Analog Devices ADM1486 a Datasheet
5 V, 0.8 mA PROFIBUS
FEATURES
Meets and exceeds EIA RS-485 and EIA RS-422 standards
30 Mbps data rate
Recommended for PROFIBUS applications
2.1 V minimum differential output with 54 Ω termination
Low power 0.8 mA I
Thermal shutdown and short-circuit protection
0.5 ns skew driver and receiver
Driver propagation delay: 11 ns
Receiver propagation delay: 12 ns
High impedance outputs with drivers disabled or power off
Superior upgrade for SN65ALS1176
Available in standard 8-lead SOIC package
APPLICATIONS
Industrial field equipment
GENERAL DESCRIPTION
The ADM1486 is a differential line transceiver suitable for high
speed bidirectional data communication on multipoint bus
transmission lines. It is designed for balanced data transmission,
complies with EIA Standards RS-485 and RS-422, and is recommended for PROFIBUS applications. The part contains a
differential line driver and a differential line receiver. Both the
driver and the receiver may be enabled independently. When
disabled or powered down, the driver outputs are high impedance.
The ADM1486 operates from a single 5 V power supply.
Excessive power dissipation caused by bus contention or output
shorting is prevented by short-circuit protection and thermal
circuitry. Short-circuit protection circuits limit the maximum
output current to ±200 mA during fault conditions. A thermal
shutdown circuit senses if the die temperature rises above
150°C and forces the driver outputs into a high impedance state
under this condition.
Up to 50 transceivers may be connected simultaneously on a
bus, but only one driver should be enabled at a time. Therefore,
it is important that the remaining disabled drivers do not load
the bus.
CC
RS-485 Transceiver
ADM1486
FUNCTIONAL BLOCK DIAGRAM
ADM1486
RO
RE
DE
1
2
3
DI
4
R
D
Figure 1.
To ensure this, the ADM1486 driver features high output
impedance when disabled and when powered down. This
minimizes the loading effect when the transceiver is not being
used. The high impedance driver output is maintained over the
entire common-mode voltage range from −7 V to +12 V.
The receiver contains a fail-safe feature that results in a logic
high output state if the inputs are unconnected (floating).
The ADM1486 is fabricated on BiCMOS, an advanced mixed
technology process combining low power CMOS with fast
switching bipolar technology. All inputs and outputs contain
protection against ESD; all driver outputs feature high source
and sink current capability. An epitaxial layer is used to guard
against latch-up.
The ADM1486 features extremely fast and closely matched
switching, enable, and disable times. Minimal driver propagation delays permit transmission at data rates up to 30 Mbps
while low skew minimizes EMI interference.
The part is fully specified over the commercial and industrial
temperature range and is available in an 8-lead SOIC package.
8
V
CC
7
B
6
A
5
GND
02603-001
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113 © 2005 Analog Devices, Inc. All rights reserved.
www.analog.com
ADM1486
TABLE OF CONTENTS
Specifications..................................................................................... 3
Applications Information.............................................................. 13
Timing Specifications....................................................................... 4
Absolute Maximum Ratings............................................................ 5
ESD Caution.................................................................................. 5
Pin Configuration and Function Descriptions............................. 6
Tes t Ci rc u it s ....................................................................................... 7
Switching Characteristics ................................................................ 8
Typical Performance Characteristics ............................................. 9
REVISION HISTORY
3/05—Rev. 0 to Rev. A
Updated Format..................................................................Universal
Added PROFIBUS Logo.................................................................. 1
Updated Outline Dimensions....................................................... 15
Changes to Ordering Guide.......................................................... 15
11/02—Revision 0: Initial Version
Differential Data Transmission ................................................ 13
Cable and Data Rate................................................................... 13
Thermal Shutdown .................................................................... 13
Propagation Delay ...................................................................... 13
Receiver Open-Circuit Fail-Safe............................................... 13
Outline Dimensions....................................................................... 15
Ordering Guide .......................................................................... 15
Rev. A | Page 2 of 16
ADM1486
SPECIFICATIONS
VCC = 5 V ±5%. All specifications T
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
DRIVER
Differential Output Voltage, V
2.1 5.0 V VCC = 5 V, R = 50 Ω (RS-422), see Figure 3
2.1 5.0 V R = 27 Ω (RS-485), see Figure 3
V
OD3
∆| VOD | for Complementary Output States 0.2 V R = 27 Ω or 50 Ω, see Figure 3
Common-Mode Output Voltage V
∆| VOC | for Complementary Output States 0.2 V R = 27 Ω or 50 Ω
Output Short-Circuit Current (V
Output Short-Circuit Current (V
CMOS Input Logic Threshold Low, V
CMOS Input Logic Threshold High, V
Logic Input Current (DE, DI) ±1.0 µA
RECEIVER
Differential Input Threshold Voltage, V
Input Voltage Hysteresis, ∆V
Input Resistance 20 30 kΩ −7 V ≤ VCM ≤ +12 V
Input Current (A, B) 0.6 mA VIN = +12 V
−0.35 mA VIN = −7 V
Logic Enable Input Current (RE)
CMOS Output Voltage Low, V
CMOS Output Voltage High, V
Short-Circuit Output Current 7 85 mA V
Three-State Output Leakage Current ±1.0 µA 0.4 V ≤ V
POWER SUPPLY CURRENT
ICC (Outputs Enabled) 1.2 2.0 mA Outputs unloaded, digital inputs = GND or V
ICC (Outputs Disabled) 0.8 1.5 mA Outputs unloaded, digital inputs = GND or V
to T
MIN
OD
OC
= High) 60 200 mA −7 V ≤ VO ≤ +12 V
OUT
= Low) 60 200 mA −7 V ≤ VO ≤ +12 V
OUT
INL
TH
, unless other wise no ted.
