Electronic Components Datasheet Search |
|
MAX3221E Datasheet(PDF) 11 Page - Maxim Integrated Products |
|
MAX3221E Datasheet(HTML) 11 Page - Maxim Integrated Products |
11 / 16 page The major difference between tests done using the Human Body Model and IEC1000-4-2 is higher peak current in IEC1000-4-2, because series resistance is lower in the IEC1000-4-2 model. Hence, the ESD with- stand voltage measured to IEC1000-4-2 is generally lower than that measured using the Human Body Model. Figure 7a shows the IEEE1000-4-2 model and Figure 7b shows the current waveform for the ±8kV IEC1000-4-2 Level 4 ESD contact-discharge test. The air-gap test involves approaching the device with a charged probe. The contact-discharge method connects the probe to the device before the probe is energized. Machine Model The Machine Model for ESD tests all pins using a 200pF storage capacitor and zero discharge resistance. Its objective is to emulate the stress caused by contact that occurs with handling and assembly during manufactur- ing. Of course, all pins require this protection during manufacturing, not just RS-232 inputs and outputs. Therefore, after PC board assembly, the Machine Model is less relevant to I/O ports. ___________Applications Information Capacitor Selection The capacitor type used for C1–C4 is not critical for proper operation; either polarized or nonpolarized capacitors may be used. The charge pump requires 0.1µF capacitors for 3.3V operation. For other supply voltages, refer to Table 3 for required capacitor values. Do not use values smaller than those listed in Table 3. Increasing the capacitor values (e.g., by a factor of 2) reduces ripple on the transmitter outputs and slightly reduces power consumption. C2, C3, and C4 can be increased without changing C1’s value. However, do not increase C1 without also increasing the values of C2, C3, and C4 to maintain the proper ratios (C1 to the other capacitors). When using the minimum required capacitor values, make sure the capacitor value does not degrade exces- sively with temperature. If in doubt, use capacitors with a larger nominal value. The capacitor’s equivalent series resistance (ESR) usually rises at low temperatures and influences the amount of ripple on V+ and V-. Power-Supply Decoupling In most circumstances, a 0.1µF VCC bypass capacitor is adequate. In applications that are sensitive to power- supply noise, use a capacitor of the same value as the charge-pump capacitor C1. Connect bypass capacitors as close to the IC as possible. Transmitter Outputs when Exiting Shutdown Figure 8 shows two transmitter outputs when exiting shut down mode. As they become active, the two trans- mitter outputs are shown going to opposite RS-232 lev- els (one transmitter output is high, the other is low). Each transmitter is loaded with 3k Ω in parallel with 1000pF. The transmitter outputs display no ringing or undesirable transients as they come out of shutdown, and are enabled only when the magnitude of V- exceeds approximately -3V. ±15kV ESD-Protected, 1µA, 3.0V to 5.5V, 250kbps, RS-232 Transceivers with AutoShutdown ______________________________________________________________________________________ 11 0.33 0.047 4.5 to 5.5 0.1 0.1 3.15 to 3.6 0.22 0.22 3.0 to 3.6 C2, C3, C4 (µF) C1, CBYPASS (µF) VCC (V) Table 3. Required Capacitor Values 40 µs/div T2OUT FORCEON = FORCEOFF T1OUT 5V/div 2V/div VCC = 3.3V C1–C4 = 0.1 µF Figure 8. Transmitter Outputs Exiting Shutdown or Powering Up 1 0.22 3.0 to 5.5 Table 4. Logic Family Compatibility with Various Supply Voltages Compatible with ACT and HCT CMOS, and with TTL. Incompatible with AC, HC, or CD4000 CMOS. 3.3 5 SYSTEM POWER- SUPPLY VOLTAGE (V) Compatible with all TTL and CMOS-logic families. 5 5 Compatible with all CMOS families. 3.3 3.3 COMPATIBILITY VCC SUPPLY VOLTAGE (V) |
Similar Part No. - MAX3221E |
|
Similar Description - MAX3221E |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |