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LTC3612EUDC#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30
LTC3612
1
3612fc
For more information www.linear.com/LTC3612
Typical applicaTion
FeaTures
applicaTions
DescripTion
3A, 4MHz Monolithic
Synchronous Step-Down
DC/DC Converter
The LT C
®
3612 is a low quiescent current monolithic syn-
chronous buck regulator using a current mode, constant
frequency architecture. The no-load DC supply current
in sleep mode is only 70µA while maintaining the output
voltage (Burst Mode operation) at no load, dropping to
zero current in shutdown. The 2.25V to 5.5V input supply
voltage range makes the L
TC3612 ideally suited for single
Li-Ion as well as fixed low voltage input applications. 100%
duty cycle capability provides low dropout operation,
extending the operating time in battery-powered systems.
The operating frequency is externally programmable up to
4MHz, allowing the use of small surface mount inductors.
For switching noise-sensitive applications, the LTC3612
can be synchronized to an external clock at up to 4MHz.
Forced continuous mode operation in the LTC3612 reduces
noise and RF interference. Adjustable compensation allows
the transient response to be optimized over a wide range
of loads and output capacitors.
The internal synchronous switch increases efficiency and
eliminates the need for an external catch diode, saving
external components and board space. The LTC3612 is
offered in a leadless 20-pin 3mm × 4mm QFN or a thermally
enhanced 20-pin TSSOP package.
Efficiency and Power Loss vs Load Current
n
3A Output Current
n
2.25V to 5.5V Input Voltage Range
n
Low Output Ripple Burst Mode
®
Operation: I
Q
= 70µA
n
±1% Output Voltage Accuracy
n
Output Voltage Down to 0.6V
n
High Efficiency: Up to 95%
n
Low Dropout Operation: 100% Duty Cycle
n
Shutdown Current: ≤1µA
n
Adjustable Switching Frequency: Up to 4MHz
n
Optional Active Voltage Positioning (AVP) with
Internal Compensation
n
Selectable Pulse-Skipping/Forced Continuous/
Burst Mode Operation with Adjustable Burst Clamp
n
Programmable Soft-Start
n
Inputs for Start-Up Tracking or External Reference
n
DDR Memory Mode, I
OUT
= ±1.5A
n
Available in Thermally Enhanced 20-Pin
(3mm × 4mm) QFN and TSSOP Packages
n
Point-of-Load Supplies
n
Distributed Power Supplies
n
Portable Computer Systems
n
DDR Memory Termination
n
Handheld Devices
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners. Protected by U.S. Patents, including 6580258, 5481178, 5994885, 6304066, 6498466,
6611131.
RUN
TRACK/SS
RT/SYNC
PGOOD
ITH
SGND
PGND
V
IN
2.5V TO 5.5V
PV
IN_DRV
DDR
SV
IN
LTC3612 SW
PV
IN
560nH
665k
210k
3612 TA01a
22µF
×2
MODE V
FB
47µF
V
OUT
2.5V
3A
OUTPUT CURRENT (mA)
30
EFFICIENCY (%)
POWER LOSS (W)
90
100
20
10
80
50
70
60
40
1 100 1000 10000
3612 TA01b
0
10
0.001
1
0.1
0.01
10
V
IN
= 5V
V
IN
= 3.3V
V
IN
= 2.8V
LTC3612
2
3612fc
For more information www.linear.com/LTC3612
absoluTe MaxiMuM raTings
PV
IN
, SV
IN
, PV
IN_DRV
Voltages ..................... –0.3V to 6V
SW Voltage ..................................–0.3V to (PV
IN
+ 0.3V)
ITH, RT/SYNC Voltages ............... –0.3V to (SV
IN
+ 0.3V)
DDR, TRACK/SS Voltages ........... –0.3V to (SV
IN
+ 0.3V)
MODE, RUN, V
FB
Voltages .......... –0.3V to (SV
IN
+ 0.3V)
PGOOD Voltage ............................................ –0.3V to 6V
(Note 1)
20 19 18 17
7 8
TOP VIEW
21
UDC PACKAGE
20-LEAD (3mm × 4mm) PLASTIC QFN
9 10
6
5
4
3
2
1
11
12
13
14
15
16
DDR
RT/SYNC
SGND
NC
SW
SW
PGOOD
RUN
SV
IN
PV
IN_DRV
SW
SW
TRACK/SS
ITH
V
FB
MODE
NC
PV
IN
PV
IN
NC
T
JMAX
= 150°C, θ
JA
= 43°C/W
EXPOSED PAD (PIN 21) IS PGND, MUST BE SOLDERED TO PCB
FE PACKAGE
20-LEAD PLASTIC TSSOP
1
2
3
4
5
6
7
8
9
10
TOP VIEW
20
19
18
17
16
15
14
13
12
11
SV
IN
RUN
PGOOD
MODE
V
FB
ITH
TRACK/SS
DDR
RT/SYNC
SGND
PV
IN_DRV
SW
NC
SW
PV
IN
PV
IN
SW
NC
SW
NC
21
T
JMAX
= 150°C, θ
JA
= 38°C/W
EXPOSED PAD (PIN 21) IS PGND, MUST BE SOLDERED TO PCB
