SP334
Programmable RS-232/RS-485 Transceiver
Description
FEATURES
■■ +5V Single Supply Operation
■■ Software Programmable RS-232 or
RS-485 Selection
■■ Three RS-232 Drivers and Five Receivers
in RS-232 Mode
■■ Two RS-485 Full-Duplex Transceivers in
RS-485 Mode
■■ Full Differential Driver Tri-State (Hi-Z)
Control
■■ Receiver Output Tri-State Control
The SP334 is a programmable RS-232 and/or RS-485 transceiver IC.
The SP334 contains three drivers and five receivers when selected
in RS-232 mode; and two drivers and two receivers when selected in
RS-485 mode.
The RS-232 transceivers can typically operate at 230kbps
while adhering to the RS-232 specifications. The RS-485
transceivers can operate up to 10Mbps while adhering to the
RS-485 specifications. The RS-485 drivers can be disabled
(High-Z output) by the TXEN enable pin. The RS-232 and RS-485
receiver outputs can be disabled by the RXEN pin.
Ordering Information - Back Page
Typical Applications Circuit
+5V
9
0.1µF
12
11
0.1µF
TTL/CMOS
13
2
5
VCC
C1+
C1-
SP334
C2+
TXEN
Vcc
TX2 7
27 TI1
T1
1 TI3
19 RX1
TX1 6
TX4 3
400KΩ
TTL/CMOS
14
0.1µF
Vcc
TTL/CMOS
V-
0.1µF
10
C2-
400KΩ
TTL/CMOS
V+
T3
TX3 4
RI1 15
R1
15KΩ
RI2 16
15KΩ
TTL/CMOS
TTL/CMOS
21 RX3
RI4 18
R3
26
8
15KΩ
RI3 17
RS-485
RS-485
RS-485
RS-485
RS-485
RS-485
RS-485
RS-485
15KΩ
RXEN
GND
RS232/ RS485
REV 1.0.1
25
+5V
1/13
SP334
Absolute Maximum Ratings
These are stress ratings only and functional operation of the
device at these ratings or any other above those indicated
in the operation sections of the specifications below is not
implied. Exposure to absolute maximum rating conditions
for extended periods of time may affect reliability.
Storage Temperature..................................-65˚C to +150˚C
VCC................................................................................. +7V
Input Voltages
ѲJA................................................. 40˚C/W
Logic......................... -0.5V to (VCC + 0.5V)
NOTE:
1. Exceeding the maximum data rate of 8Mbps at TA = 85˚C may permanently
damage the device.
Drivers...................... -0.5V to (VCC + 0.5V)
Power Dissipation
28-pin WSOIC.............................. 1000mW
Package Derating
28-pin WSOIC
Receivers.........................±30V @ ≤100mA
Driver Outputs.............................................................. ±15V
Maximum Data Rate................................................ 8Mbps(1)
Electrical Characteristics
Limits are specified at TA = 25°C and VCC = +5.0V unless otherwise noted.
PARAMETER
MIN.
TYP.
MAX.
UNITS
0.8
V
CONDITIONS
Logic Inputs
VIL
VIH
2.0
V
Logic Outputs
VOL
VOH
0.4
2.4
Output Tri-state Leakage
10
V
IOUT = -3.2mA
V
IOUT = 1.0mA
µA
0.4V ≤ VOUT ≤ +2.4V
RS-232 Driver
DC Characteristics
HIGH Level Output
+5.0
+15.0
V
RL = 3kΩ, VIN = 0.8V
LOW Level Output
-15.0
-5.0
V
RL = 3kΩ, VIN = 2.0V
-15
+15
V
±100
mA
Open Circuit Voltage
Short Circuit Current
Power Off Impedance
300
Ω
VOUT = 0V
VCC = 0V, VOUT = ±2.0V
AC Characteristics
Slew Rate
Transistion Time
Maximum Data Rate
120
30
V/µs
1.56
µs
235
kbps
Propagation Delay tPHL
2
8
µs
Propagation Delay tPLH
2
8
µs
1.7
3.0
V
RL = 3kΩ, CL = 50pF; VCC = +5.0V, TA @ 25°C
RL = 3kΩ, CL = 2500pF; between ±3V,
TA @ +25°C
RL = 3kΩ, CL = 2500pF
Measured from 1.5V of VIN to 50% of VOUT;
RL = 3kΩ
RS-232 Receiver
DC Characteristics
HIGH Threshold
LOW Threshold
0.8
1.2
3
5
Receiver Open Circuit Bias
Input Impedance
V
+2.0
V
7
kΩ
REV 1.0.1
VIN = +15V to -15V
2/13
SP334
Electrical Characteristics (Continued)
Limits are specified at TA = 25°C and VCC = +5.0V unless otherwise noted.
