1.62V to 5.5V Logic Supply Pin for Flexible Digital Interface
Common Mode Working Voltage: 560V
PEAK
High Input Impedance Failsafe RS485 Receiver
Current Limited Drivers and Thermal Shutdown
Compatible with TIA/EIA-485-A Specification
High Impedance Output During Internal Fault Condition
Low Current Shutdown Mode (< 10μA)
General Purpose CMOS Isolated Channel
Small, Low Profile (15mm
×
11.25mm
×
2.8mm)
Surface Mount LGA Package
APPLICATIONS
n
n
n
Isolated RS485/RS422 Interface
Industrial Networks
Breaking RS485 Ground Loops
TYPICAL APPLICATION
Isolated Half-Duplex RS485 μModule Transceiver
3.3V
V
CC
ISOLATION BARRIER
V
L
RO
RE
TE
DE
DI
GND
PWR
A
B
TWISTED-PAIR
CABLE
Y
Z
GND2
2881 TA01
LTM2881 Operating Through 35kV/μs CM Transient
MULTIPLE SWEEPS
OF COMMON MODE
TRANSIENTS
500V/DIV
LTM2881
DI
1V/DIV
1V/DIV
RO
50ns/DIV
2881 TA01a
2881f
1
LTM2881
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
1
A
B
C
D
E
F
G
H
J
K
L
D
IN
SLO
Y
Z
B
A
V
CC2
2.8mm)
GND2
GND
V
CC
2
3
4
5
6
7
8
DI DE
RE
RO V
L
ON
V
CC
to GND .................................................. –0.3V to 6V
V
CC2
to GND2 ............................................... –0.3V to 6V
V
L
to GND .................................................... –0.3V to 6V
Interface Voltages
(A, B, Y, Z) to GND2 ........................ V
CC2
–15V to 15V
Signal Voltages ON, RO, DI, DE,
RE,
TE, D
OUT
to GND ......................... –0.3V to V
L
+0.3V
Signal Voltages
SLO,
D
IN
to GND2 ....................................–0.3V to V
CC2
+0.3V
Operating Temperature Range
LTM2881C................................................ 0°C to 70°C
LTM2881I.............................................–40°C to 85°C
Storage Temperature Range...................–55°C to 125°C
Peak Reflow Temperature (Soldering, 10 sec) ...... 245°C
D
OUT
TE
LGA PACKAGE
32-PIN (15mm 11.25mm
T
JMAX
= 125°C,
θ
JA
= 32°C/W WEIGHT = 1
g
ORDER INFORMATION
LEAD FREE FINISH
LTM2881CV-3#PBF
LTM2881IV-3#PBF
LTM2881CV-5#PBF
LTM2881IV-5#PBF
TRAY
LTM2881CV-3#PBF
LTM2881IV-3#PBF
LTM2881CV-5#PBF
LTM2881IV-5#PBF
PART MARKING*
LTM2881V-3
LTM2881V-3
LTM2881V-5
LTM2881V-5
PACKAGE DESCRIPTION
32-Pin (15mm
×
11.25mm
×
2.8mm) LGA
32-Pin (15mm
×
11.25mm
×
2.8mm) LGA
32-Pin (15mm
×
11.25mm
×
2.8mm) LGA
32-Pin (15mm
×
11.25mm
×
2.8mm) LGA
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
This product is only offered in trays. For more information go to:
http://www.linear.com/packaging/
2881f
2
LTM2881
ELECTRICAL CHARACTERISTICS
SYMBOL
Power Supply
V
CC
V
L
I
CCPOFF
I
CCS
V
CC2
V
CC2NOLOAD
I
CC2S
Driver
|V
OD
|
Differential Driver Output Voltage
R = ∞ (Figure 1)
R = 27Ω (RS485) (Figure 1)
R = 50Ω (RS422) (Figure 1)
R = 27Ω or R = 50Ω (Figure 1)
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. LTM2881-3 V
CC
= 3.3V, LTM2881-5 V
CC
= 5.0V, V
L
= 3.3V, GND = GND2 =
0V, ON = V
L
unless otherwise noted.
