1/11
May 2002
s
1
A SUPPLY CURRENT ACHIEVED WHEN
IN AUTO-POWERDOWN
s
250Kbps MINIMUM GUARANTEED DATA
RATE
s
GUARANTEED 6V/
s SLEW RATE RANGE
s
GUARANTEED MOUSE DRIVEABILITY
s
0.1
F EXTERNAL CAPACITORS
s
MEET EIA/TIA-232 SPECIFICATIONS DOWN
TO 3V
s
AVAILABLE IN SO-28, SSOP-28 AND
TSSOP28
DESCRIPTION
The ST3243 device consists of 3 drivers, 5
receivers and a dual charge-pump circuit. The
device meets the requirements of EIA/TIA and
V.28/V.24 comunication standards providing high
data rate capability.
The receiver R2 is always active to implement a
wake-up feature for serial port.
The ST3243 has a proprietary low-dropout
transmitter output stage enabling true RS-232
performance from a 3.0V to 5.5V supply with a
dual charge pump. The device is guaranteed to
run at data rates of 250kbps while maintaining
RS-232 output levels.
The Auto-powerdown feature functions when
FORCEON is low and FORCEOFF is high. During
this mode of operation, if the device does not
sense a valid RS-232 signal, the driver outputs are
disabled. If FORCEOFF is set low, both drivers
and receivers (expert R2B) are shut off, and
supply current is reduced to 1mA. Disconnecting
the serial port or turning off the peripheral drives
causes the auto-powerdown condition to occur.
Auto-powerdown can be disabled when
FORCEON and FORCEOFF are high, and should
be done when driving a serial mouse. With
Auto-powerdown enabled, the device is activated
automatically when a valid signal is applied to any
receiver input.
Typical application are in notebook, subnotebook,
palmtop computers, battery-powered equipment,
hand-held equipment, peripherals and printers.
ST3243
3 TO 5.5V, 400KBPS, RS-232
TRANSCEIVER WITH AUTO-POWERDOWN
SSOP
SOP
TSSOP
ST3243
2/11
ORDERING CODES
PIN DESCRIPTION
Type
Temperature
Range
Package
Comments
ST3243CD
0 to 70 C
SO-28 (Tube)
27parts per tube / 12tube per box
ST3243BD
-40 to 85 C
SO-28 (Tube)
27parts per tube / 12tube per box
ST3243CDR
0 to 70 C
SO-28 (Tape & Reel)
1000 parts per reel
ST3243BDR
-40 to 85 C
SO-28 (Tape & Reel)
1000 parts per reel
ST3243CPR
0 to 70 C
SSOP-28 (Tape & Reel)
1350 parts per reel
ST3243BPR
-40 to 85 C
SSOP-28 (Tape & Reel)
1350 parts per reel
ST3243CTR
0 to 70 C
TSSOP28 (Tape & Reel)
2500 parts per reel
ST3243BTR
-40 to 85 C
TSSOP28 (Tape & Reel)
2500 parts per reel
PlN N
SYMBOL
NAME AND FUNCTION
1
C
2
+
Positive Terminal of Inverting Charge Pump Capacitor
2
C
2
-
Negative Terminal of Inverting Charge Pump Capacitor
3
V-
-5.5V Generated by the Charge Pump
4
R1
IN
First Receiver Input Voltage
5
R2
IN
Second Receiver Input Voltage
6
R3
IN
Third Receiver Input Voltage
7
R4
IN
Fourth Receiver Input Voltage
8
R5
IN
Fifth Receiver Input Voltage
9
T1
OUT
First Transmitter Output Voltage
10
T2
OUT
Second Transmitter Output Voltage
11
T3
OUT
Third Transmitter Output Voltage
12
T3
IN
Third Transmitter Input Voltage
13
T2
IN
Second Transmitter Input Voltage
14
T1
IN
First Transmitter Input Voltage
15
R5
OUT
Fifth Receiver Output Voltage
16
R4
OUT
Fourth Receiver Output Voltage
17
R3
OUT
Third Receiver Output Voltage
18
R2
OUT
Second Receiver Output Voltage
19
R1
OUT
First Receiver Output Voltage
20
R2
OUTB
Non-inverting Complementary Receiver Output, always active
for wake-up
21
INVALID
Output of the valid signal detector. Indicates if a valid RS-232
level is present on receiver inputs logic "1"
22
FORCEOFF
Drive low to shut down transmitters and on-board power
supply. This over-rides all automatic circuitry and FORCEON
23
FORCEON
Drive high to override automatic circuitry keeping transmitters
on (FORCEOFF must be high)
24
C
1
-
Negative Terminal of Voltage- Charge Pump Capacitor
25
GND
Ground
26
V
CC
Supply Voltage
27
V+
5.5V Generated by the Charge Pump
28
C
1
+
Positive Terminal of Voltage- Charge Pump Capacitor
ST3243
3/11
PIN CONFIGURATION
TRUTH TABLE
* If the part is in auto-powerdown mode (FORCE OFF = V
CC
, FORCE ON = GND) it is shutdown , if no valid RS-232 levels are present on
all receiver input
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied. V+ and V- can have a maximum magnitude of +7V, but their absolute addition can not exceed 13 V.
