Linear Technology LT1081IN, LT1081CSW, LT1081CN, LT1081CJ, LT1081 Datasheet

Advanced Low Power

5V RS232 Dual Driver/Receiver

FEATURES

DESCRIPTIOU

■

Superior to CMOS

The LT®1080/LT1081 are the only dual RS232 driver/

– Improved Speed: Operates over 120kBaud

receiver with charge pump to guarantee absolutely no

– Improved Protection: Outputs Can Be Forced

latchup. These interface optimized devices provide a real-

to ±30V without Damage

istic balance between CMOS levels of power dissipation

– Three-State Outputs Are High

and real world requirements for ruggedness. The driver

Impedance When Off

outputs are fully protected against overload and can be

– Only Needs 1 F Capacitors

shorted to ±30V. Unlike CMOS, the advanced architecture

■

Absolutely No Latchup

of the LT1080/LT1081 does not load the signal line when

■

CMOS Comparable Low Power: 60mW

“shut down” or when power is off. Both the receiver and

■

Can Power Additional RS232 Drivers: 10mA

RS232 outputs are put into a high impedance state. An

■

Supply Current in Shutdown: 1 A

advanced output stage allows driving higher capacitive

■

Available in SO Package

loads at higher speeds with exceptional ruggedness

■

Available with or without Shutdown

against ESD.

APPLICATIOUS

For applications requiring up to five drivers and five

receiverswithchargepumpinonepackageseetheLT1130A

Portable Computers

Series data sheet. A version of the LT1080/LT1081, the

■

LT1180A and LT1181A that use only 0.1 F capacitors, is

■

Battery-Powered RS232 Systems

also available. All of Linear Technology’s RS232 ICs are

Power Supply Generator

■

available in standard surface mount packages.

■

Terminals

, LTC and LT are registered trademarks of Linear Technology Corporation.

■

Modems

TYPICAL APPLICATIOU

	2			17	5V INPUT
1 F	4			3
					9V OUTPUT
		LT1080			1 F
	5			7	–9V OUTPUT
1 F	6				1 F
	12			15	RS232 OUTPUT
LOGIC
INPUTS	11			8	RS232 OUTPUT
	13			14	RS232 INPUT
LOGIC			5k
OUTPUTS	10			9
					RS232 INPUT
	18		5k	16
ON/OFF
					1080/81 • TA01

Supply Generator Outputs

	10				V+ OUTPUT
	8
		RL TO V–
	6							RL TO GND
(V)	4
VOLTAGE	2
	0	VCC = 5V
OUTPUT	–2
	–4							RL TO GND
	–6	RL TO V+
	–8				V– OUTPUT
	–10
	0	2	4	6	8	10	12	14	16	18	20
				OUTPUT CURRENT (mA)

1080/81 TA01a

1

LT1080/LT1081

ABSOLUTE

WAXIWUW

RATIUGS (Note 1)

Supply Voltage (VCC)	................................................. 6V
V+ ...........................................................................................	12V
V– .......................................................................................	– 12V
Input Voltage	V – to V+
Driver ...........................................................
Receiver .................................................	– 30V to 30V
ON/OFF Pin ..............................................	GND to 12V
Output Voltage	(V – + 30V) to (V + – 30V)
Driver .................................
Receiver ..................................	– 0.3V to (V CC + 0.3V)

Short-Circuit Duration
V+ ......................................................................................	30 sec
V– ......................................................................................	30 sec
Driver Output ...............................................	Indefinite
Receiver Output ...........................................	Indefinite
Operating Temperature Range	0°C to 70°C
LT1080C/LT1081C .................................
LT1080I/LT1081I ................................	–40°C to 85°C
LT1080M/LT1081M ..........................	–55°C to 125°C
Storage Temperature Range ..................	–65°C to 150°C
Lead Temperature (Soldering, 10 sec).................	300°C

PACKAGE/ORDER IUFORWATIOU

	TOP VIEW
NC	1	18	ON/OFF
C1+	2	17	VCC
V+	3	16	GND
C1–	4	15	TR1 OUT
C2+	LT1080
	5	14	REC1 IN
C2–	6	13	REC1 OUT
V–	7	12	TR1 IN
TR2 OUT	8	11	TR2 IN
REC2 IN	9	10	REC2 OUT
J PACKAGE		N PACKAGE
18-LEAD CERDIP		18-LEAD PDIP
	SW PACKAGE
	18-LEAD PLASTIC SO WIDE

TJMAX = 150°C, θJA = 100°C/W, θJC = 40°C/W (J) TJMAX = 150°C, θJA = 120°C/W, θJC = 50°C/W (N) TJMAX = 150°C, θJA = 90°C/W, θJC = 26°C/W (SW)

ORDER PART

NUMBER

LT1080CJ

LT1080CN

LT1080CSW

LT1080IN

LT1080ISW

LT1080MJ

TOP VIEW

C1+	1		16	VCC
V+	2		15	GND
C1–	3		14	TR1 OUT
C2+	4	LT1081	13	REC1 IN
C2–	5		12	REC1 OUT
V–	6		11	TR1 IN
TR2 OUT	7		10	TR2 IN
REC2 IN	8		9	REC2 OUT

J PACKAGE	N PACKAGE
16-LEAD CERDIP	16-LEAD PDIP

SW PACKAGE

16-LEAD PLASTIC SO WIDE

TJMAX = 150°C, θJA = 100°C/W, θJC = 40°C/W (J) TJMAX = 150°C, θJA = 120°C/W, θJC = 50°C/W (N) TJMAX = 150°C, θJA = 95°C/W, θJC = 27°C/W (SW)

ORDER PART

NUMBER

LT1081CJ

LT1081CN

LT1081CSW

LT1081IN

LT1081ISW

LT1081MJ

2

LT1080/LT1081

ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Driver

Output Voltage Swing

Load = 3k to GND Both Outputs

Positive

●

5

7.3

V

Negative

●

–5

–6.5

V

Logic Input Voltage Level

Input Low Level (VOUT = High)

●

1.4

0.8

V

Input High Level (VOUT = Low)

●

2

1.4

V

Logic Input Current

VIN ≥ 2V

●

5

20

µA

VIN ≤ 0.8V

●

5

20

µA

Output Short-Circuit Current

Sourcing Current, VOUT = 0V

9

12

mA

Sinking Current, VOUT = 0V

–9

–12

mA

Output Leakage Current

SHUTDOWN (Note 3), VOUT = ±30V

●

10

100

µA

Data Rate (Note 6)

RL = 3k, CL = 2500pF

120

kBd

RL = 3k, CL = 1000pF

250

kBd

Slew Rate

RL = 3k, CL = 51pF

4

15

30

V/µs

Receiver

Input Voltage Thresholds

Input Low Threshold

Commercial

●

0.8

1.3

V

Industrial and Military

●

0.2

1.3

V

Input High Threshold

Commercial

●

1.7

2.4

V

Industrial and Military

●

1.7

3.0

V

Hysteresis

●

0.1

0.4

1

V

Input Resistance

VIN = ±10V

3

5

7

kΩ

Output Voltage

Output Low, IOUT = –1.6mA

●

0.2

0.4

V

Output High, IOUT = 160µA (VCC = 5V)

●

3.5

4.8

V

Output Short-Circuit Current

Sinking Current, VOUT = VCC

–10

–20

mA

Sourcing Current, VOUT = 0V

0.6

1

mA

Output Leakage Current

SHUTDOWN (Note 3), 0V ≤ VOUT ≤ VCC

●

1

10

µA

Power Supply Generator (Note 4)

V+ Output Voltage

IOUT = 0mA

8.0

9.0

V

IOUT = 10mA

7.0

8.0

V

IOUT = 15mA

6.5

7.5

V

V– Output Voltage

IOUT = 0mA

–7.5

–8.5

V

IOUT = –10mA

–5.5

–6.5

V

IOUT = –15mA

–5.0

–6.0

V

Supply Current

●

12

22

mA

Supply Leakage Current (VCC)

SHUTDOWN (Note 3), LT1080 Only

●

1

100

µA

0V ≤ VON/OFF

≤ 5V, LT1080 Only

µA

ON/OFF

Pin Current

●

–15

80

Supply Rise Time

(Note 5), LT1080 Only

1

ms

Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.

Note 2: These parameters apply for 4.5V ≤ VCC ≤ 5.5V and VON/OFF = 3V, unless otherwise specified.

Note 3: VON/OFF = 0.4V for –55°C ≤ TA ≤ 50°C, and VON/OFF = 0.2V for 50°C ≤ TA ≤ 125°C. (LT1080 only)

Note 4: Unless otherwise specified, VCC = 5V, external loading of V+ and V– equals zero and the driver outputs are low (inputs high).

