LTC3115-1
40V, 2A Synchronous
Buck-Boost DC/DC
Converter
FEATURES
DESCRIPTION
Wide VIN Range: 2.7V to 40V
nn Wide V
OUT Range: 2.7V to 40V
nn 1A Output Current for V ≥ 3.6V, V
IN
OUT = 5V
nn 2A Output Current in Step-Down Operation
for VIN ≥ 6V
nn Programmable Frequency: 100kHz to 2MHz
nn Synchronizable Up to 2MHz with an External Clock
nn Up to 95% Efficiency
nn 30µA No-Load Quiescent Current in Burst Mode®
Operation
nn Ultralow Noise Buck-Boost PWM
nn Internal Soft-Start
nn 3µA Supply Current in Shutdown
nn Programmable Input Undervoltage Lockout
nn Small 4mm × 5mm × 0.75mm DFN Package
nn Thermally Enhanced 20-Lead TSSOP Package
nn AEC-Q100 Qualified for Automotive Applications
The LTC®3115-1 is a high voltage monolithic synchronous
buck-boost DC/DC converter. Its wide 2.7V to 40V input
and output voltage ranges make it well suited to a wide
variety of automotive and industrial applications. A proprietary low noise switching algorithm optimizes efficiency
with input voltages that are above, below or even equal
to the output voltage and ensures seamless transitions
between operational modes.
nn
Programmable frequency PWM mode operation provides low noise, high efficiency operation and the ability
to synchronize switching to an external clock. Switching
frequencies up to 2MHz are supported to allow use of
small value inductors for miniaturization of the application circuit. Pin selectable Burst Mode operation
reduces standby current and improves light load efficiency which, combined with a 3µA shutdown current,
make the LTC3115-1 ideally suited for battery-powered
applications. Additional features include output disconnect in shutdown, short-circuit protection and internal soft-start. The LTC3115-1 is available in thermally
enhanced 16-lead 4mm × 5mm × 0.75mm DFN and
20‑lead TSSOP packages.
APPLICATIONS
24V/28V Industrial Applications
Automotive Power Systems
nn Telecom, Servers and Networking Equipment
nn FireWire Regulator
nn Multiple Power Source Supplies
nn
nn
All registered trademarks and trademarks are the property of their respective owners. Protected
by U.S. Patents including 6404251, 6166527 and others pending.
TYPICAL APPLICATION
Efficiency vs VIN
10µH
95
2.7V TO
40V
BST1 SW1
4.7µF
BURST PWM
OFF ON
PVIN
VIN
SW2 BST2
PVOUT
PWM/SYNC
VC
RUN
FB
60.4k
3300pF
PGND
1M
33pF
15k
PVCC
VCC
GND
5V
1A VIN > 3.6V
2A VIN ≥ 6V
47µF
LTC3115-1
RT
47.5k
ILOAD = 0.5A
0.1µF
249k
4.7µF
90
EFFICIENCY (%)
0.1µF
ILOAD = 1A
85
80
75
(OPTIONAL)
3115 TA01a
70
VOUT = 5V
2
10
INPUT VOLTAGE (V)
40
31151 TA01b
Rev. C
Document Feedback
For more information www.analog.com
1
LTC3115-1
ABSOLUTE MAXIMUM RATINGS
(Note 1)
VIN, PVIN, PVOUT......................................... –0.3V to 45V
VSW1
