
Electrical Characteristics
(Continued)
Specifications in standard type face are for T
J
= +25C and those in
boldface type
apply over the full operating junction tem-
perature range. Unless otherwise specified: V
IN
= 48V, V
CC
= 10V, and RT = 26.7K
Symbol
Parameter
Conditions
Min
(Note 4)
Typ
(Note 5)
Max
(Note 4)
Units
Oscillator
Frequency1 (RT = 26.7K)
Frequency2 (RT = 8.2K)
Sync threshold
175
510
200
600
3.2
225
690
3.8
kHz
kHz
V
PWM Comparator
Delay to Output
COMP set to 2V CS
stepped 0 to 0.4V, Time
to onset of OUT transition
low
Inferred from deadtime
COMP=0V
30
ns
Max Duty Cycle
Min Duty Cycle
COMP to PWM Comparator
Gain
COMP Open Circuit Voltage
COMP Short Circuit Current
Slope Compensation
Slope Comp Amplitude
47.5
49
50
0
%
%
0.34
V
FB
= 0V
V
FB
= 0V, COMP=0V
4.3
0.6
5.2
1.1
6.1
1.5
V
mA
Delta increase at PWM
Comparator to CS
80
105
130
mV
Output Section
Deadtime
Output High Saturation
Output Low Saturation
Rise Time
Fall Time
Cload = 0, 10% to 10%
Iout = 50mA, V
CC
- V
OUT
I
OUT
= 100mA
Cload = 1nF
Cload = 1nF
85
135
0.25
0.25
16
16
185
0.75
0.75
ns
V
V
ns
ns
Thermal Shutdown
Tsd
Thermal Shutdown Temp.
Thermal Shutdown Hysteresis
165
15
C
C
Note 1:
Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device
is intended to be functional. For guaranteed specifications and test conditions, see the Electrical Characteristics.
Note 2:
The maximum allowable power dissipation is a function of the maximum junction temperature, T
J(MAX)
, the junction-to-ambient thermal resistance,
θ
JA
, and
the ambient temperature, T
A
. The maximum allowable power dissipation at any ambient temperture is calculated using:
Where the value of
θ
JA
for the mini SO-10 (MM) package is 200C/W. Exceeding the maximum allowable dissipation will cause excessive die temperature, and the
device will go into thermal shutdown.
Note 3:
The human body model is a 100pF capacitor discharged through a 1.5k
resistor into each pin. The machine model is a 200pF capacitor discharged directly
into each pin. The machine model ESD rating for pin 5 and pin 6 is 150V.
Note 4:
Limits are 100% production tested at 25C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control
(SQC) methods. The limits are used to calculate National’s Average Outgoing Quality Level (AOQL).
Note 5:
Typical numbers represent the most likely parametric norm for 25C operation.
L
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