Electronic Components Datasheet Search |
|
AS1748 Datasheet(PDF) 11 Page - ams AG |
|
AS1748 Datasheet(HTML) 11 Page - ams AG |
11 / 17 page www.austriamicrosystems.com/Analog-Switches/AS1747-50 Revision 1.02 10 - 16 AS1747, AS1748, AS1749, AS1750 Datasheet - D e t a i l e d D e s c r i p t i o n 8 Detailed Description The AS1747– AS1750 are operating from a +1.8V to +5.5V supply and feature a negative signal capability that allows signals below ground to pass through without distortion. A break-before-make switching and a low on-resistance are also included in this analog dual SPDT switches. The device is fully specified for a 3.0V application. A headphone or mute detection is included in the AS1748 and AS1750. This function is realized with a comparator which has an internally generated thresh-hold of about 1/3 of VCC. To reduce click-and-pop sounds when switching between precharged points the AS1749 and AS1750 have an internal shunt switch. This shunt switch automatically discharges any capacitance at the NO and NC connection points. 9 Application Information Digital Control Inputs The logic inputs of the AS1747– AS1750 accept up to +5.5V independent of the supply voltage. Due to this a mixing of the logic levels in a system is possible. For example, with a +3.3V supply, IN_ can be driven low to GND and high to +5.5V. For a +1.8V supply voltage, the logic levels are 0.5V (low) and 1.4V (high); for a +5V supply voltage, the logic levels are 0.8V (low) and 2.0V (high). Analog Signal Levels The change of the on-resistance of the AS1747– AS1750 is very little for analog input signals over the whole supply voltage range. The switches are bi-directional, so the NO_, NC_, and COM_ pins can be either inputs or outputs. The AS1747– AS1750 pass signals as low as VCC - 5.5V, including signals below ground with minimal distortion. Comparator (AS1748 1 /AS1750) To implement a mute and headphone function, a comparator is included in the AS1748 and AS1750. The negative ter- minal of this comparator is connected to the outside (via pin CMP-) while the positive terminal is internally set to VCC/3. The output of the comparator (CMPO) is logic high when the negative terminal (CMP-) is below the threshold. CMPO is logic low when CMP- is higher than VCC/3. Headphone audio signals are typical biased to VCC/2 so a comparator threshold of VCC/3 is sufficient for the head- phone detection. Shunt Switch (AS1749 1 /AS1750) Due to the switching between audio sources, audible click-and-pop sounds occur. To reduce this sounds a 100 Ω shunt switch is implemented in the AS1749 and AS1750. This shunt switch automatically discharges any capacitance at the NC_ or NO_ terminals when they are unconnected to COM_. Audible clicks and pops are caused when a step DC voltage is switched into the speaker. By automatically discharging the side that is not connected, any residual DC voltage is removed, thereby reducing the clicks and pops. Power-Supply Sequencing and Overvoltage Protection Caution: Stresses beyond the listed absolute maximum ratings in Table 3 on page 4 may cause permanent damage to the device. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Proper power-supply sequencing is recommended for all CMOS devices. Always apply VCC before applying analog signals, especially if the analog signal is not current-limited. 1. on request |
Similar Part No. - AS1748 |
|
Similar Description - AS1748 |
|
|
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 |