DEMO MANUAL DC2569A
LTM4661
1.8V-5.5V Input,
Synchronous Step-Up µModule Regulator
DESCRIPTION
Demonstration circuit 2569A is ultrathin step-up µModule
regulator featuring the
LTM4661.
The DC2569A operates
over 1.8V to 5.5V input and it generates 12V, 1A output
from 5V input. Also, the LTM4661 has precision voltage
reference, which can generate output voltage with 3%
tolerance over the full operating conditions. The 1MHz
switching frequency operation results in small and effi-
cient circuit. The converter operates with only one phase
in burst mode and achieves over 90% efficiency with
100mA load. The demonstration circuit can be easily
modified to generate different output voltages.
The DC2569 has small circuit footprint. It is a high perfor-
mance and cost effective solution for generating output
voltages up to 15V from inputs as low as 1.8V.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2569A
All registered trademarks and trademarks are the property of their respective owners.
PERFORMANCE SUMMARY
PARAMETER
Minimum Input Voltage
Maximum Input Voltage
V
OUT
Output Voltage Ripple
Nominal Switching Frequency
Specifications are at T
A
= 25°C
VALUE
1.8V
5.5V
12V ±3%
20mV
P-P
1MHz
CONDITIONS
I
OUT
= 0A to 0.3A
I
OUT
= 0A to 1A
V
IN
= 1.8V to 5.5V, I
OUT
= 0A
V
IN
= 5V, I
OUT
= 1A
BOARD PHOTO
dc2569af
1
DEMO MANUAL DC2569A
QUICK START PROCEDURE
Demonstration circuit DC2569 is easy to set up to evaluate
the performance of the LTM4661. For proper measure-
ment equipment setup refer to Figure 1 and follow the
procedure below:
NOTE: When measuring the input or output voltage ripple,
care must be taken to minimize the length of oscilloscope
probe ground lead. Measure the input or output voltage
ripple by connecting the probe tip directly across the V
IN
or V
OUT
and GND terminals as shown in Figure 2.
1. With power off, connect the input power supply to V
IN
and GND.
2. Keep the load set to 0A or disconnected.
3. Turn the input power source on and slowly increase the
input voltage. Be careful not to exceed 5.5V.
NOTE: Make sure that the input voltage V
IN
does not
exceed 5.5V.
4. Set the input voltage to 5V and check for the proper
output voltage of 12V. If there is no output, temporarily
disconnect the load to make sure that the load is not
set too high.
5. Once the proper output voltage is established, adjust
the load and observe the output voltage regulation,
ripple voltage, efficiency and other parameters.
+
+
–
I
IN
–
+
–
V
IN
+
+
–
I
OUT
–
+
LAB
SUPPLY
V
OUT
LOAD
–
DC2569A
Figure 1. Proper Measurement Equipment Setup
+
V
OUT
C
OUT
GND
–
Figure 2. Measuring Input or Output Ripple
2
dc2569af
DEMO MANUAL DC2569A
QUICK START PROCEDURE
CHANGING THE OUTPUT VOLTAGE
To change the output voltage from the programmed
12V, change the voltage setting resistors connected to
LTM4661 FB pin (see the schematic on page 5).
CONVERTER OUTPUT CURRENT
The DC2569 output current capability depends on the
input voltage and programmed input current limit. Typi-
cal performance of DC2569A is shown in Figure 3. As can
be seen from Figure 3, the maximum output current is 1A
with 5V input. Switching the mode of operation to BURST
mode can increase the efficiency at light loads.
93
91
89
EFFICIENCY (%)
87
85
83
81
79
77
75
73
0
0.2
V
OUT
= 12V, 1A DC
0.4
0.8
0.6
LOAD CURRENT (A)
1
1.2
4661 G02
OUTPUT LOAD STEP RESPONSE
The load step response of DC2569A is dependent on the
amount and type of output caps used. If higher load steps
need to be handled more output capacitance can be added
in order to keep the voltage transients at the desired level.
The 200mA to 400mA load step transients with 3.3V input
are shown in Figure 5. Other types of low ESR and high
value capacitors can be used if space is available to reduce
load transients to desired level.
V
OUT
(AC)
200mV/DIV
LOAD STEP
200mA
TO 400mA
500µs/DIV
V
IN
= 3.3V, V
OUT
= 12V
f
S
= 1MHz (DEFAULT)
200mA TO 400mA LOAD STEP
C
OUT
= 2×22µF CERAMIC
4661 G05
Figure 5. The LTM4661 Has Good Load Step Response
with Small Output Capacitors (2× 22µF)
Figure 3. The 5V Input Efficiency is 90% at 0.6A Load
START-UP AND SOFT-START FUNCTION
The DC2569 features internal soft-start circuit that ramps
the output voltage up in monotonic fashion. The soft-start
circuit also prevents output voltage overshoot when out-
put voltage ramp reaches regulation.
