www.fairchildsemi.com KA3502 PC SMPS Supervisory IC Features Descriptions • • • • • • • • • • The KA3502 is complete housekeeping circuitry for use in the secondary side of SMPS(Switched Mode Power Supply). It contains various functions, which are two Precision Voltage References, Over Voltage/Current Protection, Remote On/Off Control, Power Good Signal Generator, Disable Logic and etc. Complete Housekeeping Circuit Few External Components Over Voltage Protection for 3.3V/5V/12V/Adj. Output Over Current Protection for 3.3V/5V/12V Output Open-Collector Output and Remote On/Off Function Remote On/Off Delay Time Control Precision Voltage Reference for Outputs, 5V/12V Uncommitment Precision Voltage Reference for +5Vs Power Good Signal Generator with Hysteresis Disable Logic of 3.3V, 5V, 12V for Complete Shutdown 20-DIP 1 Internal Block Diagram PWM FB1 VREF1 UV 14 11 6 15 VCC 5 R5 R3 R1 V33 V5 V12 1 2 3 Vcc R6 R4 R2 Adj 4 + + + + - R8 1k COMP1 1.26V Ichg R10 39k R15 5.1k 9 Ion R9 10k R13 5.2V PG + Vcc S Vcc Q R Tsur 17 Vcc 2.7V IS5 19 -+ 50mV IS33 20 -+ 135mV IS12 18 + COMP2 Vcc + COMP3 Vcc Vcc + - + COMP7 Vcc Q1 REFERENCE1 Vcc Vcc 2.8V + COMP6 + - + - COMP4 65mV R11 5.4k R12 - + Q2 12 FB2 1.28V↔1.24V R14 2V↔0.7V Ion+ Ioff COMP9 2V↔1.3V + COMP8 COMP5 2V Q3 REFERENCE2 1.4V 13 VREF2 R7 7 REM 8 Trem 16 GND 10 Topr Rev. 5.0 ©2000 Fairchild Semiconductor International KA3502 Pin Assignments #1 #20 V33 IS33 V5 IS5 V12 IS12 Adj VCC PWM 2 NO NAME 1 V33 2 Tsur K A 3 5 0 2 GND FB1 REM VREF1 Trem VREF2 PG FB2 Topr UV #10 #11 FUNCTION NO NAME FUNCTION +3.3 V OUTPUT VOLTAGE 11 UV PG INPUT for Det V5 +5 V OUTPUT VOLTAGE 12 FB2 FEEDBACK for REFERENCE 2 3 V12 +12 V OUTPUT VOLTAGE 13 VREF2 PRECISION REFERENCE 4 Adj ADJUSTABLE OVP INPUT 14 VREF1 PRECISION REFERENCE 5 VCC SUPPLY VOLTAGE 15 FB1 FEEDBACK for REFERENCE 1 6 PWM REMOTE ON/OFF OUTPUT 16 GND GROUND 7 REM REMOTE ON/OFF INPUT 17 Tsur OCP DELAY 8 Trem REMOTE ON/OFF DELAY 18 IS12 Current INPUT for +12V 9 PG POWER GOOD OUTPUT 19 IS5 Current INPUT for +5V 10 Topr PG DELAY 20 IS33 Current INPUT for +3.3V KA3502 Pin Description Pin Number Pin Name 1 V33 +3.3 V Output Voltage of SMPS Secondary side 2 V5 +5 V Output Voltage of SMPS Secondary side 3 V12 +12 V Output Voltage of SMPS Secondary side 4 ADJ Adjustable OVP Input. Its Threshold Voltage is 1.26 V. This pin can be used for another protection signal. 5 VCC Supply Voltage. Operating range is 15 V ~ 24 V. Vcc=18 V, Ta=25°C at test. PWM Remote On/Off Output. This signal controls the primary power switch (PWM IC) through an Opto-coupler. Maximum current rating is 30 mA. When PWM="Low", the main SMPS is operational and If PWM="High", the main SMPS is turned-off. REM Remote On/Off Input. It is TTL operation and its threshold voltage is 1.4 V. Voltage at this pin can reach normally 