MAX
5.0 V R = Infinity, see Figure 3
2.1 5.0 V V
3.0 V R = 27 Ω or 50 Ω, see Figure 3
0.8 V
INH
TH
2.0 V
−0.2 +0.2 V −7 V ≤ VCM ≤ +12 V
70 mV VCM = 0 V
= −7 V to +12 V, see Figure 4
TST
±1.0 µA
OL
OH
0.4 V I
4.0 V I
= +4.0 mA
OUT
= −4.0 mA
OUT
= GND or V
OUT
≤ 2.4 V
OUT
CC
CC
CC
Rev. A | Page 3 of 16
ADM1486
TIMING SPECIFICATIONS
VCC = 5 V ±5%. All specifications T
Table 2.
Parameter Min Typ Max Unit Test Conditions/Comments
DRIVER
Propagation Delay Input to Output t
11 13 ns R
Driver O/P to O/P t
Driver Rise/Fall Time tR, t
SKEW
F
Driver Enable to Output Valid tZH, t
Driver Disable Timing tHZ, t
LZ
Matched Enable Switching
| t
− t
|, | t
− t
AZH
BZL
BZH
| 1 3 ns RL = 110 Ω, CL = 50 pF, see Figure 6
AZL
Matched Disable Switching
| t
− t
|, | t
− t
AHZ
BLZ
BHZ
| 2 5 ns RL = 110 Ω, CL = 50 pF, see Figure 6
ALZ
RECEIVER
Propagation Delay Input to Output t
Skew | t
Receiver Enable tZH, t
Receiver Disable tHZ, t
1
Guaranteed by characterization.
PLH
− t
| 0.4 2 ns CL = 15 pF1, see Figure 7
PHL
ZL
LZ
MIN
ZL
to T
PLH
PLH
, unless other wise no ted.
MAX
, t
4 11 17 ns R
PHL
0.5 2 ns R
8 15 ns R
9 15 ns RL = 110 Ω, CL = 50 pF, see Figure 6
9 15 ns RL = 110 Ω, CL = 50 pF, see Figure 6
, t
6 12 20 ns CL = 15 pF, see Figure 7
PHL
7 13 ns CL = 15 pF, RL = 1 kΩ, see Figure 8
7 13 ns CL = 15 pF, RL = 1 kΩ, see Figure 8
= 54 Ω, CL1 = CL2 = 100 pF, see Figure 5
LDIFF
= 54 Ω, CL1 = CL2 = 100 pF @ TA = 25°C
LDIFF
= 54 Ω, CL1 = CL2 = 100 pF, see Figure 5
LDIFF
= 54 Ω, CL1 = CL2 = 100 pF, see Figure 5
LDIFF
1
Rev. A | Page 4 of 16
ADM1486
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Table 3.
Parameter Rating
V
CC
Inputs
Driver Input (DI) −0.3 V to VCC + 0.3 V
Control Inputs (DE, RE)
Receiver Inputs (A, B) −9 V to +14 V
Outputs
Driver Outputs −9 V to +14 V
Receiver Outputs −0.5 V to VCC + 0.5 V
Power Dissipation 8-Lead SOIC 450 mW
θJA, Thermal Impedance 170°C/W
Operating Temperature Range
Industrial (A Version) −40°C to +85°C
Storage Temperature Range −65°C to +150°C
Lead Temperature (Soldering, 10 sec) 300°C
Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C
7 V
−0.3 V to V
+ 0.3 V
CC
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods of time may
affect device reliability.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. A | Page 5 of 16
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