FSDH321, FSDL321

www.onsemi.com

5

ELECTRICAL CHARACTERISTICS (Ta = 25

°C unless otherwise noted) (continued)

Symbol

Unit

Max

Typ

Min

Condition

Parameter

TOTAL DEVICE SECTION

IOP

Operating Supply Current (control part

only)

VCC = 14 V, VFB = 0 V

1

3

5

mA

ICH

Start−Up Charging Current

VCC = 0 V

0.7

0.85

1.0

mA

VSTR

Vstr Supply Voltage

VCC = 0 V

35

−

−

V

Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product

performance may not be indicated by the Electrical Characteristics if operated under different conditions.

8. Pulse test: Pulse width

≤ 300us, duty ≤ 2%

9. These parameters, although guaranteed, are tested in EDS (wafer test) process

10. These parameters, although guaranteed, are not 100% tested in production

Table 3. COMPARISON BETWEEN FSDM311 AND FSDx321

Function

FSDM311

FSDx321

FSDx321 Advantages

Soft−Start

15 ms

15 ms

(same for both devices)

S Gradually increasing current limit during soft−start

further reduces peak current and voltage stresses

S Eliminates external components used for soft−start

in most applications

S Reduces or eliminates output overshoot

External Current Limit

not applicable

Programmable of

default current limit

S Smaller transformer

S Allows power limiting (constant over−load power)

S Allows use of larger device for lower losses and

higher efficiency

Frequency Modulation

not applicable

±3.0 KHz @ 100 KHz

±1.5 KHz @ 50 KHz

S Reduces conducted EMI

Burst Mode Operation

Built into controller

Built into controller

(same for both devices)

S Improves light load efficiency

S Reduces power consumption at no−load

S Transformer audible noise reduction

Drain Creepage

at Package

7.62 mm

7.62 mm

(same for both devices)

S Greater immunity to arcing provoked by dust, debris

and other contaminants