42V, 750mA Synchronous
0.1µF
4.7µF
1µF
22µF
X7R
1206
10pF
4.7µH
18.2k
1M
187k
100k
10nF
V
IN
EN/UV
SYNC
LT8607
INTV
CC
TR/SS
RT
GND
FB
PG
SW
BST
VIN5.7V to 42V
V
OUT
5V
750mA
POWER
GOOD
fSW = 2MHz
8607 TA01a
fSW = 2MHz
L = 4.7µH
I
OUT
(mA)0125
250
375
500
625
7505055
6065707580859095100
8607 TA01b
Step-Down Regulator with
2.5µA Quiescent Current
FEATURES DESCRIPTION
LT8607/LT8607B
Wide Input Voltage Range: 3.0V to 42V
®
Ultralow Quiescent Current Burst Mode
n
<3µA IQ Regulating 12VIN to 3.3V
n
Output Ripple <10mV
P-P
Operation:
OUT
High Efficiency 2MHz Synchronous Operation:
n
>93% Efficiency at 0.5A, 12VIN to 5V
OUT
750mA Maximum Continuous Output
Fast Minimum Switch-On Time: 35ns
Adjustable and Synchronizable: 200kHz to 2.2MHz
Spread Spectrum Frequency Modulation for Low EMI
Allows Use of Small Inductors
Low Dropout
Peak Current Mode Operation
Accurate 1V Enable Pin Threshold
Internal Compensation
Output Soft-Start and Tracking
Small Thermally Enhanced 10-Lead MSOP Package or
8-Lead 2mm × 2mm DFN Package
APPLICATIONS
General Purpose Step-Down Converter
Low EMI Step
Down
The LT®8607 is a compact, high efficiency, high speed syn-
chronous monolithic step-down switching regulator that
consumes only 1.7µA of non-switching quiescent current.
The LT8607 can deliver 750mA of continuous current.
Low ripple Burst Mode operation enables high efficiency
down to very low output currents while keeping the output
ripple below 10mV
. Internal compensation with peak
P-P
current mode topology allows the use of small inductors
and results in fast transient response and good loop stability. The EN/UV pin has an accurate 1V threshold and
can be used to program VIN undervoltage lockout or to
shut down the LT8607 reducing the input supply current
to 1µA. The PG pin signals when V
is within ±8.5% of
OUT
the programmed output voltage as well as fault conditions.
The MSOP package includes a SYNC pin to synchronize
to an external clock, or to select Burst Mode operation
or pulse-skipping with or without spread spectrum; the
TR/SS pin programs soft-start or tracking. The DFN package omits these pins and can be purchased in pulse-skipping or Burst Mode operation.
PACKAGE SYNC FUNCTIONALITY
LT8607MSE MSE Programmable
LT8607DFN DFN Burst Mode Operation
LT8607BDFN DFN Pulse-Skipping Mode
All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION
5V, 2MHz Step-Down
12VIN to 5V
For more information www.analog.comDocument Feedback
Efficiency
OUT
Rev. C
1
LT8607/LT8607B
TOP VIEW
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
ABSOLUTE MAXIMUM RATINGS
(Note 1)
VIN, EN/UV, PG ..........................................................42V
FB, TR/SS .
SYNC Voltage .
.................................................................4V
............................................................6V
PIN CONFIGURATION
Operating Junction Temperature Range (Note 2)
LT8607E ............................................ –40°C to 125°C
LT8607I ............................................. –40°C to 125°C
LT8607H ............................................ –40°C to 150°C
Storage Temperature Range
.................. –65°C to 150°C
TOP VIEW
10
1
BST
2
SW
INTV
CC
RT
SYNC
10-LEAD PLASTIC MSOP
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
3
4
5
MSE PACKAGE
θ
JA
11
GND
= 40°C/W
EN/UV
9
V
IN
PG
8
TR/SS
7
FB
6
1
BST
2
SW
3
INTV
CC
RT
4
8-LEAD (2mm × 2mm) PLASTIC DFN
DC PACKAGE
= 102°C/W
θ
JA
9
GND
8
7
6
5
EN/UV
V
IN
PG
FB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT8607EMSE#PBF LT8607EMSE#TRPBF LTGXJ 10-Lead Plastic MSOP –40°C to 125°C
LT8607IMSE#PBF LT8607IMSE#TRPBF LTGXJ 10-Lead Plastic MSOP –40°C to 125°C
LT8607HMSE#PBF LT8607HMSE#TRPBF LTGXJ 10-Lead Plastic MSOP –40°C to 150°C
LT8607EDC#PBF LT8607EDC#TRPBF LGXK 8-Lead Plastic (2mm × 2mm) Plastic DFN –40°C to 125°C
LT8607IDC#PBF LT8607IDC#TRPBF LGXK 8-Lead Plastic (2mm × 2mm) Plastic DFN –40°C to 125°C
LT8607HDC#PBF LT8607HDC#TRPBF LGXK 8-Lead Plastic (2mm × 2mm) Plastic DFN –40°C to 150°C
LT8607BEDC#PBF LT8607BEDC#TRPBF LGXM 8-Lead Plastic (2mm × 2mm) DFN –40°C to 125°C
LT8607BIDC#PBF LT8607BIDC#TRPBF LGXM 8-Lead Plastic (2mm × 2mm) DFN –40°C to 125°C
LT8607BHDC#PBF LT8607BHDC#TRPBF LGXM 8-Lead Plastic (2mm × 2mm) DFN –40°C to 150°C
Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix.
