ST ST3222B, ST3222C User Manual

ST3222B

ST3222C

3 to 3.6 V, low power, up to 400 kbps RS-232 drivers and receivers

Features

■ 300 µA supply current

■ 250 kbps minimum guarantee data rate

■ 6 V/µs minimum guarantee slew rate

■ Meet EIA/TIA-232 specification down to 3 V

Description	TSSOP20

The ST3222 is a 3 V powered EIA/TIA-232 and V.28/V.24 communications interface with low power requirements and high data-rate capabilities. ST3222 has a proprietary low dropout transmitter output stage providing true RS-232 performance from 3 to 3.6 V power supplies. The device requires only four small 0.1 mF standard external capacitors for operating from 3 V supply. The ST3222 has two receivers and two drivers. The ST3222 features a 1 mA shutdown mode that reduces power consumption and extends battery life in portable systems. Its receivers can remain active in shutdown mode, allowing external devices such as modems to be monitored using only 1 mA supply current. The device is guaranteed to run at data rates of

250 Kbps while maintaining RS-232 output levels. Typical applications are notebooks, subnotebooks and palmtop computers, battery powered equipment, hand-held equipment, peripherals and printers.

	Table 1.	Device summary
	Order codes		Temperature	Package	Packaging
			range
	ST3222CTR		0 to 70 °C	TSSOP20 (tape and reel)	2500 parts per reel
	ST3222BTR		-40 to 85 °C	TSSOP20 (tape and reel)	2500 parts per reel

August 2010

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Contents	ST3222B - ST3222C

Contents

1	Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. 3
2	Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4
3	Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5
	3.1	Receiver electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
4	Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		7
	4.1	Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	8
5	Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		9
6	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		12

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ST3222B - ST3222C	Pin configuration

1 Pin configuration

Figure 1. Pin connections

CS02220

Table 2.	Pin descriptions
Pin n°		Symbol	Name and function
1		EN	Receiver enable control. Drive low for normal operation. Drive high to force the receivers
			outputs (R_OUT) into a high-impedance state.
2		C1+	Positive terminal for the first charge pump capacitor
3		V+	5.5 V Generated by the charge pump.
4		C1-	Negative terminal for the first charge pump capacitor
5		C2+	Positive terminal for the second charge pump capacitor
6		C2-	Negative terminal for the second charge pump capacitor
7		V-	-5.5 V Generated by the charge pump.
8		T2OUT	Second transmitter output voltage
9		R2IN	Second receiver Input voltage
10		R2OUT	Second receiver output voltage
11		NC	Not connected
12		T2IN	Second transmitter input voltage
13		T1IN	First transmitter Input voltage
14		NC	Not connected
15		R1OUT	First receiver output voltage
16		R1IN	First receiver input voltage
17		T1OUT	First transmitter output voltage
18		GND	Ground
19		VCC	Supply voltage
20		SHDN	Active low shutdown control input. Drive low to shutdown transmitter and charge pump

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Maximum ratings			ST3222B - ST3222C
2	Maximum ratings
Table 3.	Absolute maximum ratings
Symbol	Parameter		Value	Unit
VCC	Supply voltage		-0.3 to 6	V
V+	Doubled voltage terminal		(VCC - 0.3) to 7	V
V-	Inverted voltage terminal		0.3 to -7	V
V+ +|V-|			13	V
TIN	Transmitter input voltage range		-0.3 to 6	V
RIN	Receiver input voltage range		± 25	V
TOUT	Transmitter output voltage range		± 13.2	V
ROUT	Receiver output voltage range		-0.3 to (VCC + 0.3)	V
tSHORT	Transmitter output short to gnd time		Continuous
Note:	Absolute maximum ratings are those values beyond which damage to the device may occur.
	Functional operation under these condition is not implied.

Externally applied V+ and V- can have a maximum magnitude of +7 V, but their absolute addition can not exceed 13 V.

Running on internal charge pump, intrinsic self limitation allows exceeding those values without any damage.

Startup voltage sequence (VCC, then V+, then V-) is critical, therefore it is not recommended to use this device using externally applied voltage to V+ and V-.

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