PARAMETER
V
CC
Supply Voltage
V
L
Supply Voltage
V
CC
Supply Current in Off Mode
V
CC
Supply Current in On Mode
Regulated V
CC2
Output Voltage, Loaded
Regulated V
CC2
Output Voltage, No Load
Efficiency
V
CC2
Short-Circuit Current
ON = 0V
LTM2881-3 DE = 0V,
RE
= V
L
, No Load
LTM2881-5 DE = 0V,
RE
= V
L
, No Load
LTM2881-3 DE = 0V,
RE
= V
L
, I
LOAD
= 100mA
LTM2881-5 DE = 0V,
RE
= V
L
, I
LOAD
= 180mA
DE = 0V,
RE
= V
L
, No Load
I
CC2
= 100mA (Note 2)
DE = 0V,
RE
= V
L
, V
CC2
= 0V
l
CONDITIONS
LTM2881-3
LTM2881-5
l
l
l
l
l
l
l
MIN
3.0
4.5
1.62
TYP
3.3
5.0
0
20
15
MAX
3.6
5.5
5.5
10
25
19
UNITS
V
V
V
μA
mA
mA
V
V
4.7
4.7
4.8
5.0
5.0
5.0
50
250
V
CC2
V
CC2
V
CC2
0.2
5.35
V
%
mA
V
V
V
V
1.5
2
Δ|V
OD
|
Difference in Magnitude of Driver Differential
Output Voltage for Complementary Output
States
Driver Common Mode Output Voltage
Difference in Magnitude of Driver
Common Mode Output Voltage for
Complementary Output States
Driver Three-State (High Impedance) Output
Current on Y and Z
Maximum Driver Short-Circuit Current
Receiver Input Resistance
Receiver Termination Resistance Enabled
Receiver Input Current (A, B)
V
OC
Δ|V
OC
|
R = 27Ω or R = 50Ω (Figure 1)
R = 27Ω or R = 50Ω (Figure 1)
l
l
3
0.2
V
V
I
OZD
I
OSD
Receiver
R
IN
R
TE
I
IN
DE = 0V, (Y or Z) = –7V, +12V
– 7V ≤ (Y or Z) ≤ 12V (Figure 2)
RE
= 0V or V
L
, V
IN
= –7V, –3V, 3V, 7V,
12V (Figure 3)
TE = V
L
, V
AB
= 2V, V
B
= – 7V, 0V, 10V
(Figure 8)
ON = 0V V
CC2
= 0V or 5V, V
IN
= 12V
(Figure 3)
ON = 0V V
CC2
= 0V or 5V, V
IN
= –7V
(Figure 3)
l
l
l
l
l
l
l
±10
– 250
96
108
125
120
156
125
–100
–0.2
25
–0.2
–0.05
0
0.4
0.2
250
μA
mA
kΩ
Ω
μA
μA
V
mV
V
V
V
V
V
V
2881f
V
TH
ΔV
TH
Logic
V
IL
V
IH
Receiver Differential Input Threshold Voltage
(A-B)
Receiver Input Failsafe Hysteresis
Receiver Input Failsafe Threshold
Logic Input Low Voltage
–7V ≤ B ≤ 12V
B = 0V
B = 0V
1.62V ≤ V
L
≤ 5.5V
D
IN
SLO
DI, TE, DE, ON,
RE:
V
L
≥ 2.35V
1.62V ≤ V
L
< 2.35V
l
l
Logic Input High Voltage
0.67•V
CC2
l
2
l
l
0.67•V
L
0.75•V
L
3
LTM2881
ELECTRICAL CHARACTERISTICS
SYMBOL
I
INL
V
HYS
V
OH
PARAMETER
Logic Input Current
Logic Input Hysteresis
Output High Voltage
(Note 2)
Output High, I
LOAD
= –4mA
(Sourcing), 5.5V ≥ V
L
≥ 3V
Output High, I
LOAD
= –1mA
(Sourcing), 1.62V ≤ V
L
< 3V
Output Low, I
LO AD
= 4mA
(Sinking), 5.5V ≥ V
L
≥ 3V
Output High, I
LOAD
= 1mA
(Sinking), 1.62V ≤ V
L
< 3V
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. LTM2881-3 V
CC
= 3.3V, LTM2881-5 V
CC
= 5.0V, V
L
= 3.3V, GND = GND2 =
0V, ON = V
L
unless otherwise noted.
CONDITIONS
l
MIN
TYP
0
150
MAX
±1
UNITS
μA
mV
V
V
V
L
–0.4
V
L
–0.4
0.4
0.4
±1
±85
V
OL
Output Low Voltage
V
V
μA
mA
I
OZR
I
OSR
Three-State (High Impedance) Output Current
RE
= V
L
, 0V ≤ RO ≤ V
L
on RO
Short-Circuit Current
0V ≤ (RO or D
OUT
) ≤ V
L
SWITCHING CHARACTERISTICS
SYMBOL
f
MAX
t
PLHD
t
PHLD
Δt
PD
t
SKEWD
t
RD
t
FD
t
ZLD
, t
ZHD
,
t
LZD
, t
HZD
f
MAX
t
PLHD
t
PHLD
Δt
PD
t
SKEWD
t
RD
t
FD
t
ZLD
, t
ZHD
,
t
LZD
, t
HZD
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 Output Enable or Disable Time
Driver
SLO
= V
CC2
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. LTM2881-3 V
CC
= 3.3V, LTM2881-5 V
CC
= 5.0V, V
L
= 3.3V, GND = GND2 =
0V, ON = V
L
unless otherwise noted.
