DC1620A-A - LINEAR TECHNOLOGY

dc1620afb

DEMO MANUAL DC1620A

DESCRIPTION

LTC2185, LTC2184, LTC2183,

LTC2182, LTC2181, LTC2180, LTC2188, LTC2145-14/-12,

LTC2144-14/-12, LTC2143-14/-12, LTC2142-14/-12, LTC2141-14/-12,

LTC2140-14/-12, LTC2270: 16-/14-/12-Bit,

20Msps to 125Msps Dual ADCs

Demonstration circuit 1620A supports a family of

16-/14-/12-bit, 20Msps to 125Msps ADCs. Each assembly

features one of the following devices: LTC

2185, LTC2184,

LTC2183, LTC2182, LTC2181, LTC2180, LTC2188,

LTC2145-14, LTC2144-14, LTC2143-14, LTC2142-14,

LTC2141-14, LTC2140-14, LTC2145-12, LTC2144-12,

LTC2143-12, LTC2142-12, LTC2141-12, or LTC2140-12,

LTC2270 high speed, high dynamic range ADCs.

Demonstration circuit 1620A supports the LTC2185/

LTC2145 family DDR LVDS output mode.

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

QuikEval and PScope are trademarks of Linear Technology Corporation. All other trademarks are

the property of their respective owners.

The versions of the 1620A demo board supporting the

LTC2185 and LTC2145 series of A/D converters are listed

in Table 1. Depending on the required resolution and

sample rate, the DC1620A is supplied with the appropri-

ate ADC. The circuitry on the analog inputs is optimized

for analog input frequencies from 5MHz to 70MHz. Refer

to the data sheet for proper input networks for different

input frequencies.

Design files for this circuit board are available at

http://www.linear.com/demo

Table 1. DC1620 Variants

DC1620 VARIANTS ADC PART NUMBER RESOLUTION MAXIMUM SAMPLE RATE INPUT FREQUENCY

1620A-A LTC2185 16-Bit 125Msps 5MHz to 140MHz

1620A-B LTC2184 16-Bit 105Msps 5MHz to 140MHz

1620A-C LTC2183 16-Bit 80Msps 5MHz to 140MHz

1620A-D LTC2182 16-Bit 65Msps 5MHz to 140MHz

1620A-E LTC2181 16-Bit 40Msps 5MHz to 140MHz

1620A-F LTC2180 16-Bit 25Msps 5MHz to 140MHz

1620A-G LTC2145-14 14-Bit 125Msps 5MHz to 140MHz

1620A-H LTC2144-14 14-Bit 105Msps 5MHz to 140MHz

1620A-I LTC2143-14 14-Bit 80Msps 5MHz to 140MHz

1620A-J LTC2142-14 14-Bit 65Msps 5MHz to 140MHz

1620A-K LTC2141-14 14-Bit 40Msps 5MHz to 140MHz

1620A-L LTC2140-14 14-Bit 25Msps 5MHz to 140MHz

1620A-M LTC2145-12 12-Bit 125Msps 5MHz to 140MHz

1620A-N LTC2144-12 12-Bit 105Msps 5MHz to 140MHz

1620A-O LTC2143-12 12-Bit 80Msps 5MHz to 140MHz

1620A-P LTC2142-12 12-Bit 65Msps 5MHz to 140MHz

1620A-Q LTC2141-12 12-Bit 40Msps 5MHz to 140MHz

1620A-R LTC2140-12 12-Bit 25Msps 5MHz to 140MHz

1620A-S LTC2188 16-Bit 20Msps 5MHz to 140MHz

1620A-T LTC2270 16-Bit 20Msps 5MHz to 140MHz

dc1620afb

DEMO MANUAL DC1620A

QUICK START PROCEDURE

PERFORMANCE SUMMARY

(TA = 25°C)

PARAMETER CONDITION VALUE

Supply Voltage—DC1620A Depending on Sampling Rate and the A/D Converter

Provided, This Supply Must Provide Up to 500mA

Optimized for 4.5V [4.5V  6.0V Min/Max]

Analog Input Range Depending on SENSE Pin Voltage 1VP-P to 2VP-P

Logic Input Voltages Minimum Logic High 1.3V

Maximum Logic Low 0.6V

Logic Output Voltages (Differential) Nominal Logic Levels (100Ω Load, 3.5mA Mode) 350mV/1.25V Common Mode

