TI1 LMZ12001EXTTZ 1a simple switcher power module Datasheet

Sample &
Buy
Product
Folder
Technical
Documents
Support &
Community
Tools &
Software
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
LMZ12001EXT 1-A SIMPLE SWITCHER® Power Module with 20-V Maximum Input Voltage
for Demanding Environments and Rugged Applications
1 Features
2 Applications
•
•
•
•
•
1
•
•
•
•
•
•
•
•
Junction Temperature Range –55°C to 125°C
Integrated Shielded Inductor
Simple PCB Layout
Flexible Startup Sequencing Using External SoftStart Capacitor and Precision Enable
Protection Against Inrush Currents and Faults
such as Input UVLO and Output Short Circuit
Single Exposed Pad and Standard Pinout for Easy
Mounting and Manufacturing
Fast Transient Response for FPGAs and ASICs
Low Output Voltage Ripple
Pin-to-Pin Compatible With Family Devices:
– LMZ14203EXT/2EXT/1EXT (42-V Maximum 3
A, 2 A, 1 A)
– LMZ14203/2/1 (42-V Maximum 3 A, 2 A, 1 A)
– LMZ12003/2/1 (20-V Maximum 3 A, 2 A, 1 A)
Fully WEBENCH® Power Designer Enabled
Performance Benefits
– Low Radiated Emissions / High Radiated
Immunity
– Passes Vibration Standard MIL-STD-883
Method 2007.2 Condition A JESD22–B103B
Condition 1
– Passes Drop standard MIL-STD-883 Method
2002.3 Condition B JESD22–B110 Condition B
Electrical Specifications
– 6-W Maximum Total Power Output
– Up to 1-A Output Current
– Input Voltage Range 4.5 V to 20 V
– Output Voltage Range 0.8 V to 6 V
– Efficiency up to 92%
Simplified Application Schematic
•
•
•
Point-of-load Conversions from 5-V and 12-V
Input Rail
Time-Critical Projects
Space-Constrained High Thermal Requirement
Applications
Negative Output Voltage Applications
(See AN-2027 SNVA425)
3 Description
The LMZ12001EXT SIMPLE SWITCHER® power
module is an easy-to-use step-down DC-DC solution
capable of driving up to 1-A load with exceptional
power conversion efficiency, line and load regulation,
and output accuracy. The LMZ12001EXT is available
in an innovative package that enhances thermal
performance and allows for hand or machine
soldering.
The LMZ12001EXT can accept an input voltage rail
between 4.5 V and 20 V, and can deliver an
adjustable and highly accurate output voltage as low
as 0.8 V. The LMZ12001EXT only requires three
external resistors and four external capacitors to
complete the power solution. The LMZ12001EXT is a
reliable and robust design with the following
protection features: thermal shutdown, input
undervoltage lockout, output overvoltage protection,
short circuit protection, output current limit, and the
device allows start-up into a prebiased output. A
single resistor adjusts the switching frequency up to 1
MHz.
Device Information(1)(2)
PART NUMBER
PACKAGE
LMZ12001EXT
BODY SIZE (NOM)
NDW (7)
10.16 mm × 9.85 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
(2) Peak reflow temperature equals 245°C. See SNAA214 for
more details.
Efficiency 5-V Input at 25°C
100
LMZ12001EXT
VOUT
90
VOUT @ 1A
CFF
RON
RFBT
Enable
EFFICIENCY (%)
FB
EN
SS
GND
VIN
RON
95
VIN
1.8
1.5
1.2
0.8
85
80
75
70
65
60
CIN
CSS
RFBB
COUT
55
50
25°C
0
0.2
0.4
0.6
0.8
1
OUTPUT CURRENT (A)
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.
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
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
3
6.1
6.2
6.3
6.4
6.5
6.6
3
3
4
4
4
6
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Typical Characteristics .............................................
Detailed Description ............................................ 12
7.1
7.2
7.3
7.4
Overview .................................................................
Functional Block Diagram .......................................
Feature Description.................................................
Device Functional Modes........................................
12
12
12
13
8
Application and Implementation ........................ 14
8.1 Application Information............................................ 14
8.2 Typical Application .................................................. 14
9 Power Supply Recommendations...................... 20
10 Layout................................................................... 20
10.1
10.2
10.3
10.4
Layout Guidelines .................................................
Layout Examples...................................................
Power Dissipation and Thermal Considerations ...
Power Module SMT Guidelines ............................
20
21
22
22
11 Device and Documentation Support ................. 24
11.1
11.2
11.3
11.4
11.5
11.6
Device Support......................................................
Documentation Support ........................................
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
24
24
24
24
24
24
12 Mechanical, Packaging, and Orderable
Information ........................................................... 25
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision F (October 2013) to Revision G
•
Page
Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation
section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and
Mechanical, Packaging, and Orderable Information section. ................................................................................................ 1
Changes from Revision E (April 2013) to Revision F
Page
•
Changed 10 mils................................................................................................................................................................... 20
•
Changed 10 mils................................................................................................................................................................... 22
•
Added Power Module SMT Guidelines................................................................................................................................. 22
2
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
5 Pin Configuration and Functions
NDW Package
7-Pin
Top View
Pin Functions
PIN
NAME
NO.
TYPE
DESCRIPTION
EN
3
Analog
Enable — Input to the precision enable comparator. Rising threshold is 1.18-V nominal; 90mV hysteresis nominal. Maximum recommended input level is 6.5 V.
EP
—
Ground
Exposed Pad — Internally connected to pin 4. Used to dissipate heat from the package
during operation. Must be electrically connected to pin 4 external to the package.
FB
6
Analog
Feedback — Internally connected to the regulation, overvoltage, and short circuit
comparators. The regulation reference point is 0.8 V at this input pin. Connected the
feedback resistor divider between the output and ground to set the output voltage.
GND
4
Ground
Ground — Reference point for all stated voltages. Must be externally connected to EP.
RON
2
Analog
ON-Time Resistor — An external resistor from VIN to this pin sets the ON-time of the
application. Typical values range from 25 kΩ to 124 kΩ.
SS
5
Analog
Soft-Start — An internal 8-µA current source charges an external capacitor to produce the
soft-start function. This node is discharged at 200 µA during disable, overcurrent, thermal
shutdown and internal UVLO conditions.
VIN
1
Power
Supply input — Nominal operating range is 4.5 V to 20 V. A small amount of internal
capacitance is contained within the package assembly. Additional external input capacitance
is required between this pin and exposed pad.
