Document
ST3243B ST3243C
3 to 5.5 V, 400 kbps, RS-232 transceiver with auto-power-down
Features
■ ■ ■ ■ ■ ■ ■
1 µA supply current achieved when in autopower-down 250 kbps minimum guaranteed data rate Guaranteed 6 V/µs slew rate range Guaranteed mouse drive ability 0.1 µF external capacitors Meet EIA/TIA-232 specifications down to 3 V Available in SSOP-28 Table 1.
Order code SSOP-28
Device summary
Temperature range -40 to 85 °C Package SSOP-28 (tape and reel) SSOP-28 (tape and reel) Packaging 1350 parts per reel 1350 parts per reel
ST3243BPR
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ST3243CPR
0 to 70 °C
October 2011
Doc ID 7539 Rev 10
1/17
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Contents
ST3243B ST3243C
Contents
1 2 3 4 5 6 7 8 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
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ST3243B ST3243C
Description
1
Description
The ST3243B / ST3243C devices consist of 3 drivers, 5 receivers and a dual charge-pump circuit. The devices meet the requirements of EIA/TIA and V.28/V.24 communication standards providing high data rate capability. The receiver R2 is always active to implement a wake-up feature for serial port. The ST3243B / ST3243C have a proprietary low-dropout transmitter output stage enabling true RS-232 performance from a 3.0 V to 5.5 V supply with a dual charge pump. The devices are guaranteed to run at data rates of 250 kbps while maintaining RS-232 output levels. The auto-power-down feature functions when FORCEON is low and FORCEOFF is high. During this mode of operation, if the device does not sense a valid RS-232 signal, the driver outputs are disabled. If FORCEOFF is set low, both drivers and receivers (expert R2B) are shut off, and supply current is reduced to 1 mA. Disconnecting the serial port or turning off the peripheral drives causes the auto-power-down condition to occur. Auto-power-down can be disabled when FORCEON and FORCEOFF are high, and should be done when driving a serial mouse. With auto-power-down enabled, the device is activated automatically when a valid signal is applied to any receiver input. Typical application are in notebook, sub-notebook, palmtop computers, battery-powered equipment, hand-held equipment, peripherals and printers.
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Doc ID 7539 Rev 10
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Pin configuration
ST3243B ST3243C
2
Figure 1.
Pin configuration
Pin configuration
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Table 2.
Pin n° 1 2 3 4 5 6 7 8 9 10 11 12 13
Pin description
Symbol C2+ C2VR1IN R2IN R3IN R4IN R5IN T1OUT T2OUT T3OUT T3IN T2IN Name and function Positive terminal of inverting charge pump capacitor Negative terminal of inverting charge pump capacitor - 5.5 V generated by the charge pump First receiver input voltage Second receiver input voltage Third receiver input voltage Fourth receiver input voltage Fifth receiver input voltage First transmitter output voltage Second transmitter output voltage Third transmitter output voltage Third transmitter input voltage Second transmitter input voltage
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ST3243B ST3243C Table 2.
Pin n° 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
Pin configuration
Pin description (continued)
Symbol T1IN R5OUT R4OUT R3OUT R2OUT R1OUT R2OUTB INVALID FORCEOFF FORCEON C1GND VCC V+ C1+ Name and function First transmitter input voltage Fifth receiver output voltage Fourth receiver output voltage Third receiver output voltage Second receiver output voltage First receiver output voltage Non-inverting complementary receiver output, always active for wake-up Output of the valid signal detector. Indicates if a valid RS-232 level is present on receiver inputs logic “1” Drive low to shut down transmitters and on-board power supply. This overrides all automatic circuitry and FORCEON Drive high to override automatic circuitry keeping transmitters on (FORCEOFF must be high) Negative terminal of voltage-charge pump capacitor Ground Supply voltage 5.5 V generated by the charge pump Positive terminal of voltage-charge pump capacitor
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Table 3.
Truth table
TOUT HIGH Z ACTIVE(1) ROUT HIGH Z.