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LM3671, LM3671-Q1
SNVS294S – NOVEMBER 2004 – REVISED MAY 2016
LM3671/-Q1 2-MHz, 600-mA Step-Down DC-DC Converter
1 Features
3 Description
•
The LM3671 step-down DC-DC converter is
optimized for powering low voltage circuits from a
single Li-Ion cell battery and input voltage rails from
2.7 V to 5.5 V. It provides up to 600-mA load current,
over the entire input voltage range. There are several
different fixed voltage output options available as well
as an adjustable output voltage version range from
1.1 V to 3.3 V.
1
•
•
•
•
•
•
•
•
•
•
•
•
LM3671-Q1 is Qualified for Automotive
Applications
AEC Q100-Qualified With the Following Results
– Device Temperature Grade 1: –40°C to
+125°C Ambient Operating Temperature
Range
16-µA Typical Quiescent Current
600-mA Maximum Load Capability
2-MHz PWM Fixed Switching Frequency (Typical)
Automatic PFM-PWM Mode Switching
Internal Synchronous Rectification for High
Efficiency
Internal Soft Start
0.01-µA Typical Shutdown Current
Operates from a Single Li-Ion Cell Battery
Only Three Tiny Surface-Mount External
Components Required (One Inductor, Two
Ceramic Capacitors)
Current Overload and Thermal Shutdown
Protection
Available in Fixed Output Voltages and Adjustable
Version
A high-switching frequency of 2 MHz (typical) allows
use of tiny surface-mount components. Only three
external surface-mount components, an inductor, and
two ceramic capacitors, are required.
Device Information(1)
2 Applications
•
•
•
•
•
•
•
•
•
•
•
The device offers superior features and performance
for mobile phones and similar portable systems.
Automatic intelligent switching between PWM lownoise and PFM low-current mode offers improved
system control. During PWM mode, the device
operates at a fixed-frequency of 2 MHz (typical).
Hysteretic PFM mode extends the battery life by
reducing the quiescent current to 16 µA (typical)
during light load and standby operation. Internal
synchronous rectification provides high efficiency
during PWM mode operation. In shutdown mode, the
device turns off and reduces battery consumption to
0.01 µA (typical).
PART NUMBER
Mobile Phones
PDAs
MP3 Players
W-LAN
Portable Instruments
Digital Still Cameras
Portable Hard Disk Drives
Automotive
Portable Medical Equipment
Handheld Transaction Terminals
Wireless Home-Automation Equipment
L1: 2.2 PH
VIN
SW
1
CIN
4.7 PF
2.00 mm × 2.00 mm (NOM)
LM3671
LM3671-Q1
SOT-23 (5)
2.90 mm × 1.60 mm (NOM)
DSBGA (5)
1.413 mm × 1.083 mm (MAX)
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Typical Application Circuit: ADJ
VIN
VOUT
2.7V to 5.5V
COUT
10 PF
GND
CIN
4.7 PF
5
COUT
LM3671ADJ
GND
C1
R1
C2
R2
10 PF
2
FB
3
VOUT
SW
1
2
EN
L1: 2.2 PH
VIN
5
LM3671
BODY SIZE
USON (6)
Typical Application Circuit: Fixed-Voltage
VIN
2.7V to 5.5V
PACKAGE
LM3671
4
EN
FB
3
4
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
LM3671, LM3671-Q1
SNVS294S – NOVEMBER 2004 – REVISED MAY 2016
www.ti.com
Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
4
4
4
5
5
5
6
7
Absolute Maximum Ratings ......................................
ESD Ratings: LM3671 ..............................................
ESD Ratings: LM3671-Q1 ........................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Dissipation Ratings ...................................................
Electrical Characteristics...........................................
Typical Characteristics ..............................................
Detailed Description ............................................ 12
7.1 Overview ................................................................. 12
7.2 Functional Block Diagram ....................................... 12
7.3 Feature Description................................................. 13
7.4 Device Functional Modes........................................ 13
8
Application and Implementation ........................ 16
8.1 Application Information............................................ 16
8.2 Typical Application .................................................. 16
9 Power Supply Recommendations...................... 20
10 Layout................................................................... 21
10.1 Layout Guidelines ................................................. 21
10.2 Layout Example .................................................... 22
10.3 DSBGA Package Assembly and Use ................... 22
11 Device and Documentation Support ................. 23
11.1
11.2
11.3
11.4
11.5
11.6
11.7
Device Support......................................................
Documentation Support ........................................
Related Links ........................................................
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
23
23
23
23
23
23
23
12 Mechanical, Packaging, and Orderable
Information ........................................................... 24
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision R (November 2014) to Revision S
Page
•
Added top nav icon for TI Design .......................................................................................................................................... 1
•
Added several new "Applications" ......................................................................................................................................... 1
•
moved storage temperature to Abs Max table ...................................................................................................................... 4
•
Changed Handling Ratings to ESD Ratings .......................................................................................................................... 4
•
Changed RθJA for USON from 165°C/W to 174.7°C/W; for SOT-23 from 130°C/W to 165.7°C/W, and for DSBGA
from 85°C/W to 181.0°C/W; added additional thermal values ............................................................................................... 5
•
Changed RθJA values in Dissipation Ratings table ................................................................................................................. 5
Changes from Revision Q (November 2013) to Revision R
•
Page
Added Device Information and Handling Rating tables, Feature Description, Device Functional Modes, Application
and Implementation, Power Supply Recommendations, Layout, Device and Documentation Support, and
Mechanical, Packaging, and Orderable Information sections; moved some curves to Application Curves section ............. 1
Changes from Revision O (April 2013) to Revision P
•
2
Page
Changed layout of National Semiconductor Data Sheet to TI format .................................................................................. 22
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SNVS294S – NOVEMBER 2004 – REVISED MAY 2016
5 Pin Configuration and Functions
DBV Package
5 Pin SOT-23
Top View
SW
5
NKH Package
6-Pin USON
FB
4
6 Fb
En 1
Pgnd 2
5 Sgnd
Vin 3
4 Sw
TOP VIEW
GND
2
VIN
1
EN
3
YZR Package
5-Pin DSBGA
VIN
A1
A3
SW
EN
GND
GND
B2
B2
C3
C1
A1
A3
FB
FB
Top View
SW
C1
C3
VIN
EN
Bottom View
Pin Functions
PIN
LM3671, LM3671Q1
SOT-23
LM3671
NAME
TYPE
DESCRIPTION
DSBGA
USON
A1
3
VIN
Power
Power supply input. Connect to the input filter capacitor (see Input Capacitor
Selection).
