LTC3626
20V, 2.5A Synchronous
Monolithic Step-Down Regulator with
Current and Temperature Monitoring
FEATURES
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DESCRIPTION
The LTC
®
3626 is a high efficiency, monolithic synchronous
buck regulator using a phase-lockable controlled on-time,
current mode architecture capable of supplying up to 2.5A
of output current. The operating supply voltage range is
3.6V to 20V, making it suitable for a wide range of power
supply applications.
The operating frequency is programmable from 500kHz to
3MHz with an external resistor allowing the use of small
surface mount inductors. For applications sensitive to
switching noise, the LTC3626 can be externally synchro-
nized over the same frequency range. An internal phase-
locked loop aligns the on-time of the top power MOSFET to
the internal or external clock. This unique controlled on-time
architecture is ideal for high step-down ratio applications
that demand high switching frequencies and fast transient
response. An internal phase lock loop servos the on-time
of the internal one-shot timer to match the frequency of
the internal clock or an applied external clock.
The LTC3626 offers two operational modes: Burst
Mode and forced continuous mode to allow the user
to optimize output voltage ripple, noise and light load
efficiency for a given application.
L,
LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered and Hot
Swap is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners. Protected by U.S. Patents, including 5481178, 5847554, 6580258,
6304066, 6476589, 6774611, 5994885.
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3.6V to 20V Input Voltage Range
Wide Output Voltage Range of 0.6V to 97% V
IN
Optimized for 0.6V to 6V
Low R
DS(ON)
Integrated Switches Provide Up to 95%
Efficiency
Up to 2.5A of Output Current
Average Input and Output Current Monitoring
Programmable Average Input/Output Current Limit
Die Temperature Monitor and Programmable Limit
Adjustable Switching Frequency: 500kHz to 3MHz
External Frequency Synchronization
Current Mode Operation for Excellent Line and Load
Transient Response
0.6V Reference with 1% Accuracy Over Temperature
User Selectable Burst Mode
®
or Forced Continuous
Operation
Short-Circuit Protected
Output Voltage Tracking Capability
Power Good Status Output
Available in Small, Thermally Enhanced, 20-Lead
(3mm
×
4mm) QFN Package
APPLICATIONS
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Distributed Power Systems
Battery-Powered Instruments
Point-of-Load Power Supply
TYPICAL APPLICATION
V
IN
3.6V TO 20V
BOOST
LTC3626
PGOOD
INTV
CC
TRACK/SS
SW
2.2µF
ITH
MODE/SYNC
V
ON
TSET
IMON
IN
FB
TMON
RT
IMON
OUT
SGND
PGND
1µF
5.1k
47µF
PV
IN
SV
IN
RUN
EFFICIENCY (%)
0.1µF
2.2µH
115k
22pF
25.5k
324k
3626 TA01
Efficiency vs Load Current
100
90
80
70
60
50
40
30
20
10
0
1
0.1
1
V
OUT
= 3.3V
10
POWER LOSS (W)
V
OUT
3.3V
47µF 2.5A
Burst Mode
0.01
OPERATION
V
IN
= 12V
V
IN
= 5V
0.001
10
100
1000
10000
3626 TA01b
LOAD CURRENT (mA)
3626f
1
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
