
1000Kbps fully loaded with 31 in parallel with
250pF.
The slew rate of the SP3220E and SP3220EB
outputs are internally limited to a maximum of 30V/
µs in order to meet the EIA standards (EIA RS-
232D 2.1.7, Paragraph 5). The transition of the
loaded output from HIGH to LOW also meets the
monotonicity requirements of the standard. The
slew rate of the SP3220EU is not internally limited.
This allows it to transmit at much faster data rates.
Figure 12 shows a loopback circuit used to test the
RS-232 driver. Figure 13 shows the test results of
the loopback circuit with the SP3220EB driver
active at 250Kbps with an RS-232 load in parallel
with a 1000pF capacitor. Figure 14 shows the test
results where the SP3220EU driver was active at
1000Kbps and loaded with an RS-232 receiver in
parallel with a 250pF capacitor. A solid RS-232
data transmission rate of 250Kbps provides com-
patibility with many designs in personal computer
peripherals and LAN applications.
THEORY OF OPERATION
The SP3220E/EB/EU driver's output stage is turned
off (high-Z) when the device is in shutdown mode.
The SP3220E/EB/EU devices are made up of
three basic circuit blocks: 1. Driver, 2. Receiver,
and 3. the Sipex proprietary charge pump.
When the power is off, the SP3220E/EB/EU de-
vice permits the outputs to be driven up to +12V.
The driver's input does not have pull-up resistors.
Driver
The driver is an inverting level transmitter that
Designers should connect an unused input to VCC
or GND.
converts TTL or CMOS logic levels to +5.0V EIA/
TIA-232 levels, inverted relative to the input logic
levels. Typically, the RS-232 output voltage swing
is +5.5V with no load and at least +5V minimum
fully loaded. The driver outputs are protected against
infinite short-circuits to ground without degrada-
tion in reliability. Driver outputs will meet EIA/TIA-
562 levels of +3.7V with supply voltages as low as
2.7V.
In the shutdown mode, the supply current falls to
less than 1µA, where SHDN = LOW. When the
SP3220E/EB/EU device is shut down, the device's
driver output is disabled (high-Z) and the charge
pump is turned off with V+ pulled down to V and
CC
V- pulled to GND. The time required to exit
shutdown is typically 100ms. Connect SHDN to
VCC if the shutdown mode is not used. SHDN has
no effect on RxOUT. Note that the driver is enabled
The SP3220EB driver typically can operate at a
data rate of 250Kbps fully loaded with 3K1 in
only when the magnitude of V- exceeds approxi-
mately 3V.
parallel with 1000pF, ensuring compatibility with
Date: 8/30/05
SP3220E/EB/EU High ESD RS-232 Driver/Receiver
© Copyright 2005 Sipex Corporation
Date: 8/22/05
SP3220E/EB/EU High ESD RS-232 Driver/Receiver
9
© Copyright 2005 Sipex Corporation
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