VOUT
7
Power
Output Voltage — Output from the internal inductor. Connect the output capacitor between
this pin and exposed pad.
6 Specifications
6.1 Absolute Maximum Ratings (1) (2) (3)
MIN
MAX
UNIT
VIN, RON to GND
–0.3
25
V
EN, FB, SS to GND
–0.3
7
V
150
°C
245
°C
150
°C
Junction Temperature
Peak Reflow Case Temperature (30 sec)
Storage Temperature, Tstg
(1)
(2)
(3)
–65
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, please contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
For soldering specifications, refer to the following document: SNOA549
6.2 ESD Ratings
V(ESD)
(1)
(2)
Electrostatic discharge
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001
(1) (2)
VALUE
UNIT
±2000
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. Manufacturing with
less than 500-V HBM is possible with the necessary precautions.
The human body model is a 100-pF capacitor discharged through a 1.5-kΩ resistor into each pin. Test method is per JESD-22-114.
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
3
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
MAX
UNIT
VIN
4.5
20
EN
0
6.5
V
–55
125
°C
Operation Junction Temperature
V
6.4 Thermal Information
LMZ12001EXT
THERMAL METRIC (1)
NDW
UNIT
7 PINS
RθJA
Junction-to-ambient thermal resistance
RθJC(top)
(1)
(2)
(2)
Junction-to-case (top) thermal resistance
4-layer JEDEC Printed-Circuit-Board, 100
vias, No air flow
19.3
2-layer JEDEC Printed-Circuit-Board, No
air flow
21.5
No air flow
1.9
°C/W
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
RθJA measured on a 1.705” x 3.0” four layer board, with one ounce copper, thirty five thermal vias, no air flow, and 1W power
dissipation. Refer to PCB layout diagrams
6.5 Electrical Characteristics
Limits are for TJ = 25°C unless otherwise specified. Minimum and Maximum limits are ensured through test, design or
statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference
purposes only. Unless otherwise stated the following conditions apply: VIN = 12 V, VOUT = 1.8 V (1).
PARAMETER
MIN (2) TYP (3)
TEST CONDITIONS
MAX (2)
UNIT
SYSTEM PARAMETERS
ENABLE CONTROL
1.18
VEN
EN threshold trip point
VEN rising
VEN-HYS
EN threshold hysteresis
VEN falling
over the junction temperature (TJ)
range of –55°C to +125°C
1.1
1.26
90
V
mV
SOFT-START
8
ISS
SS source current
ISS-DIS
SS discharge current
VSS = 0 V
over the junction temperature (TJ)
range of –55°C to +125°C
4.9
11
–200
µA
µA
CURRENT LIMIT
2
ICL
Current limit threshold
d.c. average
over the junction temperature (TJ)
range of –55°C to +125°C
1.4
3
A
ON/OFF TIMER
tON-MIN
ON timer minimum pulse
width
150
ns
tOFF
OFF timer pulse width
260
ns
(1)
(2)
(3)
4
EN 55022:2006, +A1:2007, FCC Part 15 Subpart B: 2007. See AN-2024 SNVA422 and layout for information on device under test.
Minimum and Maximum limits are 100% production tested at 25°C. Limits over the operating temperature range are ensured through
correlation using Statistical Quality Control (SQC) methods. Limits are used to calculate Average Outgoing Quality Level (AOQL).
Typical numbers are at 25°C and represent the most likely parametric norm.
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
Electrical Characteristics (continued)
Limits are for TJ = 25°C unless otherwise specified. Minimum and Maximum limits are ensured through test, design or
statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference
purposes only. Unless otherwise stated the following conditions apply: VIN = 12 V, VOUT = 1.8 V(1).
PARAMETER
TEST CONDITIONS
MIN (2) TYP (3)
MAX (2)
UNIT
REGULATION AND OVERVOLTAGE COMPARATOR
VFB
In-regulation feedback
voltage
VSS >+ 0.8 V, TJ
= –55°C to 125°C over the junction temperature (TJ)
IO = 1 A
range of –55°C to +125°C
VSS >+ 0.8 V, TJ = 25°C, IO = 10 mA
VFB-OV
Feedback over-voltage
protection threshold
IFB
Feedback input bias
current
IQ
Non-switching input
current
VFB= 0.86 V
ISD
Shutdown quiescent
current
VEN= 0 V
0.798
0.777
0.786
0.818
0.802
V
0.818
0.92
V
5
nA
1
mA
25
μA
THERMAL CHARACTERISTICS
TSD
Thermal shutdown
Rising
165
°C
TSD-HYST
Thermal shutdown
hysteresis
Falling
15
°C
8
mVPP
PERFORMANCE PARAMETERS
ΔVO
Output voltage ripple
ΔVO/ΔVIN
Line regulation
VIN = 8 V to 20 V, IO= 1 A
ΔVO/ΔVIN
Load regulation
VIN = 12 V
η
Efficiency
VIN = 12 V, VO = 1.8 V, IO = 1 A
.01%
1.5
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
mV/A
85%
5
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
6.6 Typical Characteristics
Unless otherwise specified, the following conditions apply: VIN = 12 V; CIN = 10-µF X7R Ceramic; CO = 100-µF X7R Ceramic;
TA = 25°C for efficiency curves and waveforms.
100
0.3
95
80
DISSIPATION (W)
EFFICIENCY (%)
1.8
1.5
1.2
0.8
85
75
70
65
60
1.5
0.2
0.15
1.2
0.8
0.1
0.05
55
50
1.8
0.25
90
25°C
25°C
0
0.2
0.4
0.6
0.8
0
1
0
0.2
OUTPUT CURRENT (A)
0.4
0.6
Figure 1. Efficiency 4.5-V Input at 25°C
Figure 2. Dissipation 4.5-V Input at 25°C
0.3
1.8
95
0.25
1.8
1.5
1.2
0.8
85
80
DISSIPATION (W)
EFFICIENCY (%)
90
75
70
65
60
1.5
0.2
0.15
1.2
0.8
0.1
0.05
55
25°C
0
0
0.2
0.4
0.6
0.8
1
25°C
0.2
0
Figure 3. Efficiency 5-V Input at 25°C
0.3
95
3.3
2.5
1.8
1.5
1.2
0.8
85
80
75
70
65
60
25°C
0.2
1.2
0.8
0.15
0.1
0
0.2
0.4
0.6
0.8
1
1.8
1.5
25°C
0.05
0
0.8
3.3
2.5
0.25
DISSIPATION (W)
EFFICIENCY (%)
90
50
0.6
Figure 4. Dissipation 5-V Input at 25°C
100
55
0.4
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
6
1
OUTPUT CURRENT (A)
100
50
0.8
1
0
0.2
0.4
0.6
0.8
1
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
Figure 5. Efficiency 6-V Input at 25°C
Figure 6. Dissipation 6-V Input at 25°C
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
Typical Characteristics (continued)
Unless otherwise specified, the following conditions apply: VIN = 12 V; CIN = 10-µF X7R Ceramic; CO = 100-µF X7R Ceramic;
TA = 25°C for efficiency curves and waveforms.
100
0.35
95
5.0
3.3
2.5
1.8
1.5
1.2
0.8
85
80
0.3
0.25
DISSIPATION (W)
EFFICIENCY (%)
90
5.0
3.3
2.5
1.8
1.5
75
70
65
0.2
1.2
0.15
0.8
0.1
60
25°C
0.05
55
50
25°C
0
0.4
0.2
0.6
0.8
0
1
0.4
Figure 7. Efficiency 8-V Input at 25°C
Figure 8. Dissipation 8-V Input at 25°C
0.45
6.0
5.0
3.3
2.5
1.8
1.5
1.2
0.8
85
80
75
70
65
3.3
2.5
0.3
1.8
1.5
0.225
1.2
0.8
0.15
25°C
60
0.075
55
50
6.0
5.0
0.375
DISSIPATION (W)
90
25°C
0
0
0.2
0.4
0.6
0.8
1
0
0.2
OUTPUT CURRENT (A)
0.6
0.4
Figure 10. Dissipation 12-V Input at 25°C
0.6
100
6.0
5.0
95
6.0
5.0
3.3
2.5
1.8
85
80
0.5
DISSIPATION (W)
90
1
0.8
OUTPUT CURRENT (A)
Figure 9. Efficiency 12-V Input at 25°C
EFFICIENCY (%)
1
OUTPUT CURRENT (A)
95
75
70
65
60
3.3
2.5
0.4
0.3
1.8
0.2
0.1
55
50
0.8
0.6
OUTPUT CURRENT (A)
100
EFFICIENCY (%)
0.2
0
25°C
25°C
0
0.2
0.4
0.6
0.8
1
0
0
0.2
0.4
0.6
0.8
1
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
Figure 11. Efficiency 20-V Input at 25°C
Figure 12. Dissipation 20-V Input at 25°C
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
7
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
Typical Characteristics (continued)
Unless otherwise specified, the following conditions apply: VIN = 12 V; CIN = 10-µF X7R Ceramic; CO = 100-µF X7R Ceramic;
TA = 25°C for efficiency curves and waveforms.
100
0.45
95
0.375
1.8
1.5
1.2
85
80
DISSIPATION (W)
EFFICIENCY (%)
90
75
70
65
0.225
1.2
0.15
85°C
60
0.075
55
50
1.8
1.5
0.3
85°C
0
0
0.2
0.4
0.6
0.8
1
0.2
0
OUTPUT CURRENT (A)
0.4
0.6
0.8
1
OUTPUT CURRENT (A)
Figure 13. Efficiency 4.5-V Input at 85°C
Figure 14. Dissipation 4.5-V Input at 85°C
0.45
100
95
0.375
1.8
1.8
1.5
1.2
85
80
DISSIPATION (W)
EFFICIENCY (%)
90
75
70
65
0.3
0.225
1.2
0.15
85°C
60
0.075
55
50
1.5
85°C
0
0
0.2
0.4
0.6
0.8
1
0
0.2
OUTPUT CURRENT (A)
0.4
0.6
1
0.8
OUTPUT CURRENT (A)
Figure 15. Efficiency 5-V Input at 85°C
Figure 16. Dissipation 5-V Input at 85°C
100
0.45
95
85
80
DISSIPATION (W)
EFFICIENCY (%)
0.375
3.3
2.5
1.8
1.5
1.2
90
75
70
65
0.3
0.225
1.2
0.15
85°C
60
0.075
55
50
85°C
0
0
0.2
0.4
0.6
0.8
1
0
0.2
0.4
0.6
0.8
1
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
Figure 17. Efficiency 6-V Input at 85°C
8
3.3
2.5
1.8
1.5
Figure 18. Dissipation 6-V Input at 85°C
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
Typical Characteristics (continued)
Unless otherwise specified, the following conditions apply: VIN = 12 V; CIN = 10-µF X7R Ceramic; CO = 100-µF X7R Ceramic;
TA = 25°C for efficiency curves and waveforms.
100
0.45
95
5.0
3.3
2.5
1.8
1.5
1.2
85
80
0.375
DISSIPATION (W)
EFFICIENCY (%)
90
75
70
65
0.3
0.225
1.2
0.15
85°C
60
0.075
55
50
5.0
3.3
2.5
1.8
1.5
85°C
0
0.2
0.4
0.6
0.8
0
1
0
0.2
OUTPUT CURRENT (A)
Figure 19. Efficiency 8-V Input at 85°C
Figure 20. Dissipation 8-V Input at 85°C
0.6
95
6.0
5.0
3.3
2.5
1.8
1.5
1.2
85
80
0.5
DISSIPATION (W)
EFFICIENCY (%)
90
75
70
65
60
6.0
5.0
3.3
2.5
0.4
0.3
1.8
1.5
1.2
0.2
0.1
55
85°C
0
85°C
0
0.2
0.4
0.6
0.8
0
1
0.2
0.4
0.6
0.8
1
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
Figure 21. Efficiency 12-V Input at 85°C
Figure 22. Dissipation 12-V Input at 85°C
0.7
100
95
85
80
DISSIPATION (W)
6.0
5.0
3.3
2.5
90
EFFICIENCY (%)
1
0.8
OUTPUT CURRENT (A)
100
50
0.6
0.4
1.8
75
70
65
0.6
6.0
5.0
3.3
0.5
2.5
0.4
0.3
1.8
1.5
0.2
1.2
60
0.1
55
50
85°C
0
85°C
0
0.2
0.4
0.6
0.8
0
1
OUTPUT CURRENT (A)
0.2
0.4
0.6
0.8
1
OUTPUT CURRENT (A)
Figure 23. Efficiency 20-V Input at 85°C
Figure 24. Dissipation 20-V Input at 85°C
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
9
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
Typical Characteristics (continued)
1.808
1.815
1.804
1.812
1.800
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
Unless otherwise specified, the following conditions apply: VIN = 12 V; CIN = 10-µF X7R Ceramic; CO = 100-µF X7R Ceramic;
TA = 25°C for efficiency curves and waveforms.
