LTC3528BEDDB-2-TRPBF 查看數據表（PDF） - Linear Technology

零件编号

产品描述 (功能)

生产厂家

LTC3528BEDDB-2-TRPBF

1A, 2MHz Synchronous Step-Up DC/DC Converter in 2mm × 3mm DFN

Linear Technology 

LTC3528B-2

APPLICATIONS INFORMATION

VIN > VOUT OPERATION

The LTC3528B-2 maintains voltage regulation even when

the input voltage is above the desired output voltage. Note

that the efficiency is much lower in this mode, and the

maximum output current capability will be less. Refer to

the Typical Performance Characteristics.

SHORT-CIRCUIT PROTECTION

The LTC3528B-2 output disconnect feature allows an output

short circuit while maintaining a maximum internally set

current limit. To reduce power dissipation under short-

circuit conditions, the peak switch current limit is reduced

to 750mA (typical).

SCHOTTKY DIODE

Although not required, adding a Schottky diode from

SW to VOUT will improve efficiency by about 2%. Note

that this defeats the output disconnect and short-circuit

protection features.

PCB LAYOUT GUIDELINES

The high speed operation of the LTC3528B-2 demands

careful attention to board layout. A careless layout will

not produce the advertised performance. Figure 2 shows

the recommended component placement. A large ground

copper area with the package backside metal pad properly

soldered will help to lower the chip temperature. A multi-

layer board with a separate ground plane is ideal, but not

absolutely necessary.

COMPONENT SELECTION

Inductor Selection

The LTC3528B-2 can utilize small surface mount chip

inductors due to their fast 2MHz switching frequency.

Inductor values between 1.5µH and 3.3µH are suitable for

most applications. Larger values of inductance will allow

slightly greater output current capability by reducing the

inductor ripple current. Increasing the inductance above

10µH will increase size while providing little improvement

in output current capability.

The minimum inductance value is given by:

( ) L

>

VIN(MIN) • VOUT(MAX) – VIN(MIN)

2 • Ripple • VOUT(MAX)

µH

where:

Ripple = Allowable inductor current ripple (amps peak-

peak)

VIN(MIN) = Minimum input voltage

VOUT(MAX) = Maximum output voltage

+

VIN

CIN

10

SHDN 1

8 VIN

FB 2

7 SGND

LTC3528B-2

PGOOD 3

6 PGND

VOUT 4

5 SW

COUT

35282 F02

MULTIPLE VIAS

TO GROUND PLANE

Figure 2. Recommended Component Placement for Single Layer Board

3528b2fa

Share Link: