November 2007 Rev 3 1/22
22
ST1480AB
ST1480AC
3.3 V powered, 15 kV ESD protected,
up to 12 Mbps true RS-485/RS-422 transceiver
Features
■ESD protection
– ±15 kV human body model
– ±8 kV IEC 1000-4-2 contact discharge
■Operate from a single 3.3 V supply - no charge
pump required
■Interoperable with 5 V logic
■1 µA low current shutdown mode max
■Guaranteed 12 Mbps data rate
■-7 to 12 common mode input voltage range
■Half duplex versions available
■Industry standard 75176 pinout
■Current limiting and thermal shutdown for
driver overload protection
■Guaranteed high receiver output state for
floating, shorted or terminated inputs with no
signal present
■Allow up to 64 transceivers on the bus
Description
The ST1480A is ±15 kV ESD protected, 3.3 V low
power transceiver for RS-485 and RS-422
communications. The device contains one driver
and one receiver in half duplex configuration.
The ST1480A transmits and receives at a
guaranteed data rate of at least 12 Mbps.
All transmitter outputs and receiver inputs are
protected to ±15 kV using Human Body Model.
Driver is short-circuit current limited and is
protected against excessive power dissipation by
thermal shutdown circuitry that places the driver
outputs into a high-impedance state.
The ST1480A input has a true fail-safe feature
that guarantees a logic high output if both inputs
are open circuit, shorted together or in the
presence of a termination with no signal on the
bus.
SO-8
DIP-8
Figure 1. Device summary
Part number Temperature range Package Packaging
ST1480ACN 0 to 70 °C DIP-8 50 parts per tube / 40 tube per box
ST1480ACDR 0 to 70 °C SO-8 (tape & reel) 2500 parts per reel
ST1480ABDR -40 to 85 °C SO-8 (tape & reel) 2500 parts per reel
www.st.com
Contents ST1480AB - ST1480AC
2/22
Contents
1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Truth tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Test circuits and typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
ST1480AB - ST1480AC Pin configuration
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1 Pin configuration
Figure 2. Pin connections
Table 1. Pin description
Pin n° Symbol Name and function
1 RO Receiver output. If A>B by 200mV, RO will be high; if A<B by 200mV, RO will be low
2RE
Receiver Output Enable. RO is enabled when RE is low; RO is high impedance when RE
is high. If RE is high and DE is low, the device will enter a low power shutdown mode.
3DE
Driver Output Enable. The driver outputs are enabled by bringing DE high. They are high
impedance when DE is low. If RE is high DE is low, the device will enter a low-power
shutdown mode. If the driver outputs are enabled, the part functions as line driver, while
they are high impedance, it functions as line receivers if RE is low.
4DI
Driver input. A low on DI forces output A low and output B high. Similarly, a high on DI
forces output A high and output B low
5 GND Ground
6 A Non-inverting receiver input and non-inverting driver output
7 B Inverting receiver input and inverting driver output
8V
CC Supply voltage: VCC= 3V to 3.6V
Truth tables ST1480AB - ST1480AC
4/22
2 Truth tables
Note: X= Don’t care; Z=High impedance
Note: X= Don’t care; Z=High impedance
Table 2. Truth table (driver)
Inputs Outputs
Mode
RE DE DI B A
XHHLH Normal
XHLHL Normal
LLXZZ Normal
H L X Z Z Shutdown
Table 3. Truth table (receiver)
Inputs Output
Mode
RE DE A-B RO
LL ≥ -0.015V H Normal
LL ≤ -0.2V L Normal
L L Inputs open H Normal
L L Inputs shorted H Normal
H L X Z Shutdown
ST1480AB - ST1480AC Maximum ratings
5/22
3 Maximum ratings
Note: Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
Table 4. Absolute maximum ratings
Symbol Parameter Value Unit
VCC Supply voltage 7 V
VIControl input voltage (RE, DE) -0.3 to 7 V
VDI Driver input voltage (DI) -0.3 to 7 V
VDO Driver output voltage (A, B) ± 14 V
VRI Receiver input voltage (A, B) ± 14 V
VRO Receiver output voltage (RO) -0.3 to (VCC + 0.3) V