PARAMETER
MIN.
TYP.
120
235
MAX.
UNITS
CONDITIONS
RS-232 Receiver (Continued)
AC Characteristics
Maximum Data Rate
kbps
Propagation Delay tPHL
0.25
1
µs
Propagation Delay tPLH
0.25
1
µs
6.0
V
5.0
V
RL = 54Ω, CL = 50pF
Balance
±0.2
V
|VT| - |VT|
Common-Mode Output
3.0
V
Measured from 50% of VIN to 1.5V of VOUT
RS-485 Driver
DC Characteristics
Open Circuit Voltage
Differential Output
Output Current
1.5
28.0
Short Circuit Current
±250
mA
RL = 54Ω
mA
Terminated in -7V to +10V
AC Characteristics
Maximum Data Rate
10
Maximum Data Rate
8
Output Transition Time
30
Propagation Delay tPHL
80
Propagation Delay tPLH
80
Driver Output Skew
Mbps
RL = 54Ω
Mbps
RL = 54Ω , TA = +85°C(1)
ns
Rise/Fall time, 10% - 90%
120
ns
120
ns
See Figures 3 & 5, RDIFF = 54Ω,
CL1 = CL2 = 100pF
5
20
ns
Per Figure 5, tSKEW = |tDPHL - tDPLH|
Enable to LOW
100
150
ns
CL = 15pF, S1 Closed
Enable to HIGH
100
150
ns
CL = 15pF, S2 Closed
Disable from LOW
100
120
ns
CL = 15pF, S1 Closed
Disable from HIGH
100
120
ns
CL = 15pF, S2 Closed
+12
V
Enable Timing
Enable Time (see Figures 4 and 6)
Disable Time (see Figures 4 and 6)
RS-485 Receiver
DC Characteristics
Common Mode Range
-7.0
Receiver Sensitivity
Input Impedance
±0.2
12
15
V
-7V ≤ VCM ≤ +12V
kΩ
-7V ≤ VCM ≤ +12V
AC Characteristics
Maximum Data Rate
10
Mbps
Maximum Data Rate
8
Mbps
Propagation Delay tPHL
130
200
ns
Propagation Delay tPLH
130
200
ns
Differential Receiver Skew
10
20
ns
REV 1.0.1
TA = +85°C(1)
See Figures 3 & 7, RDIFF = 54Ω,
CL1 = CL2 = 100pF
tSKEW = |tPHL - tPLH|, RDIFF = 54Ω,
CL1 = CL2 = 100pF, see Figure 8
3/13
SP334
Electrical Characteristics, Continued
Limits are specified at TA = 25°C and VCC = +5.0V unless otherwise noted.
PARAMETER
MIN.
TYP.
MAX.
