RS485/422 transceivers operating on 5V supplies. The
receiver includes a logic-selectable 120Ω termination,
one-eighth unit load supporting up to 256 nodes per bus
(C-, I-grades), and a failsafe feature that guarantees a high
output state under conditions of floating or shorted inputs.
The driver features a logic-selectable low-EMI 250kbps
operating mode, and maintains a high output impedance
over the entire common mode range when disabled or
when the supply is removed. Excessive power dissipation
caused by bus contention or a fault is prevented by current
limiting all outputs and by a thermal shutdown.
Enhanced ESD protection allows the LTC2859 and LTC2861
to withstand ±15kV (human body model) on the transceiver
interface pins without latchup or damage.
n
n
n
n
n
n
n
n
n
Integrated, Logic-Selectable 120Ω Termination
Resistor
20Mbps Max Data Rate
No Damage or Latchup to ESD: ±15kV HBM
High Input Impedance Supports 256 Nodes
(C-, I-Grades)
Operation Up to 105°C (LTC2859H)
250kbps Low-EMI Mode
Guaranteed Failsafe Receiver Operation Over the
Entire Common Mode Range
Current Limited Drivers and Thermal Shutdown
Delayed Micropower Shutdown (5µA Max)
Power Up/Down Glitch-Free Driver Outputs
Low Operating Current (900µA Max in Receive Mode)
Meets All TIA/EIA-485-A Specifications
Available in 10-Pin 3mm
×
3mm DFN, 12-Pin
4mm
×
3mm DFN and 16-Pin SSOP Packages
applicaTions
n
n
n
proDucT selecTion GuiDe
PART NUMBER
LTC2859
LTC2861
DUPLEX
Half
Full
PACKAGE
DFN-10
SSOP-16, DFN-12
Low Power RS485/RS422 Transceiver
Level Translator
Backplane Transceiver
L,
LT, LTC, LTM, Linear Technology, the Linear logo and µModule are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
Typical applicaTion
LTC2859
RO
RE
TE
DE
DI
SLO
D
LTC2859
2859/61 TA01
LTC2859
R
RO
RE
TE
DE
D
DI
SLO
R
LTC2859 at 20Mbps
DI
Y
Z
Y–Z
120Ω
120Ω
120Ω
2V/DIV
R
D
20ns/DIV
285961 TA02
RO
RE
TE DE
DI
SLO
285961fc
1
LTC2859/LTC2861
absoluTe maximum raTinGs
(Note 1)
Supply Voltage (V
CC
) ................................... –0.3V to 7V
Logic Input Voltages (RE, DE, DI, TE,
SLO)
.... –0.3V to 7V
Interface I/O:
A, B, Y, Z .......................................(V
CC
–15V) to +15V
(A-B) or (B-A) with Terminator Enabled ..................6V
Receiver Output Voltage (RO) ........–0.3V to (V
CC
+0.3V)
Operating Temperature (Note 4)
LTC2859C, LTC2861C .............................. 0°C to 70°C
LTC2859I, LTC2861I ............................–40°C to 85°C
LTC2859H .......................................... –40°C to 105°C
Storage Temperature Range .................. –65°C to 125°C
Lead Temperature (Soldering, 10 sec)
GN Package ...................................................... 300°C
