SNOSB87D
March 2011 – May 2019
LM21215A
PRODUCTION DATA.
1
Features
2
Applications
Efficiency at 2.5 V, 500 kHz
3
Description
Typical Application Circuit
Device Images
4
Revision History
5
Pin Configuration and Functions
Pin Functions
6
Specifications
6.1
Absolute Maximum Ratings
6.2
ESD Ratings
6.3
Recommended Operating Conditions
6.4
Thermal Information
6.5
Electrical Characteristics
6.6
Typical Characteristics
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
Precision Enable
7.3.2
Input Voltage UVLO
7.3.3
Soft-Start Capability
7.3.4
PGOOD Indicator
7.3.5
Frequency Synchronization
7.3.6
Current Limit
7.3.7
Short Circuit Protection
7.4
Device Functional Modes
7.4.1
Light-Load Operation
7.4.2
Overvoltage and Undervoltage Handling
7.4.3
Thermal Shutdown
8
Application and Implementation
8.1
Application Information
8.2
Typical Applications
8.2.1
Typical Application 1
8.2.1.1
Design Requirements
8.2.1.2
Detailed Design Procedure
8.2.1.2.1
Custom Design With WEBENCH® Tools
8.2.1.2.2
Output Voltage Setpoint
8.2.1.2.3
Precision Enable
8.2.1.2.4
Filter Inductor Selection
8.2.1.2.5
Output Capacitor Selection
8.2.1.2.6
Input Capacitor Selection
8.2.1.2.7
Control Loop Compensation
8.2.1.3
Application Curves
8.2.2
Typical Application 2
8.2.2.1
Design Requirements
8.2.2.2
Detailed Design Procedure
9
Power Supply Recommendations
10
Layout
10.1
Layout Guidelines
10.1.1
Compact PCB Layout for EMI Reduction
10.1.2
Thermal Design
10.1.3
Ground Plane Design
10.2
Layout Example
11
Device and Documentation Support
11.1
Device Support
11.1.1
Third-Party Products Disclaimer
11.1.2
Development Support
11.1.2.1
Custom Design With WEBENCH® Tools
11.2
Documentation Support
11.2.1
Related Documentation
11.3
Community Resources
11.4
Trademarks
11.5
Electrostatic Discharge Caution
11.6
Glossary
12
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
PWP|20
MHTS001G
Thermal pad, mechanical data (Package|Pins)
PWP|20
PPTD299
Orderable Information
snosb87d_oa
snosb87d_pm
6.6
Typical Characteristics
Unless otherwise specified: V
IN
= 5 V, V
OUT
= 1.2 V, L
F
= 0.56 µH (1.8 mΩ R
DCR
), C
SS
= 33 nF, f
SW
= 500 kHz, T
A
= 25°C for efficiency curves, loop gain plots and waveforms, and T
J
= 25°C for all others.
Figure 1.
Efficiency
Figure 3.
Efficiency (V
OUT
= 2.5 V, F
SW
= 500 kHz, Inductor P/N SER2010-601MLD)
Figure 5.
Line Regulation
Figure 7.
Non-Switching I
AVIN
and I
PVIN
vs Temperature
Figure 9.
Enable Threshold and Hysteresis vs Temperature
Figure 11.
Enable Low Current vs Temperature
Figure 13.
Minimum On-Time vs Temperature
Figure 15.
Peak Current Limit vs Temperature
Figure 17.
SYNC Signal Acquired, 10 µs/div
Figure 19.
Startup with Prebiased Output, 2 ms/Div
Figure 21.
Startup with Tracking Signal Applied, 200 ms/Div
Figure 2.
Efficiency
Figure 4.
Load Regulation
Figure 6.
Non-Switching I
Q(TOTAL)
vs V
IN
Figure 8.
Feedback (FB) Voltage vs Temperature
Figure 10.
UVLO Threshold and Hysteresis vs Temperature
Figure 12.
OVP/UVP Threshold vs Temperature
Figure 14.
MOSFET On-State Resistance vs Temperature
Figure 16.
SYNC Signal Removed, 4 µs/Div
Figure 18.
Load Transient Response, 100 µs/Div
Figure 20.
Startup with SS/TRK Open Circuit, 200 µs/Div
Figure 22.
Output Overcurrent Condition, 10 µs/Div