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AD8218 spice model is messed up.

What does the real device do when connected as you simulated?

Also, unspecified on the data sheet, what happens if ENB is tied to GND, but REF has 2.5V tied to it? ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson
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Another amusement, node ENB only exists in the node list of the subcircuit declaration, but not within the subcircuit netlist, except inside an "IF" statement... strange! ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

e model and data sheet are here

rcuit in Figure 34. I tied Vs and ENB to +IN because Ltspice doesn't like t hose pins floating. I set the shunt resistor to 0.02 ohms, the battery volt age to 24V, the reference to 1.25v and vary the Load from -5Amps to 5Amps i n 0.05amp increments. My results show the part offsetting by twice the refe rence voltage instead of the reference voltage. I can reproduce the graph w ith the 1.25V reference but the datasheet shows a 2.5v reference. Here is t he spice netlist.

I received a reply from Analog Devices

"I think we can acknowledge the error in the model. I will have the enginee r that created the model fix the error and have the corrected version up on the web within the week."

Reply to
wanderer

Congratulations on your success! I E-mailed the manager of that department and he ignored me... probably because I harass AD constantly about the poor quality of their models ;-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

You'll note they didn't say within which week?

--
Anyone wanting to run for any political office in the US should have to 
have a DD214, and a honorable discharge.
Reply to
Michael A. Terrell

Looks like "within the week" really means the same as RSN >:-} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

[snip]

Or, now, "within the two weeks" ;-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

[snip]

Seems clear that ADI is not going to produce a revised Spice model as promised.

So... does anyone have an AD8218 device at hand and could make a few measurements? Not covered or vaguely defined in the data sheet...

(1) What is the potential of Vs (pin 2) when no external supply is attached? (+IN & -IN both at +5V)

(2) What is the potential on ENB (pin 3) when floating?

(3) What is the potential on REF (pin 7) when ENB is grounded and no external reference is applied?

(4) What is the potential on REF (pin 7) when ENB is floating and no external reference is applied?

(5) What potential is on OUT (pin 5) when ENB is grounded _and_ REF (pin 7) has 2.5V applied? (+IN & -IN both at +5V)

If I can get the above information I'll write my own model... many fewer lines than the 157 lines of the ADI-provided model >:-} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Did you send an email to Alex Bordodynov?

Reply to
RobertMacy

My first cut at it... with no part in hand, and one of the most useless data sheets I've seen in years...

From: Jim Thompson Newsgroups: alt.binaries.schematics.electronic Subject: AD8218 Subcircuit - AD8218_JT.lib Date: Sun, 18 Aug 2013 14:30:26 -0700 Message-ID:

If there's further interest I'll get a part, take some measurements myself and refine all the details.

(My lab is currently boxed up while the new house is being built. When it's finished I'll have a complete shop ;-)

This is just a self-amusement to demonstrate that I can write better models than those... >:-}

Please report any bugs or incongruities with your brand of Spice simulator. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

My first cut at it... with no part in hand, and one of the most useless data sheets I've seen in years...

From: Jim Thompson Newsgroups: alt.binaries.schematics.electronic Subject: AD8218 Subcircuit - AD8218_JT.lib Date: Sun, 18 Aug 2013 14:30:26 -0700 Message-ID:

If there's further interest I'll get a part, take some measurements myself and refine all the details.

(My lab is currently boxed up while the new house is being built. When it's finished I'll have a complete shop ;-)

This is just a self-amusement to demonstrate that I can write better models than those... >:-}

Please report any bugs or incongruities with your brand of Spice simulator. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

My first cut at it... with no part in hand, and one of the most useless data sheets I've seen in years...

From: Jim Thompson Newsgroups: alt.binaries.schematics.electronic Subject: AD8218 Subcircuit - AD8218_JT.lib Date: Sun, 18 Aug 2013 14:30:26 -0700 Message-ID:

If there's further interest I'll get a part, take some measurements myself and refine all the details.

