Linear Technology DC1839A Demo Manual

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Page 1

DESCRIPTION

DEMO MANUAL DC1839A

LTC3634

15V Dual 3A Monolithic

Step-Down Regulator Board

for DDR Power

Demonstration circuit 1839A is a dual output regulator focused specifically for DDR memory power applications. It’s built based on the LTC3634, a high voltage dual channel, controlled on-time monolithic synchronous buck regulator. The DC1839A has an input voltage range of 3.6V to 15V. The output voltage of the first channel, V

, of the DC1839A

DDQ

has three fixed voltage settings; 1.5V, 1.8V, and 2.5V, and is capable of delivering up to 3A of output current. The second channel, V

, is set to regulate to half the voltage

on the VDDQIN pin, which can be either the channel1 output or an external reference voltage. It can source or sink a maximum of 3A. The LTC3634 also provides a 10mA buffered output of half VDDQIN – VTTR, which is used to provide the reference voltage needed for DDR applications. With the use of a timing resistor, the DC1839A can have its operating frequency programmed from 500kHz to 4MHz, or the DC1839A can be easily synchronized to an external clock, due to an internal phase-locked loop. The DC1839A

output can operate in either Burst Mode® operation or

DDQ

forced continuous mode. In Burst Mode operation, which is the preferred mode of low load current operation, the DC supply current is typically only 1.3mA (both channels) at no load (sleep mode), and less than 15μA in shutdown. In Burst Mode operation or continuous mode operation, the DC1839A is a very efficient circuit at high load currents: over 80% for either channel. The LTC3634 is also capable of in-phase or 180° out-of-phase operation, and to allow its output to track an external voltage, either coincidentally or ratiometrically. The LTC3634 comes in a 28-pin QFN or leaded package, which each having an exposed pad on the bottom side of the IC for better thermal performance. All of these features make the DC1839A an ideal circuit for powering DDR memory applications.

Design files for this circuit board are available at http://www.linear.com/demo

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

PERFORMANCE SUMMARY

PARAMETER CONDITIONS VALUE

Minimum Input Voltage 3.6V

Maximum Input Voltage 15V

Output Voltage V

Typical Output Ripple V

Output Voltage V

Typical Output Ripple V

Nominal Switching Frequencies RT = 324k 1MHz

Burst Mode-to-CCM transition Channel 1: V

INTV

VTTR VDDQIN = 2.5V 1.25V

OUT1

OUT2

– V

DDQ

VIN = 3.6V to 15V, I

VIN = 12V, I

VIN = 3.6V to 15V, I

VIN = 12V, I

(TA = 25°C)

= 0A to 3A 1.5V ±2% (1.47V to 1.53V)

OUT1

= 3A (20MHz BW) < 20mV

OUT1

= 0A to ±3A V

OUT2

= ±3A (20MHz BW) < 20mV

OUT2

= 12V, V

= 1.8V, fSW = 1 MHz I

OUT1

= 1.5V 0.75V ±3% (0.7275V to 0.7725V)

OUT1

= 1.8V 0.9V ±3% (0.873V to 0.927V)

OUT1

= 2.5V 1.25V ±3% (1.2125V to 1.2875V)

OUT1

1.8V ±2% (1.764V to 1.836V)

2.5V ±2% (2.45V to 2.55V)

P-P

= 1.6A

OUT1

3.3V

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DEMO MANUAL DC1839A

QUICK START PROCEDURE

The DC1839A is easy to set up to evaluate the performance of the LTC3634. For a proper measurement equipment configuration, set up the circuit according to the diagram in Figure 1.

NOTE: When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage ripple by touching the probe tip directly across the V or V

and GND terminals. See the proper scope probe

OUT

technique in Figure 2.

Please follow the procedure outlined below for proper operation.

1. Connect the input power supply to the V terminals. Connect the loads between the V

and GND

OUT

terminals. Refer to Figure 1 for the proper measurement equipment setup.

Before proceeding to operation, insert jumper shunts

XJP1 and XJP2 into the OFF positions of headers JP1 and JP2, shunt XJP3 into the forced continuous mode (FCM) position of MODE header JP3, shunt XJP4 into the 180° (out-of-phase) position of PHASE header JP4, shunt XJP5 into the soft-start positions of TRACK/SS header JP5, and shunt XJP6 into the V

OUT1

voltage

options of choice of header JP6: 1.2V, 1.5V, or 1.8V.

2. Apply 5V at V

. Measure both V

s; they should read

OUT

0V. If desired, one can measure the shutdown supply current at this point. The supply current should be less than 30μA in shutdown.

