Os motores de busca de Datasheet de Componentes eletrônicos |
|
ISL54401IRZ-T Folha de dados(PDF) 11 Page - Intersil Corporation |
|
ISL54401IRZ-T Folha de dados(HTML) 11 Page - Intersil Corporation |
11 / 15 page 11 FN6240.3 July 12, 2006 where the two SPDT switches work in tandem, the ISL54402 gives you independent control over each SPDT switch. USB Switches The two NO (normally open) USB switches (D+, D-, NOx) are 5 Ω bidirectional switches that are designed to pass low speed and full-speed USB differential signals typically in the range of 0V to 3.6V. The switches have low capacitance and high bandwidth to pass USB full-speed signals (12Mbps) with minimum edge and phase distortion to meet USB 2.0 signal quality specifications. See eye diagram Figure 11 on page 13. For the ISL54400 and ISL54401 parts, the maximum signal range for the USB switches is from -1.5V to VBUS. The signal voltage should not be allowed to exceed the VBUS voltage rail or go below ground by more than -1.5V. For the ISL54402 part, the maximum signal range is from -1.5V to VDD. The signal voltage should not be allowed to exceed the VDD voltage rail or go below ground by more than -1.5V. When using the ISL54400 and ISL54401 parts, the USB switches are active (turned ON) whenever the VBUS voltage is ≥ to VDD + 0.8V. VBUS is internally pulled low, so when VBUS is floating the USB switches are OFF. Note: Whenever the USB switches are ON the audio drivers of the CODEC, connected at R and L (pins 6 and 7), need to be at AC or DC ground or floating to keep from interfering with the data transmission. When using the ISL54402 part, the NO1 USB switch is active (turned ON) whenever logic pin IN1 (pin 10) is HIGH. The NO2 USB switch is active (turned ON) whenever the logic pin IN2 (pin 2) is HIGH. Unlike the ISL54400 and ISL54401 parts where the two SPDT switches work in tandem, the ISL54402 gives you independent control over each SPDT switch. ISL54400 and ISL54401 Operation The ISL54400 and ISL54401 function the same except the ISL54401 does not have the VTERM feature. The discussion that follows pertains to both devices and will discuss using the parts in the typical application shown in the block diagram on page 10. LOGIC CONTROL The state of the ISL54400 and ISL54401 devices are determined by the voltage at the VBUS pin (pin 2). The VBUS pin is internally pulled low and can be left floating. If VBUS (pin 2) is floating or the VBUS voltage ≤ VDD + 0.2V the part will be in the Audio mode. In Audio mode the L (left) and R (right) 1 Ω audio switches are ON and the D- and D+ 5 Ω switches are OFF (high impedance). In this state, power to the part will be provided by the DC voltage connected at the VDD pin (pin 1). In a typical application VDD will be in the range of 2.5V to 3.6V and will be connected to the battery or LDO of the MP3 player or cellphone. When a headphone is plugged into the common connector, nothing gets connected at the VBUS pin (it’s floating) and the ISL54400 and ISL54401 parts remain in the audio mode and the MP3 player or cellphone audio drivers can drive the headphones and play music. If VBUS (pin 2) voltage is greater than VDD by 0.8V the part will go into USB mode. In USB mode the D- and D+ 5 Ω switches are ON and the L and R 1 Ω audio switches are OFF (high impedance). In this state the part will be powered by the voltage connected at the VBUS pin (pin 2). When a USB cable from a computer or USB hub is connected at the common connector the VBUS voltage is driven to between 4.4V and 5.25V. The ISL54400 and ISL54401 parts will go into the USB mode. In USB mode the computer or USB hub transceiver and the MP3 player or cellphone USB transceiver are connected and digital data will be able to be transmitted back and forth. When the USB cable is disconnected the switch automatically turns the D+ and D- switches OFF and turns the L and R audio switches ON. POWER In audio mode the power supply connected at VDD (pin 1) provides power to the ISL54400 and ISL54401 parts. Its voltage should be kept in the range of 2.5V to 3.6V when used in a USB/Audio application to ensure you get proper switching when the VBUS voltage is at its lower limit of 4.4V. In USB mode power for the ISL54400 and ISL54401 parts is provided from the VBUS line from the host USB controller of the computer or USB hub. Its voltage will be between 4.4V and 5.25V. VTERM OPERATION (ISL54400 ONLY) When a USB cable from a computer is connected to a USB device a VTERM voltage must be applied to a speed indicating pull-up resistor to properly terminate the bus and identify whether the USB device is a full-speed or low-speed device to facilitate proper digital transmission. When the cable is removed from the device this VTERM voltage must be disconnected from the speed indicating pull-up resistor. The ISL54400 device can perform this operation. When VDD ≥ 2.5V and VBUS ≥ VDD + 0.8V, the VTERM pin (pin 10) outputs an open circuit voltage equal to the voltage at the VBUS pin. Otherwise the VTERM pin will be in a HI-Z state. The ISL54400 VTERM circuitry has an internal series resistor approximately equal to 5.3k Ω. For a full speed USB application, it is recommended you use a 3k Ω ±5% speed indicating pull-up resistor. When the USB bus is in the idle state, a 3k Ω ±5% resistor will put the D+ line voltage in the range of 2.7V to 3.6V as required by the USB specification. For low-speed USB application, it is recommended you use ISL54400, ISL54401, ISL54402 |
Nº de peça semelhante - ISL54401IRZ-T |
|
Descrição semelhante - ISL54401IRZ-T |
|
|
Ligação URL |
Privacy Policy |
ALLDATASHEETPT.COM |
ALLDATASHEET é útil para você? [ DONATE ] |
Sobre Alldatasheet | Publicidade | Contato conosco | Privacy Policy | roca de Link | 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 |