Datasheet LTC1320 Datasheet (Linear Technology)

LTC1320

AppleTalk© Transceiver

EATU

F

■

Single Chip Provides Complete

RE

S

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

U

O

PPLICATI

A

■

LocalTalk Peripherals

■

Notebook/Palmtop Computers

■

Battery-Powered Systems

AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc.

S

DUESCRIPTIO

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.

The LTC1320 is available in the 18-pin SOL package.

DATA IN

TX ENABLE

RX ENABLE

DATA OUT

SHUTDOWN

A

PPLICATITYPICAL

Typical LocalTalk Connection

5V

1

3

LTC1320

5

8

4

914

18

#1

–5V

22Ω

17

22Ω

16

22Ω

11

22Ω

10

O

22Ω

100pF

22Ω

100pF

22Ω

100pF

22Ω

100pF

U

LocalTalk

TRANSFORMER

1k

1k

LTC1320 • TA01

120Ω

DATA IN

SIGNALS

ON LINE

DATA OUT

(REMOTE

RECEIVER)

Output Waveforms

5V/DIV

2V/DIV

2V/DIV

5V/DIV

50ns/DIV

1

LTC1320

WU

U

PACKAGE

/

O

RDER I FOR ATIO

W

O

A

LUTEXI T

S

A

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

DC ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OD

V

OC

V

OH

V

OL

I

DD

I

SS

Differential Driver Output Voltage No Load ● 8.0 V

Change in Magnitude of Driver RL = 100Ω (Figure 1) 0.2 V
Differential Output Voltage

Driver Common-Mode Output Voltage RL = 100Ω (Figure 1) 3 V
Output Common-Mode Range SD = 5V or Power Off ● ±10 V
Single-Ended Driver Output Voltage No Load ● ±4.0 V

Input High Voltage All Logic Input Pins ● 2.0 V
Input Low Voltage All Logic Input Pins ● 0.8 V
Input Current All Logic Input Pins ● ±1 ±20 µA
Three-State Output Current SD = 5V or Power Off, –10V < VO < 10V ● ±2 ±100 µA
Driver Short-Circuit Current –5V < VO < 5V ● 35 350 500 mA
Receiver Input Resistance – 7V < VIN < 7V ● 12 kΩ
Receiver Output High Voltage IO = –4mA ● 3.5 V
Receiver Output Low Voltage IO = 4mA ● 0.4 V
Receiver Output Short-Circuit Current 0V < VO < 5V ● 785mA
Receiver Output Three-State Current 0V < VO < 5V ● ±2 ±100 µA
Differential Receiver Threshold Voltage –7V < VCM < 7V ● –200 200 mV
Differential Receiver Input Hysteresis –7V < VCM < 7V 70 mV
Single-Ended Receiver Input Low Voltage ● 0.8 V
Single-Ended Receiver Input High Voltage ● 2V
Supply Current No Load, SD = 0V ● 1.2 3.0 mA

Supply Current No Load, SD = 5V ● 2 350 µ A

WUW

ARB

U
G

S

I

TOP VIEW

1

TXD

2

TXI

3

TXDEN

4

SD

5

RXEN

6

RXO

7

RXO

8

RXDO

9

GND

S PACKAGE

18-LEAD PLASTIC SOL

T

= 150°C, θJA = 100°C/W

JMAX

Consult factory for Industrial and Military grade parts.

18
17
16
15
14
13
12
11
10



V

DD

TXD–

+

TXD



TXO



V

SS

RXI
RXI

–

RXD

+

RXD

LTC1320 • PO01



VS = ±5V ±5%, TA = 0°C to 70°C (Notes 2, 3)

RL = 100Ω (Figure 1) ● 2.0 V

RL = 400Ω ● ±3.4 V

No Load, SD = 5V ● 30 350 µA

ORDER PART

NUMBER

LTC1320CS

2

LTC1320

TEMPERATURE (°C)

0

0

SUPPLY CURRENT (mA)

