LINER LTC1320 Appletalk transceiver Datasheet

LTC1320
AppleTalk© Transceiver
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DESCRIPTIO
FEATURES
■
■
■
■
■
■
■
■
Single Chip Provides Complete
LocalTalk©/AppleTalk© Port
Low Power: ICC = 1.2mA Typ
Shutdown Pin Reduces ICC to 30µA Typ
Drivers Maintain High Impedance in Three-State
or with Power Off
30ns Driver Propagation Delay Typ
5ns Driver Skew Typ
Thermal Shutdown Protection
Drivers are Short-Circuit Protected
The LTC1320 is an RS422/RS562 line transceiver designed to operate on LocalTalk networks. It provides one
differential RS422 driver, one single-ended RS562 driver,
two single-ended RS562 receivers, and one differential
RS422 receiver. The LTC1320 draws only 1.2mA quiescent current when active and 30µA in shutdown, making
it ideal for use in battery-powered devices and other
systems where power consumption is a primary concern.
The LTC1320 drivers are specified to drive ±2V into 100Ω.
Additionally, the driver outputs three-state when disabled,
during shutdown, or when the power is off; they maintain
high impedance even with output common-mode voltages beyond the power supply rails. Both the driver
outputs and receiver inputs are protected against ESD
damage to beyond 5kV.
UO
APPLICATI
■
■
■
S
LocalTalk Peripherals
Notebook/Palmtop Computers
Battery-Powered Systems
The LTC1320 is available in the 18-pin SOL package.
AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc.
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TYPICAL APPLICATI
Output Waveforms
Typical LocalTalk Connection
5V
18
DATA IN
TX ENABLE
3
RX ENABLE
SHUTDOWN
22Ω
16 22Ω
100pF
22Ω
1
5
DATA OUT
17 22Ω
DATA IN
5V/DIV
120Ω
2V/DIV
100pF
LTC1320
#1
1k
8
4
9
LocalTalk
TRANSFORMER
14
–5V
11 22Ω
22Ω
10 22Ω
100pF
22Ω
1k
SIGNALS
ON LINE
2V/DIV
LTC1320 • TA01
100pF
5V/DIV
DATA OUT
(REMOTE
RECEIVER)
50ns/DIV
1
LTC1320
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RATI GS
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ABSOLUTE
PACKAGE/ORDER I FOR ATIO
Supply Voltage (VDD) ................................................ 7V
Supply Voltage (VSS) .............................................. – 7V
Input Voltage (Logic Inputs) ......... – 0.3V to VDD + 0.3V
Input Voltage (Receiver Inputs) ............................ ±15V
Driver Output Voltage (Forced) ............................. ±15V
Output Short-Circuit Duration ......................... Indefinite
Operating Temperature Range ................... 0°C ot 70°C
Storage Temperature Range ................ – 65°c to 150°C
Lead Temperature (Soldering, 10 sec)................ 300°C
TOP VIEW
TXD
1
18 VDD
TXI
2
17 TXD –
TXDEN
3
16 TXD +
SD
4
15 TXO
RXEN
5
14 VSS
RXO
6
13 RXI
RXO
7
12 RXI
RXDO
8
11 RXD –
GND
9
10 RXD+
ORDER PART
NUMBER
LTC1320CS
S PACKAGE
18-LEAD PLASTIC SOL
LTC1320 • PO01
TJMAX = 150°C, θJA = 100°C/W
Consult factory for Industrial and Military grade parts.
