SP332
RS-232/RS-485 Multi-Mode Serial Transceiver
Description
FEATURES
■■ 5V only single supply operation
■■ Software programmable RS-232 or
RS-485 selection
■■ 4 drivers, 4 receivers RS-232
■■ 2 drivers, 2 receivers RS-485
■■ Loop back function for self test
■■ 28-pin WSOIC package
The SP332 is a monolithic device that contains both RS-232 and
RS-485 line drivers and receivers. The configuration of the SP332
can be changed at any time by changing the logic state of two control
pins. The device also includes a loop back function which internally
connects driver outputs to receiver inputs for a chip self test. An
MaxLinear-patented charge pump allows 5V-only operation.
Ordering Information - Back Page
Typical Applications Circuit
RS-232 Mode
Full Duplex RS-485 Mode Mode
5V
9
0.1µF
12
11
0.1µF
0V
0V
TTL/CMOS
TTL/CMOS
TTL/CMOS
TTL/CMOS
TTL/CMOS
13
24
5V
5
VCC
C1+
C1-
V+
C2+
V+
SP332
C2SEL A
SEL B
26 TI1
27 TI2
28 TI3
1 TI4
19 RX1
VCC
0.1µF
+5V
TTL/CMOS
VCC
VCC
VCC
+5V
400KΩ
20 RX2
21 RX3
22 RX4
400KΩ
GND
TX2 7
T2
400KΩ
TX3 4
T3
400KΩ
TX4 3
T4
RI1 15
R1
RS-232
TTL/CMOS
TTL/CMOS
RS-232
RS-232
TTL/CMOS
TTL/CMOS
RS-232
24
2
VCC
C1-
V+
C2+
V+
SP332
C2SEL A
SEL B
26 TI1
R3
RS-232
TTL/CMOS
RI4 18
23
TX2 7
400KΩ
T1
TX1 6
27 TI2
28 TI3
TX4 3
400KΩ
TTL/CMOS
RS-485
RS-485
TX3 4
1 TI4
19 RX1
R1
150KΩ
RI1 15
20 RX2
TTL/CMOS
TTL/CMOS
RS-232
21 RX3
R3
150KΩ
RS-485
RS-485
GND
RS-485
GND
RI3 17
22 RX4
150KΩ
RS-485
GND
RI4 18
RS-232
RS-485
T3
150KΩ
GND
R4
14
0.1µF
LOOPBACK
VCC
GND
RI3 17
0.1µF
10
RI12 16
RS-232
GND
R2
13
5
C1+
VCC
TTL/CMOS
RI2 16
5KΩ
8
TX1 6
T1
5KΩ
TTL/CMOS
23
12
11
14
0.1µF
LOOPBACK
5KΩ
TTL/CMOS
0.1µF
10
2
5KΩ
TTL/CMOS
9
0.1µF
RS-485
GND
GND
SHUTDOWN
25
8
TTL/CMOS
REV 1.0.1
GND
SHUTDOWN
25
TTL/CMOS
1/11
SP332
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 to the specifications below is not
implied. Exposure to absolute maximum rating conditions
for extended periods of time may affect reliability.
VCC................................................................................... 7V
Storage Temperature................................... -65°C to 150°C
Input Voltages
Power Dissipation
Logic......................... -0.5V to (VCC + 0.5V)
Drivers...................... -0.5V to (VCC + 0.5V)
Power Derating, øJA
Receivers.........................±30V @ ≤100mA
28-pin WSOIC.............................. 1000mW
28-pin WSOIC................................ 40°C/W
Driver Outputs.............................................................. ±15V
Maximum Data Rate................................................ 8Mbps(1)
Electrical Characteristics
Limits are specified at TA = 25°C and VCC = 5.0V unless otherwise noted.
Parameters
Min.
Typ.
Max.
