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LTC1685CS8#PBF

P1-P3P4-P6P7-P9P10-P12
1
LTC1685
FEATURES
APPLICATIO S
U
TYPICAL APPLICATION
U
DESCRIPTIO
U
52Mbps, Precision Delay,
RS485 Fail-Safe Transceiver
■
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 Receiver Operation Over the
Entire Common Mode Range
■
High Receiver 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 LTC485
■
45dB CMRR at 26MHz
The LTC
®
1685 is a high speed, precision delay RS485
transceiver that can operate at data rates as high as 52Mbps.
The device also meets 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 LTC1685 RS485 transceiver guarantees receiver fail-
safe operation over the
entire
common mode range (–7V
to 12V). Input resistance will remain ≥22k when the device
is unpowered or disabled.
The LTC1685 operates from a single 5V supply and draws
only 7mA of supply current.
10Mbps Data Pulse
400ft Category 5 UTP
1685 TA02
DRIVER INPUT
RECEIVER
INPUT
RECEIVER
OUTPUT
100ns/DIV
1V/DIV
2V/DIV
5V/DIV
CABLE DELAY
, LTC and LT are registered trademarks of Linear Technology Corporation.
■
High Speed RS485/RS422 Transceivers
■
Level Translator
■
Backplane Transceiver
■
STS-1/OC-1 Data Transceiver
■
Fast-20, Fast-40 SCSI Transceivers
V
CC1
GND1
R
RO1
RE1
DE1
DI1
D
Rt
Rt
1685 TA01
V
CC2
GND2
R
RO2
RE2
DE2
DI2
D
2
LTC1685
WU
U
PACKAGE
/
O
RDER I FOR ATIO
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
Short-Circuit Duration (Driver V
OUT
: –7V to 10V,
Receiver V
OUT
: 0V to V
DD
) ............................... Indefinite
Operating Temperature Range
LTC1685C ............................................... 0°C to 70°C
LTC1685I............................................. –40°C to 85°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
1
2
3
4
8
7
6
5
TOP VIEW
V
DD
B
A
GND
S8 PACKAGE
8-LEAD PLASTIC SO
RO
RE
DE
DI
R
D
T
JMAX
= 125°C, θ
JA
= 150°C/W
Consult factory for Military grade parts.
S8 PART MARKING
DC ELECTRICAL CHARACTERISTICS
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 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 DE, DI, RE ● 2V
V
IL
Input Low Voltage DE, DI, RE ● 0.8 V
I
IN1
Input Current DE, DI, RE ● –1 1 µA
I
IN2
Input Current (A, B) V
A
, V
B
= 12V, DE = 0, V
DD
= 0V or 5.25V ● 500 µA
V
A
, V
B
= –7V, DE = 0, 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
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
DD
Supply Current No Load, Pins 2, 3, 4 = 0V or V
DD
● 712 mA
I
OSD1
Driver Short-Circuit Current, V
OUT
= HIGH V
OUT
= –7V or 10V (Note 5) ● 20 mA
LTC1685CS8
LTC1685IS8
1685
1685I
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 5V ± 5%, unless otherwise noted. (Notes 2, 3)
3
LTC1685
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
PLH
, t
PHL
Driver Input-to-Output R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF, Figures 3, 5,
Propagation Delay LTC1685C
● 15 18.5 22 ns
LTC1685I
● 13 18.5 25 ns
t
SKEW
Driver Output A-to-Output R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF, 500 ps
B Skew 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 C
L
= 15pF, Figures 3, 7
Propagation Delay LTC1685C
● 15 18.5 22 ns
LTC1685I
● 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 Same Temperature (Note 4) 1.5 ns
Minimum Input Pulse Width V
DD
= 5V ± 5% (Note 4)
LTC1685C
● 17 19.2 ns
LTC1685I
● 20 25 ns
Maximum Data Rate V
DD
= 5V ± 5% (Note 4)
LTC1685C
● 52 60 Mbps
LTC1685I
● 40 50 Mbps
Maximum Input Frequency V
DD
= 5V ± 5% (Note 4)
LTC1685C
● 26 30 MHz
LTC1685I
● 20 25 MHz
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
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 Inputs, D, DE, RE 3 pF
Open-Circuit Input Voltage, Figure 5 V
DD
= 5V (Note 4) ● 3.2 3.3 3.4 V
Fail-Safe Time Time to Detect Fail-Safe Condition 2 µs
CMRR Receiver Input Common Mode Rejection Ratio V
CM
= 2.6V, f = 26MHz 45 dB
C
LOAD
Receiver and Driver Output Load Capacitance (Note 4) ● 500 pF
DC ELECTRICAL CHARACTERISTICS
SWITCHING CHARACTERISTICS
U
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 5V ±5%, unless otherwise noted. (Notes 2, 3)
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 5V, unless otherwise noted. (Notes 2, 3)
P1-P3P4-P6P7-P9P10-P12

LTC1685CS8#PBF

Mfr. #:
Buy LTC1685CS8#PBF
Manufacturer:
Analog Devices Inc.
Description:
RS-485 Interface IC 52Mbps, Prec Delay, RS485 Fail-Safe Tran
Lifecycle:
New from this manufacturer.
Delivery:
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