Linear Technology DC2197A Demo Manual

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Page 1

Description

DEMO MANUAL DC2197A

Quad 12-/10-/8-Bit

PWM to VOUT DACs

with 10ppm/°C Reference

Demonstration circuit 2197A features the LT C®2645, Quad 12-/10-/8-Bit PWM to VOUT DACs with 10ppm/°C reference in a tiny 4.9mm × 4mm 16-lead MSOP package. DC2197A-A is populated with the 2.5V, 12-bit version of the LTC2645.

The LTC2645 measures the period and pulse width of the Pulse Width Modulation (PWM) input and updates the volt age output DAC at each rising edge. The PW

M frequency

can be any frequency between 30Hz and 100kHz. The input

BoarD photo

OPTIONAL LOGIC

SUPPLY CONNECTION

1.71V TO 5.5V (SEE TEXT)

level can be between 1.71V and 5.5V, set by a separate IOVCC pin. This device solves many of the problems associated with

filtering a PWM signal to produce an analog voltage, producing a fast-settling, accurate analog voltage in response to a digital PWM input.

Design files for this circuit board are available at

http://www.linear.com/demo

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.

PWM

INPUTS

IOVCC

VCC CONNECTION

2.7V TO 5.5V (SEE TEXT)

POWER-DOWN, REFERENCE

CONNECTIONS (SEE TEXT)

Figure 1. Basic Connections

ANALOG OUTPUTS

HEADERS ON REVERSE SIDE ARE FOR OPERATION WITH A LINDUINO BOARD. (SEE TEXT)

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DEMO MANUAL DC2197A

Quick start proceDure

Standalone Operation

DC2197A makes evaluation of the LTC2645 very easy. Figure 1 shows the basic connections to operate the DC2197A as a standalone board. Connect a 2.7V to

5.5V supply to the VCC turret and a GND turret. IOVCC is connected to VCC by default such that the input logic level matches the VCC supply. If a different logic level is required, move the IOVCC jumper to the EXT position and connect a supply equal to the PWM signals’ logic level to the IOVCC and GND turrets. There is no sequencing requirement between VCC and IOVCC.

Any convenient PWM source can be used. A pulse genera tor with a computer interface (GPIP, USB, Ethernet, etc.) can be used for characterization. In the end application, signals can originate from an FPGA, microcontroller, programmable logic controller (PLC), optocoupler, etc.

Linduino Operation

DC2197A is in an “Arduino Shield” form factor, compat ible with other convenient way to evaluate the LTC2645 under computer control. The Linduino board has two PWM outputs with 16-bit resolution and four with 8-bit resolution. INA and INB are connected digital pins 9 and 10, INC and IND are connected to 8-bit PWM capable outputs on digital pins 5 and 6; these can be remapped by removing R8 – R11 and making appro priate connections (“sketch”) provides a simple terminal interface allowing voltages or codes to be entered manually. It can also be controlled by any programming language that can com municate with C change or add functionality.

Install the DC2197A onto the DC2026 as shown in Figure 2. Ensure that the IOVCC jumper is set to VCC.

Linear Technology’s DC2026 Linduino board and

Arduino Uno compatible boards. This provides a

to 16-bit PWM

to TPA – TPD. The Linduino program

, C#, etc.) The program can be modified as desired to

a USB virtual COM port (Matlab, Python,

capable outputs on

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Quick start proceDure

DEMO MANUAL DC2197A

LINE UP AND INSERT CONNECTORS

ANALOG OUTPUTS

USB

CONNECTION

TO COMPUTER

Figure 2. Linduino Connections

Follow the procedure for installing drivers and sketchbook in the DC2026 Demo Manual. Upload the DC2197 program (“sketch”). Select:

File → Sketchbook → Part Number → 2000 → 2600 →2645 → DC2197

Then click the “Upload” button. Open the Serial Monitor to interact with the program.

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DEMO MANUAL DC2197A

Quick start proceDure

Altera C5G Board Operation

Altera’s C5G evaluation board for the Cyclone 5 GX FPGA has an Arduino shield port that is compatible with the DC2197A. The C5G provides 5V to the LTC2645’s VCC supply, so IOVCC must be changed to 3.3V to match the voltage of the digital signals coming from the FPGA. Remove the IOVCC jumper and solder a 100Ω resistor from the IOVCC turret post to the test point indicated in Figure 3. Make sure gaps between connectors in the up per and lower rows line up properly. The upper row (JP3 and JP4 on the C5G board) will match perfectly; JP10 will

REMOVE JUMPER

have two empty holes on the left-hand side and JP11 will have two empty holes on the right-hand side.

A Quartus archive project and FPGA configuration bi nary file are included with the DC2197A design files. The program sends PWM signals to all four DACs. Tw o quadrature numerically controlled oscillators supply data to the PWM generator. While not normally intended for AC signal generation, this demonstration shows the cycle by

cycle updating operation of the LTC2645. Figure 4 shows all four DAC outputs, and Figure 5 shows

the details of

the relationship between the PWM input and DAC output.

2 EMPTY LOCATIONS

IOVCC TO PIN 2

Figure 3. Altera C5G Connections

2 EMPTY LOCATIONS

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Quick start proceDure

DEMO MANUAL DC2197A

Figure 4. Altera Program Operation

Figure 5. PWM Details

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DEMO MANUAL DC2197A

Quick start proceDure

EXTERNAL CONNECTIONS

GND: Four ground turrets are provided. These are con-

nected directly connection for all supplies and signals.

IOVCC: I/O supply voltage that sets the high level of the PWM inputs. Connect to digital supply voltage between

1.71 and 5.5V. Often this can be connected to the same supply as the device that is providing the PWM signal (processor, FPGA, etc.).