DC............................................ –0.3V to (PVIN + 0.3V)
Pulsed ( 3.6V
2A VIN ≥ 6V
RFF
249k
27pF
RBOT
249k
D1
31151 TA02a
C1
4.7µF
CIN: MURATA GRM55DR61H106K
CO: POSCAP 6TPB330M (7.3mm × 4.3mm × 2.8mm)
D1: PANASONIC MA785
L1: COILCRAFT MSS1260
PWM Mode Efficiency
vs Load Current
100
100
95
95
90
90
85
85
EFFICIENCY (%)
EFFICIENCY (%)
PWM Mode Efficiency
vs Load Current
80
75
70
65
60
VIN = 5V
VIN = 3.6V
VIN = 2.7V
55
50
0.01
0.1
LOAD CURRENT (A)
1
80
75
70
65
60
VIN = 12V
VIN = 24V
VIN = 36V
55
50
0.01
0.1
LOAD CURRENT (A)
31151 TA02b
VOUT Transient for a 0A to 1A Load Step
31151 TA02c
VOUT Transient for a 0A to 2A Load Step, VIN = 24V
VOUT
(200mV/DIV)
VIN = 36V
VOUT
(200mV/DIV)
VIN = 12V
VOUT
(200mV/DIV)
VOUT
(200mV/DIV)
VIN = 5V
INDUCTOR CURRENT
(2A/DIV)
VOUT
(200mV/DIV)
VIN = 3.6V
2ms/DIV
1
LOAD CURRENT
(2A/DIV)
31151 TA02d
2ms/DIV
31151 TA02e
Rev. C
For more information www.analog.com
33
LTC3115-1
TYPICAL APPLICATIONS
Wide Input Voltage Range (10V to 40V) 1MHz 24V Supply at 500mA
L1
15µH
CBST1
0.1µF
CBST2
0.1µF
BST1 SW1
10V TO 40V
UVLO
PROGRAMMED
TO 10V (1.3V
HYSTERESIS)
R1
953k
SW2 BST2
PVIN
VIN
CIN
10µF
RUN
PVOUT
RTOP
1M
CFB
RFB 3300pF
10k
LTC3115-1
R2
130k
24V
500mA
CO
10µF
VC
RFF
10k
FB
RT
35.7k
RBOT
43.2k
PWM/SYNC
PVCC
VCC
RT
GND
CFF
22pF
C1
4.7µF
PGND
31151 TA03a
L1: WÜRTH 744 066 150
Maximum Load Current vs VIN
Efficiency vs VIN
92
2.5
EFFICIENCY (%)
LOAD CURRENT (A)
2.0
1.5
1.0
0.5
0
ILOAD = 0.5A
90
86
84
82
80
10
ILOAD = 1A
88
30
20
INPUT VOLTAGE (V)
40
10
20
30
INPUT VOLTAGE (V)
40
31151 TA03c
31151 TA03b
Power-Up/Down Waveforms,
ILOAD = 0.5A
VIN
(5V/DIV)
VOUT
(10V/DIV)
INDUCTOR
CURRENT
(2A/DIV)
50ms/DIV
34
31151 TA03d
Rev. C
For more information www.analog.com
LTC3115-1
TYPICAL APPLICATIONS
Industrial 12V 1MHz Regulator with Custom Input Undervoltage Lockout Thresholds
L1
10µH
CBST2
0.1µF
CBST1
0.1µF
BST1 SW1
10V TO
40V
ENABLED WHEN VIN
REACHES 10.6V
DISABLED WHEN VIN
FALLS BELOW 8.7V
SW2 BST2
PVIN
VIN
CIN
10µF
R1
2M
PVOUT
LTC3115-1
VC
RUN
R2
255k
RT
35.7k
CO
22µF
CFB
RFB 820pF
40.2k
FB
PWM/SYNC
PVCC
VCC
RT
GND
PGND
12V
1.4A
RTOP
1M
CFF
33pF
RFF
10k
RBOT
90.9k
C1
4.7µF
31151 TA04a
CIN: MURATA GRM55DR61H106K
CO: TDK CKG57NX5R1H226M
L1: WÜRTH 744065100
PWM Mode Efficiency
vs Load Current
0A to 1.5A Load Step, VIN = 24V
100
VOUT
(500mV/DIV)
EFFICIENCY (%)
90
80
INDUCTOR
CURRENT
(1A/DIV)
70
60
VIN = 10.6V
VIN = 12V
VIN = 24V
VIN = 36V
50
40
0.01
0.1
LOAD CURRENT (A)
500µs/DIV
31151 TA04c
1
31151 TA04b
0A to 1.5A Load Step, VIN = 10.6V
0A to 1.5A Load Step, VIN = 40V
VOUT
(500mV/DIV)
VOUT
(500mV/DIV)
INDUCTOR
CURRENT
(1A/DIV)
INDUCTOR
CURRENT
(1A/DIV)
500µs/DIV
31151 TA04d
500µs/DIV
31151 TA04e
Rev. C
For more information www.analog.com
35
LTC3115-1
TYPICAL APPLICATIONS
