LTC3410
2.25MHz, 300mA
Synchronous Step-Down
Regulator in SC70
FEATURES
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DESCRIPTIO
High Efficiency: Up to 96%
Low Ripple (20mV
P-P
) Burst Mode Operation: I
Q
26
µ
A
Low Output Voltage Ripple
300mA Output Current at V
IN
= 3V
380mA Minimum Peak Switch Current
2.5V to 5.5V Input Voltage Range
2.25MHz Constant Frequency Operation
No Schottky Diode Required
Low Dropout Operation: 100% Duty Cycle
Stable with Ceramic Capacitors
0.8V Reference Allows Low Output Voltages
Shutdown Mode Draws < 1µA Supply Current
±2%
Output Voltage Accuracy
Current Mode Operation for Excellent Line and
Load Transient Response
Overtemperature Protected
Available in Low Profile SC70 Package
The LTC
®
3410 is a high efficiency monolithic synchro-
nous buck regulator using a constant frequency, current
mode architecture. The device is available in adjustable
and fixed output voltage versions. Supply current during
operation is only 26µA, dropping to <1µA in shutdown.
The 2.5V to 5.5V input voltage range makes the LTC3410
ideally suited for single Li-Ion battery-powered applica-
tions. 100% duty cycle provides low dropout operation,
extending battery life in portable systems.
Switching frequency is internally set at 2.25MHz, allowing
the use of small surface mount inductors and capacitors.
The LTC3410 is specifically designed to work well with
ceramic output capacitors, achieving very low output
voltage ripple and a small PCB footprint.
The internal synchronous switch increases efficiency and
eliminates the need for an external Schottky diode. Low
output voltages are easily supported with the 0.8V feed-
back reference voltage. The LTC3410 is available in a tiny,
low profile SC70 package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All
other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 5994885.
APPLICATIO S
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Cellular Telephones
Wireless and DSL Modems
Digital Cameras
MP3 Players
Portable Instruments
TYPICAL APPLICATIO
V
IN
2.7V
TO 5.5V
V
IN
RUN
V
FB
GND
SW
Efficiency and Power Loss
vs Output Current
100
1
90
V
OUT
2.5V
EFFICIENCY (%)
4.7µH
C
IN
4.7µF
CER
LTC3410
10pF
C
OUT
4.7µF
CER
80
70
60
50
40
30
20
10
0
0.1
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
1
10
100
OUTPUT CURRENT (mA)
POWER LOSS
EFFICIENCY
887k
412k
3410 TA01a
U
0.1
POWER LOSS (W)
U
U
0.01
0.001
0.0001
1000
3410 TA01b
3410fb
1
LTC3410
ABSOLUTE
AXI U
RATI GS
(Note 1)
Peak SW Sink and Source Current .................... 630mA
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Junction Temperature (Notes 3, 5) ...................... 125°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
Input Supply Voltage .................................. – 0.3V to 6V
RUN, V
FB
Voltages ..................................... – 0.3V to V
IN
SW Voltage (DC) ......................... – 0.3V to (V
IN
+ 0.3V)
P-Channel Switch Source Current (DC) ............. 500mA
N-Channel Switch Sink Current (DC) ................. 500mA
PACKAGE/ORDER I FOR ATIO
TOP VIEW
RUN 1
GND 2
SW 3
6 V
FB
5 GND
4 V
IN
SC6 PACKAGE
6-LEAD PLASTIC SC70
T
JMAX
= 125°C,
θ
JA
= 250°C/ W
ORDER PART NUMBER
LTC3410ESC6
SC6 PART MARKING
LBSD
Order Options
Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges. *A separate data sheet is available for the LT3410-1.875.
ELECTRICAL CHARACTERISTICS
The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C.
V
IN
= 3.6V unless otherwise specified.
