DC797A - Demo Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 797
1MHZ SYNCHRONOUS BUCK-BOOST IN 3MM X 3MM DFN
LTC3440EDD
DESCRIPTION
Demonstration Circuit 797 is a constant-frequency
synchronous Buck-Boost converter using the
LTC3440EDD. The input range is from 2.5V to 5.5V,
making it ideal for single-cell Lithium-Ion or three-cell
NiCd/NiMH battery applications. This converter provides up to 95% efficiency, much higher than traditional Buck-Boost converters. For 2.5V minimum input voltage, this converter can provide up to 540mA
load current.
The output voltage is set at 3.3V. A different output
voltage in the range of 2.5V to 5.25V can be obtained
by changing one of the feedback resistors. The
switching frequency is set at 1MHz, which is a good
trade-off between efficiency and size. The frequency
can be modified by changing R6 or by synchronizing
to an external clock. In shutdown, the IC itself draws
less than 1µA.
When using long wire connections to the input
sources (such as wall adaptors), there can be input
over voltage transients during initial plug-in. C8 is
installed on DC797 to damp the possible voltage
transients. C8 is not needed for any application when
the input source is close to the regulator. Please refer
to Application Note 88 for details.
Design files for this circuit board are available. Call
the LTC factory.
LTC is a trademark of Linear Technology Corporation
Table 1. Performance Summary (TA = -40°°C to 85°°C unless otherwise noted)
PARAMETER
CONDITION
VALUE
Minimum Input Voltage
2.5V
Maximum Input Voltage
5.5V
Output Voltage VOUT
VIN = 2.5V to 5.5V, IOUT = 0mA to 540mA
3.3V ±4%
Maximum Output Current
VIN = 2.5V
540mA
Maximum Output Current
VIN = 2.7V
600mA
Typical Output Ripple VOUT
VIN = 2.5V, IOUT = 500mA (20MHz BW)
12mVPP (measured at C2)
Typical Switching Frequency
Efficiency (Fixed Freq.)
On/Off Control
22mVPP (measured across E4
and E5)
1MHz
VIN = 4.2V, IOUT = 100mA
94% Typical
VIN = 4.2V, IOUT = 500mA
91% Typical
Off
0.4V MAX
On
1.5V MIN
1
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 797
1MHZ SYNCHRONOUS BUCK-BOOST CONVERTER IN 3MM X 3MM DFN
QUICK START PROCEDURE
Demonstration circuit 797 is easy to set up to evaluate the performance of the LTC3440EDD . Refer to
Figure 1 for proper measurement equipment setup
and follow the procedure below:
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.
1. Place jumpers in the following positions:
2. With power off, connect the input power supply to
Vin and GND.
3. Turn on the power at the input.
NOTE: Make sure that the input voltage does not exceed 5.5V.
4. Check for the proper output voltage. Vout = 3.17V
to 3.43V.
NOTE: 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, ad-
JP1
RUN
JP2
FIXED FREQ.
just the load within the operating range and observe the output voltage regulation, ripple voltage,
efficiency and other parameters.
2
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 797
1MHZ SYNCHRONOUS BUCK-BOOST CONVERTER IN 3MM X 3MM DFN
Figure 1. Proper Measurement Equipment Setup
GND
VIN
Figure 2. Measuring Input or Output Ripple
3
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 797
1MHZ SYNCHRONOUS BUCK-BOOST CONVERTER IN 3MM X 3MM DFN
Efficiency vs. Load
100%
90%
80%
Efficiency%
70%
60%
50%
2.7Vin PWM
40%
3.6Vin PWM
30%
2.7Vin Burst
4.2Vin PWM
3.6Vin Burst
20%
4.2Vin Burst
10%
0%
0.1
1
10
100
1000
Iout (mA)
Figure 3. Efficiency of DC797
Figure 4. Load Transient Response (Vin=3.6V; Channel 1: Vout, 100mV/div; Channel 2: Iout load step: 100mA to 500mA)
4
5
4
*
3
2
D3 IS RECOMMENDED FOR VIN>4.5V.
PLEASE REFER TO DATASHEET FOR DETAILS.