(My lab is currently boxed up while the new house is being built. When it's finished I'll have a complete shop ;-)

This is just a self-amusement to demonstrate that I can write better models than those... >:-}

Please report any bugs or incongruities with your brand of Spice simulator. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

e model and data sheet are here

rcuit in Figure 34. I tied Vs and ENB to +IN because Ltspice doesn't like t hose pins floating. I set the shunt resistor to 0.02 ohms, the battery volt age to 24V, the reference to 1.25v and vary the Load from -5Amps to 5Amps i n 0.05amp increments. My results show the part offsetting by twice the refe rence voltage instead of the reference voltage. I can reproduce the graph w ith the 1.25V reference but the datasheet shows a 2.5v reference. Here is t he spice netlist.

I received the new AD8218.cir file. I haven't tried it yet. It should be on the ADI website within the next week or so.

  • AD8218 SPICE Macro-model
  • Description: Current Shunt Monitor, high side current sensing
  • Generic Desc: 4.0V to 80V operation, 8S6DPTMRNJIX
  • Developed by: DK
  • Revision History:
  • 1.0 (9/2012) - DK - initial release
  • 2.0 (8/2013) - PB - modified gain of voltages on VREF to output from 2x t o 1x

  • Copyright 2012 by Analog Devices, Inc.

*
  • Refer to
    formatting link
  • for License Statement. Use of this model indicates your acceptance
  • of the terms and provisions in the License Statement.
* *
  • Not Modeled:
  • Temperature effects
  • PSRR vs Frequency
*
  • Parameters modeled include:
  • CMRR vs Frequency
  • VOS (RTI)
  • Bandwidth
  • Gain Error
  • Voltage Spectral Noise: 110nV/rt hz at 1kHz
  • Output Impedance: 2 ohms
  • Slew Rate
  • Common Mode Range: 4.0V to 80V
*
  • END Notes
  • Maximum output voltage limited to 5.2V
*
  • Node Assignments
  • noninverting input
* | inverting input * | | Vs
  • | | | ref
  • | | | | enable
  • | | | | | ground
  • | | | | | | output .SUBCKT AD8218 +IN -IN VS REF ENB GND OUT

*** Input Stage *** EV 99 0 Value={ IF( V(VS) 5.5, V(+IN), V(VS) )) } Q1 3 1 7. 0 NPN Q2 4 2 8 0 NPN R1 99 3 1129 R2 99 4 1129 R3 7. 9 1e3 R4 8 9 1e3 I1 9 GND 400E-6 Ibp +IN GND 124E-6 Ibn -IN GND 124E-6

*** Input and Feedback Resistors *** EOS 5 1 poly(1) (201,GND) 0 -1 R9 5 +IN 75e3 R10 REF 5 1.5e6 R11 -IN 2 75.045e3 R12 20 2 1.5e6