Minimum Logic Levels (100Ω Load, 3.5mA Mode) 247mV/1.25V Common Mode

Sampling Frequency (Convert Clock Frequency) See Table 1

Convert Clock Level Single-Ended Encode Mode (ENC– Tied to GND) 0V to 3.6V

Differential Encode Mode (ENC– Not Tied to GND) 0.2V to 3.6V

Resolution See Table 1

Input frequency range See Table 1

SFDR See Applicable Data Sheet

SNR See Applicable Data Sheet

Demonstration circuit 1620A is easy to set up to evaluate

the performance of the LTC2185/LTC2145 A/D converter

family. Refer to Figure 1 for proper measurement equip-

ment setup and follow the procedure below:

Setup

If a DC890 USB data acquisition and collection system

was supplied with the DC1620A demonstration circuit,

follow the DC890 Quick Start Guide to install the required

software and for connecting the DC890 to the DC1620A

and to a PC.

DC1620A Demonstration Circuit Board Jumpers

The DC1620A demonstration circuit board should have

the following jumper settings as default positions: (as

per Figure 1)

JP2-PAR/SER: Selects Parallel or Serial programming

mode. (Default: Serial)

JP3-Duty Cycle Stabilizer: Enables/Disable Duty Cycle

Stabilizer. (Default: Enable)

JP4-SHDN: Enables and disables the LTC2185/LTC2145.

(Default: Enable)

JP5-NAP: Enables and disables NAP mode (Default:

disable)

JP6-LVDS/CMOS: Selects between LVDS and CMOS output

signaling. (Default: LVDS)

Applying Power and Signals to the DC1620A

Demonstration Circuit

If a DC890 is used to acquire data from the DC1620A, the

DC890 must first be connected to a powered USB port

or provided an external 6V to 9V before applying +4.5V

to +6.0V across the pins marked V+ and GND on the

DC1620A. DC1620A requires 4.5V for proper operation.

Regulators on the board produce the voltages required for

the ADC. The DC1620A demonstration circuit requires up

to 500mA depending on the sampling rate and the A/D

converter supplied.

The DC890 data collection board is powered by the USB

cable and does require an external power supply when

collecting data from an LVDS demo board. It must be

supplied from an external 6V to 9V on turrets G7(+) and

G1(–) or the adjacent 2.1mm power jack.

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DEMO MANUAL DC1620A

QUICK START PROCEDURE

Figure 1. DC1620 Setup (Zoom for Detail)

Analog Input Network

For optimal distortion and noise performance, the RC

network on the analog inputs may need to be optimized

for different analog input frequencies. For input frequen-

cies above 140MHz, refer to the respective ADC data sheet

for a proper input network. Other input networks may be

more appropriate for input frequencies less that 5MHz or

above 140MHz.

In almost all cases, filters will be required on both analog

the input and encode clock to provide data sheet SNR. In

the case of the DC1620A a bandpass filter used for the clock

should be used prior to the DC1075 clock divider board.

The filters should be located close to the inputs to avoid

reflections from impedance discontinuities at the driven

end of a long transmission line. Most filters do not present

50Ω outside the passband. In some cases, 3dB to 10dB

pads may be required to obtain low distortion.

If your generator cannot deliver full-scale signals without

distortion, you may benefit from a medium power amplifier

based on a Gallium Arsenide gain block prior to the final

filter. This is particularly true at higher frequencies where

IC-based operational amplifiers may be unable to deliver

the combination of low noise figure and high IP3 point

required. A high order filter can be used prior to this final

amplifier, and a relatively lower Q filter used between the

amplifier and the demo circuit.

Encode Clock

Note: Apply an encode clock to the SMA connector on

the DC1620A demonstration circuit board marked J3.

As a default, the DC1620A is populated to have a single-

ended input.

For the best noise performance, the encode input must

be driven with a very low jitter, square wave source. The

amplitude should be large, up to 3VP-P or 13dBm. When

using a sinusoidal signal generator a squaring circuit can

be used. Linear Technology also provides demo board

DC1075 that divides a high frequency sine wave by four,

producing a low jitter square wave for best results with

the LTC2185/LTC2145.

