**Part Number:** TPS61087

Hi team,

I am a hardware engineer. Now I will use TPS61087. Input=3.3V, Output:4.5V, The max output current is 100mA.

Q1: I want to confirm my circuit works in CCM mode or DCM mode?

The datasheet shows"The converter operates in continuous conduction mode (CCM) as soon as the input current increases above half the ripple current in the inductor, for lower load currents it switches into

discontinuous conduction mode (DCM). If the load is further reduced, the part starts to skip pulses to maintain the output voltage." So, I guess my circuit work in DCM mode, correct?

Q2: If my circuit work in DCM mode, Can I use the formula in **8.2.2 Detailed Design Procedure **of the datasheet**? **Does the formula only be used for CCM mode?

Q3: Also, I use the **8.2.2 Detailed Design Procedure formula **to calculate the inductor peak current. The inductor peak is about **360mA **When I choose** 2.2uH inductor, Fs=1.2M. **

**If the 8.2.2 Detailed Design Procedure formula can be suitable for my circuit, I will select the inductor **saturation current is 1.7A.

When I use** 8.2.2.1 Inductor Selection** formula to calculate the inductor value. VIN=3.3V, VS=4.5V, IOUT=100mA, FS=1.2M, η=90%, **L is about 13uH. It is very large.**

**And , Wehn I use Webwench, The circuit is as below:**

**The inductor is 6uH. **

**I want to verify why the inductor value that is 8.2.2.1 Inductor Selection formula is very big?**

**I want to use the smaller inductor package for my application since my board size is limited, such as 2.2uH.**

**So, How can I select the inductor? **

** **

**Q4: Converter switching frequency:**

**When FREQ pin is connected to VIN, the typ s witching frequency is 1.2M. **

**When my output current is 100mA or less than 100mA that is very LOW courrent, will the switching frequency be dropped or keep 1.2M? **

**I note the switching frequency will be dropped when the load current is low in some boost devices. Because the boost**

**device will enter the burst mode when the load current is very low.**