Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
ISL3232EIRZ Datasheet(PDF) 7 Page - Intersil Corporation |
|
ISL3232EIRZ Datasheet(HTML) 7 Page - Intersil Corporation |
7 / 14 page 7 FN6045.6 May 13, 2010 Detailed Description The ISL4221E, ISL4223E and ISL3232E operate from a single +2.7V to +5.5V supply, guarantee a 250kbps minimum data rate, require only four small external 0.1µF capacitors, feature low power consumption, and meet all ElA RS-232C and V.28 specifications even with VCC = 3.0V. The circuit is divided into three sections: The charge pump, the transmitters and the receivers. Charge-Pump Intersil’s new RS-232 devices utilize regulated on-chip dual charge pumps as voltage doublers, and voltage inverters to generate ±5.5V transmitter supplies from a VCC supply as low as 3.0V. This allows them to maintain RS-232 compliant output levels over the ±10% tolerance range of 3.3V powered systems. The efficient on-chip power supplies require only four small, external 0.1µF capacitors for the voltage doubler and inverter functions. The charge pumps operate discontinuously (i.e., they turn off as soon as the V+ and V- supplies are pumped up to the nominal values), resulting in significant power savings. Transmitters The transmitters are proprietary, low dropout, inverting drivers that translate TTL/CMOS inputs to EIA/TIA-232 output levels. Coupled with the on-chip ±5.5V supplies, these transmitters deliver true RS-232 levels over a wide range of single supply system voltages. All ISL4221E, ISL4223E transmitter outputs disable and assume a high impedance state when the device enters the power-down mode (see Table 2). These outputs may be driven to ±12V when disabled. The devices guarantee a 250kbps data rate for full load conditions (3k Ω and 1000pF), V CC ≥ 3.0V, with one transmitter operating at full speed. Under more typical conditions of VCC ≥ 3.3V, RL = 3kΩ, and CL = 250pF, one transmitter easily operates at 900kbps. Transmitter inputs float if left unconnected, and may cause ICC increases. Connect unused inputs to GND for the best performance. Receivers All these RS-232 devices contain standard inverting receivers, and the ISL4221E, ISL4223E receivers three-state via the EN control line. All the receivers convert RS-232 signals to CMOS output levels and accept inputs up to ±25V while presenting the required 3k Ω to 7kΩ 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. Receivers driving a powered down UART must be disabled to prevent current flow through, and possible damage to, the UART’s protection diodes (see Figures 2 and 3). This can be accomplished on the ISL4221E, ISL4223E by driving the EN input high whenever the UART powers down. Figure 3 also shows that the INVALID output can be used to determine when the UART should be powered down. When the RS-232 cable is disconnected, INVALID switches low indicating that the UART is no longer needed. Reconnecting the cable drives INVALID back high, indicating that the UART should be powered up. 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 FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN ISL4221E, ISL4223E TRANSITION RX TX INVALID ROUT TIN VCC VCC TO RIN TOUT VOUT = HI-Z POWERED DETECTOR DOWN UART WAKE-UP LOGIC EN = VCC ISL3232E, ISL4221E, ISL4223E |
Número de pieza similar - ISL3232EIRZ |
|
Descripción similar - ISL3232EIRZ |
|
|
Enlace URL |
Política de Privacidad |
ALLDATASHEET.ES |
¿ALLDATASHEET es útil para Ud.? [ DONATE ] |
Todo acerca de Alldatasheet | Publicidad | Contáctenos | Política de Privacidad | Intercambio de Enlaces | Lista de Fabricantes 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 |