+–

ANALOG INPUT

CHANNEL 1

PARALLEL/SERIAL

PROGRAMMING MODE

PARALLEL DATA

OUTPUT TO DC890

DUTY CYCLE

STABILIZER

SHDN

LVDS/CMOS

SINGLE-ENDED

ENCODE CLOCK

FROM DC1075

4.5V TO 6V

NAP

ANALOG INPUT

CHANNEL 2

dc1620afb

DEMO MANUAL DC1620A

QUICK START PROCEDURE

Using bandpass filters on the clock and the analog input

will improve the noise performance by reducing the

wideband noise power of the signals. In the case of the

DC1620A a bandpass filter used for the clock should be

used prior to the DC1075. Data sheet FFT plots are taken

with 10-pole LC filters made by TTE (Los Angeles, CA) to

suppress signal generator harmonics, non-harmonically

related spurs and broadband noise. Low phase noise Agilent

8644B generators are used with TTE bandpass filters for

both the clock input and the analog input.

Apply the analog input signal of interest to the SMA con-

nectors on the DC1620A demonstration circuit board

marked J5 AIN+. These inputs are capacitive coupled to

Balun transformers ETC1-1-13 (lead free part number:

MABA007159-000000).

An internally generated conversion clock output is available

on J1 which could be collected via a logic analyzer, or other

data collection system if populated with a SAMTEC MEC8-

150 type connector or collected by the DC890 QuikEval™-II

data acquisition board using PScope™ software.

Software

The DC890 is controlled by the PScope system software

provided or downloaded from the Linear Technology

website at http://www.linear.com/software/. If a DC890

was provided, follow the DC890 Quick Start Guide and

the instructions below.

To start the data collection software if “PScope.exe” is

installed (by default) in \Program Files\LTC\PScope\, double

click the PScope icon or bring up the run window under

the start menu and browse to the PScope directory and

select PScope.

If the DC1620A demonstration circuit is properly connected

to the DC890, PScope should automatically detect the

DC1620A, and configure itself accordingly. If necessary

the procedure below explains how to manually configure

PScope.

Under the Configure menu, go to ADC Configuration. Check

the Config Manually box and use the following configura-

tion options, see Figure 2:

Manual configuration settings:

Bits: 16

Alignment: 16

FPGA Ld: DDR LVDS

Channs: 2

Bipolar: Unchecked

Positive-Edge Clk: Checked

If everything is hooked up properly, powered, and a suitable

convert clock is present, clicking the Collect button will

result in time and frequency plots displayed in the PScope

window. Additional information and help for PScope is

available in the DC890 Quick Start Guide and in the online

help available within the PScope program itself.

Serial Programming

PScope has the ability to program the DC1620A board

serially through the DC890. There are several options

available in the LTC2185 family that are only available

through serially programming. PScope allows all of these

features to be tested.

These options are available by first clicking on the Set

Demo Bd Options icon on the PScope toolbar (Figure 3).

Figure 2: ADC Configuration

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DEMO MANUAL DC1620A

QUICK START PROCEDURE

This will bring up the menu shown in Figure 4.

• Nap – ADC core powers down while references stay

active

• Shutdown – The entire ADC is powered down

Clock Inversion: Selects the polarity of the CLKOUT signal.

• Normal (Default) – Normal CLKOUT polarity

• Inverted – CLKOUT polarity is inverted

Clock Delay: Selects the phase delay of the CLKOUT signal.

• None (Default) – No CLKOUT delay

• 45° – CLKOUT delayed by 45°

• 90° – CLKOUT delayed by 90°

• 135° – CLKOUT delayed by 135°

Clock Duty Cycle: Enable or disables Duty Cycle Stabilizer.

• Stabilizer off (Default) – Duty cycle stabilizer disabled

• Stabilizer on – Duty cycle stabilizer enabled

Output Current: Selects the LVDS output drive current.

• 1.75mA (Default) - LVDS output driver current

• 2.1mA – LVDS output driver current

• 2.5mA – LVDS output driver current

• 3.0mA – LVDS output driver current

• 3.5mA – LVDS output driver current

• 4.0mA – LVDS output driver current

• 4.5mA – LVDS output driver current

Internal Termination: Enables LVDS internal termination.

