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LTC3542EDC#TRMPBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16
LTC3542
1
3542fa
500mA, 2.25MHz
Synchronous Step-Down
DC/DC Converter
The LTC
®
3542 is a high effi ciency monolithic synchronous
buck converter using a constant frequency, current mode
architecture. Supply current during operation is only
26μA, dropping to <1μA in shutdown. The 2.5V to 5.5V
input voltage range makes the LTC3542 ideally suited for
single Li-Ion battery-powered applications. 100% duty
cycle provides low dropout operation, extending battery
life in portable systems. The output voltage is adjustable
from 0.6V to V
IN
. Internal power switches are optimized
to provide high effi ciency and eliminate the need for an
external Schottky diode.
Switching frequency is internally set at 2.25MHz, allowing
the use of small surface mount inductors and capacitors,
and it can synchronize to an external clock signal with a
frequency range of 1MHz to 3MHz through the MODE/
SYNC pin. The LTC3542 is specifi cally designed to work
well with ceramic output capacitors, achieving very low
output voltage ripple and a small PCB footprint.
The LTC3542 can be confi gured for the power saving Burst
Mode
®
Operation. For reduced noise and RF interference,
the MODE/SYNC pin can be confi gured for pulse skipping
operation.
■
Cellular Telephones
■
Wireless and DSL Modems
■
Digital Cameras
■
MP3 Players
■
PDAs and Other Handheld Devices
■
High Effi ciency: Up to 96%
■
High Peak Switch Current: 1000mA
■
Low Output Ripple (<20mV
P-P
Typical)
Burst Mode Operation: Only 26μA
■
Very Low Quiescent Current: Only 26μA
■
2.5V to 5.5V Input Voltage Range
■
2.25MHz Constant Frequency Operation
■
1MHz to 3MHz External Frequency Synchronization
■
Low Dropout Operation: 100% Duty Cycle
■
No Schottky Diode Required
■
Internal Soft-Start Limits Inrush Current
■
0.6V 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 6-Lead 2mm × 2mm DFN and Small TSOT
, LT, LTC, LTM and Burst Mode 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.
V
IN
LTC3542
RUN
75k
3542 TA01a
150k
22pF
2.2μH
C
IN
10μF
CER
C
OUT
10μF
CER
SW
V
IN
2.7V TO 5.5V
V
OUT
1.8V
500mA
V
FB
MODE/SYNC
GND
Effi ciency and Power Loss vs Output Current
OUTPUT CURRENT (mA)
30
EFFICIENCY (%)
POWER LOSS (mW)
90
100
20
10
80
50
70
60
40
0.1 10 100 1000
3542 TA01b
0
100
1000
10
1
0.1
1
V
IN
= 3.6V
V
OUT
= 1.8V
FEATURES DESCRIPTION
APPLICATIONS
TYPICAL APPLICATION
LTC3542
2
3542fa
ELECTRICAL CHARACTERISTICS
Input Supply Voltage (V
IN
) ........................... –0.3V to 6V
V
FB
, RUN Voltages .......................................–0.3V to V
IN
MODE Voltage ................................–0.3V to (V
IN
+ 0.3V)
SW Voltage ....................................–0.3V to (V
IN
+ 0.3V)
Operating Temperature Range (Note 2)
LTC3542E ............................................ –40°C to 85°C
LTC3542I ........................................... –40°C to 125°C
The ● denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 3.6V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Operating Voltage Range
●
2.5 5.5 V
I
FB
Feedback Input Current ±30 nA
V
FB
Feedback Voltage (Note 4)
●
0.588 0.6 0.612 V
ΔV
LINE_REG
Reference Voltage Line Regulation (Note 4) V
IN
= 2.5V to 5.5V 0.04 0.2 %/V
ΔV
LOAD_REG
Output Voltage Load Regulation (Note 4) I
LOAD
= 100mA to 500mA 0.02 0.2 %
Junction Temperature (Note 7) ............................. 125°C
Storage Temperature Range ................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
TSOT-23 ............................................................ 300°C
Refl ow Peak Body Temperature (DFN) .................. 260°C
ABSOLUTE MAXIMUM RATINGS
(Note 1)
TOP VIEW
RUN
SW
V
FB
V
IN
GND
DC PACKAGE
6-LEAD (2mm × 2mm) PLASTIC DFN
4
5
7
6
3
2
1
MODE
/
SYNC
T
JMAX
= 125°C, θ
JA
= 102°C/W, θ
JC
= 20°C/W (SOLDERED TO A 4-LAYER BOARD, NOTE 3)
EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB
V
IN
1
GND 2
V
FB
3
6 SW
5 MODE/SYNC
4 RUN
TOP VIEW
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
JMAX
= 125°C, θ
JA
= 215°C/W
PIN CONFIGURATION
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3542EDC#PBF LTC3542EDC#TRPBF LCFR 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C
LTC3542IDC#PBF LTC3542IDC#TRPBF LCFR 6-Lead (2mm × 2mm) Plastic DFN –40°C to 125°C
LTC3542ES6#PBF LTC3542ES6#TRPBF LCFS 6-Lead Plastic TSOT-23 –40°C to 85°C
LTC3542IS6#PBF LTC3542IS6#TRPBF LCFS 6-Lead Plastic TSOT-23 –40°C to 125°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based fi nish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/
LTC3542
3
3542fa
TYPICAL PERFORMANCE CHARACTERISTICS
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. No pin should exceed 6V.