3. Turn on V

OUT1

DDQ

, and V

, VTT, by shifting shunts

OUT2

, V XJP1 and XJP2 from the OFF positions to the ON positions. Both output voltages should be within a tolerance of ±1%.

4. Vary the input voltage from 3.6V to 15V, the channel 1 load current from 0 to 3A, and the channel 2 load current from 0 to ±3A (The V

channel sinks as well as

sources current. An easy way to test this capability is shown in the test set-up diagram; connect a variable

resistor from V current will be V

resistor value). V

to V

DDQ

, along with an ampmeter. The

OUT

minus V

divided by the variable

OUT

output voltage tolerance should

be within ±2%, whereas the output voltage tolerance

should be within ±3%.

of V

5. Set the load current of both outputs to 3A and the input voltage to 12V, then measure each output ripple voltage (refer to Figure 2 for proper measurement technique); they should each measure less than 20mVAC. Also, observe the voltage waveform at either switch node (pins 16 and 17 for channel 1, and 23 and 24 for channel 2) of each regulator. (Both switch node waveforms should be rectangular in shape and 180°out-of-phase with each other). The switching frequencies should be between 800kHz and 1.2MHz (T = 1.25μs and 0.833μs).

6. With the board under proper operation, observe the load regulation, efficiency, in-phase operation (by changing jumper XJP4 to the 90° position), or BurstMode operation (by changing jumper XJP3 to the Burst Mode position).

7. (Optional) Moving the zero ohm resistor at RV inserting it into R V

allows channel2 output voltage (VTTR) to be

DDQIN

, and applying a voltage to turret

DDQIN

DDQ

adjusted to any desired voltage (to one-half the voltage at VDDQIN).

When finished, insert shunts XJP1 and XJP2 to the OFF position(s) and disconnect the power.

Warning: If the power for the demo board is carried in long leads, the input voltage at the part could ring, which could affect the operation of the circuit or even exceed the maximum voltage rating of the IC. To eliminate the ringing, a small Poscap capacitor (for instance, AVX part number TPSY226M035R0200) is inserted on the pads between the input power and return terminals on the bottom of the demo board. The (greater) ESR of the Poscap will dampen the (possible) ringing voltage due to the use of long input leads. On a normal, typical PCB, with short traces, this capacitor is not needed.

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QUICK START PROCEDURE

DEMO MANUAL DC1839A

VARIABLE RESISTOR

Figure 1. Proper Measurement Equipment Setup

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DEMO MANUAL DC1839A

QUICK START PROCEDURE

Figure 2. Measuring Input or Output Ripple

100

EFFICIENCY (%)

VIN

GND

VIN = 12V

= 2.5V

DDQ

= 1.25V

= 1MHz

Burst Mode OPERATION L1 = 1μH L2 = 0.47μH VISHAY 2020BZ

LOAD CURRENT (A)

3.01.5 2.51.0 2.00.5

dc1839a F03

Figure 3. LTC3634 DC1839A Efficiency

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QUICK START PROCEDURE

DEMO MANUAL DC1839A

VIN = 12V

= 1.8V

DDQ

3A LOAD STEP (0A TO 3A) FORCED CONTINUOUS MODE

= 1MHz

EXTERNAL COMPENSATION: R TRACE 3: OUTPUT VOLTAGE (50mV/DIV AC) TRACE 4: OUTPUT CURRENT (1A/DIV)

Figure 4. V

= 18.2k, C

ITH1

Load Step Response Figure 5. VTT Load Step Response

DDQ

dc1839a F04

= 680pF

ITH1

VIN = 12V

= 1.8V

DDQ

= 0.9V

3A LOAD (EACH) FORCED CONTINUOUS MODE

= 1MHz

= 4700pF

TRACE 1: V TRACE 2: V TRACE 3: VT TR OUTPUT (1V/DIV) TRACE 4: V

OUTPUT (500mV/DIV)

DDQ

OUTPUT (500mV/DIV)

VOLTAGE (2V/DIV)