DC ELECTRICAL CHARACTERISTICS
VS = ±5V ±5%, TA = 0°C to 70°C (Notes 2, 3)
SYMBOL
PARAMETER
CONDITIONS
VOD
Differential Driver Output Voltage
No Load
RL = 100Ω (Figure 1)
Change in Magnitude of Driver
Differential Output Voltage
RL = 100Ω (Figure 1)
Driver Common-Mode Output Voltage
RL = 100Ω (Figure 1)
Output Common-Mode Range
SD = 5V or Power Off
●
Single-Ended Driver Output Voltage
No Load
RL = 400Ω
●
●
±4.0
±3.4
V
V
Input High Voltage
All Logic Input Pins
●
2.0
V
Input Low Voltage
All Logic Input Pins
●
Input Current
All Logic Input Pins
●
Three-State Output Current
SD = 5V or Power Off, – 10V < VO < 10V
●
Driver Short-Circuit Current
– 5V < VO < 5V
●
35
Receiver Input Resistance
– 7V < VIN < 7V
●
12
3.5
VOC
MIN
●
●
8.0
2.0
Receiver Output High Voltage
IO = – 4mA
●
Receiver Output Low Voltage
IO = 4mA
●
Receiver Output Short-Circuit Current
0V < VO < 5V
●
Receiver Output Three-State Current
0V < VO < 5V
●
Differential Receiver Threshold Voltage
– 7V < VCM < 7V
●
Differential Receiver Input Hysteresis
– 7V < VCM < 7V
V
V
±10
V
0.8
V
±1
±20
µA
±2
±100
µA
350
500
mA
kΩ
V
7
±2
– 200
0.4
V
85
mA
±100
µA
200
mV
70
●
●
UNITS
V
V
3
VOL
Single-Ended Receiver Input High Voltage
MAX
0.2
VOH
Single-Ended Receiver Input Low Voltage
TYP
mV
0.8
V
2
V
IDD
Supply Current
No Load, SD = 0V
No Load, SD = 5V
●
●
1.2
30
3.0
350
mA
µA
ISS
Supply Current
No Load, SD = 5V
●
2
350
µA
2
LTC1320
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SWITCHI G CHARACTERISTICS
VS = ±5V ±5%, TA = 0°C to 70°C (Notes 2, 3)
SYMBOL
PARAMETER
CONDITIONS
TYP
MAX
UNITS
tPLH, HL
Differential Driver Propagation Delay
RL = 100Ω, CL = 100pF (Figures 2, 8)
●
40
120
ns
tSKEW
Differential Driver Output to Output
RL = 100Ω, CL = 100pF (Figures 2, 8)
●
10
50
ns
tr, f
Differential Driver Rise/Fall Time
RL = 100Ω, CL = 100pF (Figures 2, 8)
●
15
80
ns
tENH, L
Driver Enable to Output Active
CL = 100pF (Figures 3, 4, 10)
●
50
150
ns
tH, Ldis
Driver Output Active to Disable
CL = 15pF (Figures 3, 4, 10)
●
50
150
ns
tPLH, HL
Single-Ended Driver Propagation Delay
RL = 450Ω, CL = 100pF (Figures 5, 11)
●
40
120
ns
tr, f
Single-Ended Driver Rise/Fall Time
RL = 450Ω, CL = 100pF (Figures 5, 12)
●
15
80
ns
tPLH, HL
Receiver Propagation Delay
CL = 15pF (Figures 13, 14)
●
60
160
ns
tENH, L
Receiver Enable to Output Active
CL = 100pF (Figures 6, 7, 15)
●
30
100
ns
tH, Ldis
Receiver Output Active to Disable
CL = 15pF (Figures 6, 7, 15)
●
30
100
ns
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
MIN
Note 2: All currents into device pins are positive; all currents out of
device pins are negative. All voltages are referenced to ground unless
otherwise specified.
Note 3: All typicals are given at VS = ±5V, TA = 25°C.
