MAX3243EEAI Просмотр технического описания (PDF) - Maxim Integrated

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MAX3243EEAI

±15kV ESD-Protected, 1µA, 3.0V to 5.5V, 250kbps, RS-232 Transceivers with AutoShutdown

Maxim Integrated 

MAX3221E/MAX3223E/MAX3243E

±15kV ESD-Protected, 1µA, 3.0V to 5.5V, 250kbps,

RS-232 Transceivers with AutoShutdown

Pin Description (continued)

MAX3221E

TQFN- SSOP/

EP TSSOP

PIN

MAX3223E

TQFN-

EP

DIP/

SSOP/

TSSOP

MAX3243E

SO/

SSOP/

TSSOP

TQFN-

EP

—

—

—

—

—

19, 20

—

—

—

—

—

9, 16,

25, 32

—

—

—

—

—

—

NAME

FUNCTION

R_OUTB

Noninverting Complementary Receiver Outputs.

Always active.

N.C. No Connection. Not internally connected.

EP

Exposed Paddle (TQFN package only). Solder the exposed

paddle to the ground plane or leave unconnected.

_______________Detailed Description

Dual Charge-Pump Voltage Converter

The MAX3221E/MAX3223E/MAX3243E’s internal power

supply consists of a regulated dual charge pump that

provides output voltages of +5.5V (doubling charge

pump) and -5.5V (inverting charge pump), over the

+3.0V to +5.5V VCC range. The charge pumps operate

in discontinuous mode: if the output voltages are less

than 5.5V, the charge pumps are enabled; if the output

voltages exceed 5.5V, the charge pumps are disabled.

Each charge pump requires a flying capacitor (C1, C2)

and a reservoir capacitor (C3, C4) to generate the V+

and V- supplies.

RS-232 Transmitters

The transmitters are inverting level translators that con-

vert CMOS-logic levels to 5.0V EIA/TIA-232 levels. They

guarantee a 250kbps data rate with worst-case loads

of 3kΩ in parallel with 1000pF, providing compatibility

with PC-to-PC communication software such as

LapLink™. Transmitters can be paralleled to drive mul-

tiple receivers. The MAX3243E has been specifically

designed to drive serial mice. Figure 1 shows a com-

plete system connection. When FORCEOFF is driven to

ground, or the AutoShutdown circuitry senses invalid

voltage levels on all receiver inputs, the transmitters are

disabled and the outputs are forced into a high-imped-

ance state. When powered off or shut down, the output

can be driven up to ±12V. The transmitter inputs do not

have pull-up resistors.

LapLink is a trademark of Traveling Software.

POWER-

MANAGEMENT

UNIT OR

KEYBOARD

CONTROLLER

FORCEOFF

FORCEON

INVALID

MAX3243E

I/O

CPU

CHIP

WITH

UART

Figure 1. Interface Under Control of PMU

RS-232

Maxim Integrated

7

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