• State TI Thinks Resolved
  • Locked Locked
  • Replies 16 replies
  • Answers 2 answers
  • Subscribers 62 subscribers
  • Views 579 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMZ13610: LMZ13610

Shafeeq Muhammed
Expert 1170 points
Part Number: LMZ13610
Other Parts Discussed in Thread: LMZ13608,

Hi,

We are using LMZ13610 in our board.I want to know what is the minimum input required to get 5V/3A output for both LMZ13610 and LMZ13608.
And i have observed that while input voltage is around 7V, the regulator will start to make some audible noise and it stops working.
Can you please suggest what will be the reason for this?

Regards,
Shafeeq

  • 0
    TI__Guru 50120 points

    Hi Shafeeq,

    Based on the user guide for the LMZ13610/8, I would expect the following "minimum input voltage of 7V required for 5V output". To fully evaluate the power module, I would recommend getting a LMZ13610EVM and test for your use case condition (VIN, VOUT, ambient tempt, etc.). This way you can have a direct comparison between the EVM and your board to understand the operational functionality of the part. I don't expect the EVM to have regulation issue for a 7VIN/5VOUT/3A condition. 

    Can you also provide me the schematic and a waveform of your switch node? The switch node can be measured indirectly by hovering your scope probe right above the part. How many of your boards exhibit this audible noise and regulation issue? Perhaps there may have been some EOS damage on the part that could have impacted the device's performance. 

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    Expert 1170 points

    Dear Jimmy,

    Thanks for your reply.
    I have tested 4 boards with 7V, And all 4 boards show the same behaviour.
    I have attached the schematic and waveform with this.

    Regards,
    Shafeeq

  • 0 in reply to Shafeeq Muhammed
    TI__Guru 50120 points

    Hi Shafeeq,

    I have ordered the LMZ13610EVM and am waiting to have it shipped to me. I will share the results once I receive the board and evaluate the EVM with your application conditions.

    In the meantime, can you try sweeping the input voltage by 100mV to see when the part starts to regulate? For a 5V/3A application I would expect the input voltage to start regulating somewhere between 7 and 9V input. Also make sure to have your input cables optimized and shorted to reduce voltage drop across the inductance of the input leads. 

    Regards,
    Jimmy  

  • 0 in reply to Jimmy Hua
    TI__Guru 50120 points

    Hi Shafeeq,

    I am still waiting to receive the EVM that should be coming in the later half of this week. Did you get a chance to do the dropout test I suggested? This way you can see when the device will start operating as you increase your input supply. 

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    Expert 1170 points

    Hi Jimmy,

    When the input voltage reaches 7V, the regulator starts to make noise. With more than 7V input, it works fine.

    Regards,
    Shafeeq

  • 0 in reply to Shafeeq Muhammed
    TI__Guru 50120 points

    Hi Shafeeq,

    When the regulator's input voltage is above 7V does the noise go away? I am still waiting for the EVM but am curious to check if the 7Vin/5Vout @ 3A is conditional stable or not. Noise coming from the regulator would indicate some instability issue. 

    Regards,
    Jimmy

  • 0 in reply to Jimmy Hua
    TI__Guru 50120 points

    Hi Shafeeq,

    Attached is a text file format of an automated efficiency test I did using the LMZ13610EVM set for 5V output. 