24V 750kHz Industrial Rail Restorer
L1
22µH
*
CBST1
0.1µF
BST1 SW1
20V TO 40V
OPEN
DRAIN
OUTPUT
R1
500k
SW2 BST2
PVIN
VIN
CIN
10µF
*OPTIONAL: INSTALL IN
APPLICATIONS SUBJECT TO
OUTPUT OVERLOAD OR
SHORT-CIRCUIT CONDITIONS
CBST2
0.1µF
RUN
PVOUT
1µF
RFB
25k
LTC3115-1
ON OFF
+
VC
CO
82µF
CFB
3300pF
CFF
47pF
RTOP
1M
RFF
51k
100pF
FB
RT
PWM/SYNC
PVCC
VCC
GND
24V
1.5A
RT
47.5k
RBOT
43.2k
C1
4.7µF
PGND
31151 TA05a
CO: OS-CON 35SVPF82M
L1: TOKO 892NBS-220M
Regulated Output Voltage from a
Time Varying Input Rail
0A to 1.5A Load Step, VIN = 20V
LOAD
CURRENT
(1A/DIV)
40V
VIN
(5V/DIV)
VOUT
(1V/DIV)
VOUT
(5V/DIV)
INDUCTOR
CURRENT
(2A/DIV)
20V
31151 TA05b
10ms/DIV
500µs/DIV
31151 TA05c
Efficiency vs Load Current
100
90
EFFICIENCY (%)
80
70
60
50
40
VIN = 20V
VIN = 24V
VIN = 36V
30
20
0.01
0.10
LOAD CURRENT (A)
1
31151 TA05d
36
Rev. C
For more information www.analog.com
LTC3115-1
TYPICAL APPLICATIONS
USB, FireWire, Automotive and Unregulated Wall Adapter to Regulated 5V (750kHz)
USB
4.1V TO 5.5V
FireWire
8V TO 36V
AUTOMOTIVE
3.6V TO 40V
WALL ADAPTER
4V TO 40V
D1
D2
L1
10µH
CBST2
0.1µF
CBST1
0.1µF
D3
D4
BST1 SW1
SW2 BST2
PVIN
VIN
10µF
PVOUT
LTC3115-1
PWM/SYNC
BURST PWM
VC
RUN
OFF ON
CO
47µF
×2
CFB
RFB 4700pF
100k
FB
RT
47.5k
PVCC
VCC
RT
GND
PGND
5V
750mA
RTOP
1M
CFF
47pF
RFF
51k
RBOT
249k
C1
4.7µF
31151 TA06a
CIN: MURATA GRM55DR61H106K
CO: GRM43ER60J476
D1-D4: B360A-13-F
L1: COILCRAFT LPS6225
Soft-Start Waveform, VIN = 24V, ILOAD = 0.5A
VRUN
(5V/DIV)
VCC
(5V/DIV)
Efficiency vs Load Current,
from Automotive Input
VOUT
(2V/DIV)
100
INDUCTOR
CURRENT
(500mA/DIV)
90
2ms/DIV
EFFICIENCY (%)
80
31151 TA06c
70
Output Voltage Transient Response,
750mA Load Step, Powered from Automotive Input
60
50
VIN = 3.6V
VIN = 5V
VIN = 12V
VIN = 24V
VIN = 36V
40
30
20
0.01
0.1
LOAD CURRENT (A)
1
31151 TA06b
VOUT
(200mV/DIV)
VIN = 36V
VOUT
(200mV/DIV)
VIN = 12V
VOUT
(200mV/DIV)
VIN = 3.6V
1ms/DIV
31151 TA06d
Rev. C
For more information www.analog.com
37
LTC3115-1
TYPICAL APPLICATIONS
Miniature Size 1.5MHz 12V Supply
L1
4.7µH
CBST2
0.1µF
CBST1
0.1µF
BST1 SW1
6V TO 40V
SW2 BST2
PVIN
VIN
CI
4.7µF
PVOUT
RUN
LTC3115-1
BURST PWM
RT
23.7k
PWM/SYNC
VC
RT
FB
CO
10µF
CFB
RFB 1000pF
15k
RTOP
1M
CFF
33pF
RFF
15k
RBOT
90.9k
PVCC
VCC
GND
12V AT 500mA
1A VIN > 10V
C1
4.7µF
PGND
31151 TA07a
CO: MURATA GRM55DR61H106K
L1: WÜRTH 7447789004
Load Step Transient Response, 0mA to 500mA,
VIN = 6V
LOAD CURRENT
(500mA/DIV)
Load Step Transient Response, 0mA to 500mA,
VIN = 24V
LOAD CURRENT
(500mA/DIV)
VOUT
(500mV/DIV)
VOUT
(500mV/DIV)
INDUCTOR
CURRENT
(1A/DIV)
INDUCTOR
CURRENT
(1A/DIV)
31151 TA07b
200µs/DIV
Efficiency vs Load Current, PWM Mode
200µs/DIV
Efficiency vs Load Current, Burst Mode Operation
100
90
90
80
70
EFFICIENCY (%)
EFFICIENCY (%)
80
70
60
50
40
VIN = 6V