*** 1st Stage *** D1 100 6 DZENER2 G1 100 10 1 2 .001 D2 10 6 DZENER1 R8 10 100 200e3

*** 2nd Stage *** G2 100 20 10 100 .005 R7 20 100 1E6 C1 20 100 11.68E-9

*** Internal Reference *** E1 100 0 7 0 1 R5 99 7 100e3 R6 7 GND 100e3

**** zero-pole stage *G4 100 30 20 100 .59e-6 G4 100 30 20 100 .588e-6 R14 30 35 1e6 R16 35 100 1.7e6 L1 30 35 .65

**** 1st pole stage G3 100 40 30 100 1e-6 R13 40 100 1E6 C2 40 100 186e-15

**** 2nd pole stage G5 100 45 40 100 1e-6 R15 45 100 1E6 C3 45 100 186e-15 *C3 45 100 1e-15

*** Spectral Noise *** VN GND 190 .65 DN 190 200 DNOISE RN 200 GND 1 VM GND 200 0 FN GND 201 VM 1 RZ 201 GND 1

*** CMRR *** *GCMR 500 0 505 0 .3e-9 *RCMR 500 501 1e6 *LCMR 501 0 80

GCMR 500 0 505 0 .3e-9 RCM1 500 501 549e6 LCMR 500 501 80 RCM2 501 0 1e6

GCM2 600 0 500 0 .85e-6 RCM3 600 0 1e6 CCM2 600 0 655e-15

RCMR1 +IN 505 10e6 RCMR2 505 -IN 10e6

*** Clamp *D3 11 20 Dlow D3 11 20 D V7 11 0 0 D4 20 12 D V8 +IN 12 .722

*** Output Stage *** EAVG AVG GND Value={ ((V(+IN) + V(-IN))*0.5 )} E02 65 0 Value={ IF( V(AVG) > 80, 5.2 , IF( V(AVG) < 4.0, 0, V(45))) } E03 70 0 Value={ IF( V(ENB) == 0, V(65) + V(600) + .08, IF( V(ENB) ! = 0, V(65) + V(600), V(65) + V(600) )) } E04 75 0 Value={ IF( V(70) > 5.2, 5.2 , IF( V(70) < 5.2, V(70)-.00491, V(

70) )) }

*** Output Resistance

*Rout 70 OUT 2 Rout 75 OUT 2 *** Output Current limiting Et 71 0 70 OUT 20 Qc 45 71 72 0 NPN Re 72 0 10

.model D D

*.model Dlow D(Rdon=0 Rdoff=1e6 Vfwd=0.7) *.model Dlow D(Ron=0 Roff=1e6 Vf=0.7) .MODEL DZENER1 D(BV=2V, IS=1E-14, IBV=1E-3) .MODEL DZENER2 D(BV=2V, IS=1E-14, IBV=1E-3) .MODEL DNOISE D(AF=0, KF=0.0195e-10.5) .model DILIM D(IS=1E-15) .model NPN NPN

.end

Reply to
wanderer

A quick play with LTspice shows it works. I've not dug deep, yet, but, at least the offset pin works like it should (and didn't with AD's model).

More later, when I've had a proper look.

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)
Reply to
Fred Abse

I'll compare it to mine, and refine mine as necessary... assuming that the ADI version matches reality >:-}

Mine has dramatically fewer lines. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Great! My plan, at retirement, has been to do both, write a book and make a business out of developing Spice models.

Now that ADI has provided a correction I'll A-B test mine against theirs. My main guessing points were input bias current and what floated nodes looked like. (I suspect they didn't address that properly ;-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Bwahahahahahaha!

ADI Model Produces Output Above Rail and Below Ground and the Wrong Value at I=0. See....

Newsgroups: alt.binaries.schematics.electronic Subject: AD8218_HighSideSense: ADI Model Produces Output Above Rail and Below Ground - AD8218_HighSideSense-ADI_Model_Produces_Output_Above_Rail_and_Below_Ground.pdf Date: Tue, 20 Aug 2013 16:40:51 -0700 Message-ID:

Makes you wonder if ADI model makers check their work :-( ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

No, they didn't. I had to add a couple of 1T resistors to their subckt, to allow floating VS and ENB, to clear Spice warnings..

Your model shows more overshoot, and ringing, on 10mV pulse input, than the ADI model.

I don't think much of the pulse generator it seems they used to measure rise time (datasheet fig.11, green trace). >100ns rise? Yecch!

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)
Reply to
Fred Abse

Better than the previous one.

Needs ".ends", not ".end"

Add to input stage:

*Allow VS and ENB to be floated Rvsfloat VS GND 1T Renbfloat ENB GND 1T

Gain error versus tempearture is stairstepped.

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)
Reply to
Fred Abse

I used my "NoFloat" and "NoFloat2Connections" parts in my subcircuit development ;-)

Yep, I just winged the AC response from the data sheet. I haven't gotten around to A-B testing yet.

I don't know. In a buck switcher, for example, the current isn't going to change rapidly. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

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