    5Vout_results.txt 
    Vin	Iin	Pin	Vout	Iout	Pout	Iout	Eff	Iout	Diss
 7.00	-----	10/23/2019	15:34	-----	-----	-----	 7.00	-----	 7.00	-----
7.1140385	0.0955927	0.6800503	4.9654564	0.1000806	0.4969456	0.1000806	73.0748305	0.1000806	0.1831047
7.0020103	0.1682459	1.1780596	4.9654767	0.2002001	0.9940891	0.2002001	84.3836029	0.2002001	0.1839705
6.9999117	0.2398970	1.6792580	4.9655021	0.3003905	1.4915895	0.3003905	88.8243229	0.3003905	0.1876684
6.9996484	0.3120677	2.1843640	4.9655059	0.4005702	1.9890335	0.4005702	91.0577872	0.4005702	0.1953305
6.9995686	0.3841137	2.6886301	4.9655453	0.4999900	2.4827228	0.4999900	92.3415549	0.4999900	0.2059073
6.9991394	0.5674527	3.9716807	4.9655262	0.7507859	3.7280473	0.7507859	93.8657346	0.7507859	0.2436334
6.9990782	0.6781186	4.7462053	4.9655250	0.9012683	4.4752703	0.9012683	94.2915453	0.9012683	0.2709350
6.9998580	0.7518237	5.2626592	4.9655250	1.0016185	4.9735617	1.0016185	94.5066268	1.0016185	0.2890975
6.9995948	0.9356597	6.5492389	4.9655936	1.2524642	6.2192282	1.2524642	94.9610833	1.2524642	0.3300107
6.9992941	1.1202797	7.8411671	4.9655859	1.5031702	7.4641208	1.5031702	95.1914512	1.5031702	0.3770463
6.9989497	1.3055547	9.1375117	4.9655580	1.7539938	8.7095579	1.7539938	95.3165178	1.7539938	0.4279537
6.9986266	1.4914388	10.4380233	4.9655669	2.0046596	9.9542714	2.0046596	95.3654836	2.0046596	0.4837519
6.9982947	1.6780967	11.7438152	4.9655605	2.2553930	11.1992904	2.2553930	95.3633054	2.2553930	0.5445248
6.9979503	1.8652340	13.0528148	4.9656012	2.5058552	12.4430776	2.5058552	95.3286916	2.5058552	0.6097372
6.9976946	2.0529457	14.3658870	4.9656317	2.7564108	13.6873208	2.7564108	95.2765451	2.7564108	0.6785662
6.9973153	2.2412875	15.6829953	4.9656444	3.0069473	14.9314310	3.0069473	95.2077758	3.0069473	0.7515643
 7.50	-----	10/23/2019	15:35	-----	-----	-----	 7.50	-----	 7.50	-----
7.5001719	0.0956892	0.7176856	4.9658197	0.1000745	0.4969519	0.1000745	69.2436806	0.1000745	0.2207337
7.4999149	0.1624905	1.2186647	4.9657638	0.2001832	0.9940625	0.2001832	81.5698108	0.2001832	0.2246022
7.4998138	0.2293557	1.7201247	4.9657359	0.3003747	1.4915812	0.3003747	86.7135502	0.3003747	0.2285435
7.4997202	0.2964587	2.2233573	4.9657791	0.4005589	1.9890869	0.4005589	89.4632124	0.4005589	0.2342704
7.4995031	0.3632600	2.7242696	4.9657664	0.4999834	2.4828010	0.4999834	91.1363910	0.4999834	0.2414686
7.4992786	0.5340162	4.0047360	4.9657105	0.7507856	3.7281837	0.7507856	93.0943706	0.7507856	0.2765522
7.4990577	0.6373250	4.7793369	4.9657003	0.9013529	4.4758482	0.9013529	93.6499830	0.9013529	0.3034887
7.4989741	0.7063955	5.2972413	4.9657003	1.0016230	4.9737596	1.0016230	93.8933945	1.0016230	0.3234816
7.4986996	0.8784502	6.5872342	4.9656876	1.2524166	6.2191096	1.2524166	94.4115444	1.2524166	0.3681247
7.4983740	1.0506522	7.8781831	4.9656800	1.5032266	7.4645423	1.5032266	94.7495397	1.5032266	0.4136409
7.4980733	1.2235860	9.1745375	4.9656825	1.7540039	8.7098265	1.7540039	94.9347742	1.7540039	0.4647110
7.4977040	1.3970877	10.4749500	4.9656190	2.0045919	9.9540396	2.0045919	95.0270845	2.0045919	0.5209104
7.4974956	1.5712678	11.7805734	4.9656419	2.2552889	11.1989571	2.2552889	95.0629198	2.2552889	0.5816164
7.4970864	1.7457008	13.0876697	4.9656419	2.5058126	12.4429680	2.5058126	95.0739765	2.5058126	0.6447017
7.4968468	1.9209555	14.4011091	4.9656571	2.7564347	13.6875095	2.7564347	95.0448292	2.7564347	0.7135996
7.4965336	2.0966277	15.7174400	4.9656851	3.0069310	14.9314725	3.0069310	94.9993922	3.0069310	0.7859675
 8.00	-----	10/23/2019	15:36	-----	-----	-----	 8.00	-----	 8.00	-----
8.0007702	0.0947652	0.7581946	4.9659265	0.1000749	0.4969647	0.1000749	65.5457985	0.1000749	0.2612299
8.0006654	0.1574387	1.2596141	4.9658947	0.2001833	0.9940893	0.2001833	78.9201488	0.2001833	0.2655248
8.0005095	0.2201347	1.7611900	4.9658363	0.3003733	1.4916045	0.3003733	84.6929939	0.3003733	0.2695855
8.0002961	0.2829025	2.2633036	4.9658629	0.4005515	1.9890837	0.4005515	87.8840858	0.4005515	0.2742199
8.0002512	0.3453847	2.7631640	4.9658883	0.5000548	2.4832164	0.5000548	89.8685860	0.5000548	0.2799476
7.9999143	0.5049730	4.0397405	4.9658172	0.7507187	3.7279318	0.7507187	92.2814670	0.7507187	0.3118087
7.9998158	0.6016162	4.8128189	4.9657346	0.9013153	4.4756928	0.9013153	92.9952466	0.9013153	0.3371261
7.9995887	0.6662945	5.3300819	4.9657283	1.0015805	4.9735766	1.0015805	93.3114491	1.0015805	0.3565052
7.9993304	0.8282833	6.6257121	4.9656825	1.2524053	6.2190471	1.2524053	93.8623198	1.2524053	0.4066650
7.9990297	0.9897655	7.9171633	4.9656647	1.5031288	7.4640336	1.5031288	94.2766156	1.5031288	0.4531297
7.9987577	1.1520057	9.2146145	4.9656635	1.7540289	8.7099173	1.7540289	94.5228617	1.7540289	0.5046972
7.9986030	1.3145485	10.5145516	4.9656444	2.0046270	9.9542648	2.0046270	94.6713206	2.0046270	0.5602867
7.9982062	1.4778205	11.8199131	4.9656546	2.2553090	11.1990855	2.2553090	94.7476130	2.2553090	0.6208276
7.9978806	1.6413751	13.1275221	4.9656622	2.5058740	12.4433238	2.5058740	94.7880623	2.5058740	0.6841983
7.9977421	1.8056240	14.4409151	4.9656774	2.7564359	13.6875715	2.7564359	94.7832695	2.7564359	0.7533436
7.9973616	1.9701769	15.7562171	4.9657028	3.0069435	14.9315878	3.0069435	94.7663242	3.0069435	0.8246293