VIN = 10V
VIN = 24V
VIN = 36V
30
20
0.01
0.1
LOAD CURRENT (A)
1
60
50
40
VIN = 6V
VIN = 10V
VIN = 24V
VIN = 36V
30
20
0.1
31151 TA07d
38
31151 TA07c
1
10
LOAD CURRENT (mA)
100
31151 TA07e
Rev. C
For more information www.analog.com
LTC3115-1
PACKAGE DESCRIPTION
DHD Package
16-Lead Plastic DFN (5mm × 4mm)
(Reference LTC DWG # 05-08-1707 Rev A)
0.70 ±0.05
4.50 ±0.05
3.10 ±0.05
2.44 ±0.05
(2 SIDES)
PACKAGE
OUTLINE
0.25 ±0.05
0.50 BSC
4.34 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
5.00 ±0.10
(2 SIDES)
9
4.00 ±0.10
(2 SIDES)
R = 0.115
TYP
0.40 ±0.10
16
2.44 ±0.10
(2 SIDES)
PIN 1
TOP MARK
(SEE NOTE 6)
PIN 1
NOTCH
8
0.200 REF
1
0.25 ±0.05
0.50 BSC
0.75 ±0.05
0.00 – 0.05
(DHD16) DFN REV A 1113
4.34 ±0.10
(2 SIDES)
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJGD-2) IN JEDEC
PACKAGE OUTLINE MO-229
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
Rev. C
For more information www.analog.com
39
LTC3115-1
PACKAGE DESCRIPTION
FE Package
20-Lead Plastic TSSOP (4.4mm)
(Reference LTC DWG # 05-08-1663 Rev L)
Exposed Pad Variation CA
6.07
(.239)
6.40 – 6.60*
(.252 – .260)
4.95
(.195)
4.95
(.195)
DETAIL A
1.98
(.078)
REF
20 1918 17 16 15 14 13 12 11
6.60 ±0.10
4.50 ±0.10
DETAIL A
2.74
(.108)
6.40
2.74
(.252)
(.108)
BSC
SEE NOTE 4
0.45 ±0.05
1.05 ±0.10
0.65 BSC
1 2 3 4 5 6 7 8 9 10
6.07
(.239)
RECOMMENDED SOLDER PAD LAYOUT
4.30 – 4.50*
(.169 – .177)
0.09 – 0.20
(.0035 – .0079)
0.25
REF
0.50 – 0.75
(.020 – .030)
NOTE:
1. CONTROLLING DIMENSION: MILLIMETERS
MILLIMETERS
2. DIMENSIONS ARE IN
(INCHES)
3. DRAWING NOT TO SCALE
40
0.56
(.022)
REF
DETAIL A IS THE PART OF
THE LEAD FRAME FEATURE
FOR REFERENCE ONLY
NO MEASUREMENT PURPOSE
1.20
(.047)
MAX
0° – 8°
0.65
(.0256)
BSC
0.195 – 0.30
(.0077 – .0118)
TYP
0.05 – 0.15
(.002 – .006)
FE20 (CA) TSSOP REV L 0117
4. RECOMMENDED MINIMUM PCB METAL SIZE
FOR EXPOSED PAD ATTACHMENT
*DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.150mm (.006") PER SIDE
Rev. C
For more information www.analog.com
LTC3115-1
REVISION HISTORY
REV
DATE
DESCRIPTION
A
4/13
Clarified Efficiency graph
1
Clarified Absolute Maximum Rating table, Package Drawing and Order Information
2
B
5/15
Clarified Electrical Characteristics table
3
Clarified Pin Functions
11
Clarified Compensation formula
25
Clarified Figure 3
17
Clarified GBUCK formula
22
Clarified Loop Compensation Example
26
Clarified PCB Layout Considerations
C
6/19
PAGE NUMBER
30, 31, 32
Added LTC3114-1 to Related Parts list
42
Added AEC-Q100 automotive models
1,3
Rev. C
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog
Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications
subject to change without notice. No license For
is granted
implication or
otherwise under any patent or patent rights of Analog Devices.