pin conFiGuraTion
TOP VIEW
TOP VIEW
RO
RE
DE
DI
TE
1
2
3
4
5
11
10 V
CC
9 B
8 A
7
SLO
6 GND
RO
RE
DE
DI
TE
GND
DD PACKAGE
10-LEAD (3mm
×
3mm) PLASTIC DFN
EXPOSED PAD (PIN 11) PCB GND CONNECTION
T
JMAX
= 125°C,
θ
JA
= 43°C/W
θ
JC
= 3°C/W
1
2
3
4
5
6
13
12 V
CC
11 A
10 B
9
8
7
Z
Y
SLO
RO
RE
DE
DI
TE
GND
NC
NC
1
2
3
4
5
6
7
8
TOP VIEW
16 V
CC
15 A
14 B
13 Z
12 Y
11
SLO
10 NC
9
NC
DE PACKAGE
12-LEAD (4mm
×
3mm) PLASTIC DFN
EXPOSED PAD (PIN 13) PCB GND CONNECTION
T
JMAX
= 125°C,
θ
JA
= 43°C/W
θ
JC
= 4.3°C/W
GN PACKAGE
16-LEAD (NARROW 0.150) PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 110°C/W
θ
JC
= 40°C/W
orDer inFormaTion
LEAD FREE FINISH
LTC2861CDE#PBF
LTC2861IDE#PBF
LTC2861CGN#PBF
LTC2861IGN#PBF
LTC2859CDD#PBF
LTC2859IDD#PBF
LTC2859HDD#PBF
TAPE AND REEL
LTC2861CDE#TRPBF
LTC2861IDE#TRPBF
LTC2861CGN#TRPBF
LTC2861IGN#TRPBF
LTC2859CDD#TRPBF
LTC2859IDD#TRPBF
LTC2859HDD#TRPBF
PART MARKING*
2861
2861
2861
2861I
LBNX
LBNX
LBNX
PACKAGE DESCRIPTION
12-Lead (4mm
×
3mm) Plastic DFN
12-Lead (4mm
×
3mm) Plastic DFN
16-Lead Plastic SSOP
16-Lead Plastic SSOP
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead (3mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
–40°C to 105°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
285961fc
2
LTC2859/LTC2861
elecTrical characTerisTics
SYMBOL
Driver
|V
OD
|
D|V
OD
|
V
OC
D|V
OC
|
I
OZD
I
OSD
Receiver
I
IN2
Receiver Input Current (A, B)
DE = TE = 0V, V
CC
= 0V or 5V, V
A
or V
B
= 12V,
Other at 0V
(H-Grade)
DE = TE = 0V, V
CC
= 0V or 5V, V
A
or V
B
= –7V,
Other at 0V
(H-Grade)
V
TH
DV
TH
V
OH
V
OL
I
OZR
R
IN
Receiver Differential Input Threshold
Voltage
Receiver Input Hysteresis
Receiver Output HIGH Voltage
Receiver Output LOW Voltage
Receiver Three-State (High
Impedance) Output Current on RO
Receiver Input Resistance
–7V ≤ V
CM
≤ 12
V
CM
= 0V
I
0
= –4mA, V
ID
= 200mV, V
CC
= 4.5V
I
0
= 4mA, V
ID
= –200mV, V
CC
= 4.5V
RE
= 5V, 0V ≤ V
O
≤ V
CC
RE
= 5V or 0V, DE = TE = 0V
–7V ≤ V
A
= V
B
≤ 12V
(H-Grade)
R
TERM
Logic
V
IH
V
IL
I
IN1
Supplies
I
SHDN
I
CCR
I
CCT
I
CCTS
I
CCL
I
CCRT
Supply Current in Shutdown Mode
Supply Current in Receive Mode
Supply Current in Transmit Mode
Supply Current in Transmit SLO Mode
Supply Current in Loopback Mode
(Both Driver and Receiver Enabled)
Supply Current in Termination Mode
DE = 0V,
RE
= V
CC
, TE = 0V
No Load, DE = 0V,
RE
= 0V, TE = 0V
No Load, DE = V
CC
,
RE
= V
CC
,
SLO
= V
CC
, TE = 0V
No Load, DE = V
CC
,
RE
= V
CC
,
SLO
= 0V, TE = 0V
No Load, DE = V
CC
,
RE=
0V,
SLO
= V
CC
, TE = 0V
DE = 0V,
RE
= V
CC
, TE = V
CC
,
SLO
= V
CC
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V unless otherwise noted (Note 2).
