LNK562-564
Conditions
SOURCE = 0 V; TJ = -40 to 125 °C
See Figure 8
Parameter
Symbol
Min
Typ
Max
Units
(Unless Otherwise Specified)
OUTPUT (cont.)
FEEDBACK Pin
Auto-Restart
VFB(AR)
TJ = 25 °C
0.8
V
Threshold Voltage
VFB = VFB(AR)
Auto-Restart
ON-Time
100
12
ms
%
TJ = 25 °C
Auto-Restart
Duty Cycle
DCAR
NOTES:
A. In a scheme using a resistor divider network at the FB pin, where RU is the resistor from the FB pin to the rectified
bias voltage and RL is the resistor from the FB pin to the SOURCE pin, the output voltage variation is influenced
by VFB and IFB variations. To determine the contribution from the VFB variation in percent, the following equation
can be used:
J
N
RU + R
RL
RU + R
RL
FB(MAX) c
L m
V
+ IFB(TYP)RU
L m
+ IFB(TYP)RU
K
K
O
O
O
x = 100 #
- 1
K
O
K
c
VFB(TYP)
L
P
To determine the contribution from IFB variation in percent, the following equation can be used:
J
N
RU + R
RL
RU + R
RL
FB(TYP) c
L m
V
+ IFB(MAX)RU
L m
+ IFB(TYP)RU
K
K
O
O
O
y = 100 #
- 1
K
O
K
c
VFB(TYP)
L
P
2
2
Since IFB and VFB are independent parameters, the composite variation in percent would be
.
! x + y
B. Total current consumption is the sum of IS1 and IDSS when FEEDBACK pin voltage is ≥2 V (MOSFET not
switching) and the sum of IS2 and IDSS when FEEDBACK pin is shorted to SOURCE (MOSFET switching).
C Since the output MOSFET is switching, it is difficult to isolate the switching current from the supply current at the
DRAIN. An alternative is to measure the BYPASS pin current at 6 V.
D. See Typical Performance Characteristics section Figure 16 for BYPASS pin startup charging waveform.
E. This current is only intended to supply an optional optocoupler connected between the BYPASS and FEEDBACK
pins and not any other external circuitry.
F. This parameter is guaranteed by design.
G. This parameter is derived from characterization.
H. Breakdown voltage may be checked against minimum BVDSS by ramping the DRAIN pin voltage up to but not
exceeding minimum BVDSS
.
10
Rev. H 11/08
POWERINT [ Power Integrations ]
