HM8332 View Datasheet(PDF) - Unspecified

Part Name

Description

Manufacturer

HM8332

Three Channels Integrated Power Management IC for Handheld Portable Equipment

Unspecified 

formula: VOUT3 = 1.212V • [1 + (R5/R6)].

H0

EN (PIN9): Enable control input for REG1, REG2, and REG3. Drive EN to the VIN, VINL or a logic high

for normal operation, drive EN to GND or a logic low to disable REG1, REG2, and REG3.

FB1 (PIN10): Output Feedback Sense. Receives the feedback voltage from an external resistive divider

across the output. The output voltage for REG1 is set by a resistive divider according to the following

formula: VOUT1 = 0.625V • [1 + (R1/R2)].

GND (PIN11): Power Ground.

Application Information

The basic HM8332 application circuit is shown in Typical Application Circuit. External component

selection is determined by the maximum load current and begins with the selection of the inductor value

and operating frequency followed by CIN and COUT.

Inductor Selection

For most applications, the value of the inductor will fall in the range of 1µH to 4.7µH. Its value is chosen

based on the desired ripple current. Large value inductors lower ripple current and small value inductors

result in higher ripple currents. Higher VIN or VOUT also increases the ripple current as shown in equation

(1). A reasonable starting point for setting ripple current is △IL = 240mA (40% of 600mA).

(1)

The DC current rating of the inductor should be at least equal to the maximum load current plus half the

ripple current to prevent core saturation. Thus, a 0.9A rated inductor should be enough for most

applications (600mA + 120mA). For better efficiency, choose a low DC-resistance inductor.

Different core materials and shapes will change the size/current and price/current relationship of an

inductor. Toroid or shielded pot cores in ferrite or perm alloy materials are small and don’t radiate much

energy, but generally cost more than powdered iron core inductors with similar electrical characteristics.

The choice of which style inductor to use often depends more on the price vs. size requirements and

any radiated field/EMI requirements than on what the HM8332 requires to operate. Table 1 shows some

typical surface mount inductors that work well in HM8332 applications.

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