2
A3
2
GND
Ground
Ground pin.
3
C1
1
EN
Digital
Enable pin. The device is in shutdown mode when voltage to this pin is < 0.4
V and enabled when > 1 V. Do not leave this pin floating.
4
C3
6
FB
Analog
Feedback analog input. Connect directly to the output filter capacitor for fixed
voltage versions. For adjustable version external resistor dividers are
required (see Typical Application: ADJ Version). The internal resistor dividers
are disabled for the adjustable version.
5
B2
4
SW
Analog
Switching node connection to the internal PFET switch and NFET
synchronous rectifier.
—
—
5
SGND
Ground
Signal ground (feedback ground).
1
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SNVS294S – NOVEMBER 2004 – REVISED MAY 2016
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
(1) (2)
VIN pin: voltage to GND
FB, SW, EN pins
MIN
MAX
UNIT
−0.2
6
V
GND − 0.2
VIN + 0.2
V
Continuous power dissipation (3)
Internally Limited
Junction temperature, TJ-MAX
Maximum lead temperature
(soldering, 10 sec.)
Storage temperature, Tstg
(1)
(2)
(3)
–65
125
°C
260
°C
150
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
If Military/Aerospace specified devices are required, contact the Texas Instruments Sales Office / Distributors for availability and
specifications.
Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ= 150°C (typical) and
disengages at TJ= 130°C (typical).
6.2 ESD Ratings: LM3671
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2000
Charged-device model (CDM), per JEDEC specification JESD22-C101 (2)
±500
Machine model
200
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 ESD Ratings: LM3671-Q1
VALUE
Human-body model (HBM), per AEC Q100-002 (1)
V(ESD)
Electrostatic discharge
Charged-device model (CDM), per
AEC Q100-011
All pins except corner pins
±500
Corner pins (1, 3, 4, and 5): SOT-23
±750
Corner pins (A1, A3, C1, and C3):
DSBGA
±750
Machine model
(1)
4
UNIT
±2000
V
±200
AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.
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6.4 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted) (1) (2)
MIN
Input voltage
(3)
MAX
UNIT
2.7
5.5
V
0
600
mA
Junction temperature, TJ
–40
125
°C
Ambient temperature, TA (4)
–40
85
°C
Recommended load current
(1)
(2)
(3)
(4)
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
All voltages are with respect to the potential at the GND pin.
The input voltage range recommended for ideal applications performance for the specified output voltages are given below: VIN = 2.7 V
to 4.5 V for 1.1 V ≤ VOUT < 1.5 VIN = 2.7 V to 5.5 V for 1.5 V ≤ VOUT < 1.8 VIN = (VOUT + VDROPOUT) to 5.5 V for 1.8 V ≤ VOUT ≤ 3.3 V
where VDROPOUT = ILOAD × (RDSON, PFET + RINDUCTOR).
In applications where high power dissipation and/or poor package resistance is present, the maximum ambient temperature may have to
be derated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX), the
maximum power dissipation of the device in the application (PD-MAX) and the junction to ambient thermal resistance of the package
(RθJA) in the application, as given by the following equation: TA-MAX = TJ-MAX − (RθJA × PD-MAX). Refer to Dissipation Ratings for PD-MAX
values at different ambient temperatures.
6.5 Thermal Information
LM3671
THERMAL METRIC
(1)
LM3671 and LM3671-Q1
NKH (USON)
DBV (SOT-23 )
YZR (DSBGA)
6 PINS
5 PINS
5 PINS
UNIT
174.7
165.7
181.0
°C/W
RθJA
Junction-to-ambient thermal resistance
RθJC(top)
Junction-to-case (top) thermal resistance
87.1
116.6
0.9
°C/W
RθJB
Junction-to-board thermal resistance
109.0
26.8
110.3
°C/W
ψJT
Junction-to-top characterization parameter
6.4
13.3
7.4
°C/W
ψJB
Junction-to-board characterization parameter
109.0
26.3
110.3
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report, SPRA953.
6.6 Dissipation Ratings
RθJA
TA≤ 25°C
POWER RATING
TA= 60°C
POWER RATING
TA= 85°C
POWER RATING
165.7°C/W (4 layer board) SOT-23
770 mW
500 mW
310 mW
181°C/W (4 layer board) 5-bump DSBGA
1179 mW
765 mW
470 mW
174.7°C/W (4 layer board) 6-pin USON
606 mW
394 mW
242 mW
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6.7 Electrical Characteristics
Unless otherwise noted, limits apply for for TJ = 25°C, and specifications apply to the LM3671MF/TL/LC with VIN = EN = 3.6
V (1) (2) (3)
PARAMETER
VIN
Input voltage
TEST CONDITION
MIN
−40°C to 125°C, see (4)
4%
2.5%
Feedback voltage (fixed) LC
−4%
4%
Feedback voltage (ADJ) MF (6)
−4%
4%
Feedback voltage (ADJ) TL
PWM mode (5), −40°C to 125°C
PWM mode (5), −40°C to 125°C
−2.5
Line regulation
2.7 V ≤ VIN ≤ 5.5 V, IO = 10 mA
Load regulation
100 mA ≤ IO ≤ 600 mA, VIN = 3.6 V
Internal reference voltage
ISHDN
Shutdown supply current
IQ
5.5
−4%
Feedback voltage (fixed) TL
VREF
MAX
−2.5%
Feedback voltage (fixed) MF
VFB
TYP
2.7
DC bias current into VIN
2.5
%/V
0.0013
%/mA
V
0.01
EN = 0 V, −40°C to 125°C
1
No load, device is not switching (FB
forced higher than programmed output
voltage)
V
0.031
0.5
EN = 0 V
UNIT
µA
16
µA
No load, device is not switching (FB
forced higher than programmed output
voltage), −40°C to 125°C
35
RDSON (P)
Pin-pin resistance for PFET
VIN = VGS = 3.6 V
380
500
mΩ
RDSON (N)
Pin-pin resistance for NFET
VIN = VGS= 3.6 V
250
400
mΩ
Open loop
(7)
ILIM
Switch peak current limit
VIH
Logic high input
−40°C to 125°C
VIL
Logic low input
−40°C to 125°C
IEN
Enable (EN) input current
ƒOSC
Internal oscillator frequency
(1)
(2)
(3)
(4)
(5)
(6)
(7)
6
1020
Open loop (7), −40°C to 125°C
830
1150
1
V
0.4
0.01
−40°C to 125°C
1
PWM Mode (5)
2
PWM Mode (5), −40°C to 125°C
1.6
mA
2.6
V
µA
MHz
Minimum (MIN) and maximum (MAX) limits are specified by design, test or statistical analysis. Typical (TYP) numbers are not specified,
but do represent the most likely norm.