Note 5: Time from either SHUTDOWN high or power on until V+ ≥ 6V and V– ≤ –6V. All external capacitors are 1µF.

Note 6: Data rate operation guaranteed by slew rate, short-circuit current and propagation delay tests.

3

LT1080/LT1081

PIU FUUCTIOUS (Pin numbers refer to LT1080)

C1+; C1–; C2+; C2– (Pins 2, 4, 5, 6): Requires an external capacitor (≥1µF) from C1+ to C1– and another from C2+ to C2–. Pin 2 can be used for connecting a second positive supply. When a separate positive supply is used, C1 can be deleted.

V+ (Pin 3): Positive Supply for RS232 Drivers.

V+ ≈ 2VCC – 1.5V. Requires an exterenal capacitor (≥1µF) for charge storage. May be loaded (up to 15mA) for external system use. Loading does reduce V+ voltage (see graphs). Capacitor may be tied to ground or +5V input supply. With multiple transceivers, the V+ and V– pins may be paralleled into common capacitors.

V– (Pin 7): Negative Supply for RS232 Drivers.

V– ≈ –(2VCC – 2.5V). Requires an external capacitor (≥1µF) for charge stroage. May be loaded (up to –15mA) for external system use. Loading does reduce V– voltage (see graphs). With multiple transceivers, the V+ and V– pins may be paralleled into common capacitors.

TR2 OUT; TR1 OUT (Pins 8, 15): Driver Outputs with RS232 Voltage Levels. Outputs are in a high impedance state when in the SHUTDOWN mode or when power is off (VCC = 0V) to allow data line sharing. Outputs are fully short-circuit protected from (V– + 30V) to (V+ – 30V) with power on, off or in the SHUTDOWN mode. Typical output breakdowns are greater than ±45V and higher applied

voltages will not damage the device if moderately current limited. Shorting one output will affect output from the other.

REC2 IN; REC1 IN (Pins 9, 14): Receiver Inputs. Accepts RS232 voltage levels (±30V) and has 0.4V of hysteresis to provide noise immunity. Input impedance is nominally 5kΩ.

REC2 OUT; REC1 OUT (Pins 10, 13): Receiver Outputs with TTL/CMOS Voltage Levels. Outputs are in a high impedance state when in the SHUTDOWN mode to allow data line sharing. Outputs are fully short-circuit protected to ground or VCC with power on, off or in the SHUTDOWN mode.

TR2 IN; TR1 IN (Pins 11, 12): RS232 Driver Input Pins. Inputs are TTL/CMOS compatible. Inputs should not be allowed to float. Tie unused inputs to VCC.

GND (Pin 16): Ground Pin.

VCC (Pin 17): Input Supply Pin. Supply current drops to zero in the SHUTDOWN mode.

ON/OFF (Pin 18): Contols the operation mode of the LT1080 and is TTL/CMOS compatible. A logic low puts the device in the SHUTDOWN mode which reduces input supply current to zero and places both driver and receiver outputs in a high impedance state. A logic high fully enables the device.

TYPICAL PERFORWAUCE CHARACTERISTICS

Driver Output Voltage	Supply Generator Outputs	Supply Generation from VCC
		or Shutdown

	10	VCC = 5.5V				OUTPUT HIGH					10				V+ OUTPUT VOLTAGE								10			V+ SUPPLY
	8										8												8
												LOADED TO V–
(V)	6										6					LOADED TO GROUND							6					VCC = 5V
		VCC = 4.5V
OUTPUTDRIVERVOLTAGE										OUTPUTVOLTAGE (V)		LOADED TO V+										VOLTAGESUPPLY (V)	–6
	–6				VCC = 5V						–6																	C1 TO C4 = 1 F
	4										4												4
	2										2												2
	0	RL = 3k									0	VCC = 5V											0
	–2				VCC = 5V						–2												–2
	–4										–4												–4
		VCC = 4.5V														LOADED TO GROUND
	–8	VCC = 5.5V				OUTPUT LOW					–8				V– OUTPUT VOLTAGE								–8			V– SUPPLY
	–10										–10												–10
	–55		–25	0	25	50	75	100	125		0	2	4	6	8	10	12	14	16	18	20		0	0.2	0.4	0.6	0.8	1.0	1.2	1.4	1.6	1.8	2.0
				TEMPERATURE (°C)										OUTPUT CURRENT (mA)													TIME (ms)
								1080/81 G01												1080/81 G02												1080/81 G03
4