PARAMETER
Differential Driver Output Voltage
CONDITIONS
R = ∞, I
O
= 0mA, V
CC
= 4.5V (Figure 1)
R = 27Ω (RS485), V
CC
= 4.5V (Figure 1)
R = 50Ω (RS422), V
CC
= 4.5V (Figure 1)
R = 27Ω or R = 50Ω (Figure 1)
l
l
l
l
MIN
TYP
MAX
V
CC
V
CC
V
CC
0.2
UNITS
V
V
V
V
1.5
2.0
Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
Driver Common Mode Output Voltage
Change in Magnitude of Driver
Common Mode Output Voltage for
Complementary Output States
Driver Three-State (High Impedance)
Output Current on Y and Z
R = 27Ω or R = 50Ω (Figure 1)
R = 27Ω or R = 50Ω (Figure 1)
l
l
3.0
0.2
V
V
DE = OV, V
O
= –7V, +12V
(LTC2861 Only)
l
l
±10
±120
±250
125
250
–100
–145
±0.2
25
2.4
0.4
±1
96
48
108
125
125
120
156
µA
mA
µA
µA
µA
µA
V
mV
V
V
µA
kΩ
kΩ
Ω
Maximum Driver Short-Circuit Current –7V ≤ (Y or Z) ≤ 12 (Figure 2)
Receiver Input Terminating Resistor
TE = 5V, V
AB
= 2V, V
B
= –7, 0, 10V
(Figure 7)
DE, DI,
RE,
TE,
SLO,
V
CC
= 4.5V
DE, DI,
RE,
TE,
SLO,
V
CC
= 4.5V
DE, DI,
RE,
TE,
SLO
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
l
l
l
2
0.8
0
0
540
630
670
660
640
±10
5
900
1000
1100
1100
1180
V
V
µA
µA
µA
µA
µA
µA
µA
285961fc
3
LTC2859/LTC2861
swiTchinG characTerisTics
SYMBOL
f
MAX
t
PLHD
, t
PHLD
Dt
PD
t
SKEWD
t
RD
, t
FD
PARAMETER
Maximum Data Rate
Driver Input to Output
Driver Input to Output Difference
|t
PLHD
-t
PHLD
|
Driver Output Y to Output Z
Driver Rise or Fall Time
Driver in Normal Mode (SLO HIGH)
Note 3
R
DIFF
= 54Ω, C
L
= 100pF (Figure 3)
R
DIFF
= 54Ω, C
L
= 100pF (Figure 3)
R
DIFF
= 54Ω, C
L
= 100pF (Figure 3)
R
DIFF
= 54Ω, C
L
= 100pF (Figure 3)
R
L
= 500Ω, C
L
= 50pF,
RE
= 0 (Figure 4)
R
L
= 500Ω, C
L
= 50pF,
RE
= V
CC
(Figure 4)
(DE =
↓,
RE
= V
CC
) or (DE = 0,
RE
↑)
(Figure 4)
Note 3
R
DIFF
= 54Ω, C
L
= 100pF (Figure 3)
R
DIFF
= 54Ω, C
L
= 100pF (Figure 3)
R
DIFF
= 54Ω, C
L
= 100pF (Figure 3)
(H-Grade)
R
DIFF
= 54Ω, C
L
= 100pF (Figure 3)
R
L
= 500Ω, C
L
= 50pF,
RE
= 0 (Figure 4)
R
L
= 500Ω, C
L
= 50pF,
RE
= 0 (Figure 4)
R
L
= 500Ω, C
L
= 50pF,
RE
= V
CC
(Figure 4)
(DE = 0,
RE
=
↑)
or (DE =
↓,
RE
= V
CC
) (Figure 4)
C
L
= 15pF, V
CM
= 1.5V, |V
AB
| = 1.5V, t
R
and t
F
<
4ns (Figure 5)
C
L
= 15pF (Figure 5)
C
L
= 15pF (Figure 5)
R
L
= 1kΩ, C
L
=15pF, DE = V
CC
(Figure 6)
DI = 0 or V
CC
R
L
= 1kΩ, C
L
= 15pF, DE = 0V (Figure 6)
DI = 0 or V
CC
V
B
= 0V, V
AB
= 2V,
RE
= V
CC
, DE = 0V (Figure 7)
l
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V, T
E
= 0 unless otherwise noted (Note 2).