UNITS
CONDITIONS
Enable to LOW
100
150
ns
CL = 15pF, S1 Closed
Enable to HIGH
100
150
ns
CL = 15pF, S2 Closed
Disable from LOW
100
120
ns
CL = 15pF, S1 Closed
Disable from HIGH
100
120
ns
CL = 15pF, S2 Closed
+5.25
V
RS-485 Receiver (Continued)
Enable Timing
Enable Time (see Figures 2 and 8)
Disable Time (see Figures 2 and 8)
Power Requirements
Supply Voltage VCC
+4.75
Supply Current ICC
No Load (TX Disabled)
12
20
mA
TXEN = 0V
No Load (RS-232 Mode)
20
50
mA
RS232/RS485 = 0V
No Load (RS-485 Mode)
15
50
mA
RS232/RS485 = +5V
0
70
ºC
Industrial (_E_)
-40
+85
ºC
Storage Temperature
-65
+150
ºC
Environmental
Operating Temperature
Commercial (_C_)
NOTE:
1. Exceeding the maximum data rate of 8Mbps at TA = 85˚C may permanently damage the device.
REV 1.0.1
4/13
SP334
Receiver Input Graph
RS-485 RECEIVER
+1.0mA
-7V
-3V
+6V
+12V
1 Unit Load
Maximum Input Current
Versus Voltage
-0.6mA
Test Circuits
R
VOD
D
R
DI
B
1kΩ
VOC
S2
Figure 1. Driver DC Test Load Circuit
A
VCC
S1
CRL
Vcc
1kΩ
Test Point
Receiver
Output
CL1
RL
CL2
A
B
Figure 2. Receiver Timing Test Load Circuit
RO
Output
Under
Test
15pF
500Ω
S1
VCC
CL
S2
Figure 4. Driver Timing Test Load #2 Circuit
Figure 3. Driver / Receiver Timing Test Circuit
REV 1.0.1
5/13
SP334
Switching Waveforms
DRIVER INPUT
f ≥ 1MHz; t R ≤ 10ns; t F ≤ 10ns
+3V
1.5V
0V
DRIVER
OUTPUT
B
1.5V
t PLH
t PHL
VO 1/2VO
A
1/2VO
t DPLH
DIFFERENTIAL VO+
OUTPUT 0V
VA – VB VO–
t DPHL
tF
tR
t SKEW = |t DPLH - t DPHL|
Figure 5. Driver Propagation Delays
TXEN
A, B
A, B
f = 1MHz; t R < 10ns; t F < 10ns
+3V
1.5V
0V
1.5V
t ZL
5V
2.3V
VOL
VOH
2.3V
0V
t LZ
Output normally LOW
0.5V
Output normally HIGH
0.5V
t ZH
t HZ
Figure 6. Driver Enable and Disable Times
A– B
f = 1MHz; t R ≤ 10ns ; t F ≤ 10ns
VOD2 +
VOD2
0V
–
VOH
RECEIVER OUT
VOL
0V
INPUT
1.5V
1.5V
OUTPUT
t PHL
t PLH
Figure 7. Receiver Propagation Delays
REV 1.0.1
6/13
SP334
Switching Waveforms (Continued)
RXEN
+3V
0V
RECEIVER OUT
5V
VIL
1.5V f = 1MHz; t ≤ 10ns; t ≤ 10ns
R
F
t ZL
1.5V
VIH
RECEIVER OUT
0V
1.5V
1.5V
t LZ
Output normally LOW
0.5V
Output normally HIGH
0.5V
t ZH
t HZ
t SKEW = | t PHL - t PLH|
Figure 8. Receiver Enable and Disable Times
TTL
Input
TTL
INPUT
Driver Output A
Driver Output B
DRIVER
OUTPUT
Differential
Output
VA - VB
Figure 9. Typical RS-232 Driver Output
Figure 10. Typical RS-485 Driver Output
REV 1.0.1
7/13
SP334
Pinout
TI3
TXEN(n/c)
TX4(n/c)
TX3
VCC
TX1
TX2
GND
C1+
V+
C2+
C1–
C2–
V–
1
2
3
4
5
6
7
8
9
10
11
12
13
14
SP334
28
27
26
25
24
23
22
21
20
19
18
17
16
15
TI2
TI1
RXEN
RS232/RS485
RI5
RX5
RX4
RX3
RX2
RX1
RI4
RI3
RI2
RI1
(in RS-232 Mode)
Figure 11. SP334 Pinout
Typical Operating Circuits
+5V
9
0.1µF
12 C111