Units
Conditions
Vcc
Volts
Unloaded; R = ∞Ω; See Figure 1
RS-485 Driver DC Characteristics
Differential output voltage
Differential output voltage
2.0
5.0
Volts
With load; R = 50Ω (RS-422); See Figure 1
Differential output voltage
1.5
5.0
Volts
With load; R = 27Ω (RS-485); See Figure 1
0.2
Volts
R = 27Ω or R = 50Ω; See Figure 1
3
Volts
R = 27Ω or R = 50Ω; See Figure 1
Volts
Applies to transmitter inputs, SEL A, SEL B, SD and LB
Change in magnitude of driver differential
output voltage for complementary states
Driver common-mode output voltage
Input high voltage
2.0
Input low voltage
0.8
Volts
Applies to transmitter inputs, SEL A, SEL B, SD and LB
Input current
±10
µA
Applies to transmitter inputs, SEL A, SEL B, SD and LB
Pull-up current
1.5
µA
Pull-down current
3.0
µA
Driver short circuit current VOUT = HIGH
35
250
mA
-7V ≤ VO ≤ 10V
Driver short circuit current VOUT = LOW
35
250
mA
-7V ≤ VO ≤ 10V
RS-485 Driver AC Characteristics
Driver data rate
10
Mbps
Driver data rate
8
Mbps
TA = 85°C(1)
Driver input to output tPLH
70
180
ns
RDIFF = 54Ω, CL1 = CL2 = 100pF; see Figures 3 and 5
Driver input to output tPHL
70
180
ns
RDIFF = 54Ω, CL1 = CL2 = 100pF; see Figures 3 and 5
Driver skew
5
10
ns
From output to output; see Figures 3 and 5
15
40
ns
From 10% to 90%; RDIFF = 54Ω, CL1 = CL2 = 100pF;
see Figures 3 and 5
Driver rise or fall time
3
REV 1.0.1
2/11
SP332
Electrical Characteristics (Continued)
Limits are specified at TA = 25°C and VCC = 5.0V unless otherwise noted.
Parameters
Min.
Typ.
Max.
Units
0.2
Volts
Conditions
RS-485 Receiver DC Characteristics
Differential input threshold
-0.2
Input hysteresis
Output voltage HIGH
70
3.5
Output voltage LOW
Input resistance
mV
0.4
12
15
-7V ≤ VCM ≤ 12V
VCM = 0V
Volts
IO = -4mA, VID = 200mV
Volts
IO = 4mA, VID = -200mV
kΩ
-7V ≤ VCM ≤ 12V
Input current (A, B); VIN = 12V
1.5
mA
VIN = 12V, A is the non-inverting receiver input. B is the
inverting receiver input
Input current (A, B); VIN = -7V
-0.8
mA
VIN = -7V
85
mA
0V ≤ VCM ≤ VCC
Short circuit current
RS-485 Receiver AC Characteristics
Receiver data rate
10
Mbps
Receiver data rate
8
Mbps
TA = 85°C(1)
Receiver input to output tPLH
130
250
ns
RDIFF = 54Ω, CL1 = CL2 = 100pF; Figures 3 and 6
Receiver input to output tPHL
130
250
ns
RDIFF = 54Ω, CL1 = CL2 = 100pF; Figures 3 and 6
Differential receiver skew
|tPHL - tPLH|
13
ns
RDIFF = 54Ω, CL1 = CL2 = 100pF; Figures 3 and 6
RS-232 Driver DC Characteristics
TTL input level VIL
0.8
Volts
Applies to transmitter inputs, SEL A, SEL B, SD and LB
Volts
Applies to transmitter inputs, SEL A, SEL B, SD and LB
TTL input level VIH
2.0
High level voltage output
5.0
15.0
Volts
RL = 3kΩ to GND
Low level voltage output
-15.0
-5.0
Volts
RL = 3kΩ to GND
Open circuit output
±15
Volts
RL = ∞
Short circuit current
±100
mA
Power off impedance
300
Ω
120
kbps
VOUT = 0V
VCC = 0V; VOUT = ±2V
RS-232 Driver AC Characteristics
Transmission rate
Transition time
1.56
µs
Rise/fall time, 3V to -3V; -3V to 3V, RL = 3kΩ,
CL = 2500pF
Propagation delay; tPHL
2
4
µs
RL = 3kΩ, CL = 2500pF, from 1.5V of TIN to 50% of
VOUT
Propagation delay; tPLH
2
4
µs
RL = 3kΩ, CL = 2500pF, from 1.5V of TIN to 50% of
VOUT
Slew rate
10
30
V/µs
RL = 3kΩ, CL = 50pF; From 3V to -3V or -3V to 3V
REV 1.0.1
3/11
SP332
Electrical Characteristics (Continued)
Limits are specified at TA = 25°C and VCC = 5.0V unless otherwise noted.
Parameters
Min.
Typ.
Max.