    When I ran the automated test I did not hear any audible noise from the regulator. Also at 7VIN the output voltage was well with no oscillation. If you can, please provide your PCB layout so I can review the layout and surrounding circuit that could impact the performance of the LMZ13610 power module. As far as EVM testing, the EVM was able to operate at 7V input for a 5V output at 3A loading.

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    TI__Guru 50120 points

    Hi Shafeeq,

    Can you get an EVM on your end and test for operation? From my testing results shown in my previous message, I was not able to recreate the failure mode that you are describing. Perhaps it is a PCB layout issue which I would suggest you post so I can help review.

    Regards,
    Jimmy

  • 0 in reply to Jimmy Hua
    TI__Guru 50120 points

    Hi Shafeeq,

    Did you get a chance to obtain an EVM to test operation and confirm operation with your application? Also, can you provide the PCB layout so I can help review for any potential issues? 

    From my end, I have no way of recreating your failure mode.

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    Expert 1170 points

    Dear Jimmy,

    I can't send the layout file in the forum.
    Is there any way to send the file to you directly?

    Regards,
    Shafeeq

  • 0 in reply to Shafeeq Muhammed
    TI__Guru 50120 points

    Hi Shafeeq,

    You can send your PCB layout files directly to me at j-hua@ti.com

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    Expert 1170 points

    Dear Jimmy,

    I have shared the layout file through the mail.

    Regards,
    Shafeeq

  • 0 in reply to Shafeeq Muhammed
    TI__Guru 50120 points

    Hi Shafeeq,

    I have received your PCB layout through direct email and will be in the process of reviewing it. I hope to provide you with a detailed review sometime this week. 

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    TI__Guru 50120 points

    Hi Shafeeq,

    I've reviewed your PCB layout. Below are my comments:

    • Analog circuit is connected to AGND first before PGND which to help provide noise immunity (√)
    • Input caps placed close to input pin to reduce high di/dt loop to minimize EMI  (√)
    • EN should be routed through middle or bottom layer like Figure 54 of datasheet to have a larger AGND connection for more noise immunity. This is a good to have but should not impact operation of the part. 
    • Overall the PCB layout looks similar to the layout example in the datasheet.

    A few additional questions I have:

    1. Can you provide a waveform of VCC_SYS (from circuit above the LMZ13610), VIN (from LMZ13610 input cap) and VOUT for 7VIN / 5VOUT at 3A condition? I see the VCC_SYS goes through multiple layers from TOP>Sig1>Bottom>Top and want to see if there are any voltage drops. 
    2. Can you add another ceramic 22uF on the input and a ceramic 47uF on the output and retest operation? This is to replicate a similar BOM as used on the EVM. The EVM works fine and the part regulates the output at 5V for the different VIN supply voltage sweeps (7V, 7.5V, and 8V) based on the efficiency graph that I've attached in my previous reply. 

    Regards,

    Jimmy 

  • 0 in reply to Jimmy Hua
    TI__Guru 50120 points

    Hi Shafeeq,

    Can you give me an update on the two questions I have? As for the layout, I don't think there should be an issue since you have local input capacitors close to the input pin to keep the high di/dt loop small. As stated before, the test results on the EVM showed regulation at 7Vin/5Vout at 3A should not be a problem. 

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    TI__Guru 50120 points

    Hi Shafeeq,

    I have not heard back from you for some time. If you have any more questions regarding this please respond back on this thread. The thread will automatically close if left inactive for too long. 

    Also attached is my direct email contact if you want to follow up on this (j-hua@ti.com)

    Regards,

    Jimmy