CONDITIONS
MIN
20
10
1
1
4
50
6
±6
12.5
70
8
100
TYP
MAX
UNITS
Mbps
ns
ns
ns
ns
ns
µs
ns
t
ZLD
, t
ZHD
, t
LZD
, Driver Enable or Disable Time
t
HZD
t
ZHSD
, t
ZLSD
t
SHDN
Driver Enable from Shutdown
Time to Shutdown
Driver in SLO Mode (SLO LOW)
f
MAXS
t
PLHDS,
t
PHLDS
Dt
PDS
t
SKEWDS
t
RDS,
t
FDS
t
ZHDS,
t
ZLDS
t
LZDS,
t
HZDS
t
ZHSDS,
t
ZLSDS
t
SHDNS
Receiver
t
PLHR
, t
PHLR
t
SKEWR
t
RR
, t
FR
Receiver Input to Output
Differential Receiver Skew
|t
PLHR
-t
PHLR
|
Receiver Output Rise or Fall Time
l
l
l
l
l
l
Maximum Data Rate
Driver Input to Output
Driver Input to Output Difference
|t
PLHR
-t
PHLR
|
Driver Output A to Output B
Driver Rise or Fall Time
Driver Enable Time
Driver Disable Time
Driver Enable from Shutdown
Time to Shutdown
l
l
l
l
l
l
l
l
l
l
250
0.95
50
200
200
0.9
1.5
500
±500
±750
1.5
300
70
8
500
50
1
3
70
6
12.5
50
8
100
kbps
µs
ns
ns
ns
µs
ns
ns
µs
ns
ns
ns
ns
ns
µs
µs
t
ZLR
, t
ZHR
, t
LZR
, Receiver Enable/Disable
t
HZR
t
ZHSR
, t
ZLSR
t
RTEN
, t
RTZ
Receiver Enable from Shutdown
Termination Enable or Disable Time
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime..
Note 2:
All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to device ground unless
otherwise specified.
Note 3:
Maximum data rate is guaranteed by other measured parameters
and is not tested directly.
Note 4:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may result in device degradation or failure.
285961fc
4
LTC2859/LTC2861
TesT circuiTs
Y
GND
DI
OR
V
CC
DRIVER
Z
+
V
OD
–
Y
GND
OR
DI
V
CC
I
OSD
DRIVER
Z
R
R
+
V
OC
–
+
–
2859/61 F01-2
–7V to +12V
Figure 1. Driver DC Characteristics
Figure 2. Driver Output Short-Circuit Current
Y
DI
DRIVER
Z
R
DIFF
C
L
C
L
DI
V
CC
OV
t
PLHD
,
t
PLHDS
V
O
1/2 V
O
t
SKEWD
, t
SKEWDS
t
PHLD
,
t
PHLDS
Y, Z
(Y-Z)
90%
10%
0
t
RD
,
t
RDS
0
90%
10%
t
FD
,
t
FDS
2859/61 F03
Figure 3. Driver Timing Measurement
R
L
Y
V
CC
OR DI
GND
DRIVER
Z
DE
C
L
R
L
C
L
GND
OR
V
CC
V
CC
DE
OV
V
CC
V
OL
V
OH
OV
V
O
1/2 V
CC
t
ZLD
,
t
ZLDS
,
t
ZLSD
,
t
ZLSDS
1/2 V
CC
Y or Z
V
CC
OR
GND
t
LZD
,
t
LZDS
0.5V
t
HZD
,
t
HZDS,
t
SHDN,
t
SHDNS
0.5V
Z or Y
1/2 V
CC
t
ZHD
,
t
ZHDS
,
t
ZHSD
,
t
ZHSDS
2859/61 F04
Figure 4. Driver Enable and Disable Timing Measurement
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