6
5
1.796
12
1.792
20
25°C
1.788
0
0.2
0.4
0.8
0.6
6
1.809
5
12
1.806
20
1.803
85°C
1.800
1
0
0.2
0.4
0.6
0.8
1
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
Figure 25. Line and Load Regulation at 25°C
Figure 26. Line and Load Regulation at 85°C
1.808
OUTPUT VOLTAGE (V)
1.804
1.800
1.796
1.792
6
5
4.5
12
1.788
1.784
20
-55°C
1.780
0
0.2
0.4
0.6
0.8
1
12 VIN 3.3 VO 1 A
OUTPUT CURRENT (A)
Figure 27. Line and Load Regulation at –55°C
Figure 28. Output Ripple
2.4
CURRENT (A)
2.3
2.2
SHORT CIRCUIT
2.1
2.0
ONSET
1.9
25°C
1.8
0
12 VIN 3.3 VO 0.6-A to 1-A Step
5
10
15
20
25
INPUT VOLTAGE (V)
Figure 29. Transient Response
10
Figure 30. Current Limit 1.8 VOUT at 25°C
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
Typical Characteristics (continued)
Unless otherwise specified, the following conditions apply: VIN = 12 V; CIN = 10-µF X7R Ceramic; CO = 100-µF X7R Ceramic;
TA = 25°C for efficiency curves and waveforms.
2.4
2.4
2.3
OUTPUT CURRENT (A)
2.3
CURRENT (A)
SHORT CIRCUIT
2.2
2.1
2.0
ONSET
SHORT CIRCUIT
2.2
2.1
2
ONSET
1.9
1.9
85C
25°C
1.8
1.8
0
5
10
15
20
25
0
5
INPUT VOLTAGE (V)
20
25
Figure 32. Current Limit 1.8 VOUT at 85°C
1.2
2.3
1
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
Figure 31. Current Limit 3.3 VOUT at 25°C
2.2
SHORT CIRCUIT
2.0
1.9
4.5Vin
0.8
12Vin
0.6
20Vin
0.4
0.2
-55°C
1.8
15
INPUT VOLTAGE (V)
2.4
2.1
10
1.8Vout
ONSET
0
5
10
15
20
25
0
50
60
70
80
90
100 110 120
AMBIENT TEMPERATURE (°C)
INPUT VOLTAGE (V)
Figure 33. Current Limit 1.8 VOUT at –55°C
Figure 34. Thermal Derating VOUT = 1.8 V
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
11
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
7 Detailed Description
7.1 Overview
The LMZ12001EXT power module is an easy-to-use step-down DC-DC solution capable of driving up to 1-A load
with exceptional power conversion efficiency, line and load regulation, and output accuracy.
7.2 Functional Block Diagram
Vin
VIN 1
Linear reg
Cvcc
5
CIN
SS
Css
CBST
3
EN
RON
2
VOUT 7
RON
Timer
CFF
6
6.8 éH
VO
Co
FB
RFBT
RFBB
0.47 éF
Regulator IC
Internal
Passives
GND
4
7.3 Feature Description
7.3.1 COT Control Circuit Overview
Constant ON-Time control is based on a comparator and an ON-time one-shot, with the output voltage feedback
compared with an internal 0.8-V reference. If the feedback voltage is below the reference, the main MOSFET is
turned on for a fixed ON-time determined by a programming resistor RON. RON is connected to VIN such that ONtime is reduced with increasing input supply voltage. Following this ON-time, the main MOSFET remains off for a
minimum of 260 ns. If the voltage on the feedback pin falls below the reference level again the ON-time cycle is
repeated. Regulation is achieved in this manner.
7.3.2 Output Overvoltage Comparator
The voltage at FB is compared to a 0.92-V internal reference. If FB rises above 0.92 V the ON-time is
immediately terminated. This condition is known as overvoltage protection (OVP). It can occur if the input voltage
is increased very suddenly or if the output load is decreased very suddenly. Once OVP is activated, the top
MOSFET ON-times will be inhibited until the condition clears. Additionally, the synchronous MOSFET will remain
on until inductor current falls to zero.
7.3.3 Current Limit
Current limit detection is carried out during the OFF-time by monitoring the current in the synchronous MOSFET.
Referring to the Functional Block Diagram, when the top MOSFET is turned off, the inductor current flows
through the load, the PGND pin and the internal synchronous MOSFET. If this current exceeds 1.5 A (typical) the
current limit comparator disables the start of the next ON-time period. The next switching cycle will occur only if
the FB input is less than 0.8 V and the inductor current has decreased below 1.5 A. Inductor current is monitored
during the period of time the synchronous MOSFET is conducting. So long as inductor current exceeds 1.5 A,
further ON-time intervals for the top MOSFET will not occur. Switching frequency is lower during current limit due
to the longer OFF-time.
NOTE
Current limit is dependent on both duty cycle and temperature as illustrated in the graphs
in the Typical Characteristics sections.
12
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
Feature Description (continued)
7.3.4 Thermal Protection
The junction temperature of the LMZ12001EXT must not be allowed to exceed its maximum ratings. Thermal
protection is implemented by an internal Thermal Shutdown circuit which activates at 165°C (typical) causing the
device to enter a low power standby state. In this state the main MOSFET remains off causing VO to fall, and
additionally the CSS capacitor is discharged to ground. Thermal protection helps prevent catastrophic failures for
accidental device overheating. When the junction temperature falls back below 145°C (typ Hyst = 20 °C) the SS
pin is released, VO rises smoothly, and normal operation resumes.
Applications requiring maximum output current especially those at high input voltage may require application
derating at elevated temperatures.
7.3.5 Zero Coil Current Detection
The current of the lower (synchronous) MOSFET is monitored by a zero coil current detection circuit which
inhibits the synchronous MOSFET when its current reaches zero until the next ON-time. This circuit enables the
DCM operating mode, which improves efficiency at light loads.
7.3.6 Prebiased Start-Up
The LMZ12001EXT will properly start up into a prebiased output. This start-up situation is common in multiple rail
logic applications where current paths may exist between different power rails during the start-up sequence. The
following scope capture shows proper behavior during this event.