(*) The device doesn't meet 1KV ESD HBM
FORCE OFF
T
OUT
R
OUT
R
2OUTB
0
HIGH Z
HIGH Z
ACTIVE *
1
ACTIVE *
ACTIVE *
ACTIVE *
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
-0.3 to 6
V
V+
Doubled Voltage Terminal
(V
CC
-0.3) to 7
V
V-
Inverted Voltage Terminal
0.3 to -7
V
V+ +|V-|
13
V
FORCEON,
FORCEOFF,
T
IN
Input Voltage
-0.3 to 6
V
R
IN
Receiver Input Voltage Range
25
V
T
OUT
Transmitter Output Voltage Range
13.2
V
R
OUT
R
OUTB
INVALID
Receiver Output Voltage Range
-0.3 to (V
CC
+ 0.3)
V
t
SHORT
Short Circuit Duration on T
OUT
(one at a time)
Continuous
T
stg
Storage Temperature Range
-65 to 150
C
ST3243
4/11
ELECTRICAL CHARACTERISTICS
(C
1
- C
4
= 0.1
F, V
CC
= 3V to 5.5V, T
A
= -40 to 85C, unless otherwise specified.
Typical values are referred to T
A
= 25C)
LOGIC INPUT ELECTRICAL CHARACTERISTICS
(C
1
- C
4
= 0.1
F, V
CC
= 3V to 5.5V, T
A
= -40 to 85C, unless otherwise specified.
Typical values are referred to T
A
= 25C)
AUTO-POWERDOWN ELECTRICAL CHARACTERISTICS
(C
1
- C
4
= 0.1
F, V
CC
= 3V to 5.5V, T
A
= -40 to 85C, unless otherwise specified.
Typical values are referred to T
A
= 25C)
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
I
ASHDN
Supply Current
Auto-powerdown
V
CC
= 3.3 or 5.0V T
A
= 25C
All R_IN open
FORCEOFF = V
CC
1
10
A
I
SHDN
Shutdown Supply Current
V
CC
= 3.3 or 5.0V T
A
= 25C
All R_IN open
FORCEOFF = GND
1
10
A
I
SHDN
Supply Current
Auto-powerdown Disabled
V
CC
= 3.3 or 5.0V T
A
= 25C
FORCEON = FORCEOFF = V
CC
No Load
0.3
1
mA
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
TIL
Input Logic Threshold Low
T-IN, FORCEON, FORCEOFF
0.8
V
V
TIH
Input Logic Threshold High
T-IN, FORCEON, FORCEOFF
V
CC
= 3.3V
V
CC
= 5V
2
2.4
V
V
V
THYS
Transmitter Input
Hysteresis
0.5
V
I
IL
Input Leakage Current
T-IN, FORCEON, FORCEOFF
0.01
1.0
A
I
OL
Output Leakage Current
Receiver Disabled
0.05
10
A
V
OL
Output Voltage Low
I
OUT
= 1.6mA
0.4
V
V
OH
Output Voltage High
I
OUT
= -1mA
V
CC
-0.6 V
CC
-0.1
V
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
RITE
Receiver Input Threshold to
Transmitter Enabled
Positive Threshold
Negative Threshold
2.7
2.7
V
V
V
RITD
Receiver Input Threshold to
Transmitter Disabled
1
A Supply Current
-0.3
0.3
V
V
IOL
INVALID Output Voltage
LOW
0.4
V
V
IOH
INVALID Output Voltage
HIGH
V
CC
-0.6
V
t
WU
Receiver Threshold to
Transmitter Enabled
I
OUT
= 1.6mA
250
s
t
invh
Receiver Positive or
Negative Threshold to
INVALID HIGH
I
OUT
= -1mA
1
s
t
invL
Receiver Positive or
Negative Threshold to
INVALID LOW
30
s
ST3243
5/11
TRANSMITTER ELECTRICAL CHARACTERISTICS
(C
1
- C
4
= 0.1
F, V
CC
= 3V to 5.5V, T
A
= -40 to 85C, unless otherwise specified.
Typical values are referred to T
A
= 25C)
RECEIVER ELECTRICAL CHARACTERISTICS
(C
1
- C
4
= 0.1
F, V
CC
= 3V to 5.5V, T
A
= -40 to 85C, unless otherwise specified.
Typical values are referred to T
A
= 25C)
TIMING CHARACTERISTICS
(C
1
- C
4
= 0.1
F, V
CC
= 3V to 5.5V, T
A
= -40 to 85C, unless otherwise specified.
