时钟和计时论坛 - 最近的话题

LMX2592: PLLatinum Sim仿真问题

Wei Fang — Tue, 16 Jun 2026 03:35:21 GMT

Part Number: LMX2592

TI的同事

您好，最近使用贵司的PLLatinum仿真LMX2592发现一个奇怪现象，仿真得到FPD杂散分别为-97.5dBc@100MHz 但是仿真图却显示4.7dBc@100MHz.如图所示，请问一下这个是软件bug 还是我设置的不对，软件使用2025.11.17发布的1.6.9.1官方最新文档，但是我使用老版本，2025.01.10发布的1.6.8.0未出现该问题，但是该版本官方已无下载渠道

RE: LMX2592: PLLatinum Sim仿真问题

Vivian Gao — Thu, 18 Jun 2026 05:04:06 GMT

左下和右下的图表有bug，您先用右边圈出来的表格里面的数据。

LMK1C1102: 交流耦合的方式给LMK1C1102提供输入信号

zhonghang wang — Tue, 16 Jun 2026 05:38:06 GMT

Part Number: LMK1C1102

如果采用交流耦合的方式给LMK1C1102提供输入信号，需要外加偏置电压吗？偏置电压是多少呢？

RE: LMK1C1102: 交流耦合的方式给LMK1C1102提供输入信号

FRANK1 — Tue, 16 Jun 2026 07:24:51 GMT

采用交流耦合的方式给LMK1C1102提供输入信号，需要外加偏置电压的，通常是1/2* VDD。

RE: LMK1C1102: 交流耦合的方式给LMK1C1102提供输入信号

FRANK1 — Tue, 16 Jun 2026 07:19:13 GMT

感谢您对TI产品的关注！
关于你的咨询，我们正在确认您的问题，感谢您的耐心等待。

RE: LMX2592: PLLatinum Sim仿真问题

Alice — Tue, 16 Jun 2026 04:46:05 GMT

您好，
已经收到了您的案例，调查需要些时间，感谢您的耐心等待。

RE: LMK1C1102: 输入一个正弦波信号是否会恶化抖动

FRANK1 — Tue, 16 Jun 2026 03:53:49 GMT

你好，新的问题请重新发个帖子

LMK1C1102: 输入一个正弦波信号是否会恶化抖动

zhonghang wang — Fri, 12 Jun 2026 03:46:59 GMT

Part Number: LMK1C1102

如果给LMK1C1102输入一个正弦波信号，幅度满足要求，但压摆率可能不满足要求，这样会恶化输出信号的抖动吗？

RE: LMK1C1102: 输入一个正弦波信号是否会恶化抖动

zhonghang wang — Tue, 16 Jun 2026 02:29:05 GMT

如果采用交流耦合的方式给LMK1C1102提供输入信号，需要外加偏置电压吗？偏置电压是多少呢？

CDCI6214: CDCI6214: Issue with 10MHz to 100MHz frequency multiplication (Reg 0x07 always reads 0x0C10)

Eric Chen — Mon, 08 Jun 2026 06:39:19 GMT

Part Number: CDCI6214

Hi everyone,

We are trying to use the CDCI6214 to multiply a 10MHz OCXO output to 100MHz for our FPGA.

Hardware Setup:

Pin 1: 10MHz square wave from the OCXO.
Pin 2: 12pF 50V capacitor to GND.
Pin 3: 3.3V supply.
Pin 4: Pulled to GND via a 4.7k resistor.
Pins 5 & 6: Left floating.
Pin 8: Connected to a reset IC.
Pins 12 & 19: Connected to the host I2C bus.

(I've attached our current schematic for reference.)

Issues Encountered: We found that the reset IC wasn't working properly, and Pin 11 doesn't support single-ended output. To work around the reset issue, we removed the reset IC and manually pulled Pin 8 low during power-up to satisfy the chip's power-up timing requirements.

After doing this, we can successfully read and write configurations via I2C from the host.