The parameters in the electrical characteristic table are tested at VIN = 3.6 V unless otherwise specified. For performance over the input
voltage range refer to datasheet curves.
Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ= 150°C (typical) and
disengages at TJ= 130°C (typical).
The input voltage range recommended for ideal applications performance for the specified output voltages are given below: VIN = 2.7 V
to 4.5 V for 1.1 V ≤ VOUT < 1.5 VIN = 2.7 V to 5.5 V for 1.5 V ≤ VOUT < 1.8 VIN = (VOUT + VDROPOUT) to 5.5 V for 1.8 V ≤ VOUT ≤ 3.3 V
where VDROPOUT = ILOAD × (RDSON, PFET + RINDUCTOR).
Test condition: for VOUT less than 2.5 V, VIN = 3.6 V; for VOUT greater than or equal to 2.5 V, VIN = VOUT + 1 V.
ADJ version is configured to 1.5 V output. For ADJ output version: VIN = 2.7 V to 4.5 V for 0.9 V ≤ VOUT < 1.1 VIN = 2.7 V to 5.5 V for 1.1
V ≤ VOUT < 3.3 V
Refer to Typical Characteristics for closed-loop data and its variation with regards to supply voltage and temperature. Electrical
Characteristics reflects open-loop data (FB = 0 V and current drawn from SW pin ramped up until cycle by cycle current limit is
activated). Closed loop current limit is the peak inductor current measured in the application circuit by increasing output current until
output voltage drops by 10%.
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6.8 Typical Characteristics
LM3671MF/TL/LC, circuit of Figure 32, VIN = 3.6 V, VOUT = 1.5 V, TA = 25°C, unless otherwise noted.
0.40
EN = VIN
EN = GND
IOUT = 0 mA
TA = 85°C
0.35
SHUTDOWN CURRENT (PA)
QUIESCENT CURRENT (PA)
20
18
TA = 25°C
16
TA = -30°C
14
12
0.30
0.25
0.20
VIN = 5.5V
0.15
VIN = 3.6V
0.10
VIN = 2.7V
0.05
10
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
0.00
-30
-10
10
30
50
70
90
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
Figure 1. Quiescent Supply Current vs Supply Voltage
Figure 2. Shutdown Current vs Temp
Figure 3. Feedback Bias Current vs Temperature
Figure 4. Switching Frequency vs Temperature
600
VIN = 2.7V
550
VIN = 4.5V
500
VIN = 3.6V
RDS(ON) (m:)
450
PFET
400
VIN = 2.7V
350
300
VIN = 4.5V
250
NFET
200
VIN = 3.6V
150
100
-30
-10
10
30
50
70
90
110
TEMPERATURE (oC)
Figure 5. RDS(ON) vs. Temperature
Figure 6. Open/Closed Loop Current Limit vs Temperature
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Typical Characteristics (continued)
LM3671MF/TL/LC, circuit of Figure 32, VIN = 3.6 V, VOUT = 1.5 V, TA = 25°C, unless otherwise noted.
1.5300
V OUT = 1.5 V
OUTPUT VOLTAGE (V)
I OUT = 10 mA
1.5200
1.5100
I OUT = 300 mA
1.5000
I OUT = 500 mA
1.4900
I OUT = 600 mA
1.4800
2.5
3
3.5
4
4.5
5
5.5
SUPPLY VOLTAGE(V)
Figure 7. Output Voltage vs. Supply Voltage
Figure 8. Output Voltage vs Supply Voltage
1.5300
1.5250
OUTPUT VOLTAGE (V)
PFM Mode
1.5200
IOUT = 10 mA
1.5150
1.5100
1.5050
IOUT = 300 mA
1.5000
1.4950
PWM Mode
1.4900
VIN = 3.6V
1.4850
IOUT = 600 mA
1.4800
-30
-10
10
30
VOUT = 1.5V
50
70
90
TEMPERATURE (oC)
Figure 9. Output Voltage vs Temperature
Figure 10. Output Voltage vs Temperature
1.54
VIN = 3.6V
OUTPUT VOLTAGE (V)
VOUT = 1.5V
PFM Mode
1.52
PWM Mode
1.5
1.48
0
100
200
300
400
500
600
OUTPUT CURRENT (mA)
Figure 11. Output Voltage vs Output Current
8
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Figure 12. Output Voltage vs Output Current
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Typical Characteristics (continued)
LM3671MF/TL/LC, circuit of Figure 32, VIN = 3.6 V, VOUT = 1.5 V, TA = 25°C, unless otherwise noted.
100
100
VOUT = 1.5V
VIN = 2.7V
90
80
VIN = 2.7V
70
VIN = 4.5V
60
VIN = 3.6V
50
EFFICIENCY (%)
EFFICIENCY (%)
80
30
10.00
100.00 1000.00
VIN = 3.6V
50
30
1.00
VIN = 4.5V
60
40
0.10
VIN = 3.0V
70
40
20
0.01
VOUT = 1.8V
VIN = 3.0V
90
20
0.01
OUTPUT CURRENT (mA)
0.10
1.00
10.00
100.00 1000.00
OUTPUT CURRENT (mA)
L = 2.2 µH
L = 2.2 µH
Figure 13. Efficiency vs Output Current
Figure 14. Efficiency vs Output Current
L = 2.2 µH
L = 2.2 µH
Figure 15. Efficiency vs Output Current
Figure 16. Efficiency vs Output Current
20 mV/DIV
AC Coupled
VOUT
3.6V
VIN
3.0V
VOUT = 1.5V
IOUT = 400 mA
40 Ps/DIV
Figure 17. Line Transient Response (PWM Mode)
Figure 18. Line Transient Response (PWM Mode)
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Typical Characteristics (continued)
LM3671MF/TL/LC, circuit of Figure 32, VIN = 3.6 V, VOUT = 1.5 V, TA = 25°C, unless otherwise noted.