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TYPICAL PERFOR A CE CHARACTERISTICS
Differential Output Swing vs
Load Current
Output Swing vs Load Current
5
OUTPUT HIGH
3
2
1
0
–1
–2
–3
OUTPUT LOW
8
SUPPLY CURRENT (mA)
DIFFERENTIAL OUTPUT SWING (V)
4
OUTPUT SWING (V)
Supply Current vs Temperature
1.2
10
6
4
0
20
60
80
40
OUTPUT CURRENT (mA)
100
IDD
1.0
0.004
2
ISS
0.002
–4
–5
1.1
0
0
20
60
80
40
OUTPUT CURRENT (mA)
LTC1320 • G01
100
LTC1320 • G02
0
0
10
50
20
30
40
TEMPERATURE (°C)
60
70
LTC1320 • G03
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PI FU CTIO S
TXD (Pin 1): RS422 Differential Driver Input (TTL Compatible).
TXI (Pin 2): RS562 Single-Ended Driver Input (TTL compatible.
TXDEN (Pin 3): RS422 Differential Driver Output Enable
(TTL Compatible). A high level on this pin forces the
RS422 driver into three-state; a low level enables the
driver. This input does not affect the RS562 single-ended
driver.
SD (Pin 4): Shutdown Input (TTL Compatible). When this
pin is high, the chip is shut down: all driver outputs threestate and the supply current drops to 30µA. A low on this
pin allows normal operation.
3
LTC1320
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PI FU CTIO S
RXEN (Pin 5): Receiver Enable (TTL Compatible). A high
level on this pin disables the receivers and three-states the
logic outputs; a low level allows normal operation. To
prevent erratic behavior at the receiver outputs during
shutdown, RXEN should be pulled high along with SD.
RXO (Pin 6): Inverting RS562 Single-Ended Receiver
Output.
RXI (Pin 12): Noninverting RS562 Receiver Input. This
input controls the RXO output; it has no effect on the RXO
output.
RXI (Pin 13): Inverting RS562 Receiver Input. This input
controls the RXO output; it has no effect on the RXO
output.
RXO (Pin 7): Noninverting RS562 Single-Ended Receiver
Output.
VSS (Pin 14): Negative Supply. – 4.75 ≥ VSS ≥ – 5.25V. The
voltage on this pin must never exceed ground on power up
or power-down.
RXDO (Pin 8): RS422 Differential Receiver Output.
TXO (Pin 15): RS562 Single-Ended Driver Output.
GND (Pin 9): Ground Pin.
TXD+ (Pin 16): RS422 Differential Driver Noninverting
Output.
RXD+ (Pin 10): RS422 Differential Receiver Noninverting
Input. When this pin is ≥ 200mV above RXD –, RXDO will
be high; when this pin is ≥ 200mV below RXD –, RXDO will
be low.
TXD – (Pin 17): RS422 Differential Driver Inverting Output.
VDD (Pin 18): Positive Supply. 4.75V ≤ VDD ≤ 5.25V.
RXD – (Pin 11): RS422 Differential Receiver Inverting
Input.
TEST CIRCUITS
TXD+
RL/2
VOD
TXD+
+
RL/2
VOC
–
–
TXD
LTC1320 • F01
VSS
LTC1320 • TCF02
OUTPUT
UNDER TEST
500Ω
RL
CL
LTC1320 • F03
Figure 3
TXO
TXI
500Ω
CL
Figure 2
Figure 1
CL
VDD
OUTPUT
UNDER TEST
CL2
TXD
OUTPUT
UNDER TEST
500Ω
CL1
RL
TXD
VDD
OUTPUT
UNDER TEST
CL
500Ω
CL
VSS
Figure 4
4
LTC1320 • F04
Figure 5
LTC1320 • F07
LTC1320 • F06
LTC1320 • F05
Figure 6
Figure 7
LTC1320
