UC3848
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATINGS (Ta=25°C, VCC=15V, unless otherwise specified)
PARAMETER
SYMBOL
RATINGS
UNIT
Supply Voltage
VCC
30
V
Input Voltage to VIN Pin
VIN
30
V
Input Voltage to FB Pin
VFB
-0.3 ~ 6.2
V
Input Voltage to CS Pin
Junction Temperature
VCS
-0.3 ~ 2.8
V
TJ
+150
°C
Operating Temperature
Storage Temperature
TOPR
TSTG
-40 ~ +125
°C
-50 ~ +150
°C
Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
RECOMMENDED OPERATING CONDITIONS
PARAMETER
SYMBOL
Supply Voltage
VCC
RATINGS
8.2 ~ 22
UNIT
V
ELECTRICAL CHARACTERISTICS (Ta=25°C, VCC=15V, unless otherwise specified)
PARAMETER
SYMBOL TEST CONDITIONS
MIN TYP MAX
SUPPLY SECTION
Start Up Current
Supply Current with switch
OFF
ON
ISTR VCC=VTHD(ON)-0.1V
IOFF VSS = 0, IFB = 0
ION VSS = 5V, IFB = 0
22
45
7
9
7
9
UNDER-VOLTAGE LOCKOUT SECTION
Start Threshold Voltage
Min. Operating Voltage
Hysteresis
VTHD(ON)
VCC(MIN)
VCC(HY)
13.5 14.2 15
7.5 8.2
9
6
INTERNAL VOLTAGE REFERENCE
Reference Voltage
VREF Measured at pin VREF
6.3 6.5 6.7
CONTROL SECTION
VFB Operating Level
Burst-Mode Enter FB Voltage
Reduce-Frequency end FB Voltage
Burst-Mode Out FB Voltage
Switch Frequency
Normal
Power-Saving
Duty Cycle
Feedback Resistor
Soft-Start Time
VMIN
VMAX
VFB-IN
VFB-END
VFB-out
F(SW)
DMAX
DMIN
RFB
TSS
VCS=0
VCS=0
VCS=0
VFB = 4V
Before enter burst mode
VFB=4.4V,VCS=0
VFB < 0.5V
VFB =0V
CSS=0.47uF
0.5
4.4
1.5
1.6
1.7
61
68
75
20
40
68
74
80
0
16
21
26
9.9 11.2 12.6
PROTECTION SECTION
OVP threshold
VOVP1 VSS < 3.5V, VFB > 5V
19
VOVP1 VSS=4.8V,VFB=3V
28
OLP threshold
VFB(OLP) VCS > 0V, SS Open
4.7 4.9 5.1
Delay Time Of OLP
TD-OLP CSS=0.47uF
55
62
70
OTP threshold
T(THR)
120 135 150
OVP Disable threshold
VSS(DEACT) VFB > 5V, VCC=22V
3.9 4.1 4.3
OLP Enable threshold
VSS(ACT) VFB > 5V
5.1 5.4 5.7
CURRENT LIMITING SECTION
LEB
tLEB
220
Peak Current Limitation
VCS VFB=4.4V
0.86 1
Threshold Voltage For IVIN=60uA
VSENSE-L IVIN=60uA
0.77
DRIVER OUTPUT SECTION
Output Voltage Low State
VOL ISOURCE = 200 mA
2.5
Output Voltage High State
VOH ISINK = 200 mA
12.2
Output Voltage Rise Time
tR CL = 1.0 nF
200 300
Output Voltage Fall Time
tF CL = 1.0 nF
50
90
UNIT
μA
mA
mA
V
V
V
V
V
V
V
V
V
kHz
kHz
%
%
kΩ
ms
V
V
mS
°C
V
V
ns
V
V
V
V
ns
ns
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
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QW-R103-033.F