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LTC1382CS

5V Low Power RS232 Transceiver with Shutdown

Linear Technology 

LTC1382

PI FU CTIO S

VCC: 5V Input Supply Pin. This pin should be decoupled

with a 0.1µF ceramic capacitor.

GND: Ground Pin.

ON/OFF: TTL/CMOS Compatible Shutdown Pin. A logic

low puts the device in the Shutdown mode. Both driver

outputs are forced into three-state and the supply current

is 0.2µA.

V+: Positive Supply Output (RS232 Drivers). V+ ≅ 2VCC –

2V. This pin requires an external capacitor C = 0.1µF for

charge storage. The capacitor may be tied to ground or

VCC. With multiple devices, the V + and V – pins may share

a common capacitor. For large numbers of devices, in-

creasing the size of the shared common storage capaci-

tors is recommended to reduce ripple.

V–: Negative Supply Output (RS232 Drivers). V – ≅ – (2VCC

– 2V). This pin requires an external capacitor C = 0.1µF for

charge storage.

C1+, C1–, C2+, C2–: Commutating Capacitor Inputs. These

pins require two external capacitors C = 0.1µF: one from

C1+ to C1– and another from C2+ to C2 –. To maintain

charge pump efficiency, the capacitor’s effective series

resistance should be less than 2Ω.

TR IN: RS232 Driver Input Pins. Inputs are TTL/CMOS

compatible. The inputs of unused drivers can be left

unconnected since 300k input pull-up resistors to VCC are

included on chip. To minimize power consumption, the

internal driver pull-up resistors are disconnected from VCC

in the Shutdown mode.

TR OUT: Driver Outputs at RS232 Voltage Levels. Outputs

are in a high impedance state when in the Shutdown or

VCC = 0V. The driver outputs are protected against ESD to

±10kV for human body model discharges.

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.

RX OUT: Receiver Outputs with TTL/CMOS Voltage Lev-

els. Outputs are in a high impedance state when in the

Shutdown mode.

UW

W

SWITCHI G TI E WAVEFOR S

DRIVER

INPUT

1.4V

DRIVER

OUTPUT

0V

t LHD

1.4V

t HLD

VCC

0V

V+

0V

V–

LTC1382 • F01

Figure 1. Driver Propagation Delay Timing

RX

1.7V

INPUT

RX

OUTPUT

0.8V

t LHR

VCC

1.3V

0V

t HLR

2.4V VCC

0V

LTC1382 • F02

Figure 2. Receiver Propagation Delay Timing

5

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