4.6 V, with absolutely maximum voltage, 5.25 V. If REM="Low", PWM="Low". That means the main SMPS is operational. When REM ="High", then PWM="High" and the main SMPS is turned-off. 8 Trem Remote On/Off delay. Ton/Toff=8 ms/24 ms (Typ.) with Ctrem=0.1uF. Its High/Low threshold voltage is 2 V/0.7 V and the maximum voltage after full charging is about 2.8 V. So, ∆V (Chg.) = 2 V, ∆V (Dischg.) = 2.1 V Typ. 9 PG Power Good output signal. PG="High" means that the power is "Good" for operation and PG="Low" means "Power Fail". 10 Topr PG Delay. Td=250 ms (Typ.) with Ctopr=2.2uF. The High/Low threshold voltage are 2 V/1.3 V and the voltage of PIN 10 is clamped at 5.2 V for Noise margin. 11 UV Under-Voltage Detect Pin. Its threshold voltage is 1.26V ± 20mV Typ. 12 FB2 Feedback for Precision Reference2. Absolute min/max current rating is 1 mA/30 mA. 13 VREF2 Precision Reference 2 input Voltage. This circuit equals to KA431 and it is designed for an Auxiliary voltage, +5 Vs. It is trimmed to ± 1.6%. 14 VREF1 Precision Reference 1 Input Voltage. This circuit equals to KA431 and it is for corrective output voltages of +5 V/+12 V. It's trimmed to ± 1.6%. 15 FB1 Feedback for Precision Reference1. Absolute min/max current rating is 2 mA/30 mA because of internal connection. 16 GND Ground 17 Tsur Timing pin for Over Current Protection blank-out time. Its threshold voltage is 2 V and clamped at 2.7 V after full charging. Target of delay time is 20 ms~30 ms and it is realized through external R & C. 18 IS12 Current Sense Input for +12V. This pin is connected to the Current Sensing resistor or inductor. If the voltage drop of the resistor or inductor is larger than the fixed offset voltage ( 65 mV Typ.), PWM becomes "High" after some delay and the main SMPS is turned-off. 19 IS5 Current Sense Input for +5 V. The OCP Offset voltage for +5 V is 50 mV 20 IS33 Current Sense Input for +3.3 V. The OCP Offset voltage for +3.3 V is 135 mV 6 7 Pin Function Descrition 3 KA3502 Absolute Maximum Ratings Parameter Symbol Value Unit Supply Voltage Vcc 15 ~ 24 V UV Input Voltage Vuv 24 V Vin (max) Vcc - 3 V Ik1, 2 1 ~ 30 mA Io (PWM) 30 mA Io (PG) 30 mA Pd 1 W Input Maximum Voltage Cathode Current for FB1, 2 PWM Maximum Current PG Output Maximum Current Power Dissipation Operating Temperature Range Topr 0 ~ 70 °C Storage Temperature Range Tstg -65 ~ 150 °C Temperature Characteristics 4 Parameter Symbol Value Unit Temperature Stability for Vref1, 2 (0°C ≤ Ta ≤ 70°C) ∆Vref1, 2 17 mV KA3502 Electrical Characteristics (Vcc = 18V, Ta = 25°°C) Parameter Symbol Condition Min. Typ. Max. Unit PROTECTION SECTION Over Voltage Protection For 3.3 V Vovp33 Pin 7 (REM)=0V 3.8 4.0 4.2 V Over Voltage Protection For 5 V Vovp5 Pin 7 (REM)=0V 5.8 6.1 6.4 V Over Voltage Protection For 12 V Vovp12 Pin 7 (REM)=0V 