ST ST3237EB User Manual

± 15 kV ESD protected, 1 µA, 3 to 5.5 V, 250 kbps

Features

■ ESD protection for RS-232 I/O pins

– ±15 kV human body model
– ±8 kV IEC 1000-4-2 contacts discharge

■ 1 µA low power shutdown with receivers active

■ Guaranteed data rate

– 250 kbps (normal operation)
– 1 Mbps (very high speed operation)

■ Guaranteed slew rate range

– 6 V/µs (normal operation)
– 24 V/µs (very high speed operation)

■ 0.1 µF external capacitors

■ Flow-through pinout

■ Low supply current 300 µA

■ Available in SSOP28 and SO-28

Description

ST3237EB

RS-232 transceiver with stand-by

SSOP

operation mode and 1 Mbps in the very high
speed operation mode while maintaining RS-232
output levels.

SOP

The ST3237E is a 3 V to 5.5 V powered EIA/TIA­232 and V.28/V.24 communication interfaces high
data-rate capability and enhanced electrostatic
discharge (ESD) protection at ±8 kV using
IEC1000-4-2 contact discharge and ±15 kV using
Human Body Model (HBM). The other pins are
protected with standard ESD protection at ±2 kV
using HBM method. The ST3237C is a
transceiver (5 drivers, 3 receivers) for fast modem
applications.

The device has a proprietary low-dropout
transmitter output stage providing true RS-232
performance from a 3 V to 5.5 V supply using a
dual charge pump. The device is guaranteed to
run at data rates of 250 kbps in the normal

Table 1. Device summary

Order code

ST3237EBDR -40 to 85 °C SO-28 (tape and reel) 1000 parts per reel

ST3237EBPR -40 to 85°C SSOP28 (tape and reel) 1350 parts per reel

November 2007 Rev 7 1/18

Temperature

range

Package Packaging

www.st.com

18

Contents ST3237EB

Contents

1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

5 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

6 Application note . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2/18

ST3237EB Pin configuration

1 Pin configuration

Figure 1. Pin connection

Table 2. Pin description

Pin n° Symbol Name and function

1C

2 GND Ground

3C

4 V- 5.5V generated by the charge pump

5T1

6T2

7T3

8R1

9R2

10 T4

11 R3

12 T5

13 EN Receiver enable, active low

14 SHDN Shutdown control, active low

15 VHSCI

16 R1

17 T5

18 R3

+ Positive Terminal of Inverting Charge Pump Capacitor

2

- Negative terminal of inverting charge pump capacitor

2

OUT

OUT

OUT

IN

IN

OUT

IN

OUT

First transmitter output voltage

Second transmitter output voltage

Third transmitter output voltage

First receiver input voltage

Second receiver input voltage

Fourth transmitter output voltage

Third receiver input voltage

Fifth transmitter output voltage

Very high speed control input. Connect to GND for normal

for 1 Mbps transmission rates.

CC

OUTB

IN

OUT

operation; connect to V

Non inverting complementary receiver output. Always active.

Fifth transmitter input voltage

Third receiver output voltage

3/18

Pin configuration ST3237EB

Table 2. Pin description (continued)

Pin n° Symbol Name and function

19 T4

20 R2

21 R1

22 T3

23 T2

24 T1

25 C

26 V

IN

OUT

OUT

IN

IN

N

- Negative terminal of voltage- charge pump capacitor

1

CC

Fourth transmitter input voltage

Second receiver output voltage

First receiver output voltage

Third transmitter input voltage

Second transmitter input voltage

First transmitter input voltage

Supply voltage

27 V+ -5.5V generated by the charge pump

28 C

+ Positive terminal of voltage- charge pump capacitor

1

4/18

ST3237EB Absolute maximum ratings

2 Absolute maximum ratings

Table 3. Absolute maximum ratings

Symbol Parameter Value Unit

V

CC

Supply voltage -0.3 to 6 V

V+ Doubled voltage terminal -0.3 to 7 V

V- Inverted voltage terminal 0.3 to -7 V

V+ +|V-| 13 V

T

IN

SHDN

VHSCI Very high speed control input -0.3 to (V

R

IN

T

OUT

R

OUT

R

OUTB

t

SHORT

T

stg

Transmitter input voltage range -0.3 to 6 V

, EN -0.3 to 6 V

+0.3) V

CC

Receiver input voltage range ± 25 V

Transmitter output voltage range ± 13.2 V

,

Receiver output voltage range -0.3 to (VCC + 0.3) V

Short circuit duration on T

(one at a time) Continuous

OUT

Storage temperature range -65 to 150 °C

Note: Absolute maximum ratings are those values beyond which damage to the device may occur.

Functional operation under these condition is not implied. V+ and V- can have a maximum
magnitude of +7 V, but their absolute addition can not exceed 13 V.

Table 4. Shutdown and enable control truth table

SHDN EN T-OUT R-OUT R-OUTB

0 0 High Z Active Active

0 1 High Z High Z Active

1 0 Active Active Active

1 1 Active High Z Active

Figure 2. ESD performance: transmitter outputs, receiver inputs

Symbol Parameter Test conditions Min. Typ. Max. Unit

ESD ESD protection voltage Human body model ±15 kV

ESD ESD protection voltage IEC-1000-4-2 contact discharge ±8kV

5/18

Electrical characteristics ST3237EB

3 Electrical characteristics

Table 5. Electrical characteristics (C

otherwise specified. Typical values are referred to T

- C4 = 0.1 µF, VCC = 3 V to 5.5 V, TA = -40 to 85 °C, unless

1

= 25 °C)

A

Symbol Parameter Test conditions Min. Typ. Max. Unit

I

SUPPLYVCC

I

SHDN

power supply current SHDN=VCC, No Load 0.3 1 mA

Shutdown supply current SHDN=GND, V

=GND or V

T_IN

CC

15µA

Table 6. Logic input (C1 - C4 = 0.1 µF, VCC = 3 V to 5.5 V, TA = -40 to 85 °C, unless otherwise

specified. Typical values are referred to T

Symbol Parameter Test conditions Min. Typ. Max. Unit

V

TIL

V

TIH

I

IL

V

HYS

1. Transmitter input hysteresis is typically 250 mV

Input logic threshold low

(1)

T-IN, VHSCI, EN, SHDN 0.8 V

Input logic threshold high T-IN, VHSCI, EN, SHDN

Input leakage current T-IN, VHSCI, EN, SHDN ± 1.0 µA

Transmitter input
hysteresis

= 25 °C)

A

VCC = 3.3V 2

= 5V 2.4

V

CC

V

0.25 V

Table 7. Transmitter (C1 - C4 = 0.1 µF tested at 3.3 V ± 10 %, VCC = 3 V to 5.5 V, TA = -40 to 85 °C,

unless otherwise specified. Typical values are referred to T

Symbol Parameter Test conditions Min. Typ. Max. Unit

= 25 °C)

A

V

R

TOUT

TOUT

I

SC

I

TOL

Output voltage swing

Transmitter output
resistance

Output short circuit current ± 60 mA

Output leakage current

All transmitter outputs are loaded with
3KΩ to GND

= 0V, V

V

CC

= 0V or 3.3V to 5.5V

V

CC

= ± 12V

V

OUT

Transmitters disable

6/18

± 5 ± 5.4 V

= ± 2V 300 10M Ω

OUT

± 25 µA