Frequency
+4.2KHz
65KHz
-4.2KHz
PWM
Frequency
+1.45KHz
22.5KHz
-1. 45KHz
VFB-G
VFB-N
VFB
Figure 7. PWM Frequency
Electrical Characteristics (Continued)
VDD = 15V and TA = 25°C unless otherwise noted.
Symbol
Parameter
Test Condition
Min.
Typ.
Max. Unit
PWM Output Section
DCYMAX
VOL
Maximum Duty Cycle
Output Voltage Low
80
8
85
90
%
V
VDD = 15V, IO = 50mA
VDD = 12V, IO = 50mA
GATE = 1nF
1.5
VOH
Output Voltage High
Rising Time
V
tR
350
50
ns
ns
V
tF
Falling Time
GATE = 1nF
VCLAMP
Gate Output Clamping Voltage
VDD = 20V
18
Over-Temperature Protection (OTP) Section(1)
IRT
Output Current of RT Pin
Threshold Voltage for OTP
RI = 26kꢀ
64
70
1.065
100
15
76
µA
V
VRTTH
1.015
1.115
tDOTP-LATCH Over-Temperature Latch-off Debounce
RI = 26kꢀ
RI = 26kꢀ
ms
kꢀ
RRT-OFF
Equivalent Impedance of RT for OTP(1)
14
16
RI Section
RINOR
RI Operating Range
13
10
36
6
kꢀ
Mꢀ
kꢀ
RIMAX
Maximum RI Value for Protection
Minimum RI Value for Protection
RIMIN
Note:
1. The relationship between RRT-OFF and RI is: RRT-OFF = VOTP-LATCH-OFF / IRT = VRT / (70μA × 26 / RI (KΩ))
(1)
© 2008 Fairchild Semiconductor Corporation
SG6846A • Rev. 1.1.4
www.fairchildsemi.com
8
FAIRCHILD [ FAIRCHILD SEMICONDUCTOR ]