0.004

1.0

1.1

1.2

10 20 30 40

LTC1320 • G03

50 60 70

0.002

I

DD

I

SS

U

SWITCHI G CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

t

PLH, HL

t

SKEW

t

r, f

t

ENH, L

t

H, Ldis

t

PLH, HL

t

r, f

t

PLH, HL

t

ENH, L

t

H, Ldis

Differential Driver Propagation Delay RL = 100Ω, CL = 100pF (Figures 2, 8) ● 40 120 ns
Differential Driver Output to Output RL = 100Ω, CL = 100pF (Figures 2, 8) ● 10 50 ns
Differential Driver Rise/Fall Time RL = 100Ω, CL = 100pF (Figures 2, 8) ● 15 80 ns
Driver Enable to Output Active CL = 100pF (Figures 3, 4, 10) ● 50 150 ns
Driver Output Active to Disable CL = 15pF (Figures 3, 4, 10) ● 50 150 ns
Single-Ended Driver Propagation Delay RL = 450Ω, CL = 100pF (Figures 5, 11) ● 40 120 ns
Single-Ended Driver Rise/Fall Time RL = 450Ω, CL = 100pF (Figures 5, 12) ● 15 80 ns
Receiver Propagation Delay CL = 15pF (Figures 13, 14) ● 60 160 ns
Receiver Enable to Output Active CL = 100pF (Figures 6, 7, 15) ● 30 100 ns
Receiver Output Active to Disable CL = 15pF (Figures 6, 7, 15) ● 30 100 ns

VS = ±5V ±5%, TA = 0°C to 70°C (Notes 2, 3)

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.

UW

LPER

5
4

OUTPUT HIGH

3
2
1
0

–1

OUTPUT SWING (V)

–2
–3
–4
–5

0

OUTPUT LOW

20

R

F

O

60

40

OUTPUT CURRENT (mA)

80

LTC1320 • G01

ATYPICA

100

CCHARA TERIST

E

C

Differential Output Swing vs
Load CurrentOutput Swing vs Load Current

10

8

6

4

2

DIFFERENTIAL OUTPUT SWING (V)

0

20

0

OUTPUT CURRENT (mA)

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.

ICS

Supply Current vs Temperature

60

80

40

100

LTC1320 • G02

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

U

UU

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 30µ A. A low on this
pin allows normal operation.

3

LTC1320

OUTPUT

UNDER TEST

C

L

500Ω

V

DD

V

SS

LTC1320 • F03

Figure 3

OUTPUT

UNDER TEST

C

L

LTC1320 • F07

500Ω

Figure 7

U

UU

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.

RXO (Pin 7): Noninverting RS562 Single-Ended Receiver
Output.

RXDO (Pin 8): RS422 Differential Receiver Output.
GND (Pin 9): Ground Pin.
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.

RXD– (Pin 11): RS422 Differential Receiver Inverting
Input.

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.

V

(Pin 14): Negative Supply. – 4.75 ≥ VSS ≥ –5.25V. The

SS

voltage on this pin must never exceed ground on power up
or power-down.

TXO (Pin 15): RS562 Single-Ended Driver Output.
TXD+ (Pin 16): RS422 Differential Driver Noninverting

Output.

TXD– (Pin 17): RS422 Differential Driver Inverting Output.
V

(Pin 18): Positive Supply. 4.75V ≤ VDD ≤ 5.25V.

DD

TEST CIRCUITS

+

TXD

V

OD

TXD

Figure 1

OUTPUT

UNDER TEST

C

L

V

Figure 4

SS

LTC1320 • F04

RL/2

R

L

500Ω

+

TXD

+

V

/2

OC

–

LTC1320 • F01

TXD

TXD

R

L

–

C

L1

C

L2

LTC1320 • TCF02

Figure 2

R

L

LTC1320 • F05

TXO

500Ω

L

V

LTC1320 • F06

DD

C

L

OUTPUT

UNDER TEST

C

Figure 6

TXI

Figure 5

4

LTC1320

U

W

SWITCHI G WAVEFOR S

3V

TXD

0V

–

TXD

+

TXD

V

O

–V

O

TXDEN

TXD+, TXD

TXD+, TXD

–5V

V

V

V

10%

3V

0V

5V

OL

OH

t

r

1.5V

f = 1MHz: t

t

PLH

1.5V

O

1/2 V

O

90%

–

–

< 10ns: tf < 10ns

r

t

SKEW

Figure 8

V

= V(TXD+) – V(TXD–)

