AAT1112IWP-0.6-T1 View Datasheet(PDF) - Analog Technology Inc

Part Name

Description

MFG CO.

AAT1112IWP-0.6-T1

1.5A, 1.4MHz Step-Down Converter

Analog Technology Inc 

AAT1112

1.5A, 1.4MHz Step-Down Converter

Design Example

Specifications

VO 3.3V @ 1.5A, Pulsed Load ΔILOAD = 1.5A

VIN 2.7V to 4.2V (3.6V nominal)

FS 1.2MHz

TAMB 85°C in TDFN33-12 Package

Output Inductor

L1 = VO(µH) = 3.3µH; see Table 2.

For Sumida inductor CDRH4D28 3.3µH DCR = 49.2mΩ max.

ΔI1 =

VO

L1 ⋅ FS

⋅

⎛⎝1

-

VO1⎞

VIN ⎠

=

3.3V

3.3µH ⋅ 1.2MHz

⋅

⎛⎝1 -

3.3V ⎞

4.2V ⎠

= 179mA

IPK1

=

IO1

+

ΔI1

2

=

1.5A

+

0.089A

=

1.59A

PL1 = IO12 ⋅ DCR = 1.5A2 ⋅ 49.2mΩ = 110mW

Output Capacitor

VDROOP = 0.2V

COUT

=

3 · ΔILOAD

VDROOP · FS

=

3 · 1.5A

0.2V · 1.2MHz

= 18.8µF; use 22µF

I = RMS(MAX)

1

2·

· (VOUT) · (VIN(MAX) - VOUT)

3

L · FS · VIN(MAX)

=1

2·

3

·

3.3V · (4.2V - 3.3V)

3.3µH · 1.2MHz · 4.2V

= 52mArms

Pesr = esr · IRMS2 = 5mΩ · (52mA)2 = 13.3µW

16

1112.2007.01.1.1

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