Figure 19. Load Transient Response (PWM Mode)
PFM Mode 0.5 mA to 50 mA
PFM Mode 0.5 mA to 50 mA
Figure 21. Load Transient Response
PFM Mode 0.5 mA to 50 mA
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Figure 22. Load Transient Response
PFM Mode 50 mA to 0.5 mA
Figure 23. Load Transient Response
10
Figure 20. Load Transient Response (PWM Mode)
Figure 24. Load Transient Response
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Typical Characteristics (continued)
LM3671MF/TL/LC, circuit of Figure 32, VIN = 3.6 V, VOUT = 1.5 V, TA = 25°C, unless otherwise noted.
Figure 25. PFM-to-PWM Mode Change by Load Transients
Figure 26. PWM-to-PFM Mode Change by Load Transients
Figure 27. Start-Up into PWM Mode
Figure 28. Start-Up into PFM Mode
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7 Detailed Description
7.1 Overview
The LM3671, a high-efficiency step-down DC-DC switching buck converter, delivers a constant voltage from a
single Li-Ion battery and input voltage rails from 2.7 V to 5.5 V to portable devices such as cell phones and
PDAs. Using a voltage mode architecture with synchronous rectification, the LM3671 has the ability to deliver up
to 600 mA depending on the input voltage, output voltage, ambient temperature and the inductor chosen.
There are three modes of operation depending on the current required: pulse width modulation (PWM), pulse
frequency modulation (PFM), and shutdown. The device operates in PWM mode at load current of approximately
80 mA or higher. Lighter load current cause the device to automatically switch into PFM for reduced current
consumption (IQ = 16 µA typical) and a longer battery life. Shutdown mode turns off the device, offering the
lowest current consumption (ISHUTDOWN = 0.01 µA typical).
Additional features include soft-start, undervoltage protection, current overload protection, and thermal shutdown
protection. As shown in the Figure 35, only three external power components are required for implementation.
The device uses an internal reference voltage of 0.5 V. TI recommends keeping the device in shutdown until the
input voltage is 2.7 V or higher.
7.2 Functional Block Diagram
VIN
EN
SW
Current Limit
Comparator
Undervoltage
Lockout
Ramp
Generator
+
-
Soft
Start
Ref1
PFM Current
Comparator
Thermal
Shutdown
+
-
2 MHz
Oscillator
Bandgap
Ref2
PWM Comparator
Error
Amp
+
Control Logic
Driver
-
pfm_low
VREF
0.5V
+
-
pfm_hi
Vcomp
1.0V
+
-
+
Zero Crossing
Comparator
Frequency
Compensation
Adj Ver
Fixed Ver
FB
12
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7.3 Feature Description
7.3.1 Circuit Operation
During the first portion of each switching cycle, the control block in the LM3671 turns on the internal PFET
switch. This allows current to flow from the input through the inductor to the output filter capacitor and load. The
inductor limits the current to a ramp with a slope of (VIN – VOUT)/L, by storing energy in a magnetic field.
During the second portion of each cycle, the controller turns the PFET switch off, blocking current flow from the
input, and then turns the NFET synchronous rectifier on. The inductor draws current from ground through the
NFET to the output filter capacitor and load, which ramps the inductor current down with a slope of –VOUT/L.
The output filter stores charge when the inductor current is high, and releases it when inductor current is low,
smoothing the voltage across the load.
The output voltage is regulated by modulating the PFET switch on time to control the average current sent to the
load. The effect is identical to sending a duty-cycle modulated rectangular wave formed by the switch and
synchronous rectifier at the SW pin to a low-pass filter formed by the inductor and output filter capacitor. The
output voltage is equal to the average voltage at the SW pin.
7.3.2 Soft Start
The LM3671 has a soft-start circuit that limits in-rush current during start-up. During start-up the switch current
limit is increased in steps. Soft start is activated only if EN goes from logic low to logic high after Vin reaches 2.7
V. Soft start is implemented by increasing switch current limit in steps of 70 mA, 140 mA, 280 mA and 1020 mA
(typical switch current limit). The start-up time thereby depends on the output capacitor and load current
demanded at startup. Typical start-up times with a 10-µF output capacitor and 300-mA load is 400 µs and with 1mA load is 275 µs.
7.4 Device Functional Modes
7.4.1 PWM Operation
During PWM operation the converter operates as a voltage-mode controller with input voltage feed forward. This
allows the converter to achieve good load and line regulation. The DC gain of the power stage is proportional to
the input voltage. To eliminate this dependence, feed forward inversely proportional to the input voltage is
introduced.
While in PWM mode, the output voltage is regulated by switching at a constant frequency and then modulating
the energy per cycle to control power to the load. At the beginning of each clock cycle the PFET switch is turned
on and the inductor current ramps up until the comparator trips and the control logic turns off the switch. The
current limit comparator can also turn off the switch in case the current limit of the PFET is exceeded. Then the
NFET switch is turned on and the inductor current ramps down. The next cycle is initiated by the clock turning off
the NFET and turning on the PFET.
VSW
2V/DIV
IL
200 mA/DIV
VIN = 3.6V
VOUT = 1.5V
IOUT = 400 mA
VOUT
10 mV/DIV
AC Coupled
TIME (200 ns/DIV)
Figure 29. Typical PWM Operation
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Device Functional Modes (continued)
7.4.1.1 Internal Synchronous Rectification
While in PWM mode, the LM3671 uses an internal NFET as a synchronous rectifier to reduce rectifier forward
voltage drop and associated power loss. Synchronous rectification provides a significant improvement in
efficiency whenever the output voltage is relatively low compared to the voltage drop across an ordinary rectifier
diode.
7.4.1.2 Current Limiting
A current limit feature allows the LM3671 to protect itself and external components during overload conditions.
PWM mode implements current limiting using an internal comparator that trips at 1020 mA (typical). If the output
is shorted to ground the device enters a timed current limit mode where the NFET is turned on for a longer
duration until the inductor current falls below a low threshold. This allows the inductor current more time to
decay, thereby preventing runaway.
7.4.2 PFM Operation
At very light load, the converter enters PFM mode and operates with reduced switching frequency and supply
current to maintain high efficiency.
