UM3243EEAS-RS232 Interface-Interface-Products-Union Semiconductor

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Reliability Report

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Key Specifications

Part Number

Description

Status

Drivers Per Package

Receivers Per Package

Logic Voltage (Min)(V)

ICC (Max)(mA)

Shutdown Control

Data Rate(kbps)

Main Supply Voltage (Nom)(V)

ESD HBM (kV)

ESD Contact (kV)

ESD Air (kV)

Operating Temperature Range(℃)

Pin/Package

EV Kit Available?

UM3243EEAS

Low Supply Current, 3V to 5.5V, 250kbps, 3-Driver/5-Receiver, Enhanced ESD Protection Smart RS-232 Transceivers

Active

Yes

250

±15 (for RS-232 Pins); ±2 (for Other Pins)

±8

-40 ~ +85

28/SSOP

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Product Description

The UM3243 series are 3-driver/5-receiver 3V-5.5V powered RS-232 transceivers featuring Auto Power-Off and low supply current, when no valid RS-232 level signal is sensed on any receiver inputs, the charge pump circuit and drivers will be powered off. Disconnection of the RS-232 cable or poweroff of the transmitters of the attaching peripherals will lead to Power-Off mode. When a valid level is applied to any RS-232 receiver inputs, the chip will turn on again. The Auto Power-Off mode helps to save power without changing the existing system.

The UM3243 transceivers have a regulated discontinuous mode dual charge pump power supply and low-dropout transmitters, which combine to deliver true RS-232 performance from a single +3V to +5.5V supply. Data rate of 250kbps is guaranteed.

The UM3243 needs only four 0.1μF capacitors in 3.3V operation, and can operate from input voltages ranging from +2.7V to +5.5V. They are ideal for 3.3V-only systems, mixed 3.3V and 5.0V systems, or 5.0V-only systems that require true RS-232 performance or EIA/TIA-562 levels of ±3.7V with supply voltages as low as 2.7V.

The UM3243 includes one complementary always-active receiver. This receiver can monitor an external device (such as a modem) in Power-Off. The UM3243 also includes an always-active INVALID(_________________) output which indicates valid RS-232 signal levels on any receiver inputs. It is usually used in UART wakeup. The UM3243 also features enhanced ESD protection with ±8kV for human body mode and ±8kV for IEC61000-4-2 contact discharge mode.

Features

- Meets True EIA/TIA-232-F Standards from a +3.0V to +5.5V Power Supply

- Meets EIA/TIA-562 Levels of ±3.7V with Supply Voltages as Low as 2.7V

- Auto Power-Off Feature to Disable Driver Outputs when No Valid RS-232 Signal is Sensed

- 250kbps Minimum Transmission Rate

- 0.1μA (Typ) Low Power-Off Current

- Accepts 5V Logic Input with 3.3V Supply

- Latch-Up Performance Exceeds 200mA

- Enhanced ESD Specifications for RS-232 Pins:

±8kV Human Body Mode

±8kV IEC61000-4-2 Contact Discharge Mode
- Available in SSOP28, TSSOP28, SOP28 and QFN32 Packages

Typical Application Circuit

Applications

- Industrial Controllers and Instruments

- Notebooks, Palmtop PCs and Laptops

- Networking Routers and Switches

- Peripherals

- Printers, PDAs and POS

Pin Configurations

SSOP28

Function Tables

Table 1. Each Transmitter (Note 1)

INPUTS				OUTPUT	TRANSMITTER STATUS
TIN	FORCEON	FORCEOFF(____________________)	VALID RIN RS-232 LEVEL	TOUT	TRANSMITTER STATUS
X	X	L	X	Z	Forced Power-Off
L	H	H	X	H	Normal Operation with Forced Power-On
H	H	H	X	L	Normal Operation with Forced Power-On
L	L	H	Yes	H	Normal Operation with Auto Power-On
H	L	H	Yes	L	Normal Operation with Auto Power-On
X	L	H	No	Z	Auto Power-Off

Note 1: H=high level, L=low level, X=irrelevant, Z=high impedance

Table 2. Each Receiver (Note 2)

INPUTS			OUTPUT	RECEIVER STATUS
RIN	FORCEON	FORCEOFF(_____________________)	ROUT	RECEIVER STATUS
X	X	L	Z	Forced Power-Off
L	X	H	H	Normal Operation
H	X	H	L
Open	X	H	H

Table 3. ROUT2B and Outputs INVALID(________________) (Note 2)

INPUTS				OUTPUTS		OUTPUT STATUS
VALID RIN RS-232 LEVEL	RIN2	FORCEON	FORCEOFF(____________________)	INVALID(_______________)	ROUT2B	OUTPUT STATUS
Yes	L	X	X	H	L	Always Active
Yes	H	X	X	H	H
Yes	Open	X	X	H	L
No	Open	X	X	L	L