Figure 35. Prebiased Start-Up
7.4 Device Functional Modes
7.4.1 Discontinuous Conduction and Continuous Conduction Modes
At light load the regulator will operate in discontinuous conduction mode (DCM). With load currents above the
critical conduction point, it will operate in continuous conduction mode (CCM). When operating in DCM the
switching cycle begins at zero amps inductor current; increases up to a peak value, and then recedes back to
zero before the end of the OFF-time. Note that during the period of time that inductor current is zero, all load
current is supplied by the output capacitor. The next ON-time period starts when the voltage on the at the FB pin
falls below the internal reference. The switching frequency is lower in DCM and varies more with load current as
compared to CCM. Conversion efficiency in DCM is maintained since conduction and switching losses are
reduced with the smaller load and lower switching frequency.
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
13
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
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 LMZ12001EXT is a step-down DC-to-DC power module. It is typically used to convert a higher DC voltage to
a lower DC voltage with a maximum output current of 1 A. The following design procedure can be used to select
components for the LMZ12001EXT. Alternately, the WEBENCH software may be used to generate complete
designs. When generating a design, the WEBENCH software utilizes iterative design procedure and accesses
comprehensive databases of components. Please go to www.ti.com for more details
8.2 Typical Application
U1
EP
VIN
Enable
VOUT
FB
1.8VO @ 1A
7
GND
SS
6
5
VIN
EN
4
3
2
1
RON
LMZ12001EXTTZ-ADJ
4.5V to 20V
RENT
32.4k
CFF
0.022 PF
RON
32.4k
RENB
11.8k
D1
OPT
CIN2
10 PF
RFBT
1.37k
CIN1
1 PF
CSS
0.022 PF
RFBB
1.07k
CO1
1 PF
CO2
100 PF
Figure 36. Evaluation Board Schematic Diagram
8.2.1 Design Requirements
For this example the following application parameters exist.
• VIN Range = Up to 20 V
• VOUT = 0.8 V to 6 V
• IOUT = 1 A
8.2.2 Detailed Design Procedure
The LMZ12001EXT is fully supported by WEBENCH and offers the following: component selection, electrical and
thermal simulations as well as the build-it board for a reduction in design time. The following list of steps can be
used to manually design the LMZ12001EXT application.
14
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
Typical Application (continued)
1.
2.
3.
4.
5.
6.
Select minimum operating VIN with enable divider resistors
Program VO with divider resistor selection
Program turnon time with soft-start capacitor selection
Select CO
Select CIN
Set operating frequency with RON
8.2.2.1 Enable Divider, RENT and RENB Selection
The enable input provides a precise 1.18-V band-gap rising threshold to allow direct logic drive or connection to
a voltage divider from a higher enable voltage such as Vin. The enable input also incorporates 90 mV (typical) of
hysteresis resulting in a falling threshold of 1.09 V. The maximum recommended voltage into the EN pin is 6.5 V.
For applications where the midpoint of the enable divider exceeds 6.5 V, a small Zener diode can be added to
limit this voltage.
The function of this resistive divider is to allow the designer to choose an input voltage below which the circuit
will be disabled. This implements the feature of programmable undervoltage lockout. This is often used in
battery-powered systems to prevent deep discharge of the system battery. It is also useful in system designs for
sequencing of output rails or to prevent early turnon of the supply as the main input voltage rail rises at powerup. Applying the enable divider to the main input rail is often done in the case of higher input voltage systems
where a lower boundary of operation must be established. In the case of sequencing supplies, the divider is
connected to a rail that becomes active earlier in the power-up cycle than the LMZ12001EXT output rail. The two
resistors must be chosen based on the following ratio:
RENT / RENB = (VIN UVLO / 1.18 V) – 1
(1)
The LMZ12001EXT demonstration and evaluation boards use 11.8 kΩ for RENB and 32.4 kΩ for RENT resulting in
a rising UVLO of 4.5 V. This divider presents 5.34 V to the EN input when the divider input is raised to 20 V.
8.2.2.2 Output Voltage Selection
Output voltage is determined by a divider of two resistors connected between VO and ground. The midpoint of
the divider is connected to the FB input. The voltage at FB is compared to a 0.8-V internal reference. In normal
operation an ON-time cycle is initiated when the voltage on the FB pin falls below 0.8 V. The main MOSFET ONtime cycle causes the output voltage to rise and the voltage at the FB to exceed 0.8 V. As long as the voltage at
FB is above 0.8 V, ON-time cycles will not occur.
The regulated output voltage determined by the external divider resistors RFBT and RFBB is:
VO = 0.8 V × (1 + RFBT / RFBB)
(2)
Rearranging terms; the ratio of the feedback resistors for a desired output voltage is:
RFBT / RFBB = (VO / 0.8 V) – 1
(3)
These resistors must be chosen from values in the range of 1.0 kΩ to 10.0 kΩ.
For VO = 0.8 V the FB pin can be connected to the output directly so long as an output preload resistor remains
that draws more than 20 µA. Converter operation requires this minimum load to create a small inductor ripple
current and maintain proper regulation when no load is present.
A feed-forward capacitor is placed in parallel with RFBT to improve load step transient response. Its value is
usually determined experimentally by load stepping between DCM and CCM conduction modes and adjusting for
best transient response and minimum output ripple.
Table 1 lists the values for RFBT , RFBB , CFF and RON.
Table 1. Bill of Materials
REF DES
DESCRIPTION
CASE SIZE
MANUFACTURER
MANUFACTURER P/N
U1
SIMPLE SWITCHER
PFM
Texas Instruments
LMZ12001EXTTZ-ADJ
Cin1
1 µF, 50 V, X7R
1206
Taiyo Yuden
UMK316B7105KL-T
Cin2
10 µF, 50 V, X7R
1210
Taiyo Yuden
UMK325BJ106MM-T
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
15
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
Typical Application (continued)
Table 1. Bill of Materials (continued)
REF DES
DESCRIPTION
CASE SIZE
MANUFACTURER
MANUFACTURER P/N
CO1
1 µF, 50 V, X7R
1206
Taiyo Yuden
UMK316B7105KL-T
CO2
100 µF, 6.3 V, X7R
1210
Taiyo Yuden
JMK325BJ10CR7MM-T
RFBT
1.37 kΩ
0603
Vishay Dale
CRCW06031K37FKEA
RFBB
1.07 kΩ
0603
Vishay Dale
CRCW06031K07FKEA
RON
32.4 kΩ
0603
Vishay Dale
CRCW060332K4FKEA
RENT
32.4 kΩ
0603
Vishay Dale
CRCW060332K4FKEA
RENB
11.8 kΩ
0603
Vishay Dale
CRCW060311k8FKEA
CFF
22 nF, ±10%, X7R, 16 V
0603
TDK
C1608X7R1H223K
CSS
22 nF, ±10%, X7R, 16 V
0603
TDK
C1608X7R1H223K
D1
5.1 V
SOD-23
—
Optional
8.2.2.3 Soft-Start Capacitor Selection
Programmable soft-start permits the regulator to slowly ramp to its steady-state operating point after being
enabled, thereby reducing current inrush from the input supply and slowing the output voltage rise-time to
prevent overshoot.