The device automatically transitions into PFM mode when either of two conditions occurs for a duration of 32 or
more clock cycles:
1. The NFET current reaches zero.
2. The peak PMOS switch current drops below the IMODE level, (Typically IMODE < 30 mA + VIN/42 Ω).
2V/DIV
VSW
IL
200 mA/DIV
VIN = 3.6V
VOUT = 1.5V
IOUT = 20 mA
VOUT
20 mV/DIV
AC Coupled
TIME (4 Ps/DIV)
Figure 30. Typical PFM Operation
During PFM operation, the converter positions the output voltage slightly higher than the nominal output voltage
during PWM operation, allowing additional headroom for voltage drop during a load transient from light to heavy
load. The PFM comparators sense the output voltage via the feedback pin and control the switching of the output
FETs such that the output voltage ramps between approximately 0.6% and 1.7% above the nominal PWM output
voltage. If the output voltage is below the high PFM comparator threshold, the PMOS power switch is turned on.
It remains on until the output voltage reaches the high PFM threshold or the peak current exceeds the IPFM level
set for PFM mode. The typical peak current in PFM mode is: IPFM = 112 mA + VIN/27 Ω.
Once the PMOS power switch is turned off, the NMOS power switch is turned on until the inductor current ramps
to zero. When the NMOS zero-current condition is detected, the NMOS power switch is turned off. If the output
voltage is below the ‘high’ PFM comparator threshold (see Figure 31), the PMOS switch is again turned on and
the cycle is repeated until the output reaches the desired level. Once the output reaches the ‘high’ PFM
threshold, the NMOS switch is turned on briefly to ramp the inductor current to zero and then both output
switches are turned off, and the device enters an extremely low power mode. Quiescent supply current during
this ‘sleep’ mode is 16 µA (typ.), which allows the device to achieve high efficiency under extremely light load
conditions.
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Device Functional Modes (continued)
If the load current should increase during PFM mode (see Figure 31) causing the output voltage to fall below the
low2 PFM threshold, the device will automatically transition into fixed-frequency PWM mode. When VIN = 2.7 V
the device transitions from PWM to PFM mode at approximately 35 mA output current and from PFM to PWM
mode at approximately 85 mA , when VIN = 3.6 V, PWM to PFM transition happens at approximately 50 mA and
PFM to PWM transition happens at approximately 100 mA, when VIN = 4.5 V, PWM to PFM transition happens at
approximately 65 mA and PFM to PWM transition happens at approximately 115 mA.
High PFM Threshold
~1.017*Vout
PFM Mode at Light Load
Load current
increases
Low1 PFM Threshold
~1.006*Vout
ZA
xi
s
High PFM
Voltage
Threshold
reached,
go into
sleep mode
Current load
increases,
draws Vout
towards
Low2 PFM
Threshold
Low PFM
Threshold,
turn on
PFET
Low2 PFM Threshold,
switch back to PWMmode
Zs
Axi
Pfet on
until
Ipfm limit
reached
Nfet on
drains
inductor
current
until
I inductor = 0
Low2 PFM Threshold
Vout
PWM Mode at
Moderate to Heavy
Loads
Figure 31. Operation in PFM Mode and Transfer to PWM Mode
7.4.3 Shutdown
Setting the EN input pin low (< 0.4 V) places the LM3671 in shutdown mode. During shutdown the PFET switch,
NFET switch, reference, control and bias circuitry of the LM3671 are turned off. Setting EN high (> 1 V) enables
normal operation. It is recommended to set EN pin low to turn off the LM3671 during system power up and
undervoltage conditions when the supply is less than 2.7 V. Do not leave the EN pin floating.
7.4.4 Low Dropout Operation (LDO)
The LM3671-ADJ can operate at 100% duty cycle (no switching; PMOS switch completely on) for low dropout
support of the output voltage. In this way the output voltage will be controlled down to the lowest possible input
voltage. When the device operates near 100% duty cycle, output voltage ripple is approximately 25 mV.
The minimum input voltage needed to support the output voltage is
VIN, MIN = ILOAD × (RDSON, PFET + RINDUCTOR) + VOUT
where
•
•
•
ILOAD: Load current
RDSON, PFET: Drain to source resistance of PFET switch in the triode region
RINDUCTOR: Inductor resistance
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The external control of this device is very easy. First make sure the correct voltage been applied at VIN pin, then
simply apply the voltage at EN pin according to the Electrical Characteristics to enable or disable the output
voltage.
8.2 Typical Application
8.2.1 Typical Application: Fixed-Voltage Version
VIN
2.7V to 5.5V
L1: 2.2 PH
VIN
SW
1
CIN
4.7 PF
VOUT
5
COUT
10 PF
LM3671
GND
2
EN
FB
3
4
Figure 32. LM3671 Fixed-Voltage Typical Application Circuit
8.2.1.1 Design Requirements
Two ceramic capacitors and one inductor required for this application. These three external components need to
be selected very carefully for property operation. Please read Detailed Design Procedure.
8.2.1.2 Detailed Design Procedure
8.2.1.2.1 Inductor Selection
There are two main considerations when choosing an inductor; the inductor should not saturate, and the inductor
current ripple should be small enough to achieve the desired output voltage ripple. Different saturation current
rating specifications are followed by different manufacturers so attention must be given to details. Saturation
current ratings are typically specified at 25°C. However, ratings at the maximum ambient temperature of
application should be requested from the manufacturer. The minimum value of inductance to specify good
performance is 1.76 µH at ILIM (typical) DC current over the ambient temperature range. Shielded inductors
radiate less noise and should be preferred.
There are two methods to choose the inductor saturation current rating.
8.2.1.2.1.1 Method 1
The saturation current should be greater than the sum of the maximum load current and the worst case average
to peak inductor current. This can be written as
ISAT ! IOUTMAX + IRIPPLE
where IRIPPLE =
§ VIN - VOUT · § VOUT · § 1 ·
¨ 2 L ¸ ¨ VIN ¸ ¨ f ¸
¹ © ¹
¹ ©
©
where
•
16
IRIPPLE: average to peak inductor current
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Typical Application (continued)
•
•
•
•
•
IOUTMAX: maximum load current (600 mA)
VIN: maximum input voltage in application
L : min inductor value including worst case tolerances (30% drop can be considered for method 1)
f : minimum switching frequency (1.6 MHz)
VOUT: output voltage
(2)
8.2.1.2.1.2 Method 2
A more conservative and recommended approach is to choose an inductor that has a saturation current rating
greater than the maximum current limit of 1150 mA.
