ST3237EB ± 15 kV ESD protected, 1 µA, 3 to 5.5 V, 250 kbps RS-232 transceiver with stand-by 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 SSOP SOP operation mode and 1 Mbps in the very high speed operation mode while maintaining RS-232 output levels. Description 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 Temperature range Package Packaging 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 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 1 C2+ Positive Terminal of Inverting Charge Pump Capacitor 2 GND Ground 3 C2- Negative terminal of inverting charge pump capacitor 4 V- 5.5V generated by the charge pump 5 T1OUT First transmitter output voltage 6 T2OUT Second transmitter output voltage 7 T3OUT Third transmitter output voltage 8 R1IN First receiver input voltage 9 R2IN Second receiver input voltage 10 T4OUT 11 R3IN 12 T5OUT 13 EN Receiver enable, active low 14 SHDN Shutdown control, active low 15 VHSCI Very high speed control input. Connect to GND for normal operation; connect to VCC for 1 Mbps transmission rates. 16 R1OUTB Non inverting complementary receiver output. Always active. 17 T5IN Fifth transmitter input voltage 18 R3OUT Third receiver output voltage Fourth transmitter output voltage Third receiver input voltage Fifth transmitter output voltage 3/18 Pin configuration Table 2. 4/18 ST3237EB Pin description (continued) Pin n° Symbol Name and function 19 T4IN Fourth transmitter input voltage 20 R2OUT Second receiver output voltage 21 R1OUT First receiver output voltage 22 T3IN Third transmitter input voltage 23 T2IN Second transmitter input voltage 24 T1N First transmitter input voltage 25 C1- Negative terminal of voltage- charge pump capacitor 26 VCC Supply voltage 27 V+ -5.5V generated by the charge pump 28 C1+ Positive terminal of voltage- charge pump capacitor ST3237EB Absolute maximum ratings 2 Absolute maximum ratings Table 3. Absolute maximum ratings Symbol Parameter Value Unit VCC 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 13 V -0.3 to 6 V -0.3 to 6 V V+ +|V-| Transmitter input voltage range TIN SHDN, EN VHSCI Very high speed control input -0.3 to (VCC +0.3) V RIN Receiver input voltage range ± 25 V ± 13.2 V -0.3 to (VCC + 0.3) V Transmitter output voltage range TOUT ROUT, ROUTB Receiver output voltage range tSHORT Short circuit duration on TOUT (one at a time) Continuous Storage temperature range -65 to 150 Tstg °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. Symbol ESD performance: transmitter outputs, receiver inputs 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 ±8 kV 5/18 Electrical characteristics ST3237EB 3 Electrical characteristics Table 5. Electrical characteristics (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 TA = 25 °C) Symbol ISUPPLY ISHDN Table 6. Parameter VTIH IIL VHYS Min. VCC power supply current SHDN=VCC, No Load Shutdown supply current SHDN=GND, VT_IN=GND or VCC Typ. Max. Unit 0.3 1 mA 1 5 µA 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 TA = 25 °C) Symbol VTIL Test conditions Parameter Input logic threshold low Test conditions (1) T-IN, VHSCI, EN, SHDN Input logic threshold high T-IN, VHSCI, EN, SHDN VCC = 3.3V VCC = 5V Input leakage current Min. Typ. Max. Unit 0.8 V 2 V 2.4 ± 1.0 T-IN, VHSCI, EN, SHDN Transmitter input hysteresis 0.25 µA V 1. Transmitter input hysteresis is typically 250 mV Table 7. Symbol 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 TA = 25 °C) Parameter Test