RUN

VIN = 12V

= 0.9V

±3A LOAD STEP (–3A TO 3A) FORCED CONTINUOUS MODE

= 1MHz

EXTERNAL COMPENSATION: R TRACE 3: OUTPUT VOLTAGE (50mV/DIV AC) TRACE 4: OUTPUT CURRENT (2A/DIV)

dc1839a F06

ITH2

= 15k, C

ITH2

dc1839a F05

= 1000pF

Figure 6. LTC3634 DC1839A Start-Up with Soft-Start

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DEMO MANUAL DC1839A

PARTS LIST

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

Required Circuit Components

1 2 CBST1, CBST2 CAP, 0603, 0.1μF, 10%, 50V, X7R NIC NMC0603X7R104K50TRPF

2 1 CFFW1 CAP, 0402, 10pF, 5%, 25V, NPO NIC NMC0402NPO100J25TRPF

3 2 CIN1, CIN2 CAP, 1210, 47μF, 20%, 16V, X5R TAIYO YUDEN EMK325BJ476MM-T

4 1 CITH1 CAP, 0402, 680pF, 10%, 25V, X7R AVX 04023C681KAT2A

5 1 CITH2 CAP, 0402, 1000pF, 10%, 25V, X7R AVX 04023C102KAT2A

6 5 COUT1-COUT4, COUT6 CAP, 1812, 100μF, 20%, 6.3V, X5R TDK C4532X5R0J107M

7 1 CTTR CAP, 0603, 10nF, 10%, 16V, X7R AVX 0603YC103KAT2A

8 1 CVCC CAP, 0603, 1μF, 10%, 16V, X5R NIC NMC0603X5R105K16TRPF

9 1 L1 IND, 1.0μH VISHAY IHLP2020BZER1R0M01

10 1 L2 IND, 0.47μH VISHAY IHLP2020BZERR47M01

11 1 RFB1 RES, 0402, 34.8kΩ, 1%, 1/16W NIC NRC04F3482TRF

12 1 RITH1 RES, 0402, 18.2kΩ, 1%, 1/16W VISHAY CRCW040218K2FKED

13 1 RITH2 RES, 0402, 15kΩ, 1%, 1/16W VISHAY CRCW040215K0FKED

14 1 RT RES, 0402, 324kΩ, 1%, 1/16W NIC NRC04F3243TRF

15 1 RVDDQ RES, 0402, 0Ω, JUMPER NIC NRC04Z0TRF

16 1 R3 RES, 0402, 11kΩ, 1%, 1/16W NIC NRC04F1102TRF

17 1 U1 IC, MONOLITHIC SYNCHRONOUS STEP-DOWN REGULATOR LINEAR TECH LTC3634EFE

Additional Demo Board Circuit Components

1 0 CC1, CC2 OPTION CAP, 0402, 10pF, 5%, 25V, NPO NIC NMC0402NPO100J25TRPF

2 0 CDDQIN OPTION CAP, 0805, 10μF, 10%, 6.3V, X5R OPTION NIC NMC0805X5R106K6.3TRPLP3KF

3 0 CIN3, CIN4 OPTION CAP, 1210, 47μF, 20%, 16V, X5R TAIYO YUDEN EMK325BJ476MM-T

4 2 CIN5, CIN6 CAP, TANT. 7343, 22μF, 20%, 35V AVX TPSY226M035R0200

5 0 COUT5, COUT8 OPTION CAP, 1812, 100μF, 20%, 6.3V, X5R TDK C4532X5R0J107M OPTION

6 2 COUT7, COUT9 CAP, 0805, 10μF, 10%, 6.3V, X5R NIC NMC0805X5R106K6.3TRPLP3KF

7 1 CTR1 CAP, 0402, 4700pF, 10%, 50V, X7R TDK C1005X7R1H472K

8 0 CTTR1 CAP, 0603, 10nF, 10%, 16V, X7R AVX 0603YC103KAT2A OPTION

9 1 CVCC1 CAP, 0603, 1μF, 10%, 16V, X5R NIC NMC0603X5R105K16TRPF

10 0 RD1, RTR2, RD2, R6, RFREQ,

RDDQIN OPTION

11 2 RPG1, RPG2 RES, 0402, 100kΩ, 5%, 1/16W NIC NRC04J104TRF

12 1 RTR1 RES, 0402, 0Ω, JUMPER NIC NRC04Z0TRF

13 2 R1, R2 RES, 0402, 1MΩ, 5%, 1/16W NIC NRC04J105TRF

14 1 R4 RES, 0402, 17.4kΩ, 1%, 1/16W NIC NRC04F1742TRF

15 1 R5 RES, 0402, 23.2kΩ, 1%, 1/16W NIC NRC04F2322TRF

16 1 R7 RES, 0402, 1kΩ, 1%, 1/16W NIC NRC04F1001TRF

Hardware/Components (For Demo Board Only)

1 17 E1-E17 TURRET MILL-MAX 2501-2-00-80-00-00-07-0

2 4 JP1, JP2, JP4, JP5 HEADER, 3-PIN, 2mm SAMTEC TMM-103-02-L-S

3 1 JP3 HEADER, 3-PIN, DBL ROW 2mm SAMTEC TMM 103-02-L-D

4 1 JP6 HEADER, 4-PIN, DBL ROW 2mm SAMTEC TMM 104-02-L-D

5 6 JP1-JP6 SHUNT, 2mm SAMTEC 2SN-BK-G

RES, 0402 OPTION

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SCHEMATIC DIAGRAM

DEMO MANUAL DC1839A

11-80-601

ETADNOITPIRCSED APPROVEDECO REV

TOM G.