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Input Voltage
Quiescent Current V
V
IN
Current in Regulation V
V
IN
2
= 0V
EN/UV
V
= 2V, Not Switching, V
EN/UV
= 6V, V
IN
V
IN
= 6V, V
OUT
OUT
= 0V or LT8607 DFN, VIN ≤ 36V
SYNC
= 2.7V, Output Load = 100µA
= 2.7V, Output Load = 1mA
For more information www.analog.com
l
l
l
l
2.5 3.0
3.2
1
1.7
56
500
12
90
700
V
5
µA
µA
µA
µA
Rev. C
LT8607/LT8607B
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Feedback Reference Voltage MSOP Package
VIN = 6V, I
V
IN
= 6V, I
LOAD
LOAD
DFN Package
V
= 6V, I
Feedback Voltage Line Regulation V
Feedback Pin Input Current V
Minimum On-Time I
Minimum Off Time I
IN
V
IN
IN
FB
LOAD
I
LOAD
LOAD
LOAD
= 6V, I
LOAD
= 4.0V to 40V
= 1V ±20 nA
= 750mA, SYNC = 0V or LT8607 DFN
= 750mA, SYNC = 1.9V or LT8607B DFN
= 300mA
Oscillator Frequency MSOP Package
= 221k, I
R
T
R
= 60.4k, I
T
R
= 18.2k, I
T
LOAD
LOAD
LOAD
DFN Package
R
= 221k, I
Top Power NMOS On-Resistance I
T
R
= 60.4k, I
T
R
= 18.2k, I
T
LOAD
LOAD
LOAD
LOAD
= 500mA 375 mΩ
Top Power NMOS Current Limit MSOP Package
DFN Package
= 100mA
= 100mA
= 100mA
= 100mA
= 350mA
= 350mA
= 350mA
= 350mA
= 350mA
= 350mA
0.774
l
0.762
0.771
l
0.753
l
l
l
l
l
155
l
640
l
1.90
l
140
l
610
l
1.85
l
1.2 1.6 2.0 A
l
1.2 1.7 2.2 A
Bottom Power NMOS On-Resistance 240 mΩ
SW Leakage Current V
EN/UV Pin Threshold EN/UV Rising
= 36V 5 µA
IN
l
0.99 1.05 1.11 V
EN/UV Pin Hysteresis 50 mV
EN/UV Pin Current V
PG Upper Threshold Offset from V
PG Lower Threshold Offset from V
FB
FB
= 2V ±20 nA
EN/UV
VFB Rising
VFB Falling
l
5.0 8.5 13.0 %
l
5.0 8.5 13.0 %
PG Hysteresis 0.5 %
PG Leakage V
PG Pull-Down Resistance V
Sync Low Input Voltage MSOP Only
Sync High Input Voltage INTV
TR/SS Source Current MSOP Only
= 42V ±200 nA
PG
= 0.1V 550 1200 Ω
PG
l
0.4 0.9 V
= 3.5V, MSOP Only
CC
l
l
1 2 3 µA
TR/SS Pull-Down Resistance Fault Condition, TR/SS = 0.1V, MSOP Only 300 900 Ω
Spread Spectrum Modulation Frequency V
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. Absolute Maximum Ratings are those values beyond
which the life of a device may be impaired.
Note 2: The LT8607E is guaranteed to meet performance specifications
from 0°C to 125°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization, and correlation with statistical process controls. The
= 3.3V, MSOP Only 0.5 3 6 kHz
SYNC
temperature range. The LT8607H is guaranteed over the full –40°C to
150°C operating junction temperature range. High junction temperatures
degrade operating lifetimes. Operating lifetime is derated at junction
temperatures greater than 125°C.
