LT1389
AppleTalk
®
Peripheral
Interface Transceiver
June 1995
FEATURES
s
s
s
s
s
s
s
DESCRIPTION
The LT
®
1389 is a complete AppleTalk DCE interface trans-
ceiver. The circuit includes one differential driver, one
differential receiver, two high speed single-ended drivers
and one RS232/RS562 receiver. Logic inputs provide
driver and receiver three-state modes and a low power
shutdown control. The differential driver may be used as
an additional single-ended driver, supporting RS562 out-
put levels.
The high speed single-ended driver and differential driver
support data clock rates to 1Mbaud, allowing direct con-
nect operation with all Macintosh peripheral devices.
The Transmit and Receive Enable controls provide flexible
operating mode control for sharing data lines between
multiple circuits.
The LT1389 is available in 18-lead PDIP and SO Wide
packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc.
s
Provides Complete AppleTalk DCE Interface
Supports Direct Connect or LocalTalk
®
Transmit Enable Controls Three-State Driver Outputs
Flow-Through Architecture for Easy PC Layout
Rugged Bipolar Design
Thermal Shutdown Protection
Outputs Assume a High Impedance State when
Off or Powered Down
Short-Circuit Protection on All Outputs
APPLICATIONS
s
s
s
Printers
Modems
Local Area Networks
TYPICAL APPLICATION
Typical LocalTalk Application
1
2
16
RD OUT
4
15
18
V
DD
18
5V 17
16
RXEN
LT1389
ON/OFF
5V
120Ω
RFI
RFI
1k
1k
1k
1k
RFI
RFI
V
SS
14
–5V
TD IN
TXEN
V
EE
–5V
7
8
9
12
11
RFI
RFI
RFI
120Ω
RFI
11
10
8
9
RXD OUT
10 V
CC
5V
22Ω
RFI
=
22Ω
100pF
Specifications on this data sheet are preliminary only, and subject to change
without notice. Contact the manufacturer before finalizing a design using this part.
U
U
U
LTC1320
1
TXD
3
4
5
TXDEN
SD = 0V
RXEN
1389 TA01
1
LT1389
ABSOLUTE
MAXIMUM
RATINGS
(Note 1)
PACKAGE/ORDER INFORMATION
TOP VIEW
RXEN
GND
RS OUT
RD OUT
TS IN
TS IN
TD IN
TXEN
V
EE
1
2
3
4
5
6
7
8
9
N PACKAGE
18-LEAD PDIP
SW PACKAGE
18-LEAD PLASTIC SO WIDE
T
JMAX
= 150°C,
θ
JA
= 100°C/ W (N)
T
JMAX
= 150°C,
θ
JA
= 100°C/ W (SW)
Supply Voltage
V
CC
........................................................................ 6V
V
EE
...................................................................... – 6V
Input Voltage
Driver ..................................................... – 0.2V to 6V
TXEN, RXEN, ON/OFF ............................. – 0.2V to 6V
Single-Ended Receiver........................... – 30V to 30V
Differential Receiver ................................ – 7V to 12V
Output Voltage
Driver .......................................... – 30V to V
CC
+ 12V
Receiver .................................... – 0.3V to V
CC
+ 0.3V
Short-Circuit Duration
Driver Output .............................................. Indefinite
Receiver Output .......................................... Indefinite
Operating Temperature Range .................... 0°C to 70°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
18
17
16
15
14
13
12
11
10
ON/OFF
RS IN
RD
+
RD
–
TS OUT
TS OUT
TD OUT
–
TD OUT
+
V
CC
ORDER PART
NUMBER
LT1389CN
LT1389CSW
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
PARAMETER
Supply Current
Supply Current in Shutdown
Logic Input Thresholds ( TXEN, ON/OFF,
TS IN, TD IN)
Differential/Single-Ended Driver
Differential Output Voltage, V
OD
V
CC
V
EE
V
CC
V
EE
0°C
≤
T
A
≤