DIFF

Figure 9

f = 1MHz: tr ≤ 10ns: tf ≤ 10ns

t

ENL

0V

OUTPUT NORMALLY LOW

OUTPUT NORMALLY HIGH

0V

t

ENH

Figure 10

t

SKEW

1.5V

t

f

t

90%

1.5V

PHL

1/2 V

LTC1320 • F08

10%

LTC1320 • F09

t

Ldis

t

Hdis

O

0.5V

0.5V

LTC1320 • F10

TXI

V
TXO

V

V

OH

V

3V

0V

OH

OL

OL

RXO

RXO

RXI

V

V

RXI

V

V

1.5V

f = 1MHz: t

t

PHL

0V

< 10ns: tf < 10ns

r

1.5V

t

PLH

0V

LTC1320 • F11

Figure 11

10%

90%

t

r

90%

10%

t

f

LTC1320 • F12

Figure 12

3V

0V

OH

OL

3V

0V

OH

OL

1.5V

1.5V

f = 1MHz: t

t

PHL

1.5V

f = 1MHz: t

t

PLH

1.5V

< 10ns: tf < 10ns

r

< 10ns: tf < 10ns

r

1.5V

1.5V

t

t

PLH

1.5V

PHL

1.5V

LTC1320 • F13

Figure 13

2.5V

–

(RXD

) – (RXD+)

–2.5V

V

RXDO

V

RXEN

RXO, RXO, RXDO

RXO, RXO, RXDO

V

V

f = 1MHz: t

0V

t

OH

OL

PHL

1.5V 1.5V

< 10ns: tf < 10ns

r

0V

t

PLH

LTC1320 • F14

Figure 14

3V

0V

5V

OL

OH

0V

f = 1MHz: tr ≤ 10ns: tf ≤ 10ns

1.5V

t

ENL

1.5V

OUTPUT NORMALLY LOW

OUTPUT NORMALLY HIGH

1.5V

t

ENH

t

Hdis

1.5V

t

Ldis

0.5V

0.5V

LTC1320 • F15

Figure 15

5

LTC1320

1511

18

0.1µF

5V

914

LTC1320 • TA04

610
138
162
1712
37
41

LTC1320

0.1µF

5

–5V

RS562 OUT
NC
NC

+

–

RS422 OUT

+
–

RS562 IN

RS422 IN

TXO

TXD

+

TXD

–

RXI

RXO

SD

RXEN

TXDEN

RXD

–

RXDO
TXI

RXO
TXD

RXD

+

RXI

V

DD

V

SS

GND

PPLICATI

A

U

O

S

I FOR ATIO

WU

U

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 30µ A 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 0.1µ F 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.