Note 3: This IC includes overtemperature protection that is intended to
protect the device during overload conditions. Junction temperature will
exceed 150°C when overtemperature protection is active. Continuous
operation above the specified maximum operating junction temperature
will reduce lifetime.
LT8607I is guaranteed over the full –40°C to 125°C operating junction
0.778
0.778
0.778
0.778
0.782
0.798
0.785
0.803
±0.02 ±0.06 %/V
35
35
65
60
ns
ns
93 130 ns
200
700
2.00
200
700
2.00
245
760
2.10
260
790
2.15
kHz
kHz
MHz
kHz
kHz
MHz
2.7 3.2 V
Rev. C
V
V
V
V
For more information www.analog.com
3
LT8607/LT8607B
INPUT VOLTAGE (V)
210182634
42
–0.20
–0.15
–0.10
–0.05
0.00
0.05
0.10
0.15
0.20
CHANGE IN V
8607 G07
TEMPERATURE (°C)
–50
–103070
110
150
775
776
777
778
779
780
FB REGULATION VOLTAGE (mV)
8607 G05
OUTPUT CURRENT (mA)
0
125
250
375
500
625
750
–0.25
–0.20
–0.15
–0.10
–0.05
0.00
0.05
0.10
0.15
0.20
0.25
CHANGE IN V
(%)
8607 G06
fSW = 2MHz
VIN = 12V
VIN = 24V
L = 4.7µH
SYNC = 0V OR LT8607 DFN
I
OUT
(mA)
0
125
250
375
500
625
7505055
6065707580859095100
EFFICIENCY (%)
8607 G01
fSW = 2MHz
VIN = 12V
VIN = 24V
L = 4.7µH
I
OUT
(mA)
0.001
0.01
0.1110
100
900010
2030405060708090100
EFFICIENCY (%)
8607 G02
SYNC = 0V OR LT8607 DFN
fSW = 2MHz
VIN = 12V
VIN = 24V
L = 2.2µH
I
OUT
(mA)
0
125
250
375
500
625
7505055
6065707580859095100
EFFICIENCY (%)
8607 G03
SYNC = 0V OR LT8607 DFN
fSW = 2MHz
VIN = 12V
VIN = 24V
L = 2.2µH
I
OUT
(mA)
0.001
0.01
0.1110
100
900
0102030405060708090100
EFFICIENCY (%)
8607 G04
SYNC = 0V OR LT8607 DFN
L = 2.2µH
INPUT VOLTAGE (V)
210182634
42
2.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
4.50
I
8607 G08
SYNC = 0V OR LT8607 DFN
TEMPERATURE (°C)
–50
–103070
110
150
1.3
1.5
1.7
1.9
2.1
2.3
2.5
2.7
2.9
3.1
3.3
8607 G09
SYNC = 0V OR LT8607 DFN
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency (5V Output, Burst Mode
Operation)
Efficiency (5V Output, Burst Mode
Operation)
TA = 25°C, unless otherwise noted.
Efficiency (3.3V Output,
Burst Mode Operation)
Efficiency (3.3V Output,
Burst Mode Operation) FB Voltage Load Regulation
4
Line Regulation
No-Load Supply Current
(3.3V Output Switching)
For more information www.analog.com
No Load Supply Current vs
Temperature (Not Switching)
Rev. C
LT8607/LT8607B
DUTY CYCLE (%)
020406080
100
1.20
1.30
1.40
1.50
1.60
1.70
TOP FET CURRENT LIMIT (A)
8607 G10
SWITCH CURRENT (mA)
0
125
250
375
500
625
750050
100
150
200
250
300
SWITCH DROP (mV)
8607 G13
TOP SW
BOT SW
DUTY CYCLE = 0
TEMPERATURE (°C)
–50
–103070
110
150
1.50
1.55
1.60
1.65
1.70
TOP FET CURRENT LIMIT (A)
8607 G11
I
OUT
= 750mA
TEMPERATURE (°C)
–50
–30
–101030507090110
130
15032333435
363738
8607 G14
SWITCH CURRENT = 750mA
TOP SW
BOT SW
TEMPERATURE (°C)
–50
–30
–101030507090110
130
15050100
150
200
250
300
350
400
450
SWITCH DROP (mV)
8607 G12
I
OUT
= 350mA
TEMPERATURE (°C)
–50
–30
–101030507090110
130
15080859095
100
105
110
MINIMUM OFF-TIME (ns)
8607 G15
L: XFL4020-472ME
OUTPUT CURRENT (A)
0
125
250
375
500
625
750
0
50
100
150
200
250
300
350
DROPOUT VOLTAGE (mV)
8607 G16
RT = 18.2kΩ
TEMPERATURE (°C)
–50
–103070
110
150
1975
1980
1985
1990
1995
2000
2005
2010
2015
2020
2025
8607 G17
SYNC = 0V OR LT8607 DFN
OUTPUT CURRENT (mA)
0255075100
125
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
8607 G18
VIN = 12V
L = 2.2µH
V
OUT
= 3.3V
TYPICAL PERFORMANCE CHARACTERISTICS
Top FET Current Limit
vs Duty Cycle
Switch Drop vs Switch Current
Top FET Current Limit
vs Temperature Switch Drop vs Temperature
Minimum On-Time
vs Temperature
TA = 25°C, unless otherwise noted.
