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LTC1338

5V Low Power RS232

5-Driver/3-Receiver Transceiver

ESCRIPTIO

■

Low Supply Current: 500µA

■

0.2µA Supply Current in SHUTDOWN

■

50µA Supply Current in RECEIVER ALIVE Mode

■

ESD Protection Over ±10kV

■

Operates from a Single 5V Supply

■

Uses Small Capacitors: 0.1µF

■

Operates to 120k Baud

■

Three-State Outputs Are High Impedance When Off

■

Output Overvoltage Does Not Force Current

Back into Supplies

■

RS232 I/O Lines Can Be Forced to ±25V

Without Damage

■

Flowthrough Architecture

The LTC1338 is a 5-driver/3-receiver RS232 trans-

ceiver with very low supply current. In the no load

condition, the supply current is only 500µA. The charge

pump only requires four 0.1µF capacitors.

In SHUTDOWN mode, the supply current is further

reduced to 0.2µA. In RECEIVER ALIVE mode, all three

receivers are kept alive and the supply current is 50µA.

All RS232 outputs assume a high impedance state in

SHUTDOWN and with the power off.

The LTC1338 is fully compliant with all data rate and

overvoltage RS232 specifications. The transceiver can

operate up to 120k baud with a 2500pF, 3kΩ load. Both

driver outputs and receiver inputs can be forced to

±25V without damage, and can survive multiple ±10kV

ESD strikes.

■

Battery-Powered Modems

■

Battery-Powered DCE

■

Notebook Computers

■

Palmtop Computers

ITY

5-Drivers/3-Receivers with SHUTDOWN

LTC1338 • TA01

C1

0.1µF

LTC1338

1

2

3

4

5

6

7

8

9

10

11

12

13

DRIVER 1 OUT

DRIVER 2 OUT

RX1 IN

DRIVER 3 OUT

RX2 IN

DRIVER 4 OUT

RX3 IN 

DRIVER 5 OUT

RX ENABLE

NC



28

27

26

25

24

23

22

21

20

19

18

17

16

C3

0.1µF

DRIVER 1 IN

DRIVER 2 IN

RX1 OUT

DRIVER 3 IN

RX2 OUT

DRIVER 4 IN

RX3 OUT

DRIVER 5 IN

GND

DRIVER ENABLE

–

C2

0.1µF

C4

0.1µF

TEMPERATURE (°C)



QUIESCENT CURRENT (µA)

1200

1000

800

600

400

200

20 40 60

LTC1338 • TA02

800

–20

1.2

1.0

0.8

0.6

0.4

0.2

0



SHUTDOWN CURRENT (µA)

QUIESCENT

CURRENT

SHUTDOWN

CURRENT

–40

TEST CONDITION:

= 5V, ALL DRIVER INPUTS TIED TO V

100

Supply Current

Summary of content (8 pages)

PAGE 1
LTC1338 5V Low Power RS232 5-Driver/3-Receiver Transceiver U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Low Supply Current: 500µA 0.2µA Supply Current in SHUTDOWN 50µA Supply Current in RECEIVER ALIVE Mode ESD Protection Over ±10kV Operates from a Single 5V Supply Uses Small Capacitors: 0.
PAGE 2
LTC1338 W U U W W W AXI U U ABSOLUTE PACKAGE/ORDER I FOR ATIO RATI GS (Note 1) Supply Voltage (VCC) ................................................ 6V Input Voltage Driver ....................................... – 0.3V to V CC + 0.3V Receiver ............................................... – 25V to 25V Driver/Receiver Enable Pin ........ – 0.3V to VCC + 0.3V Output Voltage Driver .................................................... – 25V to 25V Receiver .................................... – 0.
PAGE 3
LTC1338 DC ELECTRICAL CHARACTERISTICS VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, unless otherwise noted.
PAGE 4
LTC1338 W U TYPICAL PERFOR A CE CHARACTERISTICS VCC Supply Current Driver Leakage in Shutdown 30 20 5 DRIVERS LOADED RL = 3k 18 SHORT-CIRCUIT CURRENT (mA) 25 40 LEAKAGE CURRENT (µA) SUPPLY CURRENT (mA) Driver Short-Circuit Current 50 20 15 10 1 DRIVER LOADED RL = 3k 5 VOUT = –20V 30 20 VOUT = 20V 10 16 ISC– 14 ISC+ 12 10 8 6 4 0 –40 –20 40 20 60 0 TEMPERATURE (°C) 80 100 0 –40 –20 40 20 0 60 TEMPERATURE (°C) 80 100 0 –40 LTC1338 • TPC05 LTC1338 • TPC04 Receiver Short-Circui
PAGE 5
LTC1338 U U U PI FU CTIO S RX IN: Receiver Inputs. These pins can be forced to ±25V without damage. The receiver inputs are protected against ESD to ±10kV for human body model discharges. Each receiver provides 0.4V of hysteresis for noise immunity. DRIVER IN: RS232 Driver Input Pins. Inputs are TTL/ CMOS compatible. Inputs should not be allowed to float. Tie unused inputs to VCC. DRIVER OUT: Driver Outputs at RS232 Voltage Levels.
PAGE 6
LTC1338 TEST CIRCUITS Receiver Timing Test Load Driver Timing Test Load DRIVER INPUT RX OUTPUT DRIVER OUTPUT RX INPUT DRIVER 51pF RX 51pF 3k LTC1338 • F04 LTC1338 • F03 ESD Test Circuit V+ C1 0.1µF VCC C2 0.1µF DRIVER 1 OUT DRIVER 2 OUT RS232 LINE PINS PROTECTED TO ±10kV RX1 IN DRIVER 3 OUT RX2 IN DRIVER 4 OUT RX3 IN DRIVER 5 OUT RX ENABLE NC 28 1 2 LTC1338 V– C4 0.1µF 27 3 26 4 25 5 24 6 23 7 22 8 21 9 20 10 19 11 18 12 17 13 16 14 15 C3 0.
PAGE 7
LTC1338 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. G Package 28-Lead SSOP 0.397 – 0.407* (10.07 – 10.33) 0.205 – 0.212* (5.20 – 5.38) 0.068 – 0.078 (1.73 – 1.99) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 0° – 8° 0.005 – 0.009 (0.13 – 0.22) 0.301 – 0.311 (7.65 – 7.90) 0.045 (1.14) 0.0256 (0.65) BSC 0.022 – 0.037 (0.55 – 0.95) 0.002 – 0.008 (0.05 – 0.21) 0.010 – 0.015 (0.25 – 0.38) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 0.045 (1.
PAGE 8
LTC1338 U.S. Area Sales Offices NORTHEAST REGION Linear Technology Corporation One Oxford Valley 2300 E. Lincoln Hwy.,Suite 306 Langhorne, PA 19047 Phone: (215) 757-8578 FAX: (215) 757-5631 SOUTHEAST REGION Linear Technology Corporation 17060 Dallas Parkway Suite 208 Dallas, TX 75248 Phone: (214) 733-3071 FAX: (214) 380-5138 SOUTHWEST REGION Linear Technology Corporation 22141 Ventura Blvd.