Units
Conditions
0.4
Volts
ISINK = 4mA
Volts
ISOURCE = -4mA
RS-232 Receiver DC Characteristics
TTL output level; VOL
TTL output level; VOH
3.5
Input high threshold
2.1
Input low threshold
0.8
Input voltage range
-15
Input impedance
Hysteresis
3.0
1.6
Volts
Volts
15
Volts
3
5
7
kΩ
0.2
0.5
1.0
Volts
VIN = ±15V
VCC = 5V
RS-232 Receiver AC Characteristics
Transmission rate
120
kbps
Transition time
50
ns
Rise/fall time, 10% to 90%
Propagation delay tPHL
100
300
ns
Propagation delay tPLH
100
200
ns
No load supply current
19
25
mA
No load; VCC = 5.0V; TA = 25°C
Full load supply current
90
120
mA
RS-232 drivers RL = 3kΩ to GND, DC input
RS-485 drivers RL = 54Ω from A to B; DC input
Shutdown supply current
5
50
µA
TA = 25°C, VCC = 5.0V
From 50% of VIN to 1.5V of ROUT
Power Requirements
NOTE
1. Exceeding the maximum data rate may damage the device.
REV 1.0.1
4/11
SP332
Test Circuits
A
R
VOD
R
1kΩ
S2
B
Figure 1: RS-485 Driver DC Test Load Circuit
DI
A
B
VCC
S1
CRL
VOC
1kΩ
Test Point
Receiver
Output
CL1
A
RDIFF
RO
B
CL2
Figure 2. Receiver Timing Test Load Circuit
15pF
S1
500Ω
Output
Under
Test
VCC
CL
S2
Figure 3: RS-485 Driver/Receiver Timing Test Circuit
DRIVER INPUT
f ≥ 1MHz; t R ≤ 10ns; t F ≤ 10ns
+3V
1.5V
0V
B
DRIVER
OUTPUT
A
Figure 4: RS-485 Driver Timing Test Load #2 Circuit
1.5V
t PLH
t PHL
VO 1/2VO
1/2VO
t DPLH
DIFFERENTIAL VO+
OUTPUT 0V
VA – VB VO–
t DPHL
tF
tR
t SKEW = |t DPLH - t DPHL|
Figure 5: RS-485 Driver Propagation Delays
A– B
f = 1MHz; t R ≤ 10ns ; t F ≤ 10ns
VOD2 +
0V
VOD2 –
VOH
RECEIVER OUT
VOL
0V
INPUT
1.5V
1.5V
OUTPUT
t PHL
t PLH
Figure 6: RS-485 Receiver Propagation Delays
REV 1.0.1
5/11
SP332
Pin Configuration
TI4
SEL_B
TX4
TX3
VCC
TX1
TX2
GND
C1+
V+
C2+
C1–
C2–
V–
SP332
1
2
3
4
5
6
7
8
9
10
11
12
13
14
TI3
TI2
TI1
SD
SEL_A
LB
RX4
RX3
RX2
RX1
RI4
RI3
RI2
RI1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Typical Applications Circuits
RS-232 Mode
Full Duplex RS-485 Mode Mode
5V
9
0.1µF
12
11
0.1µF
0V
0V
TTL/CMOS
TTL/CMOS
TTL/CMOS
TTL/CMOS
TTL/CMOS
13
24
5V
5
VCC
C1+
C1-
V+
C2+
V+
SP332
C2SEL A
SEL B
26 TI1
27 TI2
28 TI3
1 TI4
19 RX1
VCC
0.1µF
+5V
TTL/CMOS
VCC
VCC
VCC
+5V
400KΩ
20 RX2
21 RX3
22 RX4
400KΩ
GND
TX2 7
T2
400KΩ
TX3 4
T3
400KΩ
TX4 3
T4
RI1 15
R1
RS-232
TTL/CMOS
TTL/CMOS
RS-232
RS-232
TTL/CMOS
TTL/CMOS
RS-232
24
2
VCC
C1-
V+
C2+
V+
SP332
C2SEL A
SEL B
26 TI1
R3
RS-232
TTL/CMOS
T1
TX1 6
27 TI2
28 TI3
TX4 3
400KΩ
TTL/CMOS
RS-485
RS-485
TX3 4
1 TI4
19 RX1
R1
150KΩ
TTL/CMOS
TTL/CMOS
RS-232
R3
150KΩ
RS-485
RI1 15
RS-485
GND
RS-485
GND
RI3 17
22 RX4
150KΩ
RS-485
GND
20 RX2
21 RX3
RS-485
T3
RI4 18
RS-232
GND
R4
23
TX2 7
400KΩ
150KΩ
RI4 18
14
0.1µF
LOOPBACK
VCC
GND
RI3 17
0.1µF
10
RI12 16
RS-232
TTL/CMOS
RI2 16
13
5
C1+
VCC
GND
R2
5KΩ
8