SUMIDA
CDRH4D28C/100
L1
10UH
1
2
2
2
*
1
VIN
+C8
C1
10UF
6.3V
1206
47UF,10V
TAJB
R4
1M
3
7
SHDN
8
2
1
SW2
VIN
SHDN/SS
C6
0.047UF
R1
340K
1%
VOUT 6
FB 9
R3
MODE/SYNC VC 10
RT
GND 5
SYNC
E3
C7
1UF
6.3V
0603
R5
2.2K
E5
GND
C5
10PF
R7
4.87M
R6
60.4K
1%
C2
22UF,6.3V
1210
C4
560PF
15K
R8
6.19M
E2
C
R2
200K
1%
SYNC
VIN
B
BURST
MODE
1
2
GND
C3
180PF
4
11
C
SW1
E4 VOUT
3.3V
VOUT
PHILIPS
U1
LTC3440EDD
D3
POWERMITE
ON SEMI
OPT
D1
PMEG2010EA
PHILIPS
D
D2
PMEG2010EA
2
1
GND
1
D
VIN E1
2.5V-5.5V
1
FIXED
FREQ.
3
SHDN
1
B
JP1
2
JP2
RUN
3
VIN
IOUT
2.5V
540mA
2.7V
600mA
NOTES: UNLESS OTHERWISE SPECIFIED
A
1. ALL RESISTORS ARE IN OHMS, 0402.
ALL CAPS. ARE 0402.
2. INSTALL SHUNTS ON JP1 AND JP2 PIN 2 AND 3.
CUSTOMER NOTICE
CONTRACT NO.
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
CIRUIT 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.
5
4
3
APPROVALS
TECHNOLOGY
DRAWN:
CHECKED: KIM T.
APPROVED:
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
TITLE:
A
1MHz SYNCHRONOUS BUCK-BOOST IN 3mm X 3mm DFN
ENGINEER:
DONGYAN Z. SIZE
DESIGNER:
A
DWG NO.
DC797A-1*LTC3440EDD
DATE: Friday, August 20, 2004
2
SHEET 1
1
REV
A
OF 1
BILL OF MATERIALS
DC797A-1
Linear Technology Corporation
LTC3440EDD
6/20/2005
10:44 AM
1MHz SYNCHRONOUS BUCK-BOOST IN 3mm X 3mm DFN
ENG.: DONGYAN ZHOU (23-30)
Item Qty Reference
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
1
1
1
1
1
1
1
1
2
1
5
2
2
1
1
1
1
1
1
1
1
1
1
Part Description
C1
C2
C3
C4
C5
C6
C7
C8
D1,D2
D3
E1,E2,E3,E4,E5
JP1,JP2
CAP., X5R, 10UF 6.3V,20%,1206
CAP., X5R, 22UF 6.3V,1210
CAP., X7R, 180PF 50V,0402
CAP., X7R, 560PF 50V,0402
CAP., NPO, 10PF 50V,0402
CAP., X5R, 0.047UF 10V
CAP., X5R 1UF 6.3V,20%,0603
CAP., TANT, 47UF 10V, 3528
DIODE, SCHOTTKY,SOD323
DIODE, SCHOTTKY,POWERMITE
TP, TURRET, .094"
HEADER, 3PIN 1 ROW .079CC
SHUNTS FOR JP1&JP2 PIN 2&3 SHUNT, 0.079" CENTER
IND, 10UH, L-CDRH4D28C
L1
R1
RES, CHIP 340K, 1%,0402
R2
RES, CHIP 200K, 1%,0402
R3
RES, CHIP 15K, 5%,0402
R4
RES, CHIP 1M, 5%,0402
R5
RES, CHIP 2.2K, 5%,0402
R6
RES, CHIP 60.4K, 1%,0402
R7
RES, CHIP 4.87M, 1%,0402
R8
RES, CHIP 6.19M, 1%,0402
IC, LTC3440EDD, 10-LEAD DFN3X3, DFN10DD
U1
Page 1 - of - 1
Manufacture / Part #
TAIYO YUDEN, JMK316BJ106ML
TAIYO YUDEN, JMK325BJ226MM
AVX, 04025C181MAT1A
AVX, 04025C561MAT1A
AVX, 04025A100KAT1A
AVX, 0402ZD473MAT1A
TAIYO YUDEN, JMK107BJ105MA
AVX, TAJB476M010
PHILIPS, PMEG2010EA
ON SEMI, MBRM120ET3
MILL-MAX, 2501-2
COMM-CON, 2802S-03-G1
COMM-CON, CCIJ2MM-138G
SUMIDA, CDRH4D28C/100
AAC, CR05-3403FM
AAC, CR05-2003FM
AAC, CR05-153JM
AAC, CR05-105JM
AAC, CR05-222JM
AAC, CR05-6042FM
AAC, CR05-4874FM
AAC, CR05-6194FM
LINEAR TECH. LTC3440EDD
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