13.4 14.2 15.0 V OVP Input Threshold Voltage for Adj Vadj Pin 7 (REM)=0V 1.22 1.26 1.30 V Comparator Offset Voltage for 3.3 V Vos33 Pin 7 (REM)=0V 125.5 135 144.5 mV Comparator Offset Voltage for 5 V Vos5 Pin 7 (REM)=0V 46.5 50 53.5 mV Comparator Offset Voltage for 12 V Vos12 Pin 7 (REM)=0V 60.5 65 69.5 mV Vth (Tsur) Pin 7 (REM)=0V 1.9 2 2.1 V V17max Pin 7 (REM)=0V - 2.7 4 V OCP Delay Comparator Input Threshold Voltage Pin 17 (Tsur) Input Clamp Voltage REMOTE ON/OFF SECTION Remote On/off Input Threshold Vtg. Vth Pin 7 (REM): “L”→”H” 1 - 1.8 V Remote On/off Input Open Voltage Vih Pin 7 Open 4 - 5.25 V Pin 7 (REM)=0 V 0 - -1.0 mA Remote On/off Input Low Current Iil ON Delay Time Ton REM: “L”→“H”, C=0.1 uF 4 8 14 msec OFF Delay Time Toff REM: “L”→“H”, C=0.1 uF 16 24 34 msec Io=0.5 mA - - 1.3 V Ileak Pin 6 (PWM)=20 V - 0.01 1 uA Vref1 IIk1=1 mA 2.46 2.50 2.54 V 15 V<Vcc<20 V - 1 - mV/V Ik1=1 mA to 10 mA - 5 20 mV PWM Saturation Voltage PWM Leakage Current Vsat (PWM) REFERENCE 1 SECTION Reference Input Voltage 1 Line Regulation 1 Vref1 (line) Current Stability 1 ∆ Vref1 Output Sinking Current Capability 1 Isink1 - 15 25 - mA Absolute Precision of Internal Three Resistors Rint - - ± 15 - % Rrate - - ±1 - % Matching Coefficient of Internal Three Resistors Temperature Stability ∆ Vref1 Ta=0 to 70°C (Note 1) - 13 17 mV Gain Bandwidth 1 GBW1 GV=1 (Note 1) - 1 - MHz 5 KA3502 Electrical Characteristics (Continued) Parameter Symbol Condition Min. Typ. Max. Unit REFERENCE 2 SECTION Reference Input Voltage 2 2.46 2.50 2.54 V Line Regulation 2 Vref2 (line) 15 V<Vcc<20 V - 1 - mV/V Current Stability 2 ∆ Vref2 Ik2 mA to 10 mA - 5 20 mV 15 25 - mA Output Sinking Current Capability 2 Vref2 Isink2 IIk2=1 mA - Temperature Stability 2 ∆ Vref2 Ta=0 to 70°C (Note 1) - 13 17 mV Gain Bandwidth 2 GBW2 GV=1 (Note 1) - 1 - MHz POWER GOOD SECTION Detecting UV Voltage Vuv Pin 7 (REM)=0V 1.22 1.26 1.30 V Detecting V5 Voltage Vin (V5) Pin 7 (REM)=0V 4.1 4.3 4.5 V Hysteresis Voltage 1 HY1 Pin 11 (UV): “L”↔“H” 20 40 80 mV Hysteresis Voltage 2 HY2 Pin 10 (Topr): “L”↔ “H” 0.2 0.7 - V High Threshold Voltage of Comp 9 Vth (H) Pin 10 (Topr): “L”↔ “H” 1.8 2.0 2.2 V Noise margin of Vtopr ∆ Vtopr Vtopr (max) - Vth (L) 2 4 - V Charging Current for PG Delay Ichg Pin 10 (Topr)=GND -12 -18 -28 uA Turn-On Delay Time for PG Topr Ctopr=2.2uF 100 250 500 msec UV Input Pull Down Resistor Ruv - 20 - kohm PG Output Rising Time Tr C=0.1nF (Note 1) - 1 - usec PG Output Falling Time Tf C=0.1nF (Note 1) - 300 - nsec Isink=15 mA - 0.3 0.4 V 4.2 - 5.25 V PG Output Saturation Voltage PG Output Voltage at High Status Vsat (PG) Vpgh - Isource=100 uA DISABLE SECTION Disable Saturation Voltage for V33 Vdis33 REM=2 V, Isink=10 mA - 0.2 0.4 V Disable Saturation Voltage for V5 Vdi5 REM=2 V, Isink=10 mA - 0.2 0.4 V Disable Saturation Voltage for V12 Vdis12 REM=2 V, Isink=10 mA - 0.2 0.4 V Vcc=18 V, REM=2V - 5 10 mA TOTAL STANDBY CURRENT Supply Current Of Vcc Icc Note: 1.These parameters, although guaranteed, but not 100% tested in production. 