TX1 6
T1
5KΩ
TTL/CMOS
23
12
11
14
0.1µF
LOOPBACK
5KΩ
TTL/CMOS
0.1µF
10
2
5KΩ
TTL/CMOS
9
0.1µF
RS-485
GND
GND
SHUTDOWN
25
8
TTL/CMOS
REV 1.0.1
GND
SHUTDOWN
25
TTL/CMOS
6/11
SP332
SP332 Control Logic Configuration
SEL A
0
0
1
1
SEL B
0
1
0
1
LB
1
1
1
1
SD
0
0
0
0
26 TI1
TX1 6
T1
26 TI1
TX1 6
T1
26 TI1
27
28
TI2
TX2 7
T2
TI3
27
TI2
28 TI3
28 TI3
1
TI4
R1
20 RX2
T3
R2
21 RX3
R3
RI1 15
19 RX1
RI2 16
R1
20 RX2
R2
R4
T1
TX3 4
28 TI3
3
1
TI4
T3
TX4 3
T4
RI1 15
RI1 15
19 RX1
R1
R1
21 RX3
R3
RI3 17
RI3 17
21 RX3
R3
22 RX4
RI4 18
R4
RI4 18
0
1
1
SEL B
0
1
0
1
LB
0
0
0
0
SD
0
0
0
0
27
28
TI2
TI3
TX1 6
T1
26
19
20
21
TI4
RX1
RX2
RX3
TX3
T3
27
6
TI2
T2
R1
R2
R3
R4
7
TX3
4
28 TI3
TI3
T3
TX4 3
T4
TX2
4
RI1 15
19
RI2 16
20
RX1
RX2
R1
R2
TX4
RI1
RI2
3
15
16
T1
T3
TX1
6
TX2
7
TX3
4
26 TI1
28 TI3
1 TI4
19 RX1
21 RX3
TX4
T4
RI1 15
R1
R3
TX1 6
T1
19
RX1
RI2 16
RX3
R3
RI4 18
17
RI4
18
22 RX4
R4
TX4 3
RI1 15
R1
RI2 16
RI3 17
21 RX3
RI3
TX2 7
TX3 4
T3
3
RI3 17
21
22 RX4
TX1
T1
26 TI1
TX2 7
T2
28
1
TI1
RI4 18
RI4 18
0
TI1
RI2 16
RI2 16
SEL A
26
TX4 3
RI1 15
19 RX1
RI2 16
RI3 17
R3
TX2 7
TX3 4
T3
RI3 17
21 RX3
22 RX4
TX4
TX1 6
26 TI1
TX2 7
TX3 4
TX4 3
T4
19 RX1
T2
TX3 4
T3
TX1 6
T1
TX2 7
RI3 17
R3
RI4 18
RI4 18
Receiver Inputs are inactive in Loopback Mode (LOOPBACK = 0)
Driver Outputs are Tri-stated in Loopback Mode (LOOPBACK = 0)
Unused Outputs are Tri-stated
REV 1.0.1
7/11
SP332
Functional Description
The SP332 is single chip device that can be configured via
software for either RS-232, RS-485 or both interface modes
at any time. The SP332 is made up of three basic circuit
elements, single-ended drivers and receivers, differential
drivers and receivers and charge pump.
Differential Driver/Receiver
RS-485, RS-422 Drivers
The differential drivers and receivers comply with
the RS-485 and RS-422 standards. The driver
circuits are able to drive a minimum of 1.5V when
terminated with a 54Ω resistor across the two
outputs. The typical propagation delay from driver
input to output is 60ns. The driver outputs are
current limited to less than 250mA, and can tolerate
shorts to ground, or to any voltage within a 10V to
-7V range with no damage.
7kΩ over a ±15V range. The maximum operating
voltage range for the receiver is ±30V, under these
conditions the input current to the receiver must
be limited to less than 100mA. Due to the on-chip
ESD protection circuitry, the receiver inputs will be
clamped to ±15V levels. The RS-232 receivers can
operate up to 120kbps.
Charge–Pump
The charge pump is a MaxLinear–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 7(a) shows the
waveform found on the positive side of capacitor
C2, and Figure 7(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.