70°C
MIN
TYP
8
3
MAX
15
5
10
10
0.8
1.4
1.4
8
3
3
4.2
– 4.0
2.0
10
UNITS
mA
mA
µA
µA
V
V
V
V
V
V
V
V
µA
µA
mA
mA
mA
ns
ns
ns
µs
µs
CONDITIONS
V
ON/OFF
= 5V
V
ON/OFF
= 0V
Input Low Level
Input High Level
No Load (Figure 1)
R
L
= 100Ω
R
L
= 50Ω
R
L
= 100Ω (Figure 1)
Output High, R
L
= 3k (Figure 2)
Output Low, R
L
= 3k
0V
≤
V
IN
≤
5V
V
TXEN
= 2V, – 5V
≤
V
OUT
≤
5V
I
SC+
I
SC–
, V
OUT
= 5V
I
SC–
, V
OUT
= 0V
R
L
= 100Ω
7
2
1.5
2.0
3.7
– 10
– 100
35
– 200
– 20
Output Common-Mode Voltage, V
OC
Single-Ended Output Voltage
Input Current
Output Leakage Current
Output Short-Circuit Current
3.0
– 3.7
10
100
150
– 35
–8
40
40
40
75
75
75
2
2
Differential Mode Propagation Delay
Driver Disable Delay
Driver Enable Delay
Single-Ended Output Fall Time
Single-Ended Output Rise Time
R
L
= 3k, C
L
= 2500pF, V
OUT
= 3V to – 3V
R
L
= 3k, C
L
= 2500pF, V
OUT
= – 3V to 3V
1
1
2
U
W
U
U
W W
W
LT1389
ELECTRICAL CHARACTERISTICS
PARAMETER
Differential Receiver
Differential Input Voltage Thresholds
Receiver Input Hysteresis
Input Resistance
Input Common-Mode Voltage
Output Voltage
Output Short-Circuit Current
Propagation Delay
Single-Ended Receiver
Input Voltage Threshold
Hysteresis
Input Resistance
Output Voltage
Output Short-Circuit Current
Propagation Delay
Single-Ended Drivers
Output Voltage
Logic Input Current
Output Leakage Current
Output Short-Circuit Current
Slew Rate
Propagation Delay
Driver Disable Delay
Driver Enable Delay
0°C
≤
T
A
≤
70°C
MIN
– 0.2
70
12
–7
12
4.0
0.2
– 10
10
40
0.4
20
70
TYP
MAX
0.2
UNITS
V
mV
kΩ
V
V
V
mA
mA
ns
V
V
V
kΩ
V
V
mA
mA
ns
ns
V
V
µA
µA
mA
mA
V/µs
100
75
100
ns
ns
ns
CONDITIONS
– 7V
≤
V
CM
≤
12V
– 7V
≤
V
CM
≤
12V
Output High, I
OUT
= 160µA
Output Low, I
OUT
= – 1.6mA
Sinking Current, V
OUT
= V
CC
Sourcing Current, V
OUT
= 0V
2.4
– 20
Input Low Threshold
Input High Threshold
– 5V
≤
V
IN
≤
5V
Output Low, I
OUT
= –1.6mA
Output High, I
OUT
= 160mA (V
CC
= 5V)
Sinking Current, V
OUT
= V
CC
Sourcing Current, V
OUT
= 0V
Output Transition High to Low, t
HL
Output Transition Low to High, t
LH
Output High, R
L
= 3k
Output Low, R
L
= 3k
Shutdown or Driver Disable Modes
Sinking Current, V
OUT
= 0V
Sourcing Current, V
OUT
= 0V
0.8
0.1
3
3.5
– 20
1.3
1.7
0.4
5
0.2
4.2
– 10
10
250
350
2.4
1.0
7
0.4
20
600
600
3.7
– 10
– 100
– 40
60
4.0
– 4.4
– 3.7
10
100
– 10
50
100
60
40
60
Note 1:
Absolute maximum ratings are those values beyond which the life
of the device may be impaired.
Note 2:
Unless otherwise specified, testing done at V
CC
= 5V, V
EE
= – 5V
and V
TXEN
= 0V. Outputs and single-ended receiver inputs are open. Driver
inputs are tied to V
CC
. Differential receiver input RD
–
is biased at 2.6V,
RD
+
at 2.4V.
Note 3:
For driver delay measurements, R
L
= 3k and C
L
= 51pF. Trigger
points are set between the driver’s input logic threshold and the output
transition to the zero crossing. (t
HL
= t
LH
= 1.4V to 0V)
Note 4:
For receiver delay measurements, C
L
= 51pF. Trigger points are
set between the receiver’s input logic threshold and the output transition
to standard TTL/CMOS logic threshold. (t
HL
= 1.3V to 2.4V and t
LH
= 1.7V
to 0.8V)
PIN FUNCTIONS
RXEN (Pin 1):
Receiver Enable Control. An open pin or a
logic low allows normal operation of the receivers. A logic
high causes receiver outputs to become high impedance,
allowing sharing of the receiver output data lines.