conditions Min. Typ. Max. Unit VTOUT Output voltage swing All transmitter outputs are loaded with 3KΩ to GND ±5 ± 5.4 V RTOUT Transmitter output resistance VCC = 0V, VOUT = ± 2V 300 10M Ω ± 60 mA 6/18 ISC Output short circuit current ITOL Output leakage current VCC = 0V or 3.3V to 5.5V VOUT = ± 12V Transmitters disable ± 25 µA ST3237EB Table 8. Symbol Electrical characteristics Receiver (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 TA = 25°C) Parameter Test conditions IOL Output leakage current Receiver disabled, EN = VCC VOL Output voltage low IOUT = 1mA VOH Output voltage high IOUT = -1mA VRIN Receiver input voltage operating range VRIL RS-232 input threshold low VRIH RS-232 input threshold high VRIHYS Input hysteresis RRIN Input resistance Table 9. Symbol DR Min. VCC-0.6 Typ. Max. Unit ± 0.05 ± 10 µA 0.4 V VCC-0.1 -25 V 25 TA = 25°C, VCC = 3.3V 0.6 1.1 TA = 25°C, VCC = 5V 0.8 1.5 V V TA = 25°C, VCC = 3.3V 1.5 2.4 TA = 25°C, VCC = 5V 1.2 2.4 V 0.3 TA = 25°C 3 V 5 7 KΩ Timing characteristics (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 TA = 25 °C) Parameter Maximum data rate Test conditions Min. Typ. Max. Unit RL = 3KΩ, CL= 1000pF one transmitter switching, VHSCI=GND 250 Kbps RL = 3KΩ, CL= 250pF one transmitter switching, VHSCI=VCC VCC= 3 to 4.5V 1000 Kbps RL = 3KΩ, CL= 1000pF one transmitter switching, VHSCI=VCC VCC= 4.5 to 5.5V 1000 Kbps tPHLR tPLHR Propagation delay input to output RIN to ROUT, CL = 150pF 0.15 tPHLR tPLHR Propagation delay input to output RL = 3kΩ, CL = 1000pF, VHSCI=VCC VHSCI=GND 400 1000 |tPHL - tTLH|, VHSCI=GND 300 ns |tPHL - tTLH|, VHSCI=VCC 50 ns |tPHL - tTLH| 100 ns tT_SKEW Transmitter skew tR_SKEW Receiver skew µs ns ns tOER Receiver output enable time Normal operation 50 ns tODR Receiver output disable time Normal operation 120 ns SRT Note: Transition slew rate TA = 25°C RL = 3 to 7KΩ, VCC = 3.3V measured from +3V to -3V or -3V to +3V CL = 150pF to 1000pF, VHSCI=GND CL = 150pF to 1000pF, VHSCI=VCC CL = 150pF to 2500pF, VHSCI=GND 6 24 4 30 150 30 V/µs V/µs V/µs Transmitter skew is measured at the transmitter zero cross points 7/18 Application ST3237EB 4 Application Figure 3. Application circuits Table 10. Capacitance value (µF) 8/18 VCC C1 C2 C3 C4 Cbypass 3.0 to 3.6 0.22 0.22 0.22 0.22 0.1 3.1 to 3.6 0.1 0.1 0.1 0.1 0.1 4.5 to 5.5 0.047 0.33 0.33 0.33 0.1 3.0 to 5.5 0.22 0.1 0.1 0.1 0.1 ST3237EB Typical performance characteristics 5 Typical performance characteristics Figure 4. (unless otherwise specified TJ = 25°C) Low level receiver output current Figure 5. Figure 6. ESD protection Note: The high ESD protected pins are the I/O RS232 line, transmitter out and receiver in. The other pins guarantee ± 2 kV HBM ESD protection versus ground by means of diodes. High level receiver output current 9/18 Application note 6 ST3237EB Application note This application note describes the procedure for determining the susceptibility and the test method to verify ST ESD advanced protection on RS-232 or RS485 I/O device. Static electricity is defined as an electrical charge caused by an imbalance of electrons on the surface of a material. This imbalance of electrons produces an electric field that can be measured and that can influence other objects at a distance. Electrostatic discharge is defined as the transfer of charge between bodies at different electrical potentials. Electrostatic discharge (ESD) can change the electrical characteristics of a semiconductor