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SWITCHI G WAVEFOR S
3V
TXD
0V
f = 1MHz: tr < 10ns: tf < 10ns
1.5V
3V
TXI
0V
1.5V
tPLH
tPHL
VOH
TXO
VOL
TXD –
TXD +
f = 1MHz: tr < 10ns: tf < 10ns
1.5V
1.5V
tPHL
tPLH
0V
0V
LTC1320 • F11
VO
1/2 VO
tSKEW
Figure 11
1/2 VO
tSKEW
LTC1320 • F08
Figure 8
VOH
VOL
VO
–VO
90%
tr
90%
10%
tr
90%
VDIFF = V(TXD+) – V(TXD–)
10%
90%
10%
tf
LTC1320 • F12
10%
tf
Figure 12
LTC1320 • F09
Figure 9
3V
RXI
0V
3V
TXDEN
0V
5V
TXD+, TXD –
VOL
VOH
TXD+, TXD –
–5V
1.5V
f = 1MHz: tr ≤ 10ns: tf ≤ 10ns
0V
VOH
RXO
VOL
tLdis
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
tHdis
1.5V
f = 1MHz: tr < 10ns: tf < 10ns
1.5V
tPLH
0.5V
0V
tPLH
1.5V
3V
RXI
0V
0.5V
tENH
1.5V
tPHL
1.5V
tENL
f = 1MHz: tr < 10ns: tf < 10ns
1.5V
LTC1320 • F10
VOH
RXO
VOL
1.5V
tPHL
1.5V
1.5V
LTC1320 • F13
Figure 10
2.5V
(RXD–) – (RXD+)
–2.5V
Figure 13
f = 1MHz: tr < 10ns: tf < 10ns
0V
tPHL
VOH
RXDO
VOL
0V
tPLH
1.5V
1.5V
LTC1320 • F14
Figure 14
3V
RXEN
0V
5V
RXO, RXO, RXDO
VOL
VOH
RXO, RXO, RXDO
0V
1.5V
f = 1MHz: tr ≤ 10ns: tf ≤ 10ns
tENL
1.5V
tLdis
1.5V OUTPUT NORMALLY LOW
0.5V
OUTPUT NORMALLY HIGH
0.5V
1.5V
tHdis
tENH
LTC1320 • F15
Figure 15
5
LTC1320
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APPLICATI
S I FOR ATIO
Thermal Shutdown Protection
The LTC1320 includes a thermal shutdown circuit which
protects the part against prolonged shorts at the driver
outputs. If any driver output is shorted to another output
or to the power supply, the current will be initially limited
to 450mA max. The die temperature will rise to about
150°C, at which point the thermal shutdown circuit turns
off the driver outputs. When the die cools to about 130°C,
the outputs re-enable. If the shorted condition still exists,
the part will heat again and the cycle will repeat. When the
short is removed, the part will return to normal operation.
This oscillation occurs at about 10Hz and prevents the part
from being damaged by excessive power dissipation.
Power Shutdown
The power shutdown feature of the LTC1320 is designed
primarily for battery-powered systems. When SD (pin 4)
is forced high, the part enters shutdown mode. In shut-
down, the supply current drops from 1.2mA to 30µA typ.
The driver outputs are three-stated and the power to the
receivers is removed. The receiver outputs are not automatically three-stated in shutdown, and can toggle erroneously due to feedthrough from the inputs. This can be
prevented by pulling RXEN high along with SD; this will
three-state the receiver outputs and prevent the generation of spurious data.
Supply Bypassing
The LTC1320 requires that both VDD and VSS are well
bypassed; data errors can result from inadequate bypassing. Bypass capacitor values of 0.1µF to 1µF from VDD to
ground and from VSS to ground are adequate. Lead lengths
and trace lengths between the capacitors and the chip
should be short to minimize lead inductance.