Current Goal & Configuration: We want to use the simplest possible configuration just to get the chip working and verify the signal path from input to output before moving on to further debugging. Our current register configuration is:

Addr Op Value
0x01 write 0x6A22
0x1A write 0x0B01
0x1B write 0x0001
0x1D write 0x4032
0x05 write 0x0000
0x00 write 0x0004
wait 1 second
0x07 read -> 0x0C10

We’ve tried several other configuration combinations, but whenever we read Register 0x07, the result is always 0x0C10.

Could anyone provide some advice or suggestions on how to troubleshoot and resolve this issue?

Thanks in advance!

RE: CDCI6214: CDCI6214: Issue with 10MHz to 100MHz frequency multiplication (Reg 0x07 always reads 0x0C10)

Alice — Mon, 15 Jun 2026 01:34:03 GMT

Hello,

Please notice that CDCI6214 is NOT RECOMMENDED FOR NEW DESIGNS and it is recommended to switch to CDCE6214.

We suggest you use https://www.ti.com/tool/TICSPRO-SW to help configure the chip.

RE: LMK1C1102: 输入一个正弦波信号是否会恶化抖动

FRANK1 — Fri, 12 Jun 2026 04:29:39 GMT

会恶化输出信号。

clock buffer，它需要输入信号快速的通过判断阈值，才能精准输出。如果压摆率低，它会在阈值区间停留多长，任何微小的噪声，都会造成输出边沿抖动。

RE: LMK1C1102: 输入一个正弦波信号是否会恶化抖动

FRANK1 — Fri, 12 Jun 2026 03:49:21 GMT

感谢您对TI产品的关注！
关于你的咨询，我们正在确认您的问题，感谢您的耐心等待。

RE: CDCI6214: CDCI6214: Issue with 10MHz to 100MHz frequency multiplication (Reg 0x07 always reads 0x0C10)

Eric Chen — Thu, 11 Jun 2026 09:19:57 GMT

Addr Op Value
0x01 write 0x6A22
0x1A write 0x0B01, which means bit 15 of the INPUT0 register is 0.
0x1B write 0x0001
0x1D write 0x4032
0x05 write 0x0000
0x00 write 0x0004

Above is current register config, but register 07h is now 0x0C10, which bit0(lock_det) means frequency unlocked.

Please provide some advice or suggestions on how to troubleshoot. Thanks.

RE: CDCI6214: CDCI6214: Issue with 10MHz to 100MHz frequency multiplication (Reg 0x07 always reads 0x0C10)

Alice — Thu, 11 Jun 2026 09:09:22 GMT

Hello,

Sorry for my misunderstanding.

When using an LVCMOS crystal input on the CDCI6214, only the XOUT/FB_P pin is used and the FB_N pin can be left floating.

Also, note that bit 15 of the INPUT0 register will need to be set to 0 to enable LVCMOS inputs.

RE: CDCI6214: CDCI6214: Issue with 10MHz to 100MHz frequency multiplication (Reg 0x07 always reads 0x0C10)

Eric Chen — Thu, 11 Jun 2026 08:55:36 GMT

Hello,

Thank you for your reply.

The single-ended input clock is designed according to the diagram shown in the user manual, as illustrated below.

Meanwhile, some replies in this forum also suggest that this design is feasible.

Could you please double-check and confirm if single-ended input clock is indeed unsupported?

RE: CDCI6214: CDCI6214: Issue with 10MHz to 100MHz frequency multiplication (Reg 0x07 always reads 0x0C10)

Alice — Thu, 11 Jun 2026 06:36:42 GMT

Hello,

There is Evaluation board page, and schematic is shared in EVM user guide.
It seems single ended input clock is not supported, do you monitor clock input between pin 1 & pin 2?
www.ti.com/.../CDCI6214EVM

I recommend you use TICSPRO-SW to get your configuration.

RE: CDCI6214: CDCI6214: Issue with 10MHz to 100MHz frequency multiplication (Reg 0x07 always reads 0x0C10)

Eric Chen — Wed, 10 Jun 2026 02:47:05 GMT

Hi, how is the verification going?