U

O

PPLICATITYPICAL

SA

Single 5V Supply RS422 to RS562/RS562 to RS422 Converter

5V

0.1µF

18

171
162
153
134

100µF

+

125
116
107

DRIVER I/O

1N5817

LTC1320 • TA03

8

0.1µF

LTC1320

914

LOGIC I/O

5V

+

+

2µF

2

10µF

4

*LTC1046 GIVES 300µA QUIESCENT
CURRENT WHEN LTC1320 IS SHUT DOWN

LT1054 PROVIDES HIGHER OUTPUT DRIVE

8

LTC1046

LT1054

*

3

5

6

LTC1320

171

18

0.1µF

5V

914

LTC1320 • TA06

LTC1320

*GENERAL SEMICONDUCTOR ICTE-22C OR EQUIVALENT

TO OUTSIDE WORLD
PROTECTED AGAINST ESD
DAMAGE TO ±25kV

DATA

INPUT/OUTPUT

0.1µF

–5V

162

153

134

125

116

107

*

*

*

*

*

*

*

TXD

TXI

SD

RXO

TXD

–

TXD

+

TXO

RXI

RXD

–

RXD

+

RXI

TXDEN

RXEN

RXO

8 RXDO

GND V

SS

V

DD

U

O

PPLICATITYPICAL

SA

Switched Negative Supply

5V

TXD
TXI
TXDEN

LOGIC I/O

SD
RXEN
RXO
RXO

8

RXDO

*SCHOTTKY DIODE PREVENTS V
GND ON POWER-UP OR POWER-DOWN

18

LTC1320

914

TXD
TXD

RXD
RXD

–5V

TXO

RXI
RXI

–
+

–
+

0.1µF

171
162
153
134

DRIVER I/O

125
116
107

0.1µF

FROM EXCEEDING 

SS

≥25k ESD Protection

1N5817*

LTC1320 • TA05

PACKAGE DESCRIPTIO

S Package

18-Lead Plastic SOL

0.009 – 0.013

(0.229 – 0.330)

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.

0.005

(0.127)

RAD MIN

0.291 – 0.299

(7.391 – 7.595)

0.010 – 0.029

(0.254 – 0.737)

SEE NOTE

× 45°

0.016 – 0.050

(0.406 – 1.270)

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.

U

SEE NOTE

(2.362 – 2.642)

0° – 8° TYP

0.093 – 0.104

0.050

(1.270)

TYP

0.447 – 0.463

(11.354 – 11.760)

14 13

15

1718

16

2345678

1

0.014 – 0.019

(0.356 – 0.482)

TYP

11

12

10

9

0.037 – 0.045

(0.940 – 1.143)

0.004 – 0.012

(0.102 – 0.305)

0.394 – 0.419

(10.007 – 10.643)

SOL18 0392

7

LTC1320

U.S. Area Sales Offices

NORTHEAST REGION CENTRAL REGION NORTHWEST REGION
Linear Technology Corporation Linear Technology Corporation Linear Technology Corporation

One Oxford Valley Chesapeake Square 782 Sycamore Dr.
2300 E. Lincoln Hwy.,Suite 306 229 Mitchell Court, Suite A-25 Milpitas, CA 95035
Langhorne, PA 19047 Addison, IL 60101 Phone: [phone]
Phone: [phone] Phone: [phone] FAX: [phone]
FAX: [phone] FAX: [phone]

SOUTHEAST REGION SOUTHWEST REGION
Linear Technology Corporation Linear Technology Corporation

17060 Dallas Parkway 22141 Ventura Blvd.
Suite 208 Suite 206
Dallas, TX 75248 Woodland Hills, CA 91364
Phone: [phone] Phone: [phone]
FAX: [phone] FAX: [phone]

International Sales Offices

FRANCE KOREA TAIWAN
Linear Technology S.A.R.L. Linear Technology Korea Branch Linear Technology Corporation

Immeuble "Le Quartz" Namsong Building, #505 Rm. 801, No. 46, Sec. 2
58 Chemin de la Justice Itaewon-Dong 260-199 Chung Shan N. Rd.
92290 Chatenay Mallabry Yongsan-Ku, Seoul Taipei, Taiwan, R.O.C.
France Korea Phone: [phone]
Phone: [phone] Phone: [phone] FAX: [phone]
FAX: [phone] FAX: [phone]

GERMANY SINGAPORE UNITED KINGDOM
Linear Techonolgy GMBH Linear Technology Pte. Ltd. Linear Technology (UK) Ltd.

Untere Hauptstr. 9 101 Boon Keng Road The Coliseum, Riverside Way
D-8057 Eching #02-15 Kallang Ind. Estates Camberley, Surrey GU15 3YL
Germany Singapore 1233 United Kingdom
Phone: [phone] Phone: [phone] Phone: [phone]
FAX: [phone] FAX: [phone] FAX: [phone]

JAPAN
Linear Technology KK

5F YZ Building
4-4-12 Iidabashi Chiyoda-Ku
Tokyo, 102 Japan
Phone: [phone]
FAX: [phone]

World Headquarters

Linear Technology Corporation

1630 McCarthy Blvd.
Milpitas, CA 95035-7487
Phone: [phone]
FAX: [phone]

10/92

8

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7487

[phone]

●

FAX

: [phone]

●

TELEX

: 499-3977

LT/GP 1192 10K REV 0

 LINEAR TECHNOLOGY CORPORATION 1992