SLVSB71E February   2012  – September 2016

PRODUCTION DATA.

1. Features
2. Applications
3. Description
1.     Device Images
4. Revision History
5. Device Comparison Table
6. Pin Configuration and Functions
7. Specifications
8. Detailed Description
1. 8.1 Overview
2. 8.2 Functional Block Diagram
3. 8.3 Feature Description
4. 8.4 Device Functional Modes
9. Application and Implementation
1. 9.1 Application Information
2. 9.2 Typical Application
1. 9.2.1 Design Requirements
2. 9.2.2 Detailed Design Procedure
1. 9.2.2.1 Programming the Output Voltage
2. 9.2.2.2 External Component Selection
1. 9.2.2.2.1 Inductor Selection
2. 9.2.2.2.2 Capacitor Selection
3. 9.2.2.3 Tracking Function
4. 9.2.2.4 Output Filter and Loop Stability
3. 9.2.3 Application Curves
3. 9.3 System Examples
10. 10Power Supply Recommendations
11. 11Layout
12. 12Device and Documentation Support
13. 13Mechanical, Packaging, and Orderable Information

• RGT|16
• RGT|16

9.2.2.2.1 Inductor Selection

The inductor selection is affected by several effects like inductor ripple current, output ripple voltage, PWM-to-PSM transition point and efficiency. In addition, the inductor selected has to be rated for appropriate saturation current and DC resistance (DCR). Equation 7 and Equation 8 calculate the maximum inductor current under static load conditions.

spacing

Equation 7.
Equation 8.

where

• IL(max) is the maximum inductor current.
• ΔIL is the Peak to Peak Inductor Ripple Current.
• L(min) is the minimum effective inductor value.
• fSW is the actual PWM Switching Frequency.

spacing

Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation current of the inductor needed. A margin of about 20% is recommended to add. A larger inductor value is also useful to get lower ripple current, but increases the transient response time and size as well. The following inductors have been used with the TLV62150 and are recommended for use:

Table 5. List of Inductors

Type Inductance [µH] Saturation Current [A](1) Dimensions [L x B x H] mm MANUFACTURER(2)
XFL4020-222ME_ 2.2 µH, ±20% 3.5 4 × 4 × 2.1 Coilcraft
XFL3012-222MEC 2.2 µH, ±20% 1.6 3 × 3 × 1.2 Coilcraft
XFL3012-332MEC 3.3 µH, ±20% 1.4 3 × 3 × 1.2 Coilcraft
VLS252012T-2R2M1R3 2.2 µH, ±20% 1.3 2.5 × 2 × 1.2 TDK
LPS3015-332 3.3 µH, ±20% 1.4 3 × 3 × 1.4 Coilcraft
744025003 3.3 µH, ±20% 1.5 2.8 × 2.8 × 2.8 Wuerth
PSI25201B-2R2MS 2.2 µH, ±20% 1.3 2 × 2.5 × 1.2 Cyntec
NR3015T-2R2M 2.2 µH, ±20% 1.5 3 × 3 × 1.5 Taiyo Yuden
Lower of IRMS at 40°C rise or ISAT at 30% drop.
See Third-Party Products Disclaimer

spacing

The inductor value also determines the load current at which Power Save Mode is entered:

Equation 9.

Using Equation 8, this current level can be adjusted by changing the inductor value.