A 2.2-µH inductor with a saturation current rating of at least 1150 mA is recommended for most applications.
Inductor resistance should be less than 0.3 Ω for good efficiency. Table 1 lists suggested inductors and
suppliers. For low-cost applications, an unshielded bobbin inductor could be considered. For noise critical
applications, a toroidal or shielded-bobbin inductor should be used. A good practice is to lay out the board with
overlapping footprints of both types for design flexibility. This allows substitution of a low-noise shielded inductor,
in the event that noise from low-cost bobbin models is unacceptable.
8.2.1.2.2 Input Capacitor Selection
A ceramic input capacitor of 4.7 µF, 6.3 V is sufficient for most applications. Place the input capacitor as close as
possible to the VIN pin of the device. A larger value may be used for improved input voltage filtering. Use X7R or
X5R types; do not use Y5V. DC bias characteristics of ceramic capacitors must be considered when selecting
case sizes like 0805 and 0603. The minimum input capacitance to specify good performance is 2.2 µF at 3-V DC
bias; 1.5 µF at 5-V DC bias including tolerances and over ambient temperature range. The input filter capacitor
supplies current to the PFET switch of the LM3671 in the first half of each cycle and reduces voltage ripple
imposed on the input power source. A ceramic capacitor’s low ESR provides the best noise filtering of the input
voltage spikes due to this rapidly changing current. Select a capacitor with sufficient ripple current rating. The
input current ripple can be calculated as:
VOUT
IRMS = IOUTMAX
VIN
§1¨
©
VOUT
VIN
+
r
2
12
·
¸
¹
(VIN - VOUT) VOUT
r=
L f IOUTMAX VIN
The worst case is when VIN = 2 VOUT
(3)
Table 1. Suggested Inductors and Their Suppliers
MODEL
VENDOR
DIMENSIONS L × W × H (mm)
D.C.R (maximum)(mΩ)
DO3314-222MX
Coilcraft
3.3 × 3.3 × 1.4
200
LPO3310-222MX
Coilcraft
3.3 × 3.3 × 1
150
ELL5GM2R2N
Panasonic
5.2 × 5.2 × 1.5
53
CDRH2D14NP-2R2NC
Sumida
3.2 × 3.2 × 1.55
94
8.2.1.2.3 Output Capacitor Selection
A ceramic output capacitor of 10 µF, 6.3 V is sufficient for most applications. Use X7R or X5R types; do not use
Y5V. DC bias characteristics of ceramic capacitors must be considered when selecting case sizes like 0805 and
0603. DC bias characteristics vary from manufacturer to manufacturer and dc bias curves should be requested
from them as part of the capacitor selection process.
The minimum output capacitance to specify good performance is 5.75 µF at 1.8-V DC bias including tolerances
and over ambient temperature range. The output filter capacitor smoothes out current flow from the inductor to
the load, helps maintain a steady output voltage during transient load changes and reduces output voltage ripple.
These capacitors must be selected with sufficient capacitance and sufficiently low ESR to perform these
functions.
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The output voltage ripple is caused by the charging and discharging of the output capacitor and by the RESR and
can be calculated as:
Voltage peak-to-peak ripple due to capacitance can be expressed by Equation 4:
VPP-C =
IRIPPLE
4*f*C
(4)
Voltage peak-to-peak ripple due to ESR can be expressed by Equation 5:
VPP-ESR = (2 × IRIPPLE) × RESR
(5)
Because these two components are out of phase the rms (root mean squared) value can be used to get an
approximate value of peak-to-peak ripple.
The peak-to-peak ripple voltage, rms value can be expressed by Equation 6:
VPP-RMS =
VPP-C2 + VPP-ESR2
(6)
Note that the output voltage ripple is dependent on the inductor current ripple and the equivalent series
resistance of the output capacitor (RESR).
The RESR is frequency dependent (as well as temperature dependent); make sure the value used for calculations
is at the switching frequency of the part.
Table 2. Suggested Capacitors and Their Suppliers
MODEL
TYPE
VENDOR
VOLTAGE RATING (V)
CASE SIZE
INCH (mm)
4.7 µF for CIN
C2012X5R0J475K
Ceramic, X5R
TDK
6.3
0805 (2012)
JMK212BJ475K
Ceramic, X5R
Taiyo-Yuden
6.3
0805 (2012)
GRM21BR60J475K
Ceramic, X5R
Murata
6.3
0805 (2012)
C1608X5R0J475K
Ceramic, X5R
TDK
6.3
0603 (1608)
10 µF for COUT
GRM21BR60J106K
Ceramic, X5R
Murata
6.3
0805 (2012)
JMK212BJ106K
Ceramic, X5R
Taiyo-Yuden
6.3
0805 (2012)
C2012X5R0J106K
Ceramic, X5R
TDK
6.3
0805 (2012)
C1608X5R0J106K
Ceramic, X5R
TDK
6.3
0603 (1608)
8.2.1.3 Application Curves
Figure 33. PFM-to-PWM Mode Change by Load Transients
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Figure 34. PWM-to-PFM Mode Change by Load Transients
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8.2.2 Typical Application: ADJ Version
VIN
2.7V to 5.5V
L1: 2.2 PH
VIN
CIN
4.7 PF
VOUT
SW
1
5
COUT
LM3671ADJ
GND
C1
R1
C2
R2
10 PF
2
EN
FB
3
4
Figure 35. Typical Application Circuit for ADJ Version
8.2.2.1 Design Requirements
DESIGN PARAMETER
EXAMPLE VALUE
Input voltage range
2.7 V to 5.5 V
Input capacitor
4.7 µF
Output capacitor
10 µF
Inductor
2.2 µH
ADJ programmable output voltage
1.1 V to 3.3 V
8.2.2.2 Detailed Design Procedure
8.2.2.2.1 Output Voltage Selection for LM3671-ADJ
The output voltage of the adjustable parts can be programmed through the resistor network connected from VOUT
to FB, then to GND. VOUT is adjusted to make the voltage at FB equal to 0.5 V. The resistor from FB to GND
(R2) should be 200 kΩ to keep the current drawn through this network well below the 16-µA quiescent current
level (PFM mode) but large enough that it is not susceptible to noise. If R2 is 200 kΩ, and VFB is 0.5 V, the
current through the resistor feedback network will be 2.5 µA. The output voltage of the adjustable parts ranges
from 1.1 V to 3.3 V.
