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LTC1687CS#PBF

P1-P3P4-P6P7-P9P10-P12
1
LTC1686/LTC1687
52Mbps Precision Delay
RS485 Fail-Safe Transceivers
DESCRIPTION
U
■
Precision Propagation Delay Over Temperature:
Receiver/Driver: 18.5ns
±
3.5ns
■
High Data Rate:
52Mbps
■
Low t
PLH
/t
PHL
Skew:
Receiver/Driver: 500ps Typ
■
–7V to 12V RS485 Input Common Mode Range
■
Guaranteed Fail-Safe Operation Over the Entire
Common Mode Range
■
High Input Resistance: ≥22k, Even When Unpowered
■
Short-Circuit Protected
■
Thermal Shutdown Protected
■
Driver Maintains High Impedance in Three-State or
with Power Off
■
Single 5V Supply
■
Pin Compatible with LTC490/LTC491
■
45dB CMRR at 26MHz
FEATURES
The LTC
®
1686/LTC1687 are high speed, precision delay,
full-duplex RS485 transceivers that can operate at data
rates as high as 52Mbps. The devices also meet the
requirements of RS422.
A unique architecture provides very stable propagation
delays and low skew over a wide common mode and
ambient temperature range.
The driver and receiver feature three-state outputs, with
disabled driver outputs maintaining high impedance over
the entire common mode range. A short-circuit feature
detects shorted outputs and substantially reduces driver
output current. A similar feature also protects the receiver
output from short circuits. Thermal shutdown circuitry
protects from excessive power dissipation.
The receiver has a fail-safe feature that guarantees a high
output state when the inputs are shorted or are left floating.
The LTC1686/LTC1687 RS485 transceivers guarantee
receiver fail-safe operation over the
entire
common mode
range (–7V to 12V). Receiver input resistance remains
≥22k when the device is unpowered or disabled.
The LTC1686/LTC1687 operate from a single 5V supply
and draw only 7mA of supply current.
APPLICATIONS
U
■
High Speed RS485/RS422 Full Duplex Transceivers
■
Level Translator
■
Backplane Transceiver
■
STS-1/OC-1 Data Transceiver
■
Signal Repeaters
, LTC and LT are registered trademarks of Linear Technology Corporation.
10Mbps Data Pulse
400 Feet Category 5 UTP
1686/87 TA02
DRIVER INPUT
RECEIVER
INPUT
RECEIVER
OUTPUT
100ns/DIV
1V/DIV
2V/DIV
5V/DIV
CABLE DELAY
LTC1686/87 • TA01
100Ω 100Ω
100Ω 100Ω
LTC1686 LTC1686
R
D
R
D
3
2
7
8
6
5
400 FT OF CATEGORY 5 UTP
RECEIVER
DRIVER
RECEIVER
DRIVER
TYPICAL APPLICATION
U
2
LTC1686/LTC1687
A
U
G
W
A
W
U
W
ARB
S
O
LU
T
EXI T
I
S
(Note 1)
Supply Voltage (V
DD
) .............................................. 10V
Control Input Currents .................... –100mA to 100mA
Control Input Voltages .................. –0.5V to V
DD
+ 0.5V
Driver Input Voltages .................... –0.5V to V
DD
+ 0.5V
Driver Output Voltages ................................. +12V/–7V
Receiver Input Voltages ................................ +12V/–7V
Receiver Output Voltages ............. –0.5V to V
DD
+ 0.5V
Receiver Input Differential ...................................... 10V
Driver Short-Circuit Duration
(V
OUT
: –7V to 10V) ..................................... Indefinite
Receiver Short-Circuit Duration
(V
OUT
: 0V to V
DD
) ........................................ Indefinite
Operating Temperature Range
LTC1686C/LTC1687C ............................. 0°C to 70°C
LTC1686I/LTC1687I .......................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OD1
Differential Driver Output (Unloaded) I
OUT
= 0 ● V
DD
V
V
OD2
Differential Driver Output (With Load) R = 50Ω (RS422) 2.0 V
R = 27Ω (RS485), Figure 1
● 1.5 V
DD
V
∆V
OD
Change in Magnitude of Driver Differential R = 27Ω or 50Ω, Figure 1 ● 0.2 V
Output Voltage for Complementary
Output States
V
OC
Driver Common Mode Output Voltage R = 27Ω or 50Ω, V
DD
= 5V, Figure 1 ● 23V
∆V
OC
Change in Magnitude of Driver Common R = 27Ω or 50Ω, Figure 1 ● 0.2 V
Mode Output Voltage for Complementary
Output States
V
IH
Input High Voltage D, DE, RE ● 2V
