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KA7552A/KA7553A
SMPS Controller
Features
•Built-in drive circuits for direct connection power MOSFET (lO = ±1.5A)
•Wide operating frequency range (5kHz ~ 600kHz)•Pulse by pulse over current limiting•Over load protection
•On/off control by external trigger •Internal UVLO
•Low standby current (typ. 90uA)•Soft start circuit
Description
The KA7552A/KA7553A are switching power control ICfor wide operating frequency range. The internal circuitsinclude pulse by pulse current limiting, protection, on/offcontrol by external trigger, low standby current, soft start,and high current totempole output for driving a POWERMOSFET. Maximum duty of the KA7552A is 70% and theKA7553A is 46%. When duty is maximum, the input
threshold voltage of pin2 & pin8 are not same in KA7552Aand KA7553A.
8-DIP
1
Internal Block Diagram
CS
+_
+-0.56 ~ 0.42V
CT7
RT1
10uA
VCC6
8
OSC
7V
UVLO
BIAS(4V)
OFF
3.6V
2.8V
4.3K
+-
2.4V1.9V+---
5
PWM
OUTPUT
R
0.24V
_+
O.C.P
QS
2FB
3IS(+)
4GND
Rev. 1.0.2
©2004 Fairchild Semiconductor Corporation
KA7552A/KA7553A
Absolute Maximum Ratings
ParameterSupply voltageOutput current
Input voltage at overcurrent detection pinInput voltage at FB pinInput current at CS pin
Total power dissipation (Ta = 25°C)Operating temperatureStorage temperature rangeJunction temperature
SymbolVCCIOVIN(IS)VIN(FB)IIN(CS)PDTOPRTSTGTj
Value30±1.5-0.3 to 4
42800-25 to 85-65 to 150+125
UnitVAVVmAmW°C°C°C
Electrical Characteristics
(VCC = 18V, FOSC = 135kHz, TA = 25°C, unless otherwise specified)Parameter
OSCILLATOR SECTIONInitial accuracyFrequency variation 1Frequency variation 2(Note1)Ramp high voltageRamp low voltageAmplitude
PULSE WIDTH MODULATION SECTIONInput threshold voltage(pin2)Input threshold voltage(pin2)(Note1) Max. duty cycle Source current(pin2)
OVERCURRENT LIMIT SECTIONInput threshold voltageSource current(pin3)Deley time(Note1)SOFT START SECTIONCharging current
Input threshold voltage(pin8)Input threshold voltage(pin8)(Note1)
ICHGVTH(CSO)VTH(CS1) (KA7552)VTH(CS2) (KA7553)
ISINK(CS)VTH(SD,CS)VTH(SD,FB)
VPIN8 = 0V
-Duty cycle = Dmax 1Duty cycle = Dmax 2VPIN8 = 6V, VPIN2 = 1V
- --150.72.21.7256.72.6
-100.92.41.9457.22.8
-51.12.62.1657.73.1
uAVVVuAVV
VTH(IS)ISOURCE(IS)
TD
VPIN3 = 0V
--0.21-0.24150
0.27-VuAns
-300-200-100
VTH(FBD)VTH(FB1) (KA7552)VTH(FB2) (KA7553)D(Max1) (KA7552)D(Max2) (KA7553)ISOURCE(FB)
VPIN2 = 0VDuty cycle = 0%Duty cycle = Dmax 1Duty cycle = Dmax 2
--0.62.11.663
0.752.31.87046
0.952.62.17449
VVV%%uA
FOSC∆F/∆V∆F/∆VVRHVRLVOSC
CT = 360pF, TJ = 25°CVCC = 10V to 30VTA = 25°C to 85°CCT = 360pF, TJ = 25°CCT = 360pF, TJ = 25°CVPIN7, peak to peak
125--2.800.61.80
135±1±1.53.080.92.18
145±3-3.301.22.50
kHz%%VVV
Symbol
Conditions
Min.Typ.Max.Unit
-660-800-960
LATCH MODE SHUTDOWN CIRCUIT SECTIONSink current(pin8)
Shutdown threshold voltage
OVERLOAD SHUTDOWN SECTIONShutdown threshold voltage
2
KA7552A/KA7553A
Electrical Characteristics (Continued)
(VCC = 18V, FOSC = 135kHz, TA = 25°C, unless otherwise specified)Parameter
UNDER VOLTAGE LOCKOUT SECTIONStart-up threshold voltageMinimum operating voltageHysteresis
ON/OFF CONTROL SECTIONSource current(pin8)On threshold voltageOff threshold voltageOUTPUT SECTIONLow output voltageHigh output voltageRise time(Note1)Fall time(Note1)OVERALLStand-by currentOperating currentPower supply current offPower supply current shutdown
ISBICC(OPR)ICC(OFF)ICC(SD)
VCC = 14VVPIN2 = 0VVPIN8 = 0VVPIN8 = 7.6V
----9091.11.1
150151.81.8
uAmAmAmA
VOLVOHTRTF
IO = 100mA, VCC = 18VIO = -100mA, VCC = 18VNo loadNo load
-16.0--1.316.55050
1.818.0--VVnsns
ISOURCE(CS)VTH(ON)VTH(OFF)
VPIN8 = 0VVPIN8 : OFF->ONVPIN8 : ON -> OFF
-150.450.30
-100.560.42
-50.700.55
uAVV
VTH(ST)VOPR(Min)VHYS
---15.58.206.40
16.08.707.30
16.59.208.20
VVV
Symbol
Conditions
Min.
Typ.
Max.
Unit
Note :
1. These parameters, although guaranteed, are not 100% tested in production.2. Recommend operating condition : -Vcc(min) = 12V-RT = 3.3kΩ ~ 10kΩ
-Oscillation frequency = 5kHz ~ 600kHz- Soft start capacitor(CS) = 0.1uF ~ 1uF
3
KA7552A/KA7553A
Mechanical Dimensions
Package
Dimensions in millimeters
8-DIP
0.018 ±0.0041.524 ±0.100.060 ±0.0040.46 ±0.106.40 ±0.200.252 ±0.008#1#.20 ±0.200.362 ±0.00.60MAX0.378#4#52.540.100(0.79)0.0317.620.3005.08MAX0.2003.40 ±0.200.134 ±0.0083.30 ±0.300.130 ±0.0120.33MIN0.0130.25–0.050.010–0.0020~15°+0.004+0.104
KA7552A/KA7553A
Ordering Information
Product Number
KA7552AKA7553A
Package8-DIP
Operating Temperature
-25 ~ +85°C
5
KA7552A/KA7553A
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein:
1.Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the user.
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2.A critical component in any component of a life support
device or system whose failure to perform can be
reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.