RS-485, RS-422 Receivers
The differential receivers of the SP332 comply with
the RS-485 and RS-422 standards. The input to the
receiver is equipped with a common mode range of
12V to -7V. The input threshold over this range is a
minimum of ±200mV. The differential receivers can
receive data up to 10Mbps. The typical propagation
delay from the receiver input to output is 90ns.
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. Cl+ 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.
Single Ended Driver / Receiver
RS-232 (V.28) Drivers
The single-ended drivers and receivers comply
with the RS-232 and V.28 standards. The drivers
are inverting transmitters which accept either TTL
or CMOS inputs and output the RS-232 signals
with an inverted sense relative to the input logic
levels. Typically, the RS-232 driver output voltage
swing is ±9V with no load and is guaranteed to be
greater than ±5V under full load. The drivers rely on
the V+ and V- voltages generated by the on-chip
charge pump to maintain proper RS-232 output
levels. With worst case load conditions of 3kΩ and
2500pF, the four RS-232 drivers can still maintain
±5V output levels. The drivers can operate up to
120kbps; the propagation delay from input to output
is typically 2µs.
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 C1 is switched to 5V and the
negative side is connected to ground.
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.
RS-232 (V.28) Receivers
The RS-232 receivers convert RS-232 input signals
to inverted TTL signals. Each of the four receivers
features 500mV of hysteresis margin to minimize
the affects of noisy transmission lines. The inputs
also have a 5kΩ resistor to ground, in an open
circuit situation the input of the receiver will be
forced low, committing the output to a logic high
state. The input resistance will maintain 3kΩ to
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
REV 1.0.1
8/11
SP332
side is connected to ground, and the cycle begins
again.
magnitude of V– compared to V+ due to the inherent
inefficiencies in the design.
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
The clock rate for the charge pump typically
operates at 15kHz. The external capacitors must
be 0.1µF with a 16V breakdown rating.
+10V
a) C2+
GND
GND
b) C2-10V
Figure 7: Charge Pump Waveforms
VCC = +5V
VCC = +5V
+10V
C1
+
C2
–
+
–
C4
+
–
+
–
VDD Storage Capacitor
VSS Storage Capacitor
C3
+5V
C1
+
C2
–
–5V
–
+
VSS Storage Capacitor
C3
VCC = +5V
C4
–
VDD Storage Capacitor
Figure 9: Charge Pump Phase 3
VCC = +5V
+
–
–
–5V
Figure 8: Charge Pump Phase 1
C1
+
C4
+
C2
+
–
–10V
+
–
–
+
VDD Storage Capacitor
VSS Storage Capacitor
C3
+5V
C1
+
C2
–
–5V
Figure 10: Charge Pump Phase 2
+
–
–5V
C4
+
–
VDD Storage Capacitor
–
+
VSS Storage Capacitor
C3
Figure 11: Charge Pump Phase 4
REV 1.0.1
9/11
SP332
Package Description
WSOIC28
Top View
Side View
Front View
Drawing No:
Revision:
REV 1.0.1
POD-00000106
A
10/11
SP332
Ordering Information(1)
Part Number
Operating Temperature Range
SP332CT-L
Lead-Free
Package
Tube
0°C to 70°C
SP332CT-L/TR
(3)
Yes(2)
SP332ET-L
-40°C to 85°C
SP332ET-L/TR
Packaging Method
28-pin WSOIC
Reel
Tube
Reel
NOTE:
1. Refer to www.exar.com/SP332 for most up-to-date Ordering Information.
2. Visit www.exar.com for additional information on Environmental Rating.
3. NRND - Not recommended for new designs.
Revision History
Revision
Date
9617RO
-
01/26/10
1.0.0
Convert to Exar Format. Add Revision History table. Change revision to 1.0.0. Add Note 1 and
change maximum RS-485 data rate at +85C. Update ABS Max Rating table.
10/16/17
1.0.1
Remove GND from Differential Output Voltage min (page 2). Update to MaxLinear logo.
Update format and ordering information table. Theory of Operation section moved to after
SP332 Control Logic Configuration section, and renamed Functional Description.
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Tel.:+1 (760) 692-0711
Fax: +1 (760) 444-8598
www.maxlinear.com
Description
Legacy Sipex Datasheet
High Performance Analog:
1060 Rincon Circle
San Jose, CA 95131
Tel.: +1 (669) 265-6100
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