C2+
13
C2-
0.1µF
25
0V
5
VCC
C1+
SP334
V+
V-
+5V
0.1µF
10
14
9
0.1µF
0.1µF
11
0V
RS232/RS485
0.1µF
Vcc
400KΩ
27 TI1
TTL/CMOS
Vcc
TX1
T1
400KΩ
28 TI2
TTL/CMOS
Vcc
T2
6
TX2
7
TX3
4
12
RS-232
TTL/CMOS
13
2
5
C1-
TTL/CMOS
TTL/CMOS
TXEN
Vcc
27 TI1
N/C
TTL/CMOS
TTL/CMOS
TTL/CMOS
2
3
19 RX1
20 RX2
21 RX3
R1
R2
TTL/CMOS
TTL/CMOS
23 RX5
TTL/CMOS
RI1 15
R4
R5
RI2 16
GND
T3
TX3 4
19 RX1
RI1 15
R1
TTL/CMOS
RS-232
RI4 18
TTL/CMOS
RI5 24
21 RX3
26
8
RS-232
5KΩ
15KΩ
RI2 16
15KΩ
RS-232
RI3 17
RI4 18
R3
15KΩ
RI3 17
RS-485
RS-485
RS-485
RS-485
RS-485
RS-485
RS-485
RS-485
15KΩ
RXEN
GND
RS232/ RS485
25
+5V
RS-232
5KΩ
RXEN
1 TI3
TX1 6
TX4 3
RS-232
5KΩ
26
8
T1
N/C
5KΩ
R3
TTL/CMOS
5KΩ
22 RX4
TX2 7
400KΩ
RS-232
14
0.1µF
Vcc
T3
V-
0.1µF
10
C2-
400KΩ
RS-232
V+
SP334
C2+
400KΩ
1 TI3
VCC
C1+
0V
Figure 12. Typical Operating Circuits
REV 1.0.1
8/13
SP334
Theory of Operation
The SP334 is made up of four separate circuit blocks: the
charge pump, drivers, receivers, and decoder. Each of
these circuit blocks is described in more detail below.
Charge-Pump
The charge pump is an Exar–patented design (U.S.
5,306,954) and uses a unique approach compared to older
less efficient designs. The charge pump still requires four
external
capacitors,
but
uses
a
four-phase
voltage shifting technique to attain symmetrical
10V power supplies. Figure 17(a) shows the
waveform found on the positive side of capacitor C2, and
Figure 17(b) shows the negative side of capacitor C2. There
is a free–running oscillator that controls the four phases of
the voltage shifting. A description of each phase follows.
External Power Supplies
For applications that do not require +5V only, external
supplies can be applied at the V+ and V– pins. The value of
the external supply voltages must be no greater than ±10V.
The current drain for the ±10V supplies is used for RS-232.
For the RS-232 driver the current requirement will be 3.5mA
per driver. The external power supplies should provide a
power supply sequence of :+10V, then +5V, followed by
-10V.
VCC = +5V
+5V
Phase 1: VSS Charge Storage
During this phase of the clock cycle, the positive side of
capacitors C1 and C2 are initially charged to +5V. C1+ is
then switched to ground and charge on C1– is transferred
to C2–. Since C2+ is connected to +5V, the voltage potential
across capacitor C2 is now 10V.
Phase 2: VSS Transfer
Phase two of the clock connects the negative terminal of
C2 to the VSS storage capacitor and the positive terminal
of C2 to ground, and transfers the generated -10V to C3.
Simultaneously, the positive side of capacitor C 1 is switched
to +5V and the negative side is connected to ground.