Table 5. ESD performance: transmitter outputs, receiver inputs
Symbol Parameter Test conditions Min. Typ. Max. Unit
ESD ESD protection voltage Human body model ± 15 kV
ESD ESD protection voltage IEC-1000-4-2 Contact discharge ± 8kV
Electrical characteristics ST1480AB - ST1480AC
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4 Electrical characteristics
Table 6. Electrical characteristics
VCC = 3 V to 3.6 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Symbol Parameter Test conditions Min. Typ. Max. Unit
ISUPPLY VCC Power supply current No Load, DI=0V or VCC
DE=VCC,
RE=0V or VCC
1.3 2.2 mA
DE=0V,
RE=0V 1.2 1.9 mA
ISHDN Shutdown supply current DE=0V, RE=VCC, DI=0V or VCC 0.002 1 µA
Table 7. Logic input electrical characteristics
VCC = 3 V to 3.6 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Symbol Parameter Test conditions Min. Typ. Max. Unit
VIL Input logic threshold low DE, DI, RE 1.3 0.8 V
VIH Input logic threshold high DE, DI, RE 2 V
IIN1 Logic input current DE, DI, RE ± 2.0 µA
IIN2 Input current (A, B) DE=0V, VCC= 0 or 3.6V VIN=12V 1 mA
VIN=-7V -0.8 mA
Table 8. Transmitter electrical characteristics
VCC = 3 V to 3.6 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOD Differential drive output
RL= 100Ω (RS-422) (Figure 2)2 V
RL= 54Ω (RS-485) (Figure 2)1.5 V
RL= 60Ω (RS-485) (Figure 3)1.5 V
ΔVOD
Change in magnitude of driver
differential output voltage for
complementary output states
(Note: 1)
RL= 54Ω or 100Ω (Figure 2)0.2V
VOC
Driver common mode output
voltage RL= 54Ω or 100Ω (Figure 2)3V
ΔVOC
Change in magnitude of driver
common mode output voltage
(Note: 1)
RL= 54Ω or 100Ω (Figure 2)0.2V
IOSD
Driver short circuit output
current ± 250 mA
ST1480AB - ST1480AC Electrical characteristics
7/22
Table 9. Receiver electrical characteristics
VCC = 3V to 3.6V, TA = -40 to 85°C, unless otherwise specified. Typical values are referred
to Ta = 25°C)
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VTH
Receiver differential
threshold voltage VCM = -7V to 12V, DE = 0 -0.2 -0.015 V
ΔVTH Receiver input hysteresis VCM = 0V 30 V
VOH
Receiver output high
voltage IOUT = -4mA, VID = 200mV, (Figure 9)2 V
VOL
Receiver output low
voltage IOUT = 4mA, VID = -200mV, (Figure 4)0.4V
IOZR
3-State (high impedance)
output current at receiver VCC = 3.6V, VO = 0V to VCC ± 1µA
RRIN Receiver input resistance VCM = -7V to 12V 24 kΩ
IOSR
Receiver short-circuit
current VRO = 0V to VCC 760mA
Table 10. Driver switching characteristics
VCC = 3V to 3.6V, TA = -40 to 85°C, unless otherwise specified. Typical values are referred
to Ta = 25°C)
Symbol Parameter Test Conditions Min. Typ. Max. Unit
DRMaximum data rate 12 15 Mbps
tDD Differential output delay RL= 60Ω, CL = 15pF, (Figure 5 and
Figure 6)18 30 ns
tTD
Differential output
transition time
RL= 60Ω, CL = 15pF, (Figure 5 and
Figure 6)12 20 ns
tPLH
tPHL
Propagation delay RL= 27Ω, CL = 15pF, (Figure 9 and
Figure 10)18 30 ns
tPDS
|tPLH - tPHL| propagation
delay skew (Note 2)
RL= 27Ω, CL = 15pF, (Figure 9 and
Figure 10)25ns
tPZL Output enable time RL= 110Ω, (Figure 11 and Figure 12)1935ns
tPZH Output enable time RL= 110Ω, (Figure 7 and Figure 8)3050ns
tPHZ Output disable time RL= 110Ω, (Figure 7 and Figure 8)1935ns
tPLZ Output disable time RL= 110Ω, (Figure 11 and Figure 12)3050ns
tSKEW
Differential output delay
skew 13ns
tZH(SHDN)
Driver enable from
shutdown to output high 30 50 ns
tZL(SHDN)
Driver enable from
shutdown to output low 19 35 ns
Electrical characteristics ST1480AB - ST1480AC
8/22
Note: 1
Δ
VOD and
Δ
VOC are the changes in VOD and VOC, respectively, when the DI input changes
state.
2 Measured on |tPLH(A)-tPHL(A)| and |tPLH(B)-tPHL(B)|
3 The transceivers are put into shutdown by bring RE high and DE low. If the input are in state
for less than 80ns, the part are guaranteed not to enter shutdown. If the inputs are in this
state for at least 300ns, the parts are guaranteed to have entered shutdown.
