MC33166D2T 查看數據表（PDF） - Motorola => Freescale

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产品描述 (功能)

比赛名单

MC33166D2T

POWER SWITCHING REGULATORS

Motorola => Freescale 

MC34166 MC33166

Table 1. Design Equations

Calculation

Step–Down

Step–Up/Down

Voltage–Inverting

ton

toff

(Notes 1, 2)

) Vout VF

* * Vin Vsat Vout

) ) Vout VF1 VF2

* * Vin VsatQ1 VsatQ2

) |Vout| VF

* Vin Vsat

ton

ǒ ) Ǔton

toff

fosc

ton

toff

1

ǒ ) Ǔton

toff

fosc

ton

toff

1

ǒ ) Ǔton

toff

fosc

ton

toff

1

Duty Cycle

(Note 3)

IL avg

ton fosc

Iout

ton fosc

ǒ Ǔ) Iout

ton

toff

1

ton fosc

ǒ Ǔ) Iout

ton

toff

1

Ipk(switch)

L

Vripple(pp)

Vout

) IL avg

DIL

2

ǒ Ǔ * * Vin

Vsat

DIL

Vout ton

Ǹǒ Ǔ ) DIL

12

8foscCo

(ESR)2

ǒ Ǔ) Vref

R2

R1

1

) IL avg

DIL

2

ǒ Ǔ * * Vin

VsatQ1

DIL

VsatQ2 ton

ǒ ǓǸǒ Ǔ ) ton

toff

1

) 1 2

foscCo

(ESR)2

ǒ Ǔ) Vref

R2

R1

1

) IL avg

DIL

2

* Vin Vsat

ǒ ǓDIL

ton

ǒ ǓǸǒ Ǔ ) ton

toff

1

) 1 2

foscCo

(ESR)2

ǒ Ǔ) Vref

R2

R1

1

NOTES: 1. Vsat – Switch Output source saturation voltage, refer to Figure 7.

2. VF – Output rectifier forward voltage drop. Typical value for 1N5822 Schottky barrier rectifier is 0.5 V.

3. Duty cycle is calculated at the minimum operating input voltage and must not exceed the guaranteed minimum DC(max) specification of 0.92.

The following converter characteristics must be chosen:

Vout – Desired output voltage.

Iout – Desired output current.

∆IL – Desired peak–to–peak inductor ripple current. For maximum output current especially when the duty cycle is greater than 0.5, it is suggested

that ∆IL be chosen to be less than 10% of the average inductor current IL avg. This will help prevent Ipk(switch) from reaching the guaranteed

minimum current limit threshold of 3.3 A. If the design goal is to use a minimum inductance value, let ∆IL = 2 (IL avg). This will proportionally

reduce the converter’s output current capability.

Vripple(pp) – Desired peak–to–peak output ripple voltage. For best performance, the ripple voltage should be kept to less than 2% of Vout. Capacitor CO

should be a low equivalent series resistance (ESR) electrolytic designed for switching regulator applications.

14

MOTOROLA ANALOG IC DEVICE DATA

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