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LTC3405AES6#TRMPBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16
1
LTC3405A
3405afa
■
High Efficiency: Up to 96%
■
Very Low Quiescent Current: Only 20
µ
A
During Operation
■
300mA Output Current at V
IN
= 3V
■
2.5V to 5.5V Input Voltage Range
■
1.5MHz 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
■
Low Profile (1mm) ThinSOT
TM
Package
The LTC
®
3405A is a high efficiency monolithic synchro-
nous buck regulator using a constant frequency, current
mode architecture. Supply current during operation is
only 20µA and drops to <1µA in shutdown. The 2.5V to
5.5V input voltage range makes the LTC3405A ideally
suited for single Li-Ion battery-powered applications. 100%
duty cycle provides low dropout operation, extending
battery life in portable systems.
Switching frequency is internally set at 1.5MHz, allowing
the use of small surface mount inductors and capacitors.
The LTC3405A 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 LTC3405A is available in a low
profile (1mm) ThinSOT package.
For fixed 1.5V and 1.8V output versions, refer to the
LTC3405A-1.5/LTC3405A-1.8 data sheet.
■
Cellular Telephones
■
Personal Information Appliances
■
Wireless and DSL Modems
■
Digital Still Cameras
■
MP3 Players
■
Portable Instruments
Figure 1a. High Efficiency Step-Down Converter
1.5MHz, 300mA
Synchronous Step-Down
Regulator in ThinSOT
Figure 1b. Efficiency vs Load Current
V
IN
C
IN
†
2.2µF
CER
V
IN
2.7V
TO 5.5V
*
**
†
††
LTC3405A
RUN
MODE
3
4.7µH**
22pF
887k
280k
3405A F01a
V
OUT
CONNECTED TO V
IN
FOR 2.7V < V
IN
< 3.3V
MURATA LQH3C4R7M34
TAIYO YUDEN LMK212BJ225MG
TAIYO YUDEN JMK212BJ475MG
5
4
6
1
2
SW
V
FB
GND
C
OUT
††
4.7µF
CER
V
OUT
*
3.3V
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
Protected by U.S. Patents, including 6580258, 5481178.
OUTPUT CURRENT (mA)
0.1
EFFICIENCY (%)
10
1000
100
95
90
85
80
75
70
65
60
3405A F01b
1 100
V
IN
= 3.6V
V
IN
= 4.2V
V
IN
= 5.5V
APPLICATIO S
U
FEATURES
TYPICAL APPLICATIO
U
DESCRIPTIO
U
2
LTC3405A
3405afa
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
VFB
Feedback Current ● ±30 nA
I
PK
Peak Inductor Current V
IN
= 3V, V
FB
= 0.7V, Duty Cycle < 35% 375 500 625 mA
V
FB
Regulated Feedback Voltage (Note 4) ● 0.784 0.8 0.816 V
∆V
OVL
∆Output Overvoltage Lockout ∆V
OVL
= V
OVL
– V
FB
● 20 50 80 mV
∆V
FB
Reference Voltage Line Regulation V
IN
= 2.5V to 5.5V (Note 4) ● 0.04 0.4 %/V
V
LOADREG
Output Voltage Load Regulation 0.5 %
V
IN
Input Voltage Range ● 2.5 5.5 V
I
S
Input DC Bias Current (Note 5)
Pulse Skipping Mode V
FB
= 0.7V, Mode = 3.6V, I
LOAD
= 0A 300 400 µA
Burst Mode
®
Operation V
FB
= 0.83V, Mode = 0V, I
LOAD
= 0A 20 35 µA
Shutdown V
RUN
= 0V, V
IN
= 4.2V 0.1 1 µA
f
OSC
Oscillator Frequency V
FB
= 0.8V ● 1.2 1.5 1.8 MHz
V
FB
= 0V 210 kHz
R
PFET
R
DS(ON)
of P-Channel FET I
SW
= 100mA 0.7 0.85 Ω
R
NFET
R
DS(ON)
of N-Channel FET I
SW
= –100mA 0.6 0.90 Ω
I
LSW
SW Leakage V
RUN
= 0V, V
SW
= 0V or 5V, V
IN
= 5V ±0.01 ±1 µA
V
RUN
RUN Threshold ● 0.3 1 1.5 V
I
RUN
RUN Leakage Current ● ±0.01 ±1 µA
V
MODE
MODE Threshold ● 0.3 1.5 2 V
I
MODE
MODE Leakage Current ● ±0.01 ±1 µA
Burst Mode is a registered trademark of Linear Technology Corporation.