• Off (Default) – Disables internal termination

• On – Enables internal termination

Outputs: Enables digital outputs.

• Enabled (Default) – Enables digital outputs

• Disabled – Disables digital outputs

Output Mode: Selects digital output mode.

• Full Rate – Full rate CMOS output mode (This mode is

not supported by the DC1620A)

Figure 3: PScope Toolbar

Figure 4: Demobd Configuration Options

This menu allows any of the options available for the

LTC2185/LTC2145 family to be programmed serially. The

LTC2185/LTC2145 family has the following options:

Power Control: Selects between normal operation, nap

and sleep modes.

• Normal (Default) – Entire ADC is powered, and active

• Ch1 Normal Ch2 Nap – Channel 1 remains active while

channel 2 is put into nap mode

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DEMO MANUAL DC1620A

• Double LVDS (Default) – double data rate LVDS output

mode

• Double CMOS – double data rate CMOS output mode

(This mode is not supported by the DC1620A)

Test Pattern: Selects Digital output test patterns.

• Off (Default) – ADC data presented at output

• All out =1 – All digital outputs are 1

• All out = 0 – All digital outputs are 0

• Checkerboard - OF, and D13-D0 Alternate between 101

0101 1010 0101 and 010 1010 0101 1010 on alternat-

ing samples

• Alternating – Digital outputs alternate between all 1’s

and all 0’s on alternating samples

QUICK START PROCEDURE

Alternate Bit: Alternate bit polarity (ABP) Mode.

• Off (Default) – Disables alternate bit polarity

• On – Enables alternate bit polarity (before enabling ABP,

be sure the part is in offset binary mode)

Randomizer: Enables data output randomizer.

• Off (Default) – Disables data output randomizer

• On – Enables data output randomizer

Two’s complement: Enables two’s complement mode.

• Off (Default) – Selects offset binary mode

• On – Selects two’s complement mode

Once the desired settings are selected hit OK and PScope

will automatically update the register of the device on the

DC1620A demo board.