Note 2: The LTC3542 is guaranteed to meet performance specifi cations
from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls. The LTC3542I is guaranteed over the full
–40°C to 125°C operating temperature range.
Note 3: Failure to solder the Exposed Pad of the package to the PC board
will result in a thermal resistance much higher than 102°C/W.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
S
Input DC Supply Current (Note 5)
Active Mode
Sleep Mode
Shutdown
V
FB
= 0.5V
V
FB
= 0.7V, MODE = 0V
RUN = 0V
26
0.1
500
35
1
μA
μA
μA
f
OSC
Oscillator Frequency V
FB
= 0.6V
●
1.8 2.25 2.7 MHz
f
SYNC
Synchronous Frequency V
FB
= 0.6V 1 3 MHz
I
LIM
Peak Switch Current V
IN
= 3V, V
FB
= 0.5V, Duty Cycle < 35% 650 1000 mA
R
DS(ON)
P-Channel On Resistance (Note 6)
N-Channel On Resistance (Note 6)
I
SW
= 100mA
I
SW
= –100mA
0.5
0.35
0.65
0.55
Ω
Ω
I
SW(LKG)
Switch Leakage Current V
IN
= 5V, V
RUN
= 0V, V
SW
= 0V or 5V ±0.01 ±1 μA
V
UVLO
Undervoltage Lockout Threshold V
IN
Rising
V
IN
Falling 1.8
2.0
1.9
2.3 V
V
V
RUN
RUN Threshold
●
0.3 1.5 V
I
RUN
RUN Leakage Current
●
±0.01 ±1 μA
V
MODE/SYNC
MODE/SYNC Threshold
●
0.3 1.2 V
I
MODE/SYNC
MODE/SYNC Leakage Current
●
±0.01 ±1 μA
Note 4: The converter is tested in a proprietary test mode that connects
the output of the error amplifi er to the SW pin, which is connected to an
external servo loop.
Note 5: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 6: The DFN switch on resistance is guaranteed by correlation to wafer
level measurements.
Note 7: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
) • (θ
JA
).
Burst Mode Operation Pulse Skip Mode Operation Start-Up from Shutdown
SW
2V/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 25mA
FIGURE 3a CIRCUIT
2μs/DIV
3542 G01
V
OUT
50mV/DIV
AC COUPLED
I
L
100mA/DIV
SW
2V/DIV
I
L
100mA/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 25mA
FIGURE 3a CIRCUIT
400ns/DIV
3542 G02
V
OUT
50mV/DIV
AC COUPLED
RUN
2V/DIV
I
L
100mA/DIV
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 0A
FIGURE 3a CIRCUIT
400μs/DIV
3542 G03
V
OUT
1V/DIV
T
A
= 25°C unless otherwise specifi ed.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 3.6V unless otherwise noted.
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16

LTC3542EDC#TRMPBF

Mfr. #:
Buy LTC3542EDC#TRMPBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators 500mA, 2.25MHz Sync Buck DC/DC Conv
Lifecycle:
New from this manufacturer.
Delivery:
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