pin conFiguraTion
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3612EUDC#PBF LTC3612EUDC#TRPBF LDQT
20-Lead (3mm × 4mm) Plastic QFN
–40°C to 125°C
LTC3612IUDC#PBF LTC3612IUDC#TRPBF LDQT
20-Lead (3mm × 4mm) Plastic QFN
–40°C to 125°C
LTC3612HUDC#PBF LTC3612HUDC#TRPBF LDQT
20-Lead (3mm × 4mm) Plastic QFN
–40°C to 150°C
LTC3612MPUDC#PBF LTC3612MPUDC#TRPBF LDQT
20-Lead (3mm × 4mm) Plastic QFN
–55°C to 150°C
LTC3612EFE#PBF LTC3612EFE#TRPBF LTC3612FE 20-Lead Plastic TSSOP –40°C to 125°C
LTC3612IFE#PBF LTC3612IFE#TRPBF LTC3612FE 20-Lead Plastic TSSOP –40°C to 125°C
LTC3612HFE#PBF LTC3612HFE#TRPBF LTC3612FE 20-Lead Plastic TSSOP –40°C to 150°C
LTC3612MPFE#PBF LTC3612MPFE#TRPBF LTC3612FE 20-Lead Plastic TSSOP –55°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
Operating Junction Temperature Range
(Notes 2, 11) .......................................... –55°C to 150°C
Storage Temperature .............................. –65°C to 150°C
Reflow Peak Body Temperature (QFN) .................. 260°C
Lead Temperature (Soldering, 10 sec)
TSSOP .............................................................. 300°C
LTC3612
3
3612fc
For more information www.linear.com/LTC3612
elecTrical characTerisTics
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 3.3V, RT/SYNC = SV
IN
, unless otherwise specified.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Operating Voltage Range
l
2.25 5.5 V
V
UVLO
Undervoltage Lockout Threshold SV
IN
Ramping Down
SV
IN
Ramping Up
l
l
1.7
2.25
V
V
V
FB
Feedback Voltage Internal Reference (Notes 3, 4) V
TRACK/SS
= SV
IN
, V
DDR
= 0V
0°C < T
J
< 85°C
–40°C < T
J
< 125°C
–55°C < T
J
< 150°C
l
l
0.594
0.591
0.589
0.6
0.606
0.609
0.611
V
V
V
Feedback Voltage External Reference
(Note 7)
(Notes 3, 4) V
TRACK/SS
= 0.3V, V
DDR
= SV
IN
0.289 0.3 0.311 V
(Notes 3, 4) V
TRACK/SS
= 0.5V, V
DDR
= SV
IN
0.489 0.5 0.511 V
I
FB
Feedback Input Current V
FB
= 0.6V
l
±30 nA
∆V
LINEREG
Line Regulation SV
IN
= PV
IN
= 2.25V to 5.5V
(Notes 3, 4) TRACK/SS = SV
IN
l
0.2 %/V
∆V
LOADREG
Load Regulation ITH from 0.5V to 0.9V (Notes 3, 4)
V
ITH
= SV
IN
(Note 5)
0.25
2.6
%
%
I
S
Active Mode V
FB
= 0.5V, V
MODE
= SV
IN
(Note 6) 1100 µA
Sleep Mode V
FB
= 0.7V, V
MODE
= 0V, ITH = SV
IN
(Note 5)
70 100 µA
V
FB
= 0.7V, V
MODE
= 0V (Note 4) 120 160 µA
Shutdown SV
IN
= PV
IN
= 5.5V, V
RUN
= 0V 0.1 1 µA
R
DS(ON)
Top Switch On-Resistance PV
IN
= 3.3V (Note 10) 70 mΩ
Bottom Switch On-Resistance PV
IN
= 3.3V (Note 10) 45 mΩ
I
LIM
Top Switch Current Limit Sourcing (Note 8), V
FB
= 0.5V
Duty Cycle <35%
Duty Cycle = 100%
5.2
3.7
6
6.8
A
A
Bottom Switch Current Limit Sinking (Note 8), V
FB
= 0.7V,
Forced Continuous Mode
–3 –4 –5 A
g
m(EA)
Error Amplifier Transconductance –5µA < I
ITH
< 5µA (Note 4) 200 µS
I
EAO
Error Amplifier Max Output Current (Note 4) ±30 µA
t
SS
Internal Soft-Start Time V
FB
from 0.06V to 0.54V,
TRACK/SS = SV
IN
0.65 1 1.5 ms
V
TRACK/SS
Enable Internal Soft-Start (Note 7 ) 0.62 V
t
TRACK/SS_DIS
Soft-Start Discharge Time at
Start-Up
70 µs
R
ON(TRACK/SS_DIS)
TRACK/SS Pull-Down Resistor at
Start-Up
200 Ω
f
OSC
Oscillator Frequency RT/SYNC = 370k
l
0.8 1 1.2 MHz
Internal Oscillator Frequency V
RT/SYNC
= SV
IN
l
1.8 2.25 2.7 MHz
f
SYNC
Synchronization Frequency 0.3 4 MHz
V
RT/SYNC
SYNC Level High 1.2 V
SYNC Level Low . 0.3 V
I
SW(LKG)
Switch Leakage Current SV
IN
= PV
IN
= 5.5V, V
RUN
= 0V 0.1 1 µA
V
DDR
DDR Option Enable Voltage SV
IN
– 0.3 V
V
MODE
(Note 9)
Internal Burst Mode Operation 0.3 V
Pulse-Skipping Mode
SV
IN
– 0.3 V
Forced Continuous Mode 1.1 SV
IN
• 0.58 V
External Burst Mode Operation 0.45 0.8 V
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LTC3612EUDC#PBF

Mfr. #:
Buy LTC3612EUDC#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators 3A, 4MHz, Monolithic Synchronous Step-Down Regulator
Lifecycle:
New from this manufacturer.
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