PARTS LIST

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

11CN1 CAP, ARRAY, 0508 2.2μF 20% 10V X5R AVX W0508L8ZD225MAT1A

2 7 R47, R48, R53, R54, R78, R79 RES, 0402 0Ω JUMPER NIC NRC04Z0TRF

3 11 C1, C2, C3, C6, C7, C13, C57-C61, C65 CAP, 0402 0.01μF 10% 16V X7R AVX 0402YC103KAT

4 4 C9, C10, C63, C64 CAP, 0402 8.2pF 5% 50V COG AVX 04025A8R2JAT2A

5 0 C11, C16 CAP, 0402 OPTION OPTION

6 9 C12, C15, C18-C21, C37, C66, C67 CAP, 0402 0.1μF 10% 10V X5R TDK C1005X5R1A104K

7 4 C14, C22, C72, C73 CAP, 0603 1μF 10% 16V X7R TDK C1608X7R1C105K

8 2 C17, C23 CAP, 0402 2.2μF 20% 6.3V X5R TAIYO YUDEN JMK105BJ225MV-T

9 1 C24 CAP, 0603 4.7μF 20% 6.3V X5R TDK C1608X5R0J475MT

10 13 C26-C32, C34-C36, C56, C75, C76 CAP, 0603 0.1μF 10% 50V X7R TDK C1608X7R1H104K

11 0 C33, C70, C71 CAP, 0603 OPTION OPTION

12 2 C51, C62 CAP, 0402 4.7pF ±0.25pF 50V NPO AVX 04025A4R7CAT2A

13 2 C54, C55 CAP, 0805 10μF 10% 16V X5R MURATA GRM21BR61C106KE15L

14 3 C68, C69, C74 CAP, 0402 22pF 5% 16V NPO AVX 0402YA220JAT2A

15 5 JP2, JP3, JP4, JP5, JP6 HEADER, 3-PIN, 2mm SAMTEC TMM-103-02-L-S

16 4 J1, J2, J3, J4 CONN, BNC, SMA 50-OHM EDGE-LANCH E.F. JOHNSON, 142-0701-851

17 2 L1, L6 IND, 0603 56μH 5% MURATA LQP18MN56NG02D

18 3 L2, L3, L4 FERRITE BEAD, 1206 MURATA BLM31PG330SN1L

19 0 L5 IND, 0603 BEAD TBD

dc1620afb

DEMO MANUAL DC1620A

PARTS LIST

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

20 1 RN2 RES ARRAY, 33Ω VISHAY CRA04SS08333R0JTD

21 4 R1, R2, R60, R74 RES, 0402 49.9Ω 1% 1/16W YAGEO RC0402FR-0749R9L

22 0 R4, R5, R49-R52, R82, R83-R85 RES, 0402 OPTION OPTION

23 1 R6 RES, 0402 10k 5% 1/16W VISHAY CRCW040210K0JNED

24 1 R7 RES, 0402 180k 1% 1/16W VISHAY CRCW0402180KFKED

25 1 R8 RES, 0402 330k 1% 1/16W VISHAY CRCW0402330KFKEA

26 8 R9, R10, R58, R59, R63, R66, R71, R73 RES, 0402 10Ω 1% 1/16W NIC NRC04F10R0TR

27 2 R11, R12 RES, 0402 3k 1% 1/16W VISHAY CRCW04023K00FKED

28 6 R14, R33, R34, R35, R80, R81 RES, 0402 1k 5% 1/16W VISHAY CRCW04021K00JNTDE3

29 1 R16 RES, 0402 100Ω 5% 1/16W VISHAY CRCW0402100RJNED

30 17 R17-R23, R30, R61, R62, R64, R68, R69,

R72, R75, R76, R77

RES, 0201 100Ω 1% 1/16W NIC NRC02F1000TRF

31 1 R24 RES, 0402 100k 5% 1/16W VISHAY CRCW0402100KJNED

32 3 R25, R26, R29 RES, 0603 4.99k 1% 1/16W AAC CR16-4991FM

33 4 R27, R28, R31, R32 RES, 0201 OPTION OPTION

34 6 R36, R44, R45, R56, R57, R65 RES, 0402 86.6Ω 1% 1/16W VISHAY CRCW040286R6FKED

35 4 R39, R40, R67, R70 RES, 0402 33.2Ω 1% 1/16W VISHAY CRCW040233R2FKED

36 2 R46, R55 RES, 0402 100Ω 1% 1/16W NIC NRC04F1000TRF

37 5 TP1, TP2, TP3, TP4, TP5 TURRETS MILLMAX 2501-2-00-80-00-00-07-0

38 3 T1, T3, T4 XFMR, 1:1 MACOM MABA-007159-000000

39 2 T2, T5 XFMR, 1:1 CT M/A-C0M MABAES0060

0 T2, T5 - ALTERNATE XFMR, 1:1 CT COILCRAFT WBC1-1LB

40 1 U1 IC, EEPROM MICROCHIP TECH. 24LC025-I/ST

41 1 U2 REFER TO SCHEMATIC TABLE LINEAR TECH.

42 2 U3, U8 IC, FIN1108 FAIRCHILD FIN1108

43 2 U4, U6 IC, SINGLE RESISTOR LOW DROPOUT

REGULATOR

LINEAR TECH. LT3080EDD

44 1 U5 IC, 8-BIT I/0 EXPANDER PHILIPS SEMI PCF8574TS/3

45 1 U7 IC, LVDS SINGLE PORT HIGH SPEED

REPEATER

FAIRCHILD FIN1101K8X

46 5 JP2, JP3, JP4, JP5, JP6 SHUNT, 2mm SAMTEC 2SN-BK-G

47 4 STANDOFF, SNAP ON KEYSTONE_8831

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DEMO MANUAL DC1620A

SCHEMATIC DIAGRAM

dc1620afb

DEMO MANUAL DC1620A

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 representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

SCHEMATIC DIAGRAM

dc1620afb

DEMO MANUAL DC1620A

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

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

LT 0812 REV B • PRINTED IN USA

DEMONSTRATION BOARD IMPORTANT NOTICE

Linear Technology Corporation (LTC) 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 LTC 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 LTC 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.

LTC 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 applica-

tion engineer.

Mailing Address:

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1630 McCarthy Blvd.

Milpitas, CA 95035