V
IL
Input Low Voltage D, DE, RE ● 0.8 V
I
IN1
Input Current D, DE, RE ● –1 1 µA
I
IN2
Input Current (A, B) V
A
, V
B
= 12V, V
DD
= 0V or 5.25V ● 500 µA
V
A
, V
B
= – 7V, V
DD
= 0V or 5.25V ● –500 µA
V
TH
Differential Input Threshold Voltage –7V ≤ V
CM
≤ 12V ● – 0.3 0.3 V
for Receiver
∆V
TH
Receiver Input Hysteresis V
CM
= 0V 25 mV
V
OH
Receiver Output High Voltage I
OUT
= – 4mA, V
ID
= 300mV ● 3.5 4.8 V
Consult factory for Industrial and Military grade parts.
V
DD
= 5V ± 5% unless otherwise noted (Notes 2, 3).
DC ELECTRICAL CHARACTERISTICS
T
JMAX
= 125°C, θ
JA
= 150°C/W
WU
U
PACKAGE
/
O
RDER I FOR ATIO
LTC1687CS
LTC1687IS
T
JMAX
= 125°C, θ
JA
= 90°C/ W
ORDER PART
NUMBER
14
13
12
11
10
9
87
6
5
4
3
2
1
TOP VIEW
S PACKAGE
14-LEAD PLASTIC SO
NC
Y
NC
Z
B
NC
V
DD
D
GND
GND
R
RE
DE
A
R
D
ORDER PART
NUMBER
LTC1686CS8
LTC1686IS8
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
1
2
3
4
8
7
6
5
TOP VIEW
V
DD
R
D
GND
A
B
Z
Y
R
D
1686
1686I
3
LTC1686/LTC1687
DC ELECTRICAL CHARACTERISTICS
V
DD
= 5V ±5% unless otherwise noted (Notes 2, 3).
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OL
Receiver Output Low Voltage I
OUT
= 4mA, V
ID
= – 300mV ● 0.4 V
I
OZR
Three-State (High Impedance) Output 0.4V ≤ V
OUT
≤ 2.4V ● –1 1 µA
Current at Receiver
I
OZD
Three-State (High Impedance) Output V
OUT
= – 7V to 12V ● –200 200 µA
Current at Driver
C
LOAD
Receiver and Driver Output Load Capacitance (Note 4) ● 500 pF
I
DD
Supply Current No Load, Pins D, DE, RE = 0V or V
DD
● 712 mA
I
OSD1
Driver Short-Circuit Current, V
OUT
= HIGH V
OUT
= – 7V or 10V (Note 5) ● 20 mA
I
OSD2
Driver Short-Circuit Current, V
OUT
= LOW V
OUT
= – 7V or 10V (Note 5) ● 20 mA
I
OSR
Receiver Short-Circuit Current V
OUT
= 0V or V
DD
(Note 5) ● 20 mA
R
IN
Input Resistance – 7V ≤ V
CM
≤ 12V ● 22 kΩ
C
IN
Input Capacitance A, B, D, DE, RE Inputs (Note 4) 3 pF
Open-Circuit Input Voltage V
DD
= 5V (Note 4), Figure 5 ● 3.2 3.3 3.4 V
Fail-Safe Time to Detect Fail-Safe Condition 2 µs
Time
CMRR Receiver Input Common Mode V
CM
= 2.5V, f = 26MHz 45 dB
Rejection Ratio
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
PLH
, t
PHL
Driver Input-to-Output Propagation Delay R
DIFF
= 54Ω, Figures 3, 5 LTC1686C/LTC1687C ● 15 18.5 22 ns
C
L1
= C
L2
= 100pF LTC1686I/LTC1687I ● 13 18.5 25 ns
t
SKEW
Driver Output A-to-Output B Skew R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF, 500 ps
Figures 3, 5
t
r
, t
f
Driver Rise/Fall Time R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF, 3.5 ns
Figures 3, 5
t
ZH
Driver Enable to Output High C
L
= 100pF, S2 Closed, Figures 4, 6 ● 25 50 ns
t
ZL
Driver Enable to Output Low C
L
= 100pF, S1 Closed, Figures 4, 6 ● 25 50 ns
t
LZ
Driver Disable from Low C
L
= 15pF, S1 Closed, Figures 4, 6 ● 25 50 ns
t
HZ
Driver Disable from High C
L
= 15pF, S2 Closed, Figures 4, 6 ● 25 50 ns
t
PLH
, t
PHL
Receiver Input-to-Output Propagation Delay C
L
= 15pF, Figures 3, 7 LTC1686C/LTC1687C ● 15 18.5 22 ns
LTC1686I/LTC1687I
● 13 18.5 25 ns
t
SQD
Receiver Skew t
PLH
– t
PHL
C
L
= 15pF, Figures 3, 7 500 ps
t
ZL
Receiver Enable to Output Low C
L
= 15pF, S1 Closed, Figures 2, 8 ● 25 50 ns
t
ZH
Receiver Enable to Output High C
L
= 15pF, S2 Closed, Figures 2, 8 ● 25 50 ns
t
LZ
Receiver Disable from Low C
L
= 15pF, S1 Closed, Figures 2, 8 ● 25 50 ns
t
HZ
Receiver Disable from High C
L
= 15pF, S2 Closed, Figures 2, 8 ● 25 50 ns
Maximum Receiver Input (Note 4) ● 2000 ns
Rise/Fall Times
t
PKG-PKG
Package-to-Package Skew C
L
= 15pF, Same Temperature (Note 4) 1.5 ns
SWITCHING CHARACTERISTICS
U
V
DD
= 5V, unless otherwise noted (Notes 2, 3).
P1-P3P4-P6P7-P9P10-P12

LTC1687CS#PBF

Mfr. #:
Buy LTC1687CS#PBF
Manufacturer:
Analog Devices Inc.
Description:
RS-485 Interface IC 52Mbps Prec Delay RS485 Fail-Safe Trans
Lifecycle:
New from this manufacturer.
Delivery:
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