+
C1
–
–
VDD Storage Capacitor
–
+
VSS Storage Capacitor
C3
–5V
Figure 13. Charge Pump Phase 1
VCC = +5V
C4
C1
+
C2
–
+
–
+
–
VDD Storage Capacitor
–
+
VSS Storage Capacitor
C3
–10V
Figure 14. Charge Pump Phase 2
VCC = +5V
+5V
C1
+
C2
–
–5V
+
–
C4
+
–
VDD Storage Capacitor
–
+
VSS Storage Capacitor
C3
–5V
Figure 15. Charge Pump Phase 3
Since both V+ and V– are separately generated from VCC in
a no–load condition, V+ and V– will be symmetrical. Older
charge pump approaches that generate V– from V+ will
show a decrease in the magnitude of V– compared to V+
due to the inherent inefficiencies in the design.
The clock rate for the charge pump typically operates at
15kHz. The external capacitors must be 0.1µF with a 16V
breakdown rating.
–
–5V
Phase 3: VDD Charge Storage
The third phase of the clock is identical to the first phase;
the charge transferred in C1 produces -5V in the negative
terminal of C1, which is applied to the negative side of
capacitor C2. Since C2+ is at +5V, the voltage potential
across C2 is 10V.
Phase 4: VDD Transfer
The fourth phase of the clock connects the negative
terminal of C2 to ground and transfers the generated
10V across C2 to C4, the VDD storage capacitor. Again,
simultaneously with this, the positive side of capacitor C1
is switched to +5V and the negative side is connected to
ground, and the cycle begins again.
+
C2
C4
+
VCC = +5V
+10V
C1
+
–
C2
+
–
C4
+
–
VDD Storage Capacitor
–
+
VSS Storage Capacitor
C3
Figure 16. Charge Pump Phase 4
REV 1.0.1
9/13
SP334
+10V
a) C2+
GND
GND
b) C2-10V
Figure 17. Charge Pump Waveforms
Drivers
The SP334 has three independent RS-232 single-ended
drivers and two differential RS-485 drivers. Control for
the mode selection is done by the RS232/RS485 select
pin. The drivers are pre-arranged such that for each mode
of operation the relative position and functionality of the
drivers are set up to accommodate the selected interface
mode. As the mode of the drivers is changed, the electrical
characteristics will change to support the requirements of
clock, data, and control line signal levels. Unused driver
inputs can be left floating; however, to ensure a desired
state with no input signal, pull–up resistors to +5V or pull–
down resistors to ground are suggested. Since the driver
inputs are both TTL or CMOS compatible, any value resistor
less than 100kΩ will suffice.
When in RS-232 mode, the single-ended RS-232 drivers
produce compliant RS-232E and ITU V.28 signals. Each
of the three drivers output single-ended bipolar signals in
excess of ±5V with a full load of 3kΩ and 2500pF applied as
specified. These drivers can also operate at least 120kbps.
When programmed to RS-485 mode, the differential RS-485
drivers produce complaint RS-485 signals. Each RS-485
driver outputs a unipolar signal on each output pin with a
magnitude of at least 1.5V while loaded with a worst case of
54Ω between the driver’s two output pins. The signal levels
and drive capability of the RS-485 drivers allow the drivers
to also comply with RS-422 levels. The transmission rate
for the differential drivers is 10Mbps.
Receivers
The SP334 has five single-ended receivers when
programmed for RS-232 mode and two differential receivers
when programmed for RS-485 mode.
Control for the mode selection is done the same select
pin as in the drivers. As the operating mode of the
receivers is changed, the electrical characteristics will
change to support the requirements of the appropriate
serial standard. Unused receiver inputs can be left floating
without causing oscillation. To ensure a desired state of
the receiver output, a pull–up resistor of 100kΩ to +5V
should be connected to the inverting input for a logic low,
or the non–inverting input for a logic high. For single-ended
receivers, a pull–down resistor to ground of 5kΩ is internally
connected, which will ensure a logic high output.