CONDITIONS
(Note 3)
R
DIFF
= 54Ω, C
L
= 100pF
(Figure 4)
R
DIFF
= 54Ω, C
L
= 100pF
(Figure 4)
R
DIFF
= 54Ω, C
L
= 100pF
(Figure 4)
R
DIFF
= 54Ω, C
L
= 100pF
(Figure 4)
R
L
= 500Ω, C
L
= 50pF
(Figure 5)
(Note 3)
R
DIFF
= 54Ω, C
L
= 100pF
(Figure 4)
R
DIFF
= 54Ω, C
L
= 100pF
(Figure 4)
R
DIFF
= 54Ω, C
L
= 100pF
(Figure 4)
R
DIFF
= 54Ω, C
L
= 100pF
(Figure 4)
R
L
= 500Ω, C
L
= 50pF
(Figure 5)
l
l
l
l
l
l
l
MIN
20
TYP
MAX
UNITS
Mbps
60
1
1
4
85
8
±8
12.5
170
ns
ns
ns
ns
ns
Driver
SLO
= GND2
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 Output Enable or Disable Time
250
1
50
±200
0.9
1.55
500
±500
1.5
400
kbps
μs
ns
ns
μs
ns
2881f
4
LTM2881
SWITCHING CHARACTERISTICS
SYMBOL
Receiver
t
PLHR
t
PHLR
t
SKEWR
t
RR
t
FR
t
ZLR
, t
ZHR
,
t
LZR
, t
HZR
t
RTEN
, t
RTZ
Receiver Input to Output
Differential Receiver Skew
|t
PLHR
- t
PHLR
|
Receiver Output Rise or Fall Time
Receiver Output Enable Time
Termination Enable or Disable Time
C
L
= 15pF, V
CM
= 2.5V, |V
AB
| = 1.4V,
t
R
and t
F
< 4ns, (Figure 6)
C
L
= 15pF
(Figure 6)
C
L
= 15pF
(Figure 6)
R
L
=1kΩ, C
L
= 15pF
(Figure 7)
RE
= 0V, DE = 0V, V
AB
= 2V, V
B
= 0V
(Figure 8)
C
L
= 15pF,
t
R
and t
F
< 4ns
ON
V
L
, No Load
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. LTM2881-3 V
CC
= 3.3V, LTM2881-5 V
CC
= 5.0V, V
L
= 3.3V, GND = GND2 =
0V, ON = V
L
unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
100
1
3
MAX
140
8
12.5
50
100
UNITS
ns
ns
ns
ns
μs
Generic Logic Input
t
PLHL1
t
PHLL1
D
IN
to D
OUT
Input to Output
l
60
100
ns
Power Supply Generator
V
CC2
–GND2 Supply Start-Up Time
(0V to 4.5V)
l
325
800
μs
ISOLATION CHARACTERISTICS
otherwise noted.
SYMBOL
V
ISO
PARAMETER
Rated Dielectric Insulation Voltage
Common Mode Transient Immunity
V
IORM
Maximum Working Insulation Voltage
Partial Discharge
Input to Output Resistance
Input to Output Capacitance
Creepage Distance
T
A
= 25°C, LTM2881-3 V
CC
= 3.3V, LTM2881-5 V
CC
= 5.0V, V
L
= 3.3V unless
MIN
2500
±4400
30
560
<5
>10
9
6
9.48
TYP
MAX
UNITS
V
RMS
V
DC
kV/μs
V
PEAK
pC
Ω
pF
mm
CONDITIONS
1 Minute (Derived from 1 Second Test)
1 Second
(Note 2)
(Note 2)
V
PR
= 1050 V
PEAK
(Note 2)
(Note 2)
(Note 2)
(Note 2)
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:
Guaranteed by design and not subject to production test.
Note 3:
Maximum Data rate is guaranteed by other measured parameters
and is not tested directly.
Note 4:
This μModule transceiver includes over temperature protection
that is intended to protect the device during momentary overload
conditions. Junction temperature will exceed 125°C when over
temperature protection is active. Continuous operation above specified
maximum operating junction temperature may result in device degradation
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