LTC1518/LTC1519
52Mbps Precision Delay
RS485 Quad Line Receivers
FEATURES
s
s
s
s
s
DESCRIPTIO
s
s
s
s
s
s
s
s
s
Precision Propagation Delay: 18.5ns
±3.5ns
Over
0°C to 70°C Temperature Range
High Data Rate:
52Mbps
Low t
PLH
/t
PHL
Skew: 500ps Typ
Low Channel-to-Channel Skew: 500ps Typ
Guaranteed Fail-Safe Operation over the Entire
Common Mode Range
–7V to 12V RS485 Input Common Mode Range
Input Resistance
≥
22k, Even When Unpowered
Hot Swap
TM
Capable
High Common Mode Rejection to 26MHz
Short-Circuit Protection: 10mA Typ Output Current
for an Indefinite Short
Three-State Output Capability
Will Not Oscillate with Slow Moving Input Signals
Single 5V Supply
Pin Compatible with LTC488, LTC489
The LTC
®
1518/LTC1519 are high speed, precision delay
differential quad bus/line receivers that can operate at data
rates as high as 52Mbps. They are pin compatible with the
LTC488/LTC489 RS485 line receivers and operate over the
entire – 7V to 12V common mode range. A unique architec-
ture provides very stable propagation delays and low skew
over wide input common mode, input overdrive and ambi-
ent temperature ranges. Propagation delay is 18.5ns
±3.5ns
over the commercial temperature range. Typical t
PLH
/t
PHL
and channel-to-channel skew is 500ps.
Each receiver translates differential input levels (V
ID
≥
300mV) into valid CMOS and TTL output levels. Its high
input resistance (≥ 22k) allows many receivers to be con-
nected to the same driver. The receiver outputs go into a
high impedance state when disabled.
The receivers have a fail-safe feature that guarantees a high
output state when the inputs are shorted or left floating.
Other protection features include thermal shutdown and a
controlled maximum short-circuit current (50mA Max).
Input resistance remains
≥
22k when the device is
unpowered or disabled, thus allowing hot swapping with-
out loading the data lines.
The LTC1518/LTC1519 operate from a single 5V supply
and draw 12mA of supply current.
APPLICATIO S
s
s
s
s
s
High Speed RS485/RS422 Receivers
STS-1/OC-1 Data Receivers
PECL Line Receivers
Level Translators
Fast-20/Fast-40 SCSI Receiver
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
RE
2
RO
1
7
DI
4
3
DE
LTC1685
6
100Ω
4 A 1
12
3
RO
2 B
Propagation Delay Guaranteed to Fall
Within Shaded Area (±3.5ns)
T
A
= 0°C TO 70°C
RECEIVER
INPUT
V
ID
= 1.5V
RECEIVER
OUTPUT
V
DD
= 5V
52Mbps Data Communication over Twisted Pair
RE
2
1
7
100Ω
4
6
3
DE
DI
RO
V
OUT
=
5V/DIV
V
IN
=
3V/DIV
EN
EN
1/4 LTC1518
LTC1685
1518/19 F08
–5
0
5
U
10 15 20 25 30 35 40 45
TIME (ns)
1518/19 TA02
U
U
1
LTC1518/LTC1519
ABSOLUTE
(Note 1)
AXI U
RATI GS
Short-Circuit Duration .................................... Indefinite
Operating Temperature Range
LTC1518C/LTC1519C ............................. 0°C to 70°C
LTC1518I/LTC1519I .......................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
Supply Voltage ....................................................... 10V
Digital Input Currents ..................... – 100mA to 100mA
Digital Input Voltages ............................... – 0.5V to 10V
Receiver Input Voltages ........................................
±14V
Receiver Output Voltages ............. – 0.5V to V
DD
+ 0.5V
Receiver Input Differential ....................................... 10V
PACKAGE/ORDER I FOR ATIO
TOP VIEW
B1 1
A1 2
OUT 1 3
EN 4
OUT 2 5
A2 6
B2 7
GND 8
16 V
DD
15 B4
14 A4
13 OUT 4
12 EN
11 OUT 3
10 A3
9
B3
ORDER PART
NUMBER
LTC1518CS
LTC1518IS
S PACKAGE
16-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 90°C/ W
Consult factory for Military grade parts.
DC ELECTRICAL CHARACTERISTICS
SYMBOL
V
CM
V
IH
V
IL
I
IN1
I
IN2
R
IN
C
IN
V
OC
V
ID(MIN)
dV
ID
V
OH
V
OL
I
OZR
I
DD
I
OSR
PARAMETER
Input Common Mode Voltage
Input High Voltage
Input Low Voltage
Input Current
Input Current (A, B)
Input Resistance
Input Capacitance
Open-Circuit Input Voltage
Differential Input Threshold Voltage
Input Hysteresis
Output High Voltage
Output Low Voltage
Three-State Output Current
Total Supply Current All 4 Receivers
Short-Circuit Current
A, B Inputs
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 5V
±5%
(Notes 2, 3) per receiver, unless otherwise noted.
CONDITIONS
q
q
q
q
q
q
q
EN, EN, EN12, EN34
EN, EN, EN12, EN34
EN, EN, EN12, EN34
V
A
, V
B
= 12V
V
A
, V
B
= – 7V
– 7V
≤
V
CM
≤
12V (Figure 5)
(Note 4)
V
DD
= 5V (Note 4) (Figure 5)
– 7V
≤
V
CM
≤
12V
V
CM
= 2.5V
I
OUT
= – 4mA, V
ID
= 0.3V, V
DD
= 5V
I
OUT
= 4mA, V
ID
= – 0.3V, V
DD
= 5V
0V < V
OUT
< 5V
V
OUT
= 0V, V
OUT
= 5V (Note 7)
V
ID
> 0.3V, No Load, Device Enabled
q
q
2
U
U
W
W W
U
W
TOP VIEW
B1 1
A1 2
OUT 1 3
EN12 4
OUT 2 5
A2 6
B2 7
GND 8
16 V
DD
15 B4
14 A4
13 OUT 4
12 EN34
11 OUT 3
10 A3
9
B3
ORDER PART
NUMBER
LTC1519CS
LTC1519IS
S PACKAGE
16-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 90°C/ W
MIN
–7
2
TYP
MAX
12
0.8
UNITS
V
V
V
µA
µA
µA
kΩ
pF
–1
– 500
22
3
3.2
– 0.3
25
4.6
3.3
1
500
q
q
3.4
0.3
V
V
mV
V
q
q
q
0.4
– 10
12
– 50
10
20
50
V
µA
mA
mA
LTC1518/LTC1519
DC ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
Max V
ID
for Fail-Safe Detection
Min Time to Detect Fault Condition
CMRR
Common Mode Rejection Ratio
V
CM
= 2.5V, f = 26MHz (Note 4)
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 5V
±5%
(Notes 2, 3) per receiver, unless otherwise noted.
CONDITIONS
–7V
≤
V
CM
≤
12V
MIN
TYP
25
2
45
MAX
UNITS
mV
µs
dB
SWITCHI G TI E CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
DD
= 5V
±5%
(Notes 2, 3) V
ID
= 1.5V, V
CM
= 2.5V, unless otherwise noted.
SYMBOL
t
PLH
, t
PHL
t
r
, t
f
t
SKD
t
ZL
t
ZH
t
LZ
t
HZ
t
CH-CH
t
PKG-PKG
t
r
, t
f
Input
PARAMETER
Input-to-Output Propagation Delay
Rise/Fall Times
t
PLH
– t
PHL
Skew
Enable to Output Low
Enable to Output High
Disable from Output Low
Disable from Output High
Channel-to-Channel Skew
Package-to-Package Skew
Maximum Input Rise or Fall Time
Minimum Input Pulse Width
f
IN(MAX)
Maximum Input Frequency
Maximum Data Rate
C
L
Load Capacitance
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
All currents into the device pins are positive; all currents out of the
device pins are negative.
