DEMO MANUAL DC1707
LTC3617EUDD
±6A Monolithic Step-Down Regulator
for DDR Termination
DESCRIPTION
Demonstration circuit 1707 is a high efficiency monolithic step-down DC/DC switching regulator designed for
double-data-rate (DDR) memory termination in computer
systems. The VTT output is capable of sourcing and sinking up to 6A with an output voltage equal to one-half the
voltage applied to the VDDQIN terminal or one-half the input
supply voltage, selected by a jumper. An additional low
current output (VTTR) also equal to one-half the voltage on
VDDQIN and can source and sink up to 10mA is included.
Input voltage range is from 2.25V to 5.5V with overvoltage protection for transients exceeding 6.5V. Switching
frequency is set to 1MHz although it can be programmed
up to 4MHz and can be synchronized to an external clock
for noise sensitive applications. Jumpers are provided for a
PERFORMANCE SUMMARY
PARAMETER
low quiescent current shutdown and for selecting internal
or external compensation. Internal soft-start is included
and a PGOOD output terminal that pulls low at start-up
and when the VTT output is outside a voltage window. The
LTC3617 is available in the 24-pin 3mm × 5mm thermally
enhanced QFN package.
The LTC3617 datasheet gives a complete description of the
part, operation and application information and should be
read in conjunction with this quick start guide.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, μModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
(TA = 25°C)
CONDITIONS
Input Voltage Range (VIN)
TYPICAL VALUE
2.25V to 5.5V
Output Voltage (VTTR)
VIN = 3.3V, VDDQIN = 1.800V
900mV ±18mV (±2%)
Output Voltage (VTT)
VIN = 3.3V, VDDQIN = 1.800V
VTTR ±10mV
Load Regulation
VIN = 3.3V, VDDQIN = 1.800V, 0A to 5A Load
2mV
Maximum Output Current
VIN = 3.3V, VDDQIN = 1.800V
±6A
Switching Frequency
1MHz ±20%
Output Voltage Ripple
VIN = 3.3V, 0A to 5A Load
25mVP-P
Efficiency
VIN = 3.3V, VOUT = 900mV, 1A Load
87%
Efficiency
VIN = 3.3V, VOUT = 900mV, 3A Load
85%
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DEMO MANUAL DC1707
QUICK START PROCEDURE
Demonstration circuit 1707 allows the user to quickly
evaluate the performance of the LTC3617. Refer to Figure 1
for proper measurement equipment setup and follow the
procedure below
1. Place jumpers in the following positions.
JP2 - EXT REF (lower)
JP1 - RUN (lower)
JP3 - VIN (upper)
2. With both power supplies turned down and switched
off, connect the supplies and digital voltmeters and
ammeters as shown in Figure 1.
3. Switch on the input supply and adjust for approximately
3.3V on VIN, and set the Reference supply to 1.800V
on VDDQIN.
4. Verify that the VTTR voltmeter is exactly one-half of
VDDQIN ±18mV or approximately 900mV.
5. Verify that the VTT voltmeter reading is equal to the
VTTR value ±10mV.
6. To evaluate sourcing current from the VTT terminal,
connect one lead of a 0.2Ω 5W load resistor to the
VTT terminal and the other lead to the GND terminal.
Verify that the voltmeter measurements still meet the
specifications shown in the table on page 1.
7. To evaluate sinking current into the VTT terminal, connect
one lead of a 0.5Ω 10 or 20W load resistor to the VTT
terminal and the other lead to the VIN terminal. Verify
that the voltmeter measurements meet the specifications
in the Performance Summary table on the front page.
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 VIN or
VOUT and GND terminals. See Figure 2 for proper scope
probe technique.
NOTE. Additional pads for are located on the board backside for larger compensation components for optimizing
loop compensation.
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DEMO MANUAL DC1707
QUICK START PROCEDURE
-
+
A
+
V
-
+
5V @ 5A
Input Power Supply
- (set to 3.3V)
V
+
Vref
1.800V
-
+
Connect 0.2Ω to GND (E7)
for Sourcing Current
A
V
-
VTT
+
+
Connect 0.5Ω to VIN (E1)
0.2/0.5Ω
for Sinking Current
10W
V
VTTR
Figure 1. Proper Measurement Equipment Setup
VOUT GND
Figure 2. Measuring Input or Output Ripple
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DEMO MANUAL DC1707
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
C1
CAP., TANT, 47μF, 10V,20%, 7343
AVX, TPSC476M010R0350
2
0
C9 (OPT)
CAP., TANT, 100μF, 10V, 20%, 7343
AVX, TPSC107M010R0150
3
4
C2, C3, C12, C13 CAP., X5R, 47μF, 10V, 20% 1206
TAIYO YUDEN, LMK316BJ476ML-T
4
1
C4
CAP., X5R, 1μF, 10V, 10% 0402
MURATA, GRM155R61A105KE15D
5
1
C5
CAP., X7R, 0.1μF, 16V, 10% 0402
MURATA, GRM155R71C104KA88D
6
2
C7, C8
CAP., X5R, 100μF, 10V, 20% 1210
TAIYO YUDEN, LMK325BJ107MM-T
7
1
C10
CAP., X5R, 470pF, 16V, 10% 0402
AVX, 0402YC471KAT2A
8
0
C6, C11(OPT)
CAP., 0402
9
10
E1-E10
TESTPOINT, TURRET, .094"
MILL-MAX, 2501-2-00-80-00-00-07
10
3
JP1-JP3
HEADER 3 PIN 0.079 SINGLE ROW
SAMTEC, TMM-103-02-L-S
11
3
JP1-JP3 SHUNT
SHUNT
SAMTEC, 2SN-BK-G
12
1
L1
INDUCTOR, 220nH IHP-2020
VISHAY, IHLP2020BZERR22M01
13
1
R1
Res., CHIP, 24, 1% 0402
VISHAY, CRCW040224R0FKED
14
1
R2
Res., CHIP, 100K, 1% 0402
VISHAY, CRCW0402100KFKED
15
1
R3
Res., CHIP, 365K, 1% 0402
VISHAY, CRCW0402365KFKED
16
1
R4
Res., CHIP, 0, 1% 0402
VISHAY, CRCW04020000Z0ED
17
1
R5
Res., CHIP, 20K, 1% 0402
NIC, NRC04F2002TRF
18
0
R6 (OPT)
Res., 0402
19
1
R7
Res., CHIP, 4.7M, 5% 0402
VISHAY, CRCW04024M70JNED
20
1
U1
IC., LTC3617EUDD QFN-24 3X5MM
LINEAR TECH., LTC3617EUDD
21
4
MH1-MH4
STAND-OFF, NYLON 0.25"
KEYSTONE, 8831 (SNAP ON)
22
1
FAB, PRINTED CIRCUIT BOARD
DEMO CIRCUIT 1707A
23
1
STENCIL
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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.
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DEMO MANUAL DC1707
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1707
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
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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.
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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
Copyright © 2004, Linear Technology Corporation
dc1707f
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Linear Technology Corporation
LT 0611 • PRINTED IN USA
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●
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