Figure 4. Thermal Image, 3.3V Input to 12V Output
at 0.8A, 200LFM Air Flow, No Heat Sink
dc2569af
3
DEMO MANUAL DC2569A
QUICK START PROCEDURE
OUTPUT SHORT CIRCUIT PROTECTION
The LTM4661 features safe short-circuit and thermal pro-
tection. The part can operate continuously with output
shorted while maintaining a maximum set current limit.
The internal peak switch current is reduced during over-
load to about 2A and is restored to 3.5A once the output
exceeds 1.5V.
I
IN
200mA/DIV
V
IN
2V/DIV
V
OUT
10V/DIV
RUN
2V/DIV
500µs/DIV
V
IN
= 3.3V,
V
OUT
= 12V
f
S
= 1MHz (DEFAULT)
C
OUT
= 2×22µF CERAMIC
4661 G07
Figure 6. The DC2569 Ramps the Output Slowly
at Start-Up without Output Voltage Overshoot
PARTS LIST
ITEM
1
QTY
1
REFERENCE
CIN1
PART DESCRIPTION
CAP
.,10µF, X5R, 16V, 20%, 0805
MANUFACTURER/PART NUMBER
AVX, 0805YD106MAT2A
KEMET, C0805C106M4PAC7800
KEMET, C0805C106M4PACTU
MURATA, GRM31CR61C226ME15L
AVX, 08053D105KAT2A
NIC, NRC06F1004TRF
PANASONIC, ERJ3EKF1004V
VISHAY, CRCW06031M00FKEA
VISHAY, CRCW060311K0FKEA
LINEAR TECHNOLOGY, LTM4661EV#PBF
OPT
OPT
Required Circuit Components
2
3
4
1
1
2
COUT1, COUT2
COUT3
R1, R6
CAP 22µF, X5R, 16V, 20%, 1206
.,
CAP 1µF, X5R, 25V, 10%, 0805
.,
RES., 1M , 1%, 1/10W, 0603
5
6
1
2
1
1
0
0
R5
U1
C1, C2, C3
R2, R3, R4
RES., 11k, 1%, 1/10W, 0603
IC,Step-Up DC/DC Power Module, LGA-25
CAP 0603, OPTION
.,
RES., OPTION, 0603
Additional Demo Board Circuit Components
4
dc2569af
5
4
3
2
1
ECO
_
1
GP
PROTOTYPE
REV
REVISION HISTORY
DESCRIPTION
APPROVED
DATE
5-31-16
SCHEMATIC DIAGRAM
D
D
+VIN
1.8V - 5.5V
+VIN
E1
+
CIN2
E2
OPT
R1
1M
CIN1
10uF
10V
0805
GND
E3
A1
B1
C1
D1
E1
VIN
VIN
VIN
VIN
VIN
U1
LTM4661EY
INTVCC
FB
COMP
R4
OPT
COUT1
22uF
25V
1206
INTVCC
C1
OPT
E4
COUT2
22uF
25V
1206
A4
VOUT
A5
VOUT
B5
VOUT
C5
VOUT
+VOUT
COUT3
1uF
25V
0805
GND
+VOUT
12V@1.5A
*
C
D5
SDB
SYNC/MODE
E4
FREQ
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
E5
D2
D3
C
R2
OPT
E3
1
2
INTVCC
R6
1M
RUN
ON
OFF
JP1
R3
OPT
3
A2
B2
C2
A3
B3
C3
B4
C4
D4
E2
R5
11K
1%
C3
OPT
C2
OPT
B
INTVCC
MODE
JP2
1
B
PWM
2
BURST
3
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.
*
OUTPUT WITH 5V INPUT
CUSTOMER NOTICE
APPROVALS
HZ
G.P.
A
NOTE: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS AND CAPACITORS ARE 0603
TECHNOLOGY
TITLE: SCHEMATIC
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
APP ENG.
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
A
STEP UP µMODULE REGULATOR
SIZE
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
N/A
SCALE = NONE
3
2
IC NO.
DATE:
Wednesday, June 08, 2016
LTM4661EY
DEMO CIRCUIT 2569A
1
REV.
1
SHEET 1
OF 1
5
4
DEMO MANUAL DC2569A
dc2569af
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MCU
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