Upon turnon, after all UVLO conditions have been passed, an internal 8-µA current source begins charging the
external soft-start capacitor. The soft-start time duration to reach steady state operation is given by the formula:
tSS = VREF × CSS / Iss = 0.8 V × CSS / 8 µA
(4)
This equation can be rearranged as follows:
CSS = tSS × 8 μA / 0.8 V
(5)
Use of a 0.022-μF capacitor results in 2.2-ms soft-start interval which is recommended as a minimum value.
As the soft-start input exceeds 0.8 V the output of the power stage will be in regulation. The soft-start capacitor
continues charging until it reaches approximately 3.8 V on the SS pin. Voltage levels between 0.8 V and 3.8 V
have no effect on other circuit operation. Note that the following conditions will reset the soft-start capacitor by
discharging the SS input to ground with an internal 200-μA current sink.
• The enable input being pulled low
• Thermal shutdown condition
• Overcurrent fault
• Internal VCC UVLO (Approx 4-V input to VIN)
8.2.2.4 CO Selection
None of the required CO output capacitance is contained within the module. At a minimum, the output capacitor
must meet the worst case minimum ripple current rating of 0.5 × ILR P-P, as calculated in Equation 16 below.
Beyond that, additional capacitance will reduce output ripple so long as the ESR is low enough to permit it. A
minimum value of 10 μF is generally required. Experimentation will be required if attempting to operate with a
minimum value. Ceramic capacitors or other low ESR types are recommended. See AN-2024 SNVA422 for more
detail.
The following equation provides a good first pass approximation of CO for load transient requirements:
CO ≥ ISTEP × VFB × L × VIN/ (4 × VO × (VIN – VO) × VOUT-TRAN)
(6)
Solving:
CO ≥ 1 A × 0.8 V × 10 μH × 12 V / (4 × 3.3 V × ( 12 V – 3.3 V) × 33 mV) ≥ 25 μF
The LMZ12001EXT demonstration and evaluation boards are populated with a 100-µF 6.3-V X5R output
capacitor. Locations for other output capacitors are provided.
16
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
8.2.2.5 CIN Selection
The LMZ12001EXT module contains an internal 0.47-µF input ceramic capacitor. Additional input capacitance is
required external to the module to handle the input ripple current of the application. This input capacitance must
be located in very close proximity to the module. Input capacitor selection is generally directed to satisfy the input
ripple current requirements rather than by capacitance value. Worst case input ripple current rating is dictated by
the equation:
I(CIN(RMS)) ≊ 1 /2 × IO × √ (D / 1-D)
where
•
D ≊ VO / VIN
(7)
As a point of reference, the worst case ripple current will occur when the module is presented with full load
current and when VIN = 2 × VO.
Recommended minimum input capacitance is 10-µF X7R ceramic with a voltage rating at least 25% higher than
the maximum applied input voltage for the application. TI recommends to pay attention to the voltage and
temperature deratings of the capacitor selected.
NOTE
Ripple current rating of ceramic capacitors may be missing from the capacitor data sheet
and you may have to contact the capacitor manufacturer for this rating.
If the system design requires a certain minimum value of input ripple voltage ΔVIN be maintained then the
following equation may be used.
CIN ≥ IO × D × (1 – D) / fSW-CCM × ΔVIN
(8)
If ΔVIN is 1% of VIN for a 20-V input to 3.3-V output application this equals 200 mV and fSW = 400 kHz.
CIN ≥ 1A × 3.3 V / 20 V × (1 – 3.3 V / 20 V) / (400000 × 0.200 V) ≥ 1.7 μF
Additional bulk capacitance with higher ESR may be required to damp any resonant effects of the input
capacitance and parasitic inductance of the incoming supply lines.
8.2.2.6 RON Resistor Selection
Many designs will begin with a desired switching frequency in mind. For that purpose the following equation can
be used.
fSW(CCM) ≊ VO / (1.3 × 10-10 × RON)
(9)
This can be rearranged as
RON ≊ VO / (1.3 × 10 -10 × fSW(CCM) )
(10)
The selection of RON and fSW(CCM) must be confined by limitations in the ON-time and OFF-time for the COT
control section.
The ON-time of the LMZ12001EXT timer is determined by the resistor RON and the input voltage VIN. It is
calculated as follows:
tON = (1.3 × 10-10 × RON) / VIN
(11)
The inverse relationship of tON and VIN gives a nearly constant switching frequency as VIN is varied. RON must be
selected such that the ON-time at maximum VIN is greater than 150 ns. The ON-timer has a limiter to ensure a
minimum of 150 ns for tON. This limits the maximum operating frequency, which is governed by the following
equation:
fSW(MAX) = VO / (VIN(MAX) × 150 ns)
(12)
This equation can be used to select RON if a certain operating frequency is desired so long as the minimum ONtime of 150 ns is observed. The limit for RON can be calculated as follows:
RON ≥ VIN(MAX) × 150 ns / (1.3 × 10 -10)
(13)
If RON calculated in Equation 10 is less than the minimum value determined in Equation 13 a lower frequency
must be selected. Alternatively, VIN(MAX) can also be limited in order to keep the frequency unchanged.
Additionally, consider the minimum OFF-time of 260 ns limits the maximum duty ratio. Larger RON (lower FSW)
must be selected in any application requiring large duty ratio.
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
17
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
8.2.2.7 Discontinuous Conduction and Continuous Conduction Modes Selection
Operating frequency in DCM can be calculated as follows:
fSW(DCM) ≊ VO × (VIN – 1) × 10 μH × 1.18 × 1020 × IO / (VIN –VO) × RON2
(14)
In CCM, current flows through the inductor through the entire switching cycle and never falls to zero during the
OFF-time. The switching frequency remains relatively constant with load current and line voltage variations. The
CCM operating frequency can be calculated using Equation 9 above.
Figure 37 is a comparison pair of waveforms of the showing both CCM (upper) and DCM operating modes.
VIN = 12 V, VO = 3.3 V, IO = 1 A/0.25 A
Figure 37. CCM and DCM Operating Modes
The approximate formula for determining the DCM/CCM boundary is as follows:
IDCB ≊ VO × (VIN – VO) / (2 × 10 μH × fSW(CCM) × VIN)
(15)
Figure 38 is a typical waveform showing the boundary condition.