Note 3:
All typicals are given for V
DD
= 5V, T
A
= 25°C.
Note 4:
Guaranteed by design, but not tested.
W
U
CONDITIONS
C
L
= 15pF, 0°C
≤
T
A
≤
70°C (Figure 1)
C
L
= 15pF, – 40°C
≤
T
A
≤
85°C (Figure 1)
C
L
= 15pF
C
L
= 15pF, Same Receiver (Note 5)
C
L
= 15pF, 0°C
≤
T
A
≤
70°C (Figure 2)
C
L
= 15pF, – 40°C
≤
T
A
≤
85°C (Figure 2)
C
L
= 15pF, 0°C
≤
T
A
≤
70°C (Figure 2)
C
L
= 15pF, – 40°C
≤
T
A
≤
85°C (Figure 2)
C
L
= 15pF, 0°C
≤
T
A
≤
70°C (Figure 2)
C
L
= 15pF, – 40°C
≤
T
A
≤
85°C (Figure 2)
C
L
= 15pF, 0°C
≤
T
A
≤
70°C (Figure 2)
C
L
= 15pF, – 40°C
≤
T
A
≤
85°C (Figure 2)
C
L
= 15pF (Figure 3, Note 6)
C
L
= 15pF, Same Temperature
(Figure 4, Note 4)
(Note 4)
0°C
≤
T
A
≤
70°C (Note 4)
– 40°C
≤
T
A
≤
85°C (Note 4)
Square Wave, 0°C
≤
T
A
≤
70°C (Note 4)
Square Wave, – 40°C
≤
T
A
≤
85°C (Note 4)
0°C
≤
T
A
≤
70°C (Note 4)
– 40°C
≤
T
A
≤
85°C (Note 4)
(Note 4)
q
q
q
q
q
q
q
q
q
q
q
q
q
MIN
15
12
TYP
18.5
2.5
500
10
15
10
15
20
25
20
25
500
1.5
MAX
22
25
UNITS
ns
ns
ns
ps
35
35
35
35
ns
ns
ns
ns
ns
ns
ns
ns
ps
ns
2000
12
16
26
20
52
40
40
30
80
65
500
19.2
25
ns
ns
ns
MHz
MHz
Mbps
Mbps
pF
Note 5:
Worst-case
t
PLH
– t
PHL
skew for a single receiver in a package
over the full operating temperature range.
Note 6:
Maximum difference between any two t
PLH
or t
PHL
transitions in a
single package over the full operating temperature range.
Note 7:
Short-circuit current does not represent output drive capability.
When the output detects a short-circuit condition, output drive current is
significantly reduced until the short is removed.
3
LTC1518/LTC1519
TYPICAL PERFOR A CE CHARACTERISTICS
CMRR vs Frequency
46.5
COMMON MODE REJECTION RATIO (dB)
25
V
CM
= 2.5V
V
ID
= 1.5V
PROPAGATION DELAY (ns)
46.0
45.5
45.0
44.5
44.0
43.5
43.0
42.5
42.0
10
1k
100k
FREQUENCY (Hz)
10M
15189 G01
SUPPLY CURRENT (mA)
T
A
= 25°C
V
CM
= 2.5V
Supply Current
vs Temperature and Data Rate
30
V
CM
= 2.5V
V
ID
= 1.5V
25 1 RECEIVER
SWITCHING
20
15
10
5
0
0
10
30
20
DATA RATE (Mbps)
40
50
15189 G04
PROPAGATION DELAY (ns)
20
15
10
5
0
5 15 25
35
55
105
LOAD CAPACITANCE (pF)
205
15189 G05
PROPAGATION DELAY (ns)
SUPPLY CURRENT (mA)
100°C
25°C
0°C
–25°C
–50°C
Propagation Delay
vs Input Differential Voltage
25
T
A
= 25°C
V
CM
= 2.5V
PROPAGATION DELAY (ns)
20
DATA RATE (Mbps)
50
40
30
20
10
0
0.3 0.5
70
60
15
10
5
1.0
1.5
2.0
INPUT DIFFERENTIAL (V)
4
U W
Propagation Delay (t
PLH
/t
PHL
)
vs Temperature
50
45
40
35
30
25
20
15
10
5
0
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
125
Supply Current vs Data Rate
T
A
= 25°C
V
CM
= 2.5V
V
ID
= 1.5V