PRODUCTION

REVISION HISTORY

VIN

CIN1

47uF

16V

OPT

CIN3

47uF

16V

35V

CIN5

22uF

[1]

E17

VON2

RD2

RITH1

CC1

INTVCC

7 8 5 6 3 4 1 2

VFB2 VTTR

PGND

SGND

ITH2

18.2k

10pF

PHASE

OPT

GND

VTT

10uF

COUT9

100uF

COUT8

100uF

COUT6

OPT

23.2k

1.5V USER SELECT

17.4k

1.8V

11k

2.5V

100uF

COUT4

100uF

COUT2

10mA

VTTR

E13

CTTR1

0805

1812

10nF

OPT

1812

6.3V

0603

OPT

GND

www.linear.com

E16

Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

TECHNOLOGY

APPROVALS

0603

10nF

INTVCC

TRACKSS

RFREQ

132

OPT

RTR2

OPT

TRACK

CTTR

CUSTOMER NOTICE

CIRCUIT THAT MEETS CUSTOMER- S UPP LI ED SPECIFICATI ONS;

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A

324k

CTR1

4700pF

JP5

15k

RITH2

CITH2

1000pF

CC2

OPT

10pF

680pF

CITH1

JP4

90°

180°

RTR1

GND

E11

CDDQIN

VIN2 VIN2

VIN1 VIN1

RUN1

OPT

JP1

0805

10uF

RVDDQ

CBST1

BOOST1

PGOOD2

PGOOD1

RUN2

JP2

INTVCC

VDDQ

10uF

COUT7

OPT

100uF

COUT5

100uF

COUT3

100uF

COUT1

CFFW1

RFB1

34.8k

VISHAY

L1 1.0uH

0.1uF

IHLP-2020BZER1R0M01

262728

SW1

LTC3634EFE

INTVCC

30603060

1uF

CVCC

1uF

CVCC1

E10

6.3V

10pF

VON1

0805

1812

MODE

OPT

RD1

VFB1

MODE/SYNC

1 2

3 4

SYNC

BURST MODE

E14

INTVCC

OPT

CBST2

BOOST2

PHMODE

5 6

FCM

(FORCED

CONTINUOUS

E12

0.47uH

VDDQ SEL

JP6

VISHAY

IHLP-2020BZERR47M01

0.1uF

SW2

ITH1

TRACKSS1

JP3

MODE)

E15

VIN

RUN1

VIN

RUN2

132

VDDQIN

RDDQIN

VDDQIN

18 19

24 25

OFF

PGOOD2

RPG2

100K

INTVCC

VIN

INTVCC

100K

RPG1

CIN2

47uF

16V

1210

7343

1210

OPT

CIN4

47uF

16V

1210

CIN6

22uF

35V

7343

[1]

.VER.ON CI

SHEET OF

LTC Confidential-For Customer Use Only

DUAL DDR MONOLITHIC

LTC3634EFE

DEMO CIRCUIT 1839A

Thursday, June 30, 2011

SYNCHRONOUS STEP-DOWN REGULATOR

SCHEMATIC

N/A

SIZE

CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT

PERFORMANCE OR RELIABILITY. CONTACT LIN EAR

DATE:

SCALE = NONE

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

PCB DES.

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

TITLE:

TOM G.

APP ENG.

APPLICATION. COMPONENT SUBSTITUTION AND PRINTED

VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL

VIN1

VIN2

3.6V - 15V PGOOD1

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.

INTVCC

GND

SYNC

GND

TRACK1

2. ALL RESISTOR AND CAPACITOR CASE SIZE ARE 0402.

RINGING VOLTAGE DUE TO THE USE OF LONG INPUT LEADS. ON A NORMAL, TYPICAL

PCB, WITH SHORT TRACES, CIN5 AND CIN6 ARE NOT NEEDED .

[1] CIN5 AND CIN6 ARE INSERTED ON TH E DC1839A TO DAMPEN THE (POSSIBLE)

NOTES: UNLESS OTHERWISE SPECIFIED

C C

B B

A A

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Page 8

DEMO MANUAL DC1839A

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 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

dc1839af

LT 0711 • PRINTED IN USA