VIN = 12 V, VO = 3.3 V, IO = 0.29 A
Figure 38. Transition Mode Operation
The inductor internal to the module is 10 μH. This value was chosen as a good balance between low and high
input voltage applications. The main parameter affected by the inductor is the amplitude of the inductor ripple
current (ILR). ILR can be calculated with:
ILR P-P = VO × (VIN – VO) / (10 µH × fSW × VIN)
where
•
VIN is the maximum input voltage and fSW is determined from Equation 9.
(16)
If the output current IO is determined by assuming that IO = IL, the higher and lower peak of ILR can be
determined. Be aware that the lower peak of ILR must be positive if CCM operation is required.
18
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
8.2.3 Application Curves
100
1.2
1
OUTPUT CURRENT (A)
EFFICIENCY (%)
90
80
70
60
0.8
0.6
0.4
0.2
25°C
50
0
0.2
0.4
0.6
0
50
1
0.8
OUTPUT CURRENT (A)
60
70
80
90
100 110 120
AMBIENT TEMPERATURE (°C)
VIN = 12 V, VOUT = 5 V
VIN = 12 V, VOUT = 5 V
Figure 40. Thermal Derating Curve
Figure 39. Efficiency
RADIATED EMISSIONS (dBµV/m)
80.0
70.0
60.0
50.0
EN 55022 CLASS B LIMIT
40.0
30.0
20.0
10.0
0.0
0
200
400
600
800
1000
FREQUENCY (MHz)
Figure 41. Radiated Emissions (EN 55022 Class B) from Evaluation Board
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
19
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
9 Power Supply Recommendations
The LMZ12001EXT device is designed to operate from an input voltage supply range between 4.5 V and 20 V.
This input supply must be well regulated and able to withstand maximum input current and maintain a stable
voltage. The resistance of the input supply rail must be low enough that an input current transient does not cause
a high enough drop at the LMZ12001EXT supply voltage that can cause a false UVLO fault triggering and
system reset. If the input supply is more than a few inches from the LMZ12001EXT, additional bulk capacitance
may be required in addition to the ceramic bypass capacitors. The amount of bulk capacitance is not critical, but
a 47-μF or 100-μF electrolytic capacitor is a typical choice.
10 Layout
10.1 Layout Guidelines
PCB 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 drop in
the traces. These can send erroneous signals to the DC-DC converter resulting in poor regulation or instability.
Good layout can be implemented by following a few simple design rules.
1. Minimize area of switched current loops.
From an EMI reduction standpoint, it is imperative to minimize the high di/dt current paths during PCB layout.
The high current loops that do not overlap have high di/dt content that will cause observable high frequency
noise on the output pin if the input capacitor CIN1 is placed a distance away for the LMZ12001. Therefore
physically place CIN1 as close as possible to the LMZ12001EXT VIN and GND exposed pad. This will
minimize the high di/dt area and reduce radiated EMI. Additionally, grounding for both the input and output
capacitor must consist of a localized top side plane that connects to the GND exposed pad (EP).
2. Have a single point ground.
The ground connections for the feedback, soft-start, and enable components must be routed to the GND pin
of the device. This prevents any switched or load currents from flowing in the analog ground traces. If not
properly handled, poor grounding can result in degraded load regulation or erratic output voltage ripple
behavior. Provide the single point ground connection from pin 4 to EP.
3. Minimize trace length to the FB pin.
Both feedback resistors, RFBT and RFBB, and the feed forward capacitor CFF, must be located close to the FB
pin. Since the FB node is high impedance, maintain the copper area as small as possible. The trace are from
RFBT, RFBB, and CFF must be routed away from the body of the LMZ12001EXT to minimize noise.
4. Make input and output bus connections as wide as possible.
This reduces any voltage drops on the input or output of the converter and maximizes efficiency. To optimize
voltage accuracy at the load, ensure that a separate feedback voltage sense trace is made to the load. Doing
so will correct for voltage drops and provide optimum output accuracy.
5. Provide adequate device heat-sinking.
Use an array of heat-sinking vias to connect the exposed pad to the ground plane on the bottom PCB layer.
If the PCB has a plurality of copper layers, these thermal vias can also be employed to make connection to
inner layer heat-spreading ground planes. For best results use a 6 × 6 via array with a minimum via diameter
of 8 mils thermal vias spaced 59 mils (1.5 mm). Ensure enough copper area is used for heat-sinking to keep
the junction temperature below 125°C.
20
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
10.2 Layout Examples
VIN
LMZ12001EXT
VIN
VO
VOUT
High
di/dt
Cin1
CO1
GND
Loop 2
Loop 1
Figure 42. Critical Current Loops to Minimize
Top View
Thermal Vias
GND
GND
EPAD
1
2
3
4 5
6 7
VIN
EN
RON
SS
GND
VOUT
FB
CIN
VIN
COUT
VOUT
RON
RENT
RFBT
CSS
RENB
CFF
RFBB
GND Plane
Figure 43. PCB Layout Guide
Figure 44. Top View of Evaluation PCB
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
21
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
Layout Examples (continued)
Figure 45. Bottom View of Evaluation PCB
10.3 Power Dissipation and Thermal Considerations
For the design case of VIN = 12 V, VO = 1.8 V, IO = 1 A, TAMB(MAX) = 85°C , and TJUNCTION = 125°C, the device
must see a thermal resistance from case to ambient of:
RθCA< (TJ-MAX – TAMB(MAX)) / PIC-LOSS – RθJC
(17)
Given the typical thermal resistance from junction to case to be 1.9°C/W .Use the 85°C power dissipation curves
in the Typical Characteristics section to estimate the PIC-LOSS for the application being designed. In this
application it is 0.4W
RθCA< (125 – 85) / 0.4 W – 1.9 = 98.1
(18)
To reach RθCA = 98.1, the PCB is required to dissipate heat effectively. With no airflow and no external heat, a
good estimate of the required board area covered by 1 oz. copper on both the top and bottom metal layers is:
Board Area_cm2 = 500°C × cm2/W / RθJC
(19)
As a result, approximately 5 square cm of 1-oz. copper on top and bottom layers is required for the PCB design.
The PCB copper heat sink must be connected to the exposed pad. Approximately thirty six, 8 mils thermal vias
spaced 59 mils (1.5 mm) apart must connect the top copper to the bottom copper. For an example of a high
thermal performance PCB layout, refer to the Evaluation Board application note AN–2024 SNVA422. For more
information on thermal design see AN–2020 and AN–2026.