The RS-232 receiver has a single–ended input with a
threshold of 0.8V to 2.4V. The RS-232 receiver has an
operating voltage range of ±15V and can receive signals up
to 120kbps. RS-232 receivers are used in RS-232 mode for
all signal types include data, clock, and control lines of the
RS-232 serial port.
The differential RS-485 receiver has an input impedance
of 15kΩ and a differential threshold of ±200mV. Since the
characteristics of an RS-422 receiver are actually subsets of
RS-485, the receivers for RS-422 requirements are identical
to the RS-485 receivers. All of the differential receivers can
receive data up to 10Mbps.
REV 1.0.1
10/13
SP334
Enable Pins
The SP334 drivers can be enabled by use of the TXEN pin.
A logic HIGH will enable the driver outputs and a logic LOW
will tri-state the outputs. The drivers can only be tri-stated
in RS-485 mode. The drivers are always active in RS-232
mode.
The Receiver outputs can also be tri-stated by the use of the
RXEN pin. A logic LOW will enable the receiver outputs and
a logic HIGH will tri-state the outputs. The receiver tri-state
capability is offered for both RS-232 and RS-485 modes.
The input impedance of the receivers during tri-state is at
least 12kΩ.
Applications
The SP334 allows the user flexibility in having a RS-232
or RS-485 serial port without using two different discrete
active IC’s. Figure 18 shows a connection to a standard
DB-9 RS-232 connector. In RS-485 mode, the SP334 is a
full duplex transceiver, however, a half duplex configuration
can be made by connecting the driver outputs to receiver
inputs.
+5V
9
0.1µF
0.1µF
0V
12 C111
C2+
13
C225
5
VCC
C1+
SP334
V+
V-
10
0.1µF
14
0.1µF
0V
RS232/RS485
Vcc
400KΩ
TxD
27 TI1
Vcc
T1
TX1
6
TX2
7
400KΩ
RTS
28 TI2
Vcc
T2
1
400KΩ
DTR
1 TI3
TX3 4
T3
DCD
DSR
RxD
RxD
CTS
DSR
19 RX1
20 RX2
21 RX3
R1
R2
RI1 15
RTS
RI2 16
CTS
5KΩ
TxD
5KΩ
DTR
RI3 17
R3
RI
5KΩ
DCD
RI
22 RX4
23 RX5
R4
R5
RI4 18
SG
RI5 24
5
GND
9
5KΩ
5KΩ
26
8
6
RXEN
0V
Figure 18. SP334 Configuration to a DB-9 Serial Port
REV 1.0.1
11/13
SP334
Mechanical Dimensions
WSOIC28
Top View
Side View
Front View
Drawing No: POD-00000106
Revision:
REV 1.0.1
B
12/13
SP334
Ordering Information(1)
Part Number
Operating Temperature Range
SP334CT-L
Lead-Free
Package
Tube
0°C to 70°C
SP334CT-L/TR
Yes(2)
SP334ET-L
-40°C to 85°C
SP334ET-L/TR
Packaging Method
28-pin WSOIC
Reel
Tube
Reel
NOTE:
1. Refer to www.exar.com/SP334 for most up-to-date Ordering Information.
2. Visit www.exar.com for additional information on Environmental Rating.
Revision History
Revision
Date
2000
SP334/10
09/09/09
1.0.0
Convert to Exar Format. Add typical application circuit to page 1 and Revision History table.
Remove EOL part numbers and update ordering information per PDN 081126-01. Change
revision to 1.0.0. Add Maximum Data Rate to Absolute Maximum Ratings. Add RS-485 Driver
and Receiver data rate column for 8Mbps maximum at Tmax and add Note 1.
03/19/18
1.0.1
Update to MaxLinear logo. Update format and ordering information table. RS-485 Enable
Timing moved on page 3.
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Description
Legacy Sipex Datasheet
High Performance Analog:
1060 Rincon Circle
San Jose, CA 95131
Tel.: +1 (669) 265-6100
Fax: +1 (669) 265-6101
Email: serialtechsupport@exar.com
www.exar.com
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