GND (Pin 2):
Ground Pin.
RS OUT (Pin 3):
Single-Ended Receiver Output with TTL/
CMOS Voltage Levels. The output is fully short-circuit
protected to GND or V
CC
.
U
U
U
3
LT1389
PIN FUNCTIONS
RD OUT (Pin 4):
Differential Receiver Output Pin with TTL/
CMOS Voltage Levels. The output is fully short-circuit
protected to GND or V
CC
.
TS IN (Pins 5, 6):
Single-Ended Driver Input Pins. These
inputs are TTL/CMOS compatible. An input logic low
causes a driver output high. Tie unused inputs to GND.
TD IN (Pin 7):
Differential Driver Input Pin. A TTL/CMOS
compatible logic input. A logic high causes driver output
RD
+
to swing high and RD
–
low. Tie input to V
CC
when not
in use.
TXEN (Pin 8):
A TTL/CMOS logic high places the driver
outputs into a high impedance state. A logic low fully
enables the transmit capabilities. Transitions occur at data
rate speeds to facilitate data line multiplexing.
V
EE
: (Pin 9):
– 5V Input Supply Pin. This pin should be
decoupled with a 0.1µF ceramic capacitor.
V
CC
(Pin 10):
5V Input Supply Pin. This pin should be
decoupled with a 0.1µF ceramic capacitor.
TD OUT
+
, TD OUT
–
(Pins 11, 12):
Differential Driver
Output Pins. Outputs drive 100Ω differential loads to
RS422 levels, and are also capable of supplying RS562
levels to single-ended loads greater than 3kΩ. Outputs are
in a high impedance state when TXEN is high or V
CC
= 0V.
Outputs are fully short-circuit protected from V
OUT
= V
EE
+ 20V to V
OUT
= V
CC
– 20V. Applying higher voltages will
not damage the device if the overdrive is moderately
current limited.
TS OUT (Pins 13, 14):
Single-Ended Driver Outputs at
RS562 Voltage Levels. Outputs are in a high impedance
state when TXEN is high or V
CC
= 0V. Outputs are fully
short-circuit protected from V
OUT
= V
EE
+ 20V to V
OUT
=
V
CC
– 20V. Applying higher voltage will not damage the
device if the overdrive is moderately current limited.
RD
–
, RD
+
(Pins 15, 16):
Differential Receiver Input Pins.
Common-mode input range is –7V to 12V. Receiver inputs
have 50mV of hysteresis for noise immunity.
RS IN (Pin 17):
Single-Ended Receiver Input. This pin
accepts RS232 or RS562 level signals (±30V) into a
protected 5k terminating resistor. The receiver input pro-
vides 0.4V of hysteresis for noise immunity. Data rates to
120kbaud are supported.
ON/OFF (Pin 18):
A logic low level on this pin shuts down
the circuit. All receiver and driver outputs are high imped-
ance. A logic high allows normal operation of the circuit.
TEST CIRCUITS
TXD
–
V
OD
TXD
+
R
L
/2
V
OC
R
L
/2
Figure 1. Differential Output Test Circuit
RELATED PARTS
PART NUMBER
LTC1320
LTC1334
LTC1337
LTC1345
LTC1348
DESCRIPTION
Appletalk Transceiver
RS232/RS485 Multi-Protocol Transceiver
5V 3-Driver/5-Receiver Micropower RS232 Transceiver
V.35 Differential Transceiver
3.3V 3-Driver/5-Receiver RS232 Transceiver
COMMENTS
Complete DTE Port
Appletalk Compatible
500µA Quiescent Current
Low Power V.35 Solution
True RS232 from 3.3V Supplies
4
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900
q
FAX
: (408) 434-0507
q
TELEX
: 499-3977
U
U
U
TXD
–
TXD
+
R
L
C
L
R
L
C
L
1389 F02
1389 F01
Figure 2. Single-Ended Output Test Circuit
LT/GP 0695 6K • PRINTED IN USA
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LINEAR TECHNOLOGY CORPORATION 1995
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