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TYPICAL APPLICATI
S
Single 5V Supply
RS422 to RS562/RS562 to RS422 Converter
5V
5V
0.1µF
0.1µF
18
LOGIC I/O
5V
18
1
17
2
16
3
15
4
13
5
LTC1320
12
6
11
7
10
+
RS422 IN
–
DRIVER I/O
RS562 IN
7 RXO
TXD+ 16
TXD – 17
TXDEN 3
RS562 OUT
NC
NC
+
–
RS422 OUT
SD 4
RXEN 5
9
14
GND
2
9
0.1µF
+
LTC1046 5
LT1054
4
*
3
100µF
1N5817
LTC1320 • TA03
*LTC1046 GIVES 300µA QUIESCENT
CURRENT WHEN LTC1320 IS SHUT DOWN
LT1054 PROVIDES HIGHER OUTPUT DRIVE
6
RXI 13
LTC1320
12 RXI
1 TXD
8
10µF
RXO 6
8 RXDO
2µF
+
TXO 15
10 RXD +
2 TXI
8
+
11 RXD –
VDD
VSS
14
–5V
0.1µF
LTC1320 • TA04
LTC1320
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TYPICAL APPLICATI
S
Switched Negative Supply
≥ 25k ESD Protection
5V
5V
0.1µF
0.1µF
18
LOGIC I/O
1 TXD
TXD – 17
2 TXI
TXD + 16
3 TXDEN
TXO 15
4 SD
RXI 13
5 RXEN
LTC1320
RXI 12
6 RXO
RXD – 11
7 RXO
RXD + 10
1 TXD
TXD – 17
*
TXD + 16
2 TXI
DRIVER I/O
DATA
INPUT/OUTPUT
8 RXDO
9
18
VDD
TXO 15
4 SD
RXI 13
LTC1320
5 RXEN
14
0.1µF
3 TXDEN
1N5817*
*
*
RXI 12
6 RXO
RXD – 11
7 RXO
RXD + 10
*
*
*
8 RXDO
–5V
GND
LTC1320 • TA05
VSS
9
*SCHOTTKY DIODE PREVENTS VSS FROM EXCEEDING
GND ON POWER-UP OR POWER-DOWN
TO OUTSIDE WORLD
PROTECTED AGAINST ESD
DAMAGE TO ±25kV
*
14
LTC1320 • TA06
0.1µF
–5V
*GENERAL SEMICONDUCTOR ICTE-22C OR EQUIVALENT
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PACKAGE DESCRIPTIO
0.447 – 0.463
(11.354 – 11.760)
18
17
16
15
14
13
12
11
10
S Package
18-Lead Plastic SOL
0.394 – 0.419
(10.007 – 10.643)
SEE NOTE
1
0.291 – 0.299
(7.391 – 7.595)
0.005
(0.127)
RAD MIN
2
3
4
5
6
7
8
0.093 – 0.104
(2.362 – 2.642)
0.010 – 0.029 × 45°
(0.254 – 0.737)
9
0.037 – 0.045
(0.940 – 1.143)
0° – 8° TYP
0.009 – 0.013
(0.229 – 0.330)
SEE NOTE
0.016 – 0.050
(0.406 – 1.270)
0.050
(1.270)
TYP
0.004 – 0.012
(0.102 – 0.305)
0.014 – 0.019
(0.356 – 0.482)
TYP
NOTE:
PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.
THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS.
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of circuits as described herein will not infringe on existing patent rights.
SOL18 0392
7
LTC1320
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Phone: (215) 757-8578
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FAX: (818) 703-0517
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Phone: (408) 428-2050
FAX: (408) 432-6331
International Sales Offices
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Immeuble "Le Quartz"
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Phone: 33-1-46316161
FAX: 33-1-46314613
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Phone: 65-293-5322
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Linear Technology (UK) Ltd.
The Coliseum, Riverside Way
Camberley, Surrey GU15 3YL
United Kingdom
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JAPAN
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Phone: 81-3-3237-7891
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World Headquarters
Linear Technology Corporation
1630 McCarthy Blvd.
Milpitas, CA 95035-7487
Phone: (408) 432-1900
FAX: (408) 434-0507
10/92
8
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900 ● FAX: (408) 434-0507 ● TELEX: 499-3977
LT/GP 1192 10K REV 0
 LINEAR TECHNOLOGY CORPORATION 1992
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