SP3223H Datasheet, PDF (10/23 Pages) Sipex Corporation – High Speed Intelligent +3.0V to +5.5V RS-232 Transceivers

DESCRIPTION
The SP3223H and SP3243H transceivers meet
the EIA/TIA-232 and ITU-T V.28/V.24 commu-
nication protocols and can be
implemented in battery-powered, portable, or
hand-held applications such as notebook or
palmtop computers. The SP3223H and SP3243H
devices feature Sipex's proprietary and patented
(U.S.-- 5,306,954) on-board charge pump cir-
cuitry that generates +5.5V RS-232 voltage lev-
els from a single +3.0V to +5.5V power supply.
The SP3223H and SP3243H devices can oper-
ate at a data rate of 460Kbps fully loaded.
The SP3223H is a 2-driver/2-receiver device,
and the SP3243H is a 3-driver/5-receiver device,
ideal for portable or hand-held applications. The
SP3243H 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_CC may be
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 T3IN
26
VCC
V+ ²⁷
SP3243H _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 SP3223H and SP3243H series is an ideal
choice for power sensitive designs. The SP3223H
and SP3243H devices feature Auto-Online cir-
cuitry which reduces the power supply drain to a
1µA supply current. In many portable or hand-
held applications, an RS-232 cable can be dis-
connected or a connected peripheral can be turned
off. Under these conditions, the internal charge
pump and the drivers will be shut down. Other-
wise, the system automatically comes online.
This
feature
allows
design
engineers to address power saving concerns
without major design changes.
THEORY OF OPERATION
The SP3223H and SP3243H series is made up of
four basic circuit blocks: 1. Drivers,
2. Receivers, 3. the Sipex proprietary charge
pump, and 4. Auto-Online 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.
The drivers can guarantee a data rate over
460Kbps fully loaded with 3KΩ in parallel with
1000pF, ensuring compatibility with PC-to-PC
communication software.
The slew rate of the driver output is 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.
Figure 11. Interface Circuitry Controlled by Micropro-
cessor Supervisory Circuit
Rev. 6/30/03
SP3223H +3.0V to +5.5V RS-232 Transceivers
10
© Copyright 2003 Sipex Corporation