device, degrading or destroying it. Any input or output port (I/O) allows access communication with other pieces of equipment by external connectors. These connectors are directly linked by the I/O pins of RS-232 or RS485 interface. ST provides the E-series by advanced high ESD protection structure. The protection functionality is tested in two different conditions: The first model is used to simulate the HUMAN BODY MODEL (HBM) event. A similar discharge can occur from a charged conductive object, such as a metallic tool or fixture. The model used to characterize this event is known as the machine model. A human body model circuit and waveform is presented in figures below. Figure 7. Human body model circuit Figure 8. Human body model current waveform 10/18 ST3237EB Application note The second model is IEC 1000-4-2 and is used to simulate the reaction of the device on equipment when subjected to electrostatic discharges, which may occur from personnel to objects near vital instrumentation. Direct (Contact) and indirect (Air Gap) applications of discharges to the equipment under test (EUT) are possible. Test characteristics are shown in circuit, waveform and table below. Figure 9. IEC 1000-4-2 circuit Figure 10. IEC 1000-4-2 current waveform Table 11. Characteristics of the ESD generator Level Indicated voltage First peak current of discharge (± 10%) 1 2 kV 7.5 A 0.7 to 1ns 4A 2A 2 4 kV 15 A 0.7 to 1ns 8A 4A 3 6 kV 22.5 A 0.7 to 1ns 12 A 6A 4 8 kV 30 A 0.7 to 1ns 16 A 8A Rise time with discharge Current at 30 ns Current at 60 ns switch (± 30%) (± 30%) 11/18 Package mechanical data 7 ST3237EB Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com. 12/18 ST3237EB Package mechanical data SO-28 mechanical data mm. inch. Dim. Min. Typ. A Max. Min. Typ. 2.65 Max. 0.104 a1 0.1 0.3 0.004 0.012 b 0.35 0.49 0.014 0.019 b1 0.23 0.32 0.009 0.012 C 0.5 0.020 c1 45° (typ.) D 17.70 18.10 0.697 0.713 E 10.00 10.65 0.393 0.419 e 1.27 0.050 e3 16.51 0.650 F 7.40 7.60 0.291 0.300 L 0.50 1.27 0.020 0.050 S 8° (max.) 0016023 13/18 Package mechanical data ST3237EB SSOP28 mechanical data mm. inch. Dim. Min. Typ. A Min. Typ. 2 A1 0.050 A2 1.65 b Max. 0.079 0.002 1.85 0.065 0.22 0.38 0.009 0.015 c 0.09 0.25 0.004 0.010 D 9.9 10.2 10.5 0.390 0.402 0.413 E 7.4 7.8 8.2 0.291 0.307 0.323 E1 5 5.3 5.6 0.197 0.209 0.220 e 14/18 Max. 1.75 0.65 BSC K 0° L 0.55 0.75 0.069 0.073 0.0256 BSC 10° 0° 0.95 0.022 10° 0.030 0.037 ST3237EB Package mechanical data Tape & reel SO-28 mechanical data mm. inch. Dim. Min. A Typ. Max. Min. 330 Max. 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 13.2 Typ. 0.504 30.4 0.519 1.197 Ao 10.8 11.0 0.425 0.433 Bo 18.2 18.4 0.716 0.724 Ko 2.9 3.1 0.114 0.122 Po 3.9 4.1 0.153 0.161 P 11.9 12.1 0.468 0.476 15/18 Package mechanical data ST3237EB Tape & reel SSOP28 mechanical data mm. inch. Dim. Min. A Max. Min. 330 13.2 Typ. Max. 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 16/18 Typ. 0.504 22.4 0.519 0.882 Ao 8.4 8.6 0.331 0.339 Bo 10.7 10.9 0.421 0.429 Ko 2.9 3.1 0.114 0.122 Po 3.9 4.1 0.153 0.161 P 11.9 12.1 0.468 0.476 ST3237EB Revision history 8 Revision history Table 12. Document revision history Date Revision Changes 21-Mar-2005 5 TSSOP has been removed. 24-Mar-2006 6 Order codes updated. 13-Nov-2007 7 Added Table 1. 17/18 ST3237EB Please Read Carefully: Information in this document is provided solely in connection with ST products. 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