4 RECEIVERS
SWITCHING
20
15
10
1 RECEIVER
SWITCHING
5
0
0
10
30
20
DATA RATE (Mbps)
40
50
15189 G03
15189 G02
Propagation Delay
vs Load Capacitance
30
25
T
A
= 25°C
V
CM
= 2.5V
V
ID
= 1.5V
Propagation Delay
vs Common Mode
25
T
A
= 25°C
V
ID
= 1.5V
20
15
10
5
0
–6 –4
–2
8
0
4
6
2
COMMON MODE (V)
10
12
15189 G06
Maximum Data Rate
vs Input Differential Voltage
T
A
= 25°C
V
CM
= 2.5V
2.5
15189 G07
0
0.3 0.5
1.0
1.5
2.0
INPUT DIFFERENTIAL (V)
2.5
15189 G08
LTC1518/LTC1519
PI FU CTIO S
LTC1518
B1 (Pin 1):
Receiver 1 Inverting Input.
A1 (Pin 2):
Receiver 1 Noninverting Input.
OUT 1 (Pin 3):
Receiver 1 Output.
EN (Pin 4):
A high enables all outputs; a low on Pin 4 and
a high on Pin 12 will put all outputs into a high impedance
state. Do not float.
OUT 2 (Pin 5):
Receiver 2 Output.
A2 (Pin 6):
Receiver 2 Noninverting Input.
B2 (Pin 7):
Receiver 2 Inverting Input.
GND (Pin 8):
Ground Pin. A ground plane is recommended
for all LTC1518 applications.
B3 (Pin 9):
Receiver 3 Inverting Input.
A3 (Pin 10):
Receiver 3 Noninverting Input.
OUT 3 (Pin 11):
Receiver 3 Output.
EN (Pin 12):
A low enables all outputs; a low on Pin 4 and
a high on Pin 12 will put all outputs into a high impedance
state. Do not float.
OUT 4 (Pin 13):
Receiver 4 Output.
A4 (Pin 14):
Receiver 4 Noninverting Input.
B4 (Pin 15):
Receiver 4 Inverting Input.
V
DD
(Pin 16):
Power Supply Input. This pin should be
decoupled with a 0.1µF ceramic capacitor as close as
possible to the pin. Recommended: V
DD
= 5V
±5%.
U
U
U
LTC1519
B1 (Pin 1):
Receiver 1 Inverting Input.
A1 (Pin 2):
Receiver 1 Noninverting Input.
OUT 1 (Pin 3):
Receiver 1 Output.
EN12 (Pin 4):
A high enables receivers 1 and 2; a low will
put the outputs of receivers 1 and 2 into a high impedance
state. Do not float.
OUT 2 (Pin 5):
Receiver 2 Output.
A2 (Pin 6):
Receiver 2 Noninverting Input.
B2 (Pin 7):
Receiver 2 Inverting Input.
GND (Pin 8):
Ground Pin. A ground plane is recommended
for all LTC1519 applications.
B3 (Pin 9):
Receiver 3 Inverting Input.
A3 (Pin 10):
Receiver 3 Noninverting Input.
OUT 3 (Pin 11):
Receiver 3 Output.
EN34 (Pin 12):
A high enables receivers 3 and 4; a low will
put the outputs of receivers 3 and 4 into a high impedance
state. Do not float.
OUT 4 (Pin 13):
Receiver 4 Output.
A4 (Pin 14):
Receiver 4 Noninverting Input.
B4 (Pin 15):
Receiver 4 Inverting Input.
V
DD
(Pin 16):
Power Supply Input. This pin should be
decoupled with a 0.1µF ceramic capacitor as close as
possible to the pin. Recommended: V
DD
= 5V
±5%.
5
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