Table 11. Receiver switching characteristics
VCC = 3V to 3.6V, TA = -40 to 85°C, unless otherwise specified. Typical values are referred
to Ta = 25°C)
Symbol Parameter Test Conditions Min. Typ. Max. Unit
tPLH
tPHL
Propagation delay VID= 0V to 3V, CL1 =15pF
(Figure 13 and Figure 14)30 50 ns
tRPDS
|tPLH - tPHL| propagation
delay skew
VID= 0V to 3V, CL1 = 15pF
(Figure 13 and Figure 14)13ns
tPZL Output enable time CRL = 15pF, (Figure 15 and Figure 19)1020ns
tPZH Output enable time CRL = 15pF, (Figure 15 and Figure 19)1020ns
tPHZ Output disable time CRL = 15pF, (Figure 15 and Figure 19)1020ns
tPLZ Output disable time CRL = 15pF, (Figure 15 and Figure 19)1020ns
tZH(SHDN)
Receiver enable from
shutdown to output high CRL = 15pF, (Figure 15 and Figure 19)1020ns
tZL(SHDN)
Receiver enable from
shutdown to output low CRL = 15pF, (Figure 15 and Figure 19)2040µs
ST1480AB - ST1480AC Test circuits and typical characteristics
9/22
5 Test circuits and typical characteristics
Figure 3. Driver and VOC test load
Figure 4. Driver VOD with varying common mode voltage test load
Figure 5. Receiver VOH and VOL test circuit
Test circuits and typical characteristics ST1480AB - ST1480AC
10/22
Figure 6. Drive differential output delay transition time test circuit
Figure 7. Drive differential output delay transition time waveform
Figure 8. Drive enable and disable times test circuit
ST1480AB - ST1480AC Test circuits and typical characteristics
11/22
Figure 9. Drive enable and disable times waveforms
Figure 10. Drive propagation time test circuit
Figure 11. Drive propagation time waveform
Test circuits and typical characteristics ST1480AB - ST1480AC
12/22
Figure 12. Drive enable and disable times test circuit
Figure 13. Drive enable and disable times waveforms
Figure 14. Receiver propagation delay time test circuit
ST1480AB - ST1480AC Test circuits and typical characteristics
13/22
Figure 15. Receiver propagation delay time waveforms
Figure 16. Receiver enable and disable times test circuit
Figure 17. Receiver enable and disable times waveform
Test circuits and typical characteristics ST1480AB - ST1480AC
14/22
Figure 18. Receiver enable and disable times waveform
Figure 19. Receiver enable and disable times waveform
Figure 20. Receiver enable and disable times waveform
ST1480AB - ST1480AC Test circuits and typical characteristics
15/22
Figure 21. Receiver output current vs output
low voltage
Figure 22. Receiver output current vs output
high voltage
Figure 23. Low level driver output capability Figure 24. High level driver output capability
Figure 25. Receiver input characteristics Figure 26. Driver short circuit current
Test circuits and typical characteristics ST1480AB - ST1480AC
16/22
Figure 27. Driver short circuit current
ST1480AB - ST1480AC Package mechanical data
17/22
6 Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a lead-free second level interconnect. The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com
Package mechanical data ST1480AB - ST1480AC
18/22
Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A3.30.130
a1 0.7 0.028
B1.39 1.65 0.055 0.065
B1 0.91 1.04 0.036 0.041
b0.5 0.020
b1 0.38 0.5 0.015 0.020
D9.80.386
E8.80.346
e 2.54 0.100
e37.62 0.300
e4 7.62 0.300
F 7.1 0.280
I4.80.189
L3.30.130
Z 0.44 1.6 0.017 0.063
Plastic DIP-8 mechanical data
P001F
ST1480AB - ST1480AC Package mechanical data
19/22
Dim. mm. inch.
Min. Typ. Max. Min. Typ. Max.
A1.35 1.75 0.0530.069
A1 0.10 0.25 0.04 0.010
A2 1.10 1.65 0.0430.065
B0.33 0.51 0.0130.020
C0.190.25 0.007 0.010
D4.80 5.00 0.189 0.197
E3.80 4.00 0.150 0.157
e 1.27 0.050
H5.80 6.20 0.2280.244
h 0.25 0.50 0.010 0.020
L 0.40 1.27 0.016 0.050
k8° (max.)
ddd 0.1 0.04
SO-8 mechanical data
0016023/C
Package mechanical data ST1480AB - ST1480AC
20/22
Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A330 12.992
C 12.813.2 0.504 0.519
D 20.2 0.795
N60 2.362
T 22.4 0.882
Ao 8.1 8.5 0.3190.335
Bo 5.5 5.90.216 0.232
Ko 2.1 2.30.082 0.090
Po 3.94.1 0.1530.161
P7.98.1 0.311 0.319
Tape & reel SO-8 mechanical data
ST1480AB - ST1480AC
22/22
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