The formula for output voltage selection is:
VOUT = VFB
§1 + R1 ·
© R2 ¹
where
•
•
•
•
VOUT: output voltage (volts)
VFB : feedback voltage = 0.5 V
R1: feedback resistor from VOUT to FB
R2: feedback resistor from FB to GND
(7)
For any output voltage greater than or equal to 1.1 V, a zero must be added around 45 kHz for stability. The
formula for calculation of C1 is:
C1 =
1
(2 * S * R1 * 45 kHz)
(8)
For output voltages higher than 2.5 V, a pole must be placed at 45 kHz as well. If the pole and zero are at the
same frequency the formula for calculation of C2 is:
C2 =
1
(2 * S * R2 * 45 kHz)
(9)
The formula for location of zero and pole frequency created by adding C1 and C2 is given below. By adding C1,
a zero as well as a higher frequency pole is introduced.
Fz =
1
(2 * S * R1 * C1)
(10)
1
Fp =
2 * S * (R1 R2) * (C1+C2)
(11)
See the Table 3 table.
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Table 3. LM3671-ADJ Configurations for Various VOUT
(Circuit of Figure 35)
VOUT (V)
R1 (kΩ)
R2 (kΩ)
C1 (pF)
C2 (pF)
L (µH)
CIN (µF)
COUT (µF)
0.9
160
200
22
none
2.2
4.7
10
1.1
240
200
15
none
2.2
4.7
10
1.2
280
200
12
none
2.2
4.7
10
1.3
320
200
12
none
2.2
4.7
10
1.5
357
178
10
none
2.2
4.7
10
1.6
442
200
8.2
none
2.2
4.7
10
1.7
432
178
8.2
none
2.2
4.7
10
1.8
464
178
8.2
none
2.2
4.7
10
1.875
523
191
6.8
none
2.2
4.7
10
2.5
402
100
8.2
none
2.2
4.7
10
2.8
464
100
8.2
33
2.2
4.7
10
3.3
562
100
6.8
33
2.2
4.7
10
8.2.2.3 Application Curves
2V/DIV
VSW
2V/DIV
VSW
IOUT = 300 mA
500 mA/DIV
IL
VOUT
VIN = 3.6V
500 mV/DIV
VOUT
VIN = 3.6V
VOUT = 1.5V
1V/DIV
IOUT = 1 mA
VOUT = 1.5V
2V/DIV
EN
2V/DIV
EN
TIME (100 Ps/DIV)
TIME (100 Ps/DIV)
Figure 36. Start-Up into PWM Mode
Figure 37. Start-Up into PFM Mode
9 Power Supply Recommendations
The LM3671 is designed to operate from a stable input supply range of 2.7 V to 5.5 V.
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10 Layout
10.1 Layout Guidelines
PC board layout is an important part of DC-DC converter design. Poor board layout can disrupt the performance
of a DC-DC converter and surrounding circuitry by contributing to EMI, ground bounce, and resistive voltage loss
in the traces. These can send erroneous signals to the DC-DC converter device, resulting in poor regulation or
instability.
Good layout for the LM3671 can be implemented by following a few simple design rules below. Refer to
Figure 38 for top layer board layout.
1. Place the LM3671, inductor and filter capacitors close together and make the traces short. The traces
between these components carry relatively high switching currents and act as antennas. Following this rule
reduces radiated noise. Special care must be given to place the input filter capacitor very close to the VIN
and GND pin.
2. Arrange the components so that the switching current loops curl in the same direction. During the first half of
each cycle, current flows from the input filter capacitor through the LM3671 and inductor to the output filter
capacitor and back through ground, forming a current loop. In the second half of each cycle, current is pulled
up from ground through the LM3671 by the inductor to the output filter capacitor and then back through
ground forming a second current loop. Routing these loops so the current curls in the same direction
prevents magnetic field reversal between the two half-cycles and reduces radiated noise.
3. Connect the ground pins of the LM3671 and filter capacitors together using generous component-side
copper fill as a pseudo-ground plane. Then, connect this to the ground-plane (if one is used) with several
vias. This reduces ground-plane noise by preventing the switching currents from circulating through the
ground plane. It also reduces ground bounce at the LM3671 by giving it a low-impedance ground connection.
4. Use wide traces between the power components and for power connections to the DC-DC converter circuit.
This reduces voltage errors caused by resistive losses across the traces.
5. Route noise sensitive traces, such as the voltage feedback path, away from noisy traces between the power
components. The voltage feedback trace must remain close to the LM3671 circuit and should be direct but
must be routed opposite to noisy components. This reduces EMI-radiated onto the voltage feedback trace of
the DC-DC converter. A good approach is to route the feedback trace on another layer and to have a ground
plane between the top layer and layer on which the feedback trace is routed. In the same manner, for the
adjustable part, the feedback dividers should be on the bottom layer.
6. Place noise sensitive circuitry, such as radio IF blocks, away from the DC-DC converter, CMOS digital blocks
and other noisy circuitry. Interference with noise-sensitive circuitry in the system can be reduced through
distance.
In mobile phones, for example, a common practice is to place the DC-DC converter on one corner of the board,
arrange the CMOS digital circuitry around it (because this also generates noise), and then place sensitive
preamplifiers and IF stages on the diagonally opposing corner. Often, the sensitive circuitry is shielded with a
metal pan and power to the circuitry is post-regulated to reduce conducted noise, using LDOs.
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10.2 Layout Example
Figure 38. Top Layer Board Layout for SOT-23
10.3 DSBGA Package Assembly and Use
Use of the DSBGA package requires specialized board layout, precision mounting, and careful re-flow
techniques, as detailed in AN-1112 DSBGA Wafer Level Chip Scale Package (SNVA009). Refer to the section
Surface Mount Technology (DSBGA) Assembly Considerations. For best results in assembly, alignment ordinals
on the PC board must be used to facilitate placement of the device. The pad style used with DSBGA package
must be the NSMD (non-solder mask defined) type. This means that the solder-mask opening is larger than the
pad size. This prevents a lip that otherwise forms if the solder-mask and pad overlap, from holding the device off
the surface of the board and interfering with mounting. See AN-1112 DSBGA Wafer Level Chip Scale Package
(SNVA009) for specific instructions how to do this. The 5-pin package used for LM3671 has 300-micron solder
balls and requires 10.82 mils pads for mounting on the circuit board. The trace to each pad must enter the pad
with a 90° entry angle to prevent debris from being caught in deep corners. Initially, the trace to each pad should
be 7 mil wide, for a section approximately 7 mil long or longer, as a thermal relief. Then each trace must neck up
or down to its optimal width. The important criteria is symmetry. This ensures the solder bumps on the LM3671
re-flow evenly and that the device solders level to the board. In particular, special attention must be paid to the
pads for bumps A1 and A3, because VIN and GND are typically connected to large copper planes, inadequate
thermal relief can result in late or inadequate re-flow of these bumps.