LTC3405AES6
T
JMAX
= 125°C, θ
JA
= 250°C/ W
ORDER PART
NUMBER
(Note 1)
Input Supply Voltage .................................. – 0.3V to 6V
MODE, RUN, V
FB
Voltages ......................... – 0.3V to V
IN
SW Voltage .................................. –0.3V to (V
IN
+ 0.3V)
P-Channel Switch Source Current (DC) ............. 400mA
N-Channel Switch Sink Current (DC) ................. 400mA
Peak SW Sink and Source Current .................... 630mA
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Junction Temperature (Note 3)............................ 125°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
S6 PART MARKING
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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.
LTZW
ABSOLUTE AXI U RATI GS
WWWU
PACKAGE/ORDER I FOR ATIO
UU
W
ELECTRICAL CHARACTERISTICS
RUN 1
GND 2
SW 3
6 MODE
5 V
FB
4 V
IN
TOP VIEW
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LTC3405AE is guaranteed to meet performance specifications
from 0°C to 70°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:
LTC3405A: T
J
= T
A
+ (P
D
)(250°C/W)
Note 4: The LTC3405A is tested in a proprietary test mode that connects
V
FB
to the output of the error amplifier.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
3
LTC3405A
3405afa
INPUT VOLTAGE (V)
2.5 3.0 4.0 5.0
EFFICIENCY (%)
4.5
95
90
85
80
75
70
65
60
55
50
3405A G02
3.5 5.5
Burst Mode OPERATION
V
OUT
= 1.8V
I
OUT
= 0.1mA
I
OUT
= 250mA
I
OUT
= 100mA
I
OUT
= 10mA
I
OUT
= 1mA
OUTPUT CURRENT (mA)
0.1
EFFICIENCY (%)
10
1000
100
90
80
70
60
50
40
30
20
10
0
3405A G03
1 100
V
IN
= 3.6V
V
IN
= 4.2V
V
IN
= 3.6V
V
IN
= 4.2V
V
OUT
= 1.8V
PULSE SKIPPING MODE
Burst Mode OPERATION
OUTPUT CURRENT (mA)
0.1
EFFICIENCY (%)
10
1000
100
90
80
70
60
50
40
3405A G04
1 100
V
IN
= 2.7V
V
IN
= 5.5V
V
IN
= 4.2V
V
IN
= 3.6V
V
OUT
= 1.8V
TYPICAL PERFOR A CE CHARACTERISTICS
UW
OUTPUT CURRENT (mA)
0.1
EFFICIENCY (%)
10
1000
100
90
80
70
60
50
40
3405A G05
1 100
V
IN
= 2.7V
V
IN
= 4.2V
V
OUT
= 1.3V
V
IN
= 3.6V
Efficiency vs Input Voltage
Efficiency vs Output Current
Efficiency vs Output Current
Efficiency vs Output Current
Reference Voltage vs
Temperature
Oscillator Frequency vs
Temperature
Oscillator Frequency vs
Supply Voltage
Output Voltage vs Load Current
R
DS(ON
) vs Input Voltage
TEMPERATURE (°C)
–50
REFERENCE VOLTAGE (V)
0.814
0.809
0.804
0.799
0.794
0.789
0.784
25 75
–25 0
50 100 125
V
IN
= 3.6V
3405A G06
TEMPERATURE (°C)
–50
FREQUENCY (MHz)
1.70
1.65
1.60
1.55
1.50
1.45
1.40
1.35
1.30
25 75
–25 0
50 100 125
V
IN
= 3.6V
3405A G07
SUPPLY VOLTAGE (V)
2
OSCILLATOR FREQUENCY (MHz)
1.8
1.7
1.6
1.5
1.4
1.3
1.2
34 56
3405A G08
LOAD CURRENT (mA)
0
OUTPUT VOLTAGE (V)
1.834
1.824
1.814
1.804
1.794
1.784
1.774
100
200 300 400
3405A G09
500 600
Burst Mode
OPERATION
PULSE SKIPPING MODE
INPUT VOLTAGE (V)
0
R
DS(0N)
(Ω)
2
4
5
3405A G10
13
6
7
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
MAIN SWITCH
SYNCHRONOUS
SWITCH
(From Figure1a Except for the Resistive Divider Resistor Values)
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16

LTC3405AES6#TRMPBF

Mfr. #:
Buy LTC3405AES6#TRMPBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators 300mA, 1.5MHz Syn Step-dwn convtr
Lifecycle:
New from this manufacturer.
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