Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
ISL54505IRUZ-T Datasheet(PDF) 8 Page - Intersil Corporation |
|
ISL54505IRUZ-T Datasheet(HTML) 8 Page - Intersil Corporation |
8 / 12 page 8 FN6552.2 October 23, 2009 microamp input current produces an insignificant voltage drop during normal operation. This method is not acceptable for the signal path inputs. Adding a series resistor to the switch input defeats the purpose of using a low rON switch. Connecting Schottky diodes to the signal pins (as shown in Figure 7) will shunt the fault current to the supply or to ground, thereby protecting the switch. These Schottky diodes must be sized to handle the expected fault current. Power-Supply Considerations The ISL54504, ISL54505 construction is typical of most single supply CMOS analog switches in that they have two supply pins: V+ and GND. V+ and GND drive the internal CMOS switches and set their analog voltage limits. Unlike switches with a 4V maximum supply voltage, the ISL54504, ISL54505 5.5V maximum supply voltage provides plenty of room for the 10% tolerance of 3.6V supplies, as well as room for overshoot and noise spikes. The minimum recommended supply voltage is 1.8V but the part will operate with a supply below 1.8V. It is important to note that the input signal range, switching times, and ON-resistance degrade at lower supply voltages. Refer to the “Electrical Specifications” tables starting on page 3 and the “Typical Performance Curves” starting on page 9 for details. V+ and GND also power the internal logic and level shiftier. The level shiftier converts the input logic levels to switched V+ and GND signals to drive the analog switch gate terminals. This family of switches cannot be operated with bipolar supplies because the input switching point becomes negative in this configuration. Logic-Level Thresholds This switch family is 1.8V CMOS compatible (0.5V and 1.4V) over a supply range of 2V to 3.6V (see Figure 14). At 3.6V the VIH level is about 0.95V. This is still below the 1.8V CMOS guaranteed high output minimum level of 1.4V, but noise margin is reduced. The digital input stages draw supply current whenever the digital input voltage is not at one of the supply rails. Driving the digital input signals from GND to V+ with a fast transition time minimizes power dissipation. High-Frequency Performance In 50Ω systems, the ISL54504/ISL54505 has a -3dB bandwidth of 250MHz (see Figure 15). The frequency response is very consistent over a wide V+ range and for varying analog signal levels. An OFF switch behaves like a capacitor and passes higher frequencies with less attenuation, resulting in signal feedthrough from a switch’s input to output. Off isolation is the resistance of this signal feedthrough. Figure 16 details the high off isolation provided by the ISL54504, ISL54505. At 1MHz, off isolation is about 70dB in 50Ω systems, decreasing approximately 20dB per decade as frequency increases. Higher load impedances decrease off isolation due to the voltage divider action of the switch OFF impedance and the load impedance. Leakage Considerations Reverse ESD protection diodes are internally connected between each analog-signal pin and both V+ and GND. One of these diodes conducts if any analog signal exceeds V+ or GND. Virtually all the analog leakage current comes from the ESD diodes to V+ or GND. Although the ESD diodes on a given signal pin are identical and therefore fairly well balanced, they are reverse biased differently. Each is biased by either V+ or GND and the analog signal. This means their leakages will vary as the signal varies. The difference in the two diode leakages to the V+ and GND pins constitutes the analog-signal-path leakage current. All analog leakage current flows between each pin and one of the supply terminals, not to the other switch terminal. This is why both sides of a given switch can show leakage currents of the same or opposite polarity. There is no connection between the analog signal paths and V+ or GND. FIGURE 7. OVERVOLTAGE PROTECTION GND VCOM VNX V+ INX OPTIONAL PROTECTION RESISTOR OPTIONAL SCHOTTKY DIODE OPTIONAL SCHOTTKY DIODE ISL54504, ISL54505 |
Número de pieza similar - ISL54505IRUZ-T |
|
Descripción similar - ISL54505IRUZ-T |
|
|
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 |