6 KA3502 2.510 2.53 2.505 2.52 Vref1, 2 (V) Vref (V) Typical Characteristics 2.500 2.50 2.495 2.490 -25 2.51 0 25 50 75 2.49 100 0 5 10 Temp (Dgree) 20 1.255 15 PWM (V) Vadj (V) 1.260 1.250 1.245 30 5 0 25 50 75 0 1.10 100 1.15 1.20 1.25 1.30 1.35 Vadj (V) Figure 3. Bandgap Voltage (Vadj) Figure 4. OVP Input Threshold Voltage for Adj 20 20 15 15 PWM (V) PWM (V) 25 10 Temp (Degree) 10 5 0 3.50 20 Figure 2. Vref1,2 Current Stability Figure 1. Temperature Stability for Vref1,2 1.240 -25 15 1k (mA) 10 5 3.75 4.00 4.25 4.50 0 5.0 5.5 6.0 6.5 7.0 V33 (V) V5 (V) Figure 3. Over Voltage Protection for +3.3V Figure 4. OCP Offiset Voltage for 3.3V 7 KA3502 Typical Characteristics (Continued) 20 20 15 15 PWM (V) PWM (V) Vos33=IS33-V33 10 5 10 5 0 12 13 14 15 0 110 16 120 V12 (V) 130 140 Figure 8. OCP Offiset Voltage for 3.3V Figure 7. Over Voltage Protection for +12V 20 20 Vos=IS12-Vo12 Vos5=IS5-V5 15 PWM (V) PWM (V) 15 10 10 5 5 0 55 0 40 45 50 55 60 60 Vos5 (mV) 20 15 15 PWM (V) PWM (V) 70 75 Figure 10. OCP Offiset Voltage for 12V 20 10 5 0 0.0 65 V8 (V) Figure 9. OCP Offiset Voltage for 5V 10 5 0.5 1.0 1.5 2.0 Vth (V) Figure 11. Remotr On/Off Input Threshold 8 150 Vos33 (mV) 0 0.0 0.5 1.0 1.5 2.0 2.5 V8 (V) Figure 12. ON/OFF Delay Threshold Voltage KA3502 Typical Characteristics (Continued) 25 6 20 5 PG (V) PWM (V) 4 15 10 3 2 5 1 0 0 5 10 15 0 1.20 20 1.22 Isink (mA) 1.30 5 4 4 3 PG (V) PG (V) 1.28 Figure 14. Detecting UV Voltage 5 2 1 3 2 1 0 5.0 4.8 4.6 4.4 4.2 0 0.5 4.0 1.0 V5 (V) 1.5 2.0 2.5 V10 (V) Figure 15. Detecting V5 Voltage for PG Figure 16. High/low Threshold Voltage of Comp9 0.4 0.4 0.3 0.3 Vdis (V) Vsat_PG (V) 1.26 Vuv (V) Figure 13. PWM Saturation Voltage 0.2 0.2 0.1 0.1 0.0 1.24 0.0 0 5 10 15 20 Isink (mA) Figure 17. PG Saturating Voltage 25 0 5 10 15 20 Isink (mA) Figure 18. Disable Saturation Voltage 9 KA3502 Typical Characteristics (Continued) 10 20 PWM 8 6 (V) Icc (mA) 15 10 4 REM 5 2 0 14 16 18 20 22 24 0 0 20 Vcc (V) Figure 19. Supply Current of Vcc Figure 20. 6 PG 5 (V) 4 3 UV 2 1 0 0.0 0.2 0.4 0.6 Time (sec) Figure 21. PG Delay 10 40 60 Time (msec) 0.8 1.0 80 100 KA3502 Mechanical Dimensions Package Dimensions in millimeters 20-DIP 11 KA3502 Ordering Information Product Number KA3502 12 Package 20-DIP Operating Temperature 0°C ~ 70°C KA3502 13 KA3502 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 INTERNATIONAL. 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. 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. www.fairchildsemi.com 9/25/00 0.0m 001 Stock#DSxxxxxxxx 2000 Fairchild Semiconductor International