Minimum Off-Time
vs Temperature
Dropout Voltage vs Output Current
Switching Frequency
vs Temperature
For more information www.analog.com
Burst Frequency vs
Output Current
Rev. C
5
LT8607/LT8607B
INPUT VOLTAGE (V)
0510152025303540
45
0
25
5075100
125
150
OUTPUT CURRENT (mA)
8607 G19
VIN = 12V
L = 2.2µH
V
OUT
= 3.3V
RT = 18.2kΩ
SS VOLTAGE (V)
0
0.1
0.2
0.4
0.5
0.6
0.7
0.8
1.0
1.1
1.200.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
FB VOLTAGE (V)
8607 G21
TEMPERATURE (°C)
–50
–30
–101030507090110
130
150
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
8607 G22
V
IN
V
OUT
R
LOAD
= 50Ω
INPUT VOLTAGE (V)
0123456
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
8607 G24
TEMPERATURE (°C)
–50
–30
–101030507090110
130
150
2.00
2.25
2.50
2.75
3.00
3.25
8607 G23
V
IN
V
OUTRLOAD
= 6.66Ω
INPUT VOLTAGE (V)
0123456
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
8607 G25
FB VOLTAGE (V)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.00250
500
750
1000
1250
1500
1750
2000
2250
2500
8607 G20
TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Load to Full
Frequency (SYNC Float to 1.9V)
(MSOP Package) or LT8607B DFN
Soft-Start Current vs Temperature
(MSOP Package)
Frequency Foldback
SYNC = 0V OR LT8607 DFN
V
TA = 25°C, unless otherwise noted.
Soft-Start Tracking
(MSOP Package)
UVLO vs Temperature
IN
6
Start-Up Dropout
Start-Up Dropout
Rev. C
For more information www.analog.com
LT8607/LT8607B
200mA/DIV
8607 G26
2MHz
8607 G29
SW
200mA/DIV
8607 G30
SW
200mA/DIV
8607 G27
2MHz
200mA/DIV
8607 G28
OUT
AMPLITUDE (dBµV/m)
50
1000
SW
TYPICAL PERFORMANCE CHARACTERISTICS
Switching Waveforms Switching Waveforms
I
LOAD
V
SW
5V/DIV
12VIN TO 5V
200mA/DIV
200ns/DIV
AT 500mA
OUT
Transient Response
I
LOAD
I
LOAD
V
SW
10V/DIV
36VIN TO 5V
OUT
200ns/DIV
AT 500mA
I
LOAD
TA = 25°C, unless otherwise noted.
Switching Waveforms
(Burst Mode)
V
OUT
20mV/DIV
I
LOAD
V
SW
10V/DIV
2µs/DIV
12VIN TO 5V
22µF C
OUT
AT 7.5mA
Transient Response
V
OUT
100mV/DIV
VIN =12V
= 5V
V
OUT
50mA TO 550mA
= 22µF
C
OUT
= 2MHz
f
45
40
35
30
25
20
15
10
5
0
–5
–10
V
OUT
100mV/DIV
200µs/DIV
VIN =12V
= 5V
V
OUT
250mA TO 750mA
= 22µF
C
OUT
= 2MHz
f
Radiated EMI Performance
(CISPR 25 Radiated Emission Test with Class 5 Peak Limits)
VERTICAL POLARIZATION
PEAK DETECTOR
CLASS 5 PEAK LIMIT
SPREAD SPECTRUM MODE
FIXED FREQUENCY
0 500 900300 700
DC2565A DEMO BOARD
WITH EMI FILTER INSTALLED
14V INPUT TO 5V OUTPUT AT 500mA, f
400 800200 600100
FREQUENCY (MHz)
= 2MHz
For more information www.analog.com
100µs/DIV
8607 G31
Rev. C
7
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