The DSBGA package is optimized for the smallest possible size in applications with red or infrared opaque
cases. Because the DSBGA package lacks the plastic encapsulation characteristic of larger devices, it is
vulnerable to light. Backside metallization and/or epoxy coating, along with front-side shading by the printed
circuit board, reduce this sensitivity. However, the package has exposed die edges. In particular, DSBGA
devices are sensitive to light, in the red and infrared range, shining on the package’s exposed die edges.
22
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Copyright © 2004–2016, Texas Instruments Incorporated
Product Folder Links: LM3671 LM3671-Q1
LM3671, LM3671-Q1
www.ti.com
SNVS294S – NOVEMBER 2004 – REVISED MAY 2016
11 Device and Documentation Support
11.1 Device Support
11.1.1 Third-Party Products Disclaimer
TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT
CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES
OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER
ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.
11.2 Documentation Support
11.2.1 Related Documentation
For additional information, see the following:
AN-1112 DSBGA Wafer Level Chip Scale Package (SNVA009).
11.3 Related Links
Table 4 lists quick access links. Categories include technical documents, support and community resources,
tools and software, and quick access to sample or buy.
Table 4. Related Links
PARTS
PRODUCT FOLDER
SAMPLE & BUY
TECHNICAL
DOCUMENTS
TOOLS &
SOFTWARE
SUPPORT &
COMMUNITY
LM3671
Click here
Click here
Click here
Click here
Click here
LM3671-Q1
Click here
Click here
Click here
Click here
Click here
11.4 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.5 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.6 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
11.7 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
Copyright © 2004–2016, Texas Instruments Incorporated
Product Folder Links: LM3671 LM3671-Q1
Submit Documentation Feedback
23
LM3671, LM3671-Q1
SNVS294S – NOVEMBER 2004 – REVISED MAY 2016
www.ti.com
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
24
Submit Documentation Feedback
Copyright © 2004–2016, Texas Instruments Incorporated
Product Folder Links: LM3671 LM3671-Q1
PACKAGE OPTION ADDENDUM
www.ti.com
27-Oct-2022
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
LM3671LC-1.2/NOPB
ACTIVE
USON
NKH
6
1000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
S39
Samples
LM3671LC-1.3/NOPB
ACTIVE
USON
NKH
6
1000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
S40
Samples
LM3671LC-1.6/NOPB
ACTIVE
USON
NKH
6
1000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
S41
Samples
LM3671LC-1.8/NOPB
ACTIVE
USON
NKH
6
1000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
S42
Samples
LM3671MF-1.2
NRND
SOT-23
DBV
5
1000
Non-RoHS
& Green
Call TI
Level-1-260C-UNLIM
-40 to 85
SBPB
LM3671MF-1.2/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SBPB
Samples
LM3671MF-1.25/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SDRB
Samples
LM3671MF-1.375/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SEDB
Samples
LM3671MF-1.5/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SBRB
Samples
LM3671MF-1.6/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SDUB
Samples
LM3671MF-1.8/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SBSB
Samples
LM3671MF-1.875/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SDVB
Samples
LM3671MF-2.5/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SJRB
Samples
LM3671MF-2.8/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SJSB
Samples
LM3671MF-3.3/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SJEB
Samples
LM3671MF-ADJ/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SBTB
Samples
LM3671MFX-1.2/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SBPB
Samples
LM3671MFX-1.25/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SDRB
Samples
LM3671MFX-1.8/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SBSB
Samples
LM3671MFX-1.875/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SDVB
Samples
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
Orderable Device
27-Oct-2022
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
LM3671MFX-2.5/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SJRB
Samples
LM3671MFX-2.8/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SJSB
Samples
LM3671MFX-3.3/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SJEB
Samples
LM3671MFX-ADJ/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
SBTB
Samples
LM3671QMF-1.2/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
SH4B
Samples
LM3671QMFX-1.2/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
SH4B
Samples
LM3671QTL-1.8/NOPB
ACTIVE
DSBGA
YZR
5
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 125
9
Samples
LM3671QTLX-1.8/NOPB
ACTIVE
DSBGA
YZR
5
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 125
9
Samples
LM3671TL-1.2/NOPB
ACTIVE
DSBGA
YZR
5
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
C
Samples
LM3671TL-1.5/NOPB
ACTIVE
DSBGA
YZR
5
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
D
Samples
LM3671TL-1.8/NOPB
ACTIVE
DSBGA
YZR
5
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
B
Samples
LM3671TL-2.5/NOPB
ACTIVE
DSBGA
YZR
5
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
L
Samples
LM3671TL-2.8/NOPB
ACTIVE
DSBGA
YZR
5
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
K
Samples
LM3671TL-3.3/NOPB
ACTIVE
DSBGA
YZR
5
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
J
Samples
LM3671TL-ADJ/NOPB
ACTIVE
DSBGA
YZR
5
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
E
Samples
LM3671TLX-1.2/NOPB
ACTIVE
DSBGA
YZR
5
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
C
Samples
LM3671TLX-1.5/NOPB
ACTIVE
DSBGA
YZR
5
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
D
Samples
LM3671TLX-1.8/NOPB
ACTIVE
DSBGA
YZR
5
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
B
Samples
LM3671TLX-2.5/NOPB
ACTIVE
DSBGA
YZR
5
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
L
Samples
LM3671TLX-2.8/NOPB
ACTIVE
DSBGA
YZR
5
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
K
Samples
LM3671TLX-3.3/NOPB
ACTIVE
DSBGA
YZR
5
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
J
Samples
Addendum-Page 2
PACKAGE OPTION ADDENDUM
www.ti.com
Orderable Device
27-Oct-2022
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
RoHS & Green
SNAGCU
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
LM3671TLX-ADJ/NOPB
ACTIVE
DSBGA
YZR
5
3000
Level-1-260C-UNLIM
-40 to 85
E
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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