SP3223EU Datasheet, PDF (10/25 Pages) Sipex Corporation – High Speed Intelligent +3.0V to +5.5V RS-232 Transceivers

DESCRIPTION
The SP3223EU and SP3243EU transceivers
meet the EIA/TIA-232 and ITU-T 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 SP3223EU and
SP3243EU devices feature Sipex's proprietary
and patented (U.S.-- 5,306,954) on-board charge
pump circuitry that generates ±5.5V RS-232
voltage levels from a single +3.0V to +5.5V
power supply. The SP3223EU and SP3243EU
devices can operate at a data rate of 1000kbps
fully loaded.
The SP3223EU is a 2-driver/2-receiver device,
and the SP3243EU is a 3-driver/5-receiver device,
ideal for portable or hand-held applications. The
SP3243EU includes one complementary
always-active receiver that can monitor an
external device (such as a modem) in shutdown.
This aids in protecting the UART or serial
controller IC by preventing forward biasing
of the protection diodes where V may be
CC
disconnected.
VCC
UART
or
Serial µC
+
C5 0.1µF
28 _C1+
+
C1 0.1µF
24 C1-
+
C2 0.1µF
1 C2+
2 C2-
TxD
14 ^T1^IN
RTS
13 T2IN
DTR
12 ^T3^IN
26
VCC
V+ ²⁷
SP3243EU _V- 3
T₁OUT ₉
T₂OUT 10
T₃OUT ₁₁
+
C3 0.1µF
C4 0.1µF
+
RS-232
OUTPUTS
RxD
CTS
DSR
DCD
RI
VCC
20 ^R2^OUT
19 ^R1^OUT
R₁IN ₄
18 ^R2^OUT
17 ^R3^OUT
5KΩ
R₂IN ₅
5KΩ
R₃IN ₆
16 ^R4^OUT
5KΩ
R₄IN ₇
15 ^R5^OUT
22
SHUTDOWN
23 _ONLINE
5KΩ
R₅IN ₈
5KΩ
21 _STATUS
GND
25
RS-232
INPUTS
RESET
µP
Supervisor
VIN
IC
The SP3223EU and SP3243EU series is an ideal
choice for power sensitive designs. The
SP3223EU and SP3243EU devices feature
AUTO ON-LINE^® circuitry which reduces the
power supply drain to a 1µA supply current. In
many portable or hand-held applications, an RS-
232 cable can be disconnected or a connected
peripheral can be turned off. Under these condi-
tions, the internal charge pump and the drivers
will be shut down. Otherwise, the system auto-
matically comes online. This feature allows de-
sign engineers to address power saving concerns
without major design changes.
THEORY OF OPERATION
The SP3223EU and SP3243EU series is made
up of four basic circuit blocks:
1. Drivers
2. Receivers
3. the Sipex proprietary charge pump, and
4. AUTO ON-LINE^® circuitry.
Drivers
The drivers are inverting level transmitters that
convert TTL or CMOS logic levels to 5.0V EIA/
TIA-232 levels with an inverted sense relative to
the input logic levels. Typically, the RS-232
output voltage swing is +5.4V with no load and
+5V minimum fully loaded. The driver outputs
are protected against infinite short-circuits to
ground without degradation in reliability. These
drivers comply with the EIA-TIA-232-F and all
previous RS-232 versions. Unused drivers in-
puts should be connected to GND or V .
CC
The drivers have a minimum data rate of
1000kbps fully loaded with 3kΩ in parallel with
250pF, ensuring compatibility with PC-to-PC
communication software.
Figure 16. Interface Circuitry Controlled by Micropro-
cessor Supervisory Circuit
Date: 06/28/04
SP3223EU/3243EU +3.0V to +5.5V RS-232 Transceivers
10
© Copyright 2004 Sipex Corporation