CDCS502: TI replacement product for the ICS840271BGILF

Hi JH,

I did some research and it looks like the ICS840271BGILF is an obsolete Renesas frequency translator in an 8-pin TSSOP package? We do not make frequency translators and this device's function of converting multiple input frequencies into one output frequency is like a clock generator backwards, but it should still be possible to create a TI solution with clock generators. Could you tell us more information about the customer's clock tree (input frequencies, output frequencies, any special requirements)?

Thanks,

Evan Su

Hi Evan,

Thanks for your help,

The customer is using the device under the conditions below.

   1. Input clock  - CASE 1 : 125MHz / CASE 2 : 156.25MHz

   2. Output clock : 25MHz

   3. Control I/F : Hardware pin control using pull-up or pull-down resistors

Are there any clock devices that can support this application?

Thanks,

JH

Hi JH,

I am looking through our clock generator portfolio for a suitable device. I have a few questions to make sure I am understanding their requirements correctly:

• Does the customer have any requirements for the input and output clock formats?
• Will the device receive 125 MHz and 156.25 MHz at the same time or one at a time? Over the same wires or different wires?
• Many of our clock generators products have a pin mode that can control reference selection, output enable, etc. but would require one-time I2C programming in order to configure the output to 25 MHz using EEPROM. Is this OK?

The ICS840271BGILF is a simple device that does not have an I2C interface because it only has 3 possible input frequencies and 1 fixed output frequency, so all of its functions can be controlled by a handful of pins. Our clock generators are more complicated and would need more work to prepare. I am currently thinking about the CDCE6214 clock generator, its EEPROM contains two pages and should be able to store a configuration for 125 MHz input --> 25 MHz output and another configuration for 156.25 MHz input --> 25 MHz output. After the programming is done, the device can operate in pin mode and switch between the configurations without much trouble.

Best,

Evan Su

Hi Evan,

Here are the customer's responses.

1. Clock format requirements : input - LVPECL or LVDS / Output - LVCMOS or LVTTL

2. 125MHz and 156.25MHz are not used on the same board. Therefore, it only needs to receive one input clock at a time.

3. I2C line cannot be connected. It should be controllable only with H/W PIN.

Thank you.

JH