L6730B datasheet(15/52 Pages) STMICROELECTRONICS

部品番号	L6730B

部品情報	Adjustable step-down controller with synchronous rectification

PDF	52 Pages

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メーカー	STMICROELECTRONICS [STMicroelectronics]

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15 / 52 page

L6730 - L6730B

Device description

Doc ID 11938 Rev 3

15/52

5.2

Internal LDO

An internal LDO supplies the internal circuitry of the device. The input of this stage is the

VCC pin and the output (5 V) is the VCCDR pin (see Figure 5).

5.3

Bypassing the LDO to avoid the voltage drop with low Vcc

The LDO can be by passed by providing 5 V voltage directly to VCCDR. In this case Vcc and

VCCDR pins must be shorted together as shown in Figure 6. VCCDR pin must be filtered with

at least 1

μF capacitor to sustain the internal LDO during the recharge of the bootstrap

capacitor. VCCDR also represents a voltage reference for Tmask pin, S/O/U pin (L6730) or

CC/O/U pin (L6730B) and PGOOD pin (see Table 4: Pin connection).

If Vcc

≈ 5 V the internal LDO works in dropout with an output resistance of about 1 Ω.

The maximum LDO output current is about 100 mA, and so the output voltage drop can be

100 mV. The LDO can be bypassed to avoid thi

Figure 5.

LDO block diagram

LDO

4.5V

÷14V

L6730B データシート(PDF) 15 Page - STMicroelectronics