INA, INB, INC, IND: PWM Inputs. Logic high level is determined by IOVCC.

VOUTA, VOUTB, VOUTC, VOUTD: DAC Voltage Outputs.

VCC: Analog Supply. Connect to low noise power supply

between 2.7V and 5.5V. PD: Active Low Power-Down Input. This signal may be

driven externally if the PD jumper is removed.

REF: Reference Output/Input. When the REFSEL jumper is set to INT, the LTC2645’s internal reference can be measured at this point. Nominal impedance is 500Ω. If it is used to drive external circuits it must be buffered ap propriately. When REFSEL is set to EXT, an external reference between 1

to the ground plane and are the common

V and VCC may be connected to this point.

Arduino Shield Connections (IOL1, IOH1, AD0, POWER headers installed on back side of board) – mate with the DC2026 Linduino and other Arduino Uno compatible microcontroller boards.

JUMPERS

IOVCC: Set to VCC to connect IOVCC directly to VCC

(default). No connection to the IOVCC turret is required in this case. Set to EXT if a separate supply is connected to the IOVCC turret.

PD: Power Down – Set to ON to enable normal operation (default.) Set to PD to put the LTC2645 into shutdown mode.

IDLSEL: Idle Mode Select Input. Determines the DAC behavior when the PWM input remains high or low for more than the Idle Mode Timeout time (50ms minimum, 70ms maximum). When set to HI-Z#/HOLD (default), a low level on a PWM input will set the DAC output to a highimpedance state. A high level will cause the DAC output to hold its last value. When set to ZS#/FS, a low level on a PWM input will set the DAC output to zero-scale, and a high level will set the DAC output to full-scale.

REFSEL: Set to INT (default) to use the internal refer ence. Set REF turret post.

to EXT to supply an external reference to the

These headers

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schematic Diagram

MARK T.PRODUCTION1 02-11-16

GND

REF

VCC

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

E16

VCC

REF

10uF

6.3V

0805

VOUTA

VOUTB

VOUTC

VOUTD

DEMO MANUAL DC2197A

www.linear.com

12A

-BIT

L12

GND

SUFFIX

LTC2645-L12

NOTE: UNLESS OTHERWISE SPECIFIED

ASSY TYPE

1. ALL RESISTORS AND CAPACITORS ARE 0603.

www.linear.com

Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

TECHNOLOGY

SCHEMATIC

QUAD 12/10/8-BIT PWM TO VOUT DACS

TITLE:

KIM T.

MARK T.

APPROVALS

PCB DES.

APP ENG.

SHEET OF

DEMO CIRCUIT 2197A

LTC2645CMS FAMILY

Thursday, February 11, 2016

IC NO. REV.

N/A

SIZE

DATE:

SIZE

DATE:

SIZE

DATE:

SCALE = NONE

LTC2645

JP3

ZS#/FS

HI-Z#/HOLD

JP2

INT

EXT

JP1

EXT

VCC

REF

VCC

IDLSEL4IOVCC7INA

REFSEL

IDLSEL

REFSEL

IOVCC

0.1uF

VCC

132

IDLSEL

132

REFSEL

VCC VCC VCC

132

IOVCC

VOUTA2VOUTB

VOUTC14VOUTD

GND

CUSTOMER NOTICE

INB

0.1uF

INB

INA

E10

E14

INB

INA

GND

PD9IND10INC

NPD

IND

INC

10k

VCC

132

JP4

E11

E13

GND

E15

E12

INC

IND

TEST PADS ALLOW REMAPPING

LINDUINO CONNECTIONS

DACS A AND B CONNECTED TO 16-BIT

CAPABLE PWM LINDUINO OUTPUTS

DACS C AND D CONNECTED TO 8-BIT

CAPABLE PWM LINDUINO OUTPUTS

R11

49.9

INC

TPC

IND

TPD

INA

TPA

INB

TPB

VCC

1 2

2 3

3 4

4 5

5 6

6 7

7 8

IOL1

HD1X8-100

1 2

2 3

3 4

4 5

5 6

6 7

IOH1

HD1X8-100

7 8

LINDUINO HEADERS

IO5

R10

49.9 IO6

49.9 IO9

49.9 IO10

OPT

49.9

IO2

IO0 IO1 IO2 IO3 IO4 IO5 IO6 IO7

IO8 IO9 IO10 IO11 IO12

VCC

IO13

AREF

SCL SDA AD3 AD2 AD1 AD0

VIN

CUSTOMER NOTICE

6 5

5 4

4 3

3 2

2 1

ADO

HD1X6-100

6 5

5 4

4 3

+3V3

RESET

POWER

HD1X6-100

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL

APPLICATION. COMPONENT SUBSTITUTION AND PRINTED

CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT

PERFORMANCE OR RELIABILITY. CONTACT LINEAR

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL

APPLICATION. COMPONENT SUBSTITUTION AND PRINTED

CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT

PERFORMANCE OR RELIABILITY. CONTACT LINEAR

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL

APPLICATION. COMPONENT SUBSTITUTION AND PRINTED

CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT

PERFORMANCE OR RELIABILITY. CONTACT LINEAR

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

D D

Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

C C

B B

A A

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DEMO MANUAL DC2197A

DEMONSTRATION BOARD IMPORTANT NOTICE

Linear Technology Corporation (LT C ) provides the enclosed product(s) under the following AS IS conditions:

This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LT C for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.

If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.

The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LT C from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.).

No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,

customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.

LT C currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.

Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and

observe good laboratory practice standards. Common sense is encouraged.

This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.

Mailing Address:

Linear Technology

1630 McCarthy Blvd.

Milpitas, CA 95035

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com

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LT 0216 REV A • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 2014