ST ST3222B, ST3222C User Manual
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
ST3222B
ST3222C
3 to 3.6 V, low power, up to 400 kbps
RS-232 drivers and receivers
Description
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.
TSSOP20
Table 1. Device summary
Order codes
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 Doc ID 7512 Rev 7 1/13
Temperature
range
Package Packaging
www.st.com
1
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
2/13 Doc ID 7512 Rev 7
ST3222B - ST3222C Pin configuration
1 Pin configuration
Figure 1. Pin connections
CS02220
Table 2. Pin descriptions
Pin n° Symbol Name and function
1EN
2C
Receiver enable control. Drive low for normal operation. Drive high to force the receivers
outputs (R_OUT) into a high-impedance state.
+ Positive terminal for the first charge pump capacitor
1
3 V+ 5.5 V Generated by the charge pump.
4C
5C
6C
- Negative terminal for the first charge pump capacitor
1
+ Positive terminal for the second charge pump capacitor
2
- Negative terminal for the second charge pump capacitor
2
7 V- -5.5 V Generated by the charge pump.
8T2
OUT
9R2
10 R2
OUT
Second transmitter output voltage
Second receiver Input voltage
IN
Second receiver output voltage
11 NC Not connected
12 T2
13 T1
Second transmitter input voltage
IN
First transmitter Input voltage
IN
14 NC Not connected
15 R1
16 R1
17 T1
OUT
OUT
First receiver output voltage
First receiver input voltage
IN
First transmitter output voltage
18 GND Ground
19 V
CC
Supply voltage
20 SHDN Active low shutdown control input. Drive low to shutdown transmitter and charge pump
Doc ID 7512 Rev 7 3/13
Maximum ratings ST3222B - ST3222C
2 Maximum ratings
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
V
CC
V+ Doubled voltage terminal (V
V- Inverted voltage terminal 0.3 to -7 V
V+ +|V-| 13 V
T
IN
R
IN
T
OUT
R
OUT
t
SHORT
Supply voltage -0.3 to 6 V
- 0.3) to 7 V
CC
Transmitter input voltage range -0.3 to 6 V
Receiver input voltage range ± 25 V
Transmitter output voltage range ± 13.2 V
Receiver output voltage range -0.3 to (VCC + 0.3) V
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 (V
, then V+, then V-) is critical, therefore it is not recommended
CC
to use this device using externally applied voltage to V+ and V-.
4/13 Doc ID 7512 Rev 7
Loading...