10.4 Power Module SMT Guidelines
The recommendations below are for a standard module surface mount assembly
• Land Pattern — Follow the PCB land pattern with either soldermask defined or non-soldermask defined pads
• Stencil Aperture
– For the exposed die attach pad (DAP), adjust the stencil for approximately 80% coverage of the PCB land
pattern
– For all other I/O pads use a 1:1 ratio between the aperture and the land pattern recommendation
• Solder Paste — Use a standard SAC Alloy such as SAC 305, type 3 or higher
• Stencil Thickness — 0.125 to 0.15 mm
• Reflow — Refer to solder paste supplier recommendation and optimized per board size and density
• Refer to Design Summary LMZ1xxx and LMZ2xxx Power Modules Family (SNAA214) for reflow information.
• Maximum number of reflows allowed is one
22
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
Power Module SMT Guidelines (continued)
Figure 46. Sample Reflow Profile
Table 2. Sample Reflow Profile Table
PROBE
MAX TEMP
(°C)
REACHED
MAX TEMP
TIME ABOVE
235°C
REACHED
235°C
TIME ABOVE
245°C
REACHED
245°C
TIME ABOVE
260°C
REACHED
260°C
1
242.5
6.58
0.49
6.39
2
242.5
7.10
0.55
6.31
0.00
–
0.00
–
0.00
7.10
0.00
–
3
241.0
7.09
0.42
6.44
0.00
–
0.00
–
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
23
LMZ12001EXT
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
www.ti.com
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.
11.1.2 Development Support
For developmental support, see the following:
WEBENCH Tool, http://www.ti.com/webench
11.2 Documentation Support
11.2.1 Related Documentation
For related documentation, see the following:
• AN-2027 Inverting Application for the LMZ14203 SIMPLE SWITCHER Power Module, (SNVA425)
• Absolute Maximum Ratings for Soldering, (SNOA549)
• AN-2024 LMZ1420x / LMZ1200x Evaluation Board (SNVA422)
• AN-2085 LMZ23605/03, LMZ22005/03 Evaluation Board (SNVA457)
• AN-2054 Evaluation Board for LM10000 - PowerWise AVS System Controller (SNVA437)
• AN-2020 Thermal Design By Insight, Not Hindsight (SNVA419)
• AN-2026 Effect of PCB Design on Thermal Performance of SIMPLE SWITCHER Power Modules (SNVA424)
• Design Summary LMZ1xxx and LMZ2xxx Power Modules Family (SNAA214)
11.3 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.
11.4 Trademarks
E2E is a trademark of Texas Instruments.
SIMPLE SWITCHER is a registered trademark of Texas Instruments.
WEBENCH is a registered trademark of Texas Insturments.
All other trademarks are the property of their respective owners.
11.5 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.
11.6 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
24
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
LMZ12001EXT
www.ti.com
SNVS661G – JUNE 2010 – REVISED SEPTEMBER 2015
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.
Submit Documentation Feedback
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMZ12001EXT
25
PACKAGE OPTION ADDENDUM
www.ti.com
9-Jul-2015
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
LMZ12001EXTTZ/NOPB
ACTIVE
TO-PMOD
NDW
7
250
Green (RoHS
& no Sb/Br)
CU SN
Level-3-245C-168 HR
-55 to 125
LMZ12001
EXT
LMZ12001EXTTZE/NOPB
ACTIVE
TO-PMOD
NDW
7
45
Green (RoHS
& no Sb/Br)
CU SN
Level-3-245C-168 HR
-55 to 125
LMZ12001
EXT
LMZ12001EXTTZX/NOPB
ACTIVE
TO-PMOD
NDW
7
500
Green (RoHS
& no Sb/Br)
CU SN
Level-3-245C-168 HR
-55 to 125
LMZ12001
EXT
(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)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
9-Jul-2015
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
8-Jul-2015
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
LMZ12001EXTTZ/NOPB
TOPMOD
NDW
7
250
330.0
24.4
10.6
14.22
5.0
16.0
24.0
Q2
LMZ12001EXTTZX/NOPB
TOPMOD
NDW
7
500
330.0
24.4
10.6
14.22
5.0
16.0
24.0
Q2
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
8-Jul-2015
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
LMZ12001EXTTZ/NOPB
TO-PMOD
NDW
7
250
367.0
367.0
45.0
LMZ12001EXTTZX/NOPB
TO-PMOD
NDW
7
500
367.0
367.0
45.0
Pack Materials-Page 2
MECHANICAL DATA
NDW0007A
BOTTOM SIDE OF PACKAGE
TOP SIDE OF PACKAGE
TZA07A (Rev D)
www.ti.com
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other
changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest
issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and
complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale
supplied at the time of order acknowledgment.
TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms
and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary
to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily
performed.
TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and
applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or
other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information
published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or
endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the
third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration
and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered
documentation. Information of third parties may be subject to additional restrictions.
Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service
voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.
TI is not responsible or liable for any such statements.
Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements
concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support
that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which
anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause
harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use
of any TI components in safety-critical applications.
In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to
help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and
requirements. Nonetheless, such components are subject to these terms.
No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties
have executed a special agreement specifically governing such use.
Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in
military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components
which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and
regulatory requirements in connection with such use.
TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of
non-designated products, TI will not be responsible for any failure to meet ISO/TS16949.
Products
Applications
Audio
www.ti.com/audio
Automotive and Transportation
www.ti.com/automotive
Amplifiers
amplifier.ti.com
Communications and Telecom
www.ti.com/communications
Data Converters
dataconverter.ti.com
Computers and Peripherals
www.ti.com/computers
DLP® Products
www.dlp.com
Consumer Electronics
www.ti.com/consumer-apps
DSP
dsp.ti.com
Energy and Lighting
www.ti.com/energy
Clocks and Timers
www.ti.com/clocks
Industrial
www.ti.com/industrial
Interface
interface.ti.com
Medical
www.ti.com/medical
Logic
logic.ti.com
Security
www.ti.com/security
Power Mgmt
power.ti.com
Space, Avionics and Defense
www.ti.com/space-avionics-defense
Microcontrollers
microcontroller.ti.com
Video and Imaging
www.ti.com/video
RFID
www.ti-rfid.com
OMAP Applications Processors
www.ti.com/omap
TI E2E Community
e2e.ti.com
Wireless Connectivity
www.ti.com/wirelessconnectivity
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2015, Texas Instruments Incorporated