RE: CDCI6214: CDCI6214: Issue with 10MHz to 100MHz frequency multiplication (Reg 0x07 always reads 0x0C10)

Vivian Gao — Mon, 08 Jun 2026 06:50:55 GMT

Thank you for your attention to TI products. We are verifying your issue, please wait for our reply.

RE: LMX2594: LMX2594 Gets Damaged Upon Power-Up

Daniel — Fri, 05 Jun 2026 00:33:00 GMT

您好

感谢您的说明，请您优先检查焊接以及电路layout的电源部分是否存在短路以及焊接粘连问题。

LMX2594: LMX2594 Gets Damaged Upon Power-Up

zhiwei liu — Thu, 04 Jun 2026 14:33:58 GMT

Part Number: LMX2594

Dear TI Support Team,

I am currently using the LMX2594 in a frequency multiplication application and have encountered a critical issue. The device gets damaged immediately upon power-up, before any register configuration is performed.

The following measurements have been taken:

VCC measurement: During power-up, the VCC voltage cannot reach the nominal 3.3V, measuring only approximately 2.6V.
Supply current: With a 5V input, the combined current drawn by the OCXO and the LMX2594 is only 700mA, which remains below the LDO’s maximum rating.
Internal LDOs: The measured voltages on various internal LDOs are incorrect compared to the expected values.

At this stage, no SPI commands have been sent to the device, and yet the LMX2594 appears to be damaged. Given these observations, I would appreciate your guidance on the following:

Could the insufficient VCC voltage during power-up be responsible for damaging the device?
Are there any known startup timing or inrush current characteristics that could explain the observed behavior?
What are the most likely design issues that could cause such a failure, particularly regarding power supply decoupling, layout, or the connection between the OCXO and the LMX2594?
Do you have any specific recommendations for debugging the internal LDOs to identify the root cause?

I have attached the relevant section of my schematic for your reference. Please let me know if additional information or measurements would be helpful for the analysis.

Thank you very much for your time and assistance.

Best regards

RE: LMX2594: LMX2594 Gets Damaged Upon Power-Up

Eirwen — Thu, 04 Jun 2026 22:51:19 GMT

Hello, we have received your case and the investigation will take some time. Thank you for your patience.

RE: LMX2694-EP: 回读寄存器无法切换

Alice — Tue, 02 Jun 2026 06:21:47 GMT

您好，

对于SPI通讯，只有通过回读正确才能确认写入是正确的。

上电成功后，所有寄存器都有默认值(R0默认值0x200C)，请问可以正确回读吗？

根据数据手册7.5.1 Recommended Initial Power-Up Sequence，上电后是否有等待时间，确认FCAL_EN = 1。

LMX2694-EP: 回读寄存器无法切换

Hui Cao22 — Wed, 27 May 2026 12:42:50 GMT

Part Number: LMX2694-EP

我需要回读寄存器，我是手动单个寄存器读写测试，可以确认写入是没有问题的（例如复位，都是没问题的），然后我将寄存器R0的bit2置为1'b0（即muxout改为回读,写入00_2008），随后再写入80_0000（回读寄存器0），发现muxout还是为锁定指示（常1'b1），像是没切换过去，请问一下是需要其他额外寄存器写入吗？

LMK04832EVM: 如何产生几百k到几十M的方波时钟信号

T yh — Tue, 26 May 2026 08:00:39 GMT

Part Number: LMK04832EVM

根据手册提供的说明，LMK04832EVM开发板默认加载122.88MHz时钟，但我想产生几百k到几十M的方波时钟信号。我对TICSPro工具使用不太清楚，调整一些参数后，它产生的总是带小数点的信号，例如1474.45MHz。
我想请问该如何配置，使用一个外部输入的时钟，然后分频产生多路整数的，几百k到几十MHZ的方波？
SetModes、CLKinX Control、PLL1and2、Clock Outputs等位置该如何设置
另外可否转告贵司中国的技术支持团队联系方式？