 |
Motore di ricerca datesheet componenti elettronici |
|
|
Motore di ricerca datesheet componenti elettronici |
|
ISL4238EIRZ-T Scheda tecnica(PDF) 9 Page - Intersil Corporation |
|
||||||||||||||||||||||||||||||
ISL4238EIRZ-T Scheda tecnica(HTML) 9 Page - Intersil Corporation |
|
|
9 / 17 page  9 Transmitter inputs on the ISL424XE float if left unconnected, and may cause ICC increases. Connect unused inputs to GND for the best performance. ISL4238E transmitter inputs incorporate an active positive feedback resistor that maintains the last input state in the absence of a forcing signal, so unused transmitter inputs may be left unconnected. Receivers ISL4238E/4XE devices contain standard inverting receivers which can tristate via the FORCEOFF control line. Additionally, they include a noninverting (monitor) receiver (denoted by the ROUTB label) that is always active, regardless of the state of any control lines. Both receiver types convert RS-232 signals to CMOS output levels and accept inputs up to ±25V while presenting the required 3kΩ to 7k Ω input impedance (see Figure 1) even if the power is off (VCC = 0V). The receivers’ Schmitt trigger input stage uses hysteresis to increase noise immunity and decrease errors due to slow input signal transitions. The ISL4238E/4XE inverting receivers disable during forced (manual) powerdown, but not during automatic powerdown (see Table 2). Conversely, the monitor receiver remains active even during manual powerdown making it extremely useful for Ring Indicator monitoring. Standard receivers driving powered down peripherals must be disabled to prevent current flow through the peripheral’s protection diodes (see Figures 2 and 3). This renders them useless for wake up functions, but the corresponding monitor receiver can be dedicated to this task as shown in Figure 3. Low Power Operation These 3V devices require a nominal supply current of 0.3mA, even at VCC = 5.5V, during normal operation (not in powerdown mode). This is considerably less than the 5mA to 11mA current required by comparable 5V RS-232 devices, allowing users to reduce system power simply by switching to this new family. TABLE 2. POWERDOWN LOGIC TRUTH TABLE RCVR OR XMTR EDGE WITHIN 30 SEC? FORCEOFF INPUT FORCEON INPUT TRANSMITTER OUTPUTS RECEIVER OUTPUTS ROUTB OUTPUTS RS-232 LEVEL PRESENT AT RECEIVER INPUT? INVALID OUTPUT MODE OF OPERATION NO H H Active Active Active NO L Normal Operation (Enhanced Auto Powerdown Disabled) NO H H Active Active Active YES H YES H L Active Active Active NO L Normal Operation (Enhanced Auto Powerdown Enabled) YES H L Active Active Active YES H NO H L High-Z Active Active NO L Powerdown Due to Enhanced Auto Powerdown Logic NO H L High-Z Active Active YES H X L X High-Z High-Z Active NO L Manual Powerdown X L X High-Z High-Z Active YES H INVALID DRIVING FORCEON AND FORCEOFF (EMULATES AUTOMATIC POWERDOWN) X NOTE 8 NOTE 8 Active Active Active YES H Normal Operation X NOTE 8 NOTE 8 High-Z High-Z Active NO L Forced Auto Powerdown NOTE: 8. Input is connected to INVALID Output. RXOUT GND ≤ VROUT ≤ VCC 5k Ω RXIN -25V ≤ VRIN ≤ +25V GND VCC FIGURE 1. INVERTING RECEIVER CONNECTIONS FIGURE 2. POWER DRAIN THROUGH POWERED DOWN PERIPHERAL OLD VCC POWERED GND SHDN = GND VCC Rx Tx VCC CURRENT VOUT = VCC FLOW RS-232 CHIP DOWN UART ISL4238E, ISL4244E, ISL4245E |
Codice articolo simile - ISL4238EIRZ-T |
|
Descrizione simile - ISL4238EIRZ-T |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEETIT.COM |
| Lei ha avuto il aiuto da alldatasheet? [ DONATE ] |
Di alldatasheet | Richest di pubblicita | contatti | Privacy Policy | scambio Link | Ricerca produttore 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 |
Italian ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