SYMBOL
I
VFB
I
VOUT
I
PK
V
FB
∆V
FB
V
OUT
PARAMETER
Feedback Current
Output Voltage Feedback Current
Peak Inductor Current
Regulated Feedback Voltage
Reference Voltage Line Regulation
Regulated Output Voltage
CONDITIONS
Adjustable Output Voltage
Fixed Output Voltage
V
IN
= 3V, V
FB
= 0.7V or V
OUT
= 90%, Duty Cycle < 35%
Adjustable Output Voltage (LTC3410E)
V
IN
= 2.5V to 5.5V
LTC3410-1.2, I
OUT
= 100mA
LTC3410-1.5, I
OUT
= 100mA
LTC3410-1.65, I
OUT
= 100mA
LTC3410-1.8, I
OUT
= 100mA
LTC3410-1.875, I
OUT
= 100mA
V
IN
= 2.5V to 5.5V
I
LOAD
= 50mA to 250mA
●
●
●
●
●
●
●
●
●
●
●
∆V
OUT
V
LOADREG
V
IN
Output Voltage Line Regulation
Output Voltage Load Regulation
Input Voltage Range
2
U
U
W
W W
U
W
TOP VIEW
RUN 1
GND 2
SW 3
6 V
OUT
5 GND
4 V
IN
SC6 PACKAGE
6-LEAD PLASTIC SC70
T
JMAX
= 125°C,
θ
JA
= 250°C/ W
ORDER PART NUMBER
LTC3410ESC6-1.2
LTC3410ESC6-1.5
LTC3410ESC6-1.65
LTC3410ESC6-1.8
LTC3410ESC6-1.875*
SC6 PART MARKING
LCHV
LCNB
LCJF
LCNC
LCFQ
MIN
TYP
3.3
MAX
±30
6
0.816
0.4
1.224
1.53
1.683
1.836
1.913
0.4
5.5
UNITS
nA
µA
mA
V
%/V
V
V
V
V
V
%/V
%
V
3410fb
380
0.784
1.176
1.47
1.617
1.764
1.837
490
0.8
0.04
1.2
1.5
1.65
1.8
1.875
0.04
0.5
2.5
LTC3410
ELECTRICAL CHARACTERISTICS
The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C.
V
IN
= 3.6V unless otherwise specified.
SYMBOL
V
UVLO
I
S
PARAMETER
Undervoltage Lockout Threshold
Input DC Bias Current
Burst Mode
®
Operation
Shutdown
Oscillator Frequency
R
DS(ON)
of P-Channel FET
R
DS(ON)
of N-Channel FET
SW Leakage
RUN Threshold
RUN Leakage Current
CONDITIONS
V
IN
Rising
V
IN
Falling
(Note 4)
V
FB
= 0.83V or V
OUT
= 104%, I
LOAD
= 0A
V
RUN
= 0V
V
FB
= 0.8V or V
OUT
= 100%
V
FB
= 0V or V
OUT
= 0V
I
SW
= 100mA
I
SW
= –100mA
V
RUN
= 0V, V
SW
= 0V or 5V, V
IN
= 5V
●
●
●
MIN
TYP
2
1.94
26
0.1
MAX
2.3
UNITS
V
V
µA
µA
MHz
kHz
Ω
Ω
µA
V
µA
35
1
2.7
0.9
0.7
±1
1.5
±1
f
OSC
R
PFET
R
NFET
I
LSW
V
RUN
I
RUN
1.8
2.25
310
0.75
0.55
±0.01
0.3
1
±0.01
Burst Mode is a registered trademark of Linear Technology Corporation.
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
The LTC3410E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC3410: T
J
= T
A
+ (P
D
)(250°C/W)
Note 4:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 5:
This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
TYPICAL PERFOR A CE CHARACTERISTICS
(From Figure1 Except for the Resistive Divider Resistor Values)
Efficiency vs Input Voltage
100
90
80
I
OUT
= 250mA
70
60
50
40
30
2.5
V
OUT
= 1.8V
3
4.5
4
3.5
INPUT VOLTAGE (V)
5
5.5
3410 G02
I
OUT
= 100mA
EFFFICIENCY (%)
I
OUT
= 10mA
EFFICIENCY (%)
I
OUT
= 1mA
60
50
40
30
20
10
V
OUT
= 1.8V
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
1000
3410 G03
EFFICIENCY (%)
I
OUT
= 0.1mA
U W
Efficiency vs Output Current
100
90
80
70
100
90
80
70
60
50
40
30
20
10
Efficiency vs Output Current
0
0.1
1
10
100
OUTPUT CURRENT (mA)
V
OUT
= 1.2V
0
1
10
100
0.1
OUTPUT CURRENT (mA)
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
1000
3410 G04
3410fb
3
LTC3410
TYPICAL PERFOR A CE CHARACTERISTICS
(From Figure 1 Except for the Resistive Divider Resistor Values)
Reference Voltage vs
Temperature
0.814
V
IN
= 3.6V
2.7
2.6
OSCILLATOR FREQUENCY (MHz)
REFERENCE VOLTAGE (V)
2.5
2.4
2.3
2.2
2.1
2.0
1.9
OSCILLATOR FREQUENCY (MHz)
–25
0
25
50
75
TEMPERATURE (°C)
100
125
0.809
0.804
0.799
0.794
0.789
0.784
–50 –25
50
25
75
0
TEMPERATURE (°C)
Output Voltage vs Load Current
1.0
1.2
V
IN
= 3.6V
V
OUT
= 1.8V
0.5
V
OUT
ERROR (%)
0
R
DS (ON)
(Ω)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
SYNCHRONOUS SWITCH
R
DS (ON)
(Ω)
–0.5
–1.0
–1.5
0
100
400
300
LOAD CURRENT (mA)
200
Dynamic Supply Current vs V
IN
50
DYNAMIC SUPPLY CURRENT (µA)
DYNAMIC SUPPLY CURRENT (µA)
V
OUT
= 1.2V
I
LOAD =
0A
40
SWITCH LEAKAGE (nA)
30
20
10
0
1
2
3
V
IN
(V)
4
4
U W
100
3410 G05
Oscillator Frequency vs
Temperature
V
IN
= 3.6V
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2.0
1.9
1.8
Oscillator Frequency vs
Supply Voltage
125
1.8
–50
2
3
5
4
SUPPLY VOLTAGE (V)
6
3410 G07
3410 G06
R
DS(ON
) vs Input Voltage
1.2
1.0
0.8
0.6
1.1
1.0
0.9
0.8
MAIN SWITCH
R
DS(ON)
vs Temperature
V
IN
= 4.2V
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
0.4
V
IN
= 2.7V
0.2
V
IN
= 3.6V
MAIN SWITCH
SYNCHRONOUS SWITCH
500
3410 G08
1
2
5
4
3
INPUT VOLTAGE (V)
6
7
3410 G09
0
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
3410 G10
Dynamic Supply Current
vs Temperature
50
110
100
40
90
80
70
60
50
40
30
20
10
Switch Leakage vs Temperature
V
IN
= 5.5V
RUN = 0V
30
SYNCHRONOUS
SWITCH
20
10
MAIN
SWITCH
5
6
3410 G11
0
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
125
0
–50
–25
50
25
0
75
TEMPERATURE (°C)
100
125
3410 G12
3410 G13
3410fb
LTC3410
TYPICAL PERFOR A CE CHARACTERISTICS
(From Figure 1 Except for the Resistive Divider Resistor Values)
Switch Leakage vs Input Voltage
600
550
500
LEAKAGE CURRENT (pA)
450
400
350
300
250
200
150
100
50
0
0
1
4
3
2
INPUT VOLTAGE (V)
5
6
3410 G14
MAIN
SWITCH
SYNCHRONOUS
SWITCH
Start-Up from Shutdown
RUN
2V/DIV
V
OUT
1V/DIV
I
L
200mA/DIV
200µs/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 0A
U W
Burst Mode Operation
Start-Up from Shutdown
SW
5V/DIV
RUN
2V/DIV
V
OUT
50mV/DIV
AC COUPLED
V
OUT
1V/DIV
I
L
100mA/DIV
I
L
200mA/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 10mA
2µs/DIV
200µs/DIV
3410 G15
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 300mA
3410 G16
Load Step
Load Step
V
OUT
100mV/DIV
AC COUPLED
V
OUT
100mV/DIV
AC COUPLED
I
L
200mA/DIV
I
L
200mA/DIV
I
LOAD
200mA/DIV
10µs/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 0mA TO 300mA
I
LOAD
200mA/DIV
10µs/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 20mA TO 300mA
3410 G19
3410 G17
3410 G18
3410fb
5
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