more by
information
www.analog.com
41
LTC3115-1
TYPICAL APPLICATION
750kHz Automotive 5V Regulator with Cold Crank Capability
L1
6.8µH
CBST2
0.1µF
CBST1
0.1µF
BST1 SW1
AUTOMOTIVE
3.6V TO 40V
SW2 BST2
PVIN
VIN
CIN
10µF
PVOUT
LTC3115-1
PWM/SYNC
BURST PWM
VC
RUN
OFF ON
CO
47µF
CFB
RFB 1000pF
54.9k
FB
CIN: MURATA GRM55DR61H106K
CO: MURATA GRM43ER60J476K
D1: PANASONIC MA785
L1: SUMIDA CDRH8D43HPNP
RT
47.5k
PVCC
VCC
RT
GND
PGND
5V
1A
CFF
33pF
RTOP
1M
RFF
42.2k
RBOT
249k
D1*
C1
4.7µF
31151 TA08a
*OPTIONAL-INSTALL D1 FOR IMPROVED EFFICIENCY AND LOWER INPUT OPERATING VOLTAGE
Cold Crank Line Transient with 1A Load
VIN
(10V/DIV)
13.8V
6V
80
VOUT
(200mV/DIV)
INDUCTOR
CURRENT
(1A/DIV)
VOUT
(200mV/DIV)
200ms/DIV
90
EFFICIENCY (%)
15ms FALL TIME
4.5V
INDUCTOR
CURRENT
(1A/DIV)
100
40V
12V
VIN
(2V/DIV)
Efficiency vs Load Current
VIN = 12V
Load Dump Line Transient with 1A Load
31151 TA08b
2ms/DIV
31151 TA08c
70
60
50
40
30
20
0.01
WITH BOOTSTRAP DIODE
WITHOUT BOOTSTRAP DIODE
0.1
1
LOAD CURRENT (A)
31151 TA08d
RELATED PARTS
PART NUMBER
LTC3114-1
DESCRIPTION
1A (IOUT), 40V Synchronous Buck-Boost DC/DC Converter
LTC3112
2.5A (IOUT), 15V Synchronous Buck-Boost DC/DC Converter
LTC3113
3A (IOUT), 2MHz Synchronous Buck-Boost DC/DC Converter
LTC3127
1A (IOUT), 1.2MHz Buck-Boost DC/DC Converter with
Programmable Input Current Limit
High Efficiency, Synchronous, 4-Switch Buck-Boost Controller
LTC3789
LTC3785
LTC3534
42
≤10A (IOUT), High Efficiency, 1MHz Synchronous, No RSENSE™
Buck-Boost Controller
7V, 500mA (IOUT), 1MHz Synchronous Buck-Boost DC/DC
Converter
COMMENTS
VIN = 2.2V to 40V, VOUT = 2.7V to 40V, IQ = 30µA, ISD < 3µA, DFN
and TSSOP Packages
VIN: 2.7V to 15V, VOUT : 2.5V to 14V, IQ = 40µA, ISD < 1µA, DFN and
TSSOP Packages
VIN: 1.8V to 5.5V, VOUT : 1.8V to 5.25V, IQ = 30µA, ISD < 1µA, DFN
and TSSOP Packages
96% Efficiency VIN: 1.8V to 5.5V, VOUT : 1.8V to 5.25V, IQ = 35µA,
ISD < 4µA, MSOP and DFN Packages
VIN: 4V to 38V, VOUT : 0.8V to 38V, IQ = 3mA, ISD < 60µA,
SSOP-28, QFN-28 Packages
VIN: 2.7V to 10V, VOUT : 2.7V to 10V, IQ = 86µA, ISD < 15µA,
QFN Package
94% Efficiency, VIN: 2.4V to 7V, VOUT : 1.8V to 7V, IQ = 25µA,
ISD < 1µA, DFN and GN Packages
Rev. C
06/19
www.analog.com
For more information www.analog.com
ANALOG DEVICES, INC. 2012-2019
