Si9121
Vishay Siliconix
www.vishay.com
2
Document Number: 71112
S-40708—Rev. C, 19-Apr-04
ABSOLUTE MAXIMUM RATINGS (ALL VOLTAGES REFERENCED TO GND = 0 V)
V
NEG
−63 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V
CS
V
NEG
−0.3 V to V
CC
+ 0.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V
CC
V
NEG
+ 13.2 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I
LX
(peak current ) 3 A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V
OUT
6 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bypass, CS V
NEG
−0.3 V to V
CC
+0.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(V
LX
− V
CS
) internal power MOSFET 70 V. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature −65 to 150_C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Junction Temperature 150_C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Dissipation (Package)
a
8-Pin SOIC (Y Suffix)
b
1.25 W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermal Impedance (Q
JA
)
a
8-Pin SOIC 100 _C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Notes
a. Device mounted with all leads soldered or welded to PC board.
b. Derate 10 mW/_C above 25_C.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation
of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
RECOMMENDED OPERATING RANGE (ALL VOLTAGES REFERENCED TO GND = 0 V)
V
NEG
−10 V to −60 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V
CC
(internally regulated) V
NEG
+ 8.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V
CC
(externally supplied) V
NEG
+ 9.5 V to V
NEG
+ 12.0 V. . . . . . . . . . . . . . . .
Digital Inputs 0 V to V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RECOMMENDED EXTERNAL COMPONENTS ( SEE TYPICAL APPLICATIONS CIRCUIT )
L = 68 mH, C
OUT
= 220 mF // 0.1 mF, CIN = 33 mF, C
BYPASS
= 0.1 mF, C
VCC
= 1 mF, R
SENSE
= 0.25 W, 0.5 W
SPECIFICATIONS
a
(All Voltages Are With Respect To V
NEG
Unless Otherwise Specified)
Test Conditions (Internally Regulated)
Unless Otherwise Specified
Limits
−40 to 85_C
Parameter Symbol
V
NEG
= −10 to −60 V
Temp
b
Min
c
Typ
d
Max
c
Unit
Output Voltage (with respect to GND = 0 V)
+5-V Converter
Full 4.80 5.00 5.20
+3.3-V Converter
V
OUT
10 mA <I
LOAD
< 250 mA
Full 3.17 3.30 3.43
V
Line Regulation (with respect to GND = 0 V)
Line Regulation −60 V v V
NEG
v −40 V Full 1 %
V
CC
(Internal Regulator)
V
CC
Bias Voltage V
CC
Full 7.5 8.5 9.5 V
UVLO
Under Voltage Lockout
V
CC
−
V
NEG
Turn-On Full 6.6 7.6 8.7
V
Hysteresis DV Room 0.6
Soft-Start
Error Amplifier Start-Up Current I
SS
V
OUT
= 0 V Room 10 mA
Oscillator
Switching Frequency f
OSC
Room 80 95 110 kHz
Error Amplifier
Transconductance gm Room 10 15 20 umho
Clamp Voltage V
CL
Internal Error Amplifier
Output Clamp Voltage
Room 3.5 V
Current Limit
Threshold Voltage V
CS
Full 0.57 0.67 0.77 V
MOSFET Switch
N-Channel MOSFET r
DS(on)
Room 1.5 2.5 W