Typical values are referred to T
A
= 25C)
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
TOUT
Output Voltage Swing
All Transmitter outputs are loaded with
3K
to GND
5
5.4
V
R
OUT
Output Resistance
V
CC
= V+ = V- = 0V
V
OUT
=
2V
300
10M
I
SC
Output Short Circuit Current
35
60
mA
V
OT
Transmitter Output Voltage
T1IN = T2IN = GND,
T3IN = V
CC
T3OUT loaded with 3K
to GND
T1OUT and T2OUT loaded with 2.5mA
each
5
V
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
RIN
Receiver Input Voltage
Operating Range
-25
25
V
V
RIL
RS-232 Input Threshold
Low
T
A
= 25C
V
CC
= 3.3V
T
A
= 25C
V
CC
= 5.0V
0.6
0.8
1.2
1.2
V
V
RIH
RS-232 Input Threshold
High
T
A
= 25C
V
CC
= 3.3V
T
A
= 25C
V
CC
= 5.0V
1.5
1.8
2.4
2.4
V
V
RIHYS
Input Hysteresis
0.5
V
R
RIN
Input Resistance
T
A
= 25C
3
5
7
K
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
D
R
Maximum Data Rate
R
L
= 3K
C
L
= 1000pF
one trasmitter switching
250
400
Kbps
t
PHL
t
PLH
Receiver Propagation Delay R
IN
to R
OUT
C
L
= 150pF
0.15
s
t
T_SKEW
Transmitter Skew
100
ns
t
R_SKEW
Receiver Skew
50
ns
t
INVH
Receiver Positive or
negative Threshold to
INVALID HIGH
1
s
t
INVL
Receiver Positive or
negative Threshold to
INVALID LOW
30
s
S
RT
Transition Slew Rate
T
A
= 25C R
L
= 3K to 7K
V
CC
= 3.3V
measured from +3V to -3V or -3V to +3V
C
L
= 150pF to 1000pF
C
L
= 150pF to 2500pF
6
4
30
30
V/
s
V/
s
ST3243
6/11
APPLICATION CIRCUITS
CAPACITANCE VALUE (
F)
V
CC
C1
C2
C3
C4
Cbypass
3.0 to 3.6
0.1
0.1
0.1
0.1
0.1
4.5 to 5.5
0.047
0.33
0.33
0.33
0.33
3.0 to 5.5
0.22
1.0
1.0
1.0
0.22
ST3243
7/11
TYPICAL PERFORMANCE CHARACTERISTICS (unless otherwise specified T
j
= 25C)
Figure 1 : INVALID HIGH Threshold Time
Figure 2 : INVALID LOW Threshold Time
Figure 3 : Receiver Propagation Delay
Figure 4 : TReceiver Output Enable & Disable
Time
Figure 5 : Output Current vs Output High Voltage
Figure 6 : Output Current vs Output Low Voltage
ST3243
8/11
DIM.
mm.
inch
MIN.
TYP
MAX.
MIN.
TYP.
MAX.
A
2.65
0.104
a1
0.1
0.3
0.004
0.012
b
0.35
0.49
0.014
0.019
b1
0.23
0.32
0.009
0.012
C
0.5
0.020
c1
45 (typ.)
D
17.70
18.10
0.697
0.713
E
10.00
10.65
0.393
0.419
e
1.27
0.050
e3
16.51
0.650
F
7.40
7.60
0.291
0.300
L
0.50
1.27
0.020
0.050
S
8 (max.)
SO-28 MECHANICAL DATA
0016023
ST3243
9/11
DIM.
mm.
inch
MIN.
TYP
MAX.
MIN.
TYP.
MAX.
A
2
0.079
A1
0.050
0.002
A2
1.65
1.75
1.85
0.065
0.069
0.073
b
0.22
0.38
0.009
0.015
c
0.09
0.25
0.004
0.010
D
9.9
10.2
10.5
0.390
0.402
0.413
E
7.4
7.8
8.2
0.291
0.307
0.323
E1
5
5.3
5.6
0.197
0.209
0.220
e
0.65 BSC
0.0256 BSC
K
0
10
0
10
L
0.55
0.75
0.95
0.022
0.030
0.037
SSOP28 MECHANICAL DATA
ST3243
10/11
DIM.
mm.
inch
MIN.
TYP
MAX.
MIN.
TYP.
MAX.
A
1.2
0.047
A1
0.05
0.15
0.002
0.004
0.006
A2
0.8
1
1.05
0.031
0.039
0.041
b
0.19
0.30
0.007
0.012
c
0.09
0.20
0.004
0.0089
D
9.6
9.7
9.8
0.378
0.382
0.386
E
6.2
6.4
6.6
0.244
0.252
0.260
E1
4.3
4.4
4.48
0.169
0.173
0.176
e
0.65 BSC
0.0256 BSC
K
0
8
0
8
L
0.45
0.60
0.75
0.018
0.024
0.030
TSSOP28 MECHANICAL DATA
0128292B
ST3243
11/11
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from
its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications
mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information
previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics
2002 STMicroelectronics - Printed in Italy - All Rights Reserved
STMicroelectronics GROUP OF COMPANIES
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