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FAIRCHILD SEMICONDUCTOR FOD2741A FOD2741B FOD2741C Manual(1)

1. Fig 14 Dark Current vs Ambient Temperature Fig 15 Collector Current vs Ambient Temperature 10000 30 Vcg 10V VcE 5V 25 1000 t lt 20mA 20 100 5 15 x 8 ILED 10mA S o A 10 10 9 9 ILEp 6mA 1 ILEp 1 04 0 40 20 0 20 40 60 80 100 0 10 20 30 40 50 60 70 80 9 100 Ta Ambient Temperature C Ta Ambient Temperature C Fig 16 Current Transfer Ratio vs LED Current Fig 17 Saturation Voltage vs Ambient Temperature 0 26 VcEp 5V 140 0 24 amp 5 022 120 8 5 S 020 9 g 100 2 0 18 25 C E G 80 046 o 70 oda 8 60 gt 0 12 40 0 10 0 5 10 15 20 25 30 35 40 45 50 40 20 0 20 40 60 80 100 ILEp Forward Current mA TA Ambient Temperature C Fig 18 Collector Current vs Collector Voltage Fig 19 Rate of Change Vref to Vout vs Temperature 35 0 32 Ta 25 C 30 0 34 20mA lt 25 036 2 8 9 20 gt 038 3 5 8 8 15 10 0 40 5 gt 9 10 S 0 42 9 ILEp 5mA 5 0 44 ILEp 1mA 0 0 46 0 1 2 3 4 5 6 7 8 9 10 60 40 20 0 20 40 60 80 100 120 VCE Collector Emitter Voltage V Temperature 2003 Fairchild Semiconductor
2. Two digit year code e g 03 Two digit work week ranging from 01 to 53 Assembly package code 2003 Fairchild Semiconductor Corporation Page 12 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C Carrier Tape Specifications Description Dimension in mm Tape Width 16 0 0 3 Tape Thickness 0 30 0 05 Sprocket Hole Pitch 4 0 0 1 Sprocket Hole Diameter 1 55 0 05 Sprocket Hole Location E 1 75 0 10 7 5 0 1 4 0 0 1 Pocket Pitch 12 0 0 1 10 30 0 20 Pocket Dimensions 10 30 0 20 4 90 0 20 Cover Tape Width 1 6 x 0 1 Pocket Location Cover Tape Thickness 0 1 max Max Component Rotation or Tilt 10 Min Bending Radius 30 oes 2003 Fairchild Semiconductor Corporation Page 13 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C Reflow Profile 245C 10 30 s 260C peak pa Time above 183 lt 160 sec o 2 o x 3 z G Ramp up 2 10C sec 25 3 Time Minute Peak reflow temperature 260 C package surface temperature Time of temperature higher than 183C for 160 seconds or less One time soldering reflow is recommended 2003 Fairchild Semiconductor Corporation Page 14 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER S
3. 0 5 t g 3 o 00 ES amp a a E 305 1 0 1 0 1 2 8 1 0 1 2 8 VcowP Cathode Voltage V VcowP Cathode Voltage V Fig 10 Reference Voltage vs Ambient Temperature Fig 11 Reference Current vs Ambient Temperature 2 510 ILEp 10mA 10mA 2 508 EP 1 10kQ 2 506 2 504 2 502 2 500 2 498 2 496 Vngr Reference Voltage V Ingr Reference Current uA 2 494 2 492 2 490 40 20 0 20 40 60 80 100 TA Ambient Temperature C Ta Ambient Temperature C Fig 12 Off State Current vs Ambient Temperature Fig 13 Forward Current vs Forward Voltage 100 20 Voc 37V 10 1 40 20 0 20 40 60 80 100 0 9 1 0 1 1 1 2 1 8 1 4 TA Ambient Temperature Vr Forward Voltage V a lorr Off State Current nA IF Forward Current mA 3 a 2003 Fairchild Semiconductor Corporation Page 7 of 15 12 9 04 22 22222222 FAIRCHILD OPTICALLY ISOLATED ERROR ANPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C
4. 77777777752 1 1 og 12 8 2 r 1 4 I gt 2174 gt 4 6 NEL A AAA Mk R1 5 1 FIG 3 TEST CIRCUIT usa 1 Ic 8 i2 4 8 12 lt Tak F L ive 5 6 6 i l 12 1 19 Dow T I i Vcomp VREF 5 I L sns sss 1 Soe TR E FIG 5 TEST CIRCUIT FIG 6 CTR VcE sa TEST CIRCUIT 2003 Fairchild Semiconductor Corporation Page 5 of 15 12 9 04 FAIRCHILD OPTICALLY ISOLATED maama ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C Voc 5V DC RL 1 8 NA Vour Ary 5 1 7 vee Ed X 3 _ 6 4 5 Fig 7 Frequency Response Test Circuit Voc 45V DC lF 0 mA A lF 10 B R1 1 8 lt VV 2 2kQ Y 10Vp p Fig 8 CMH and CML Test Circuit eer 2003 Fairchild Semiconductor Corporation Page 6 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C TYPICAL PERFORMANCE CURVES Fig 9a LED Current vs Cathode Voltage Fig 9b LED Current vs Cathode Voltage 1 0 TA 25 C Vcomp VFB
5. resistor The value of the resistor sets the amount of current through the LED and thus must be carefully selected in conjunction with the selection of the primary side resistor Feedback Output voltage of a converter is determined by selecting a resistor divider from the regulated output to the FB pin The FOD2741 attempts to regulate its FB pin to the reference voltage 2 5V The ratio of the two resistors should thus be _ Vout _ eeu Rc 5 VREF The absolute value of the top resistor is set by the input offset current of 5 2uA To achieve 0 5 accuracy the resistance of should be Vour 2 5 OUT 104040A Compensation The compensation pin of the FOD2741 provides the opportu nity for the designer to design the frequency response of the converter A compensation network may be placed between the COMP pin and the FB pin In typical low bandwidth Systems a 0 1uF capacitor may be used For converters with more stringent requirements a network should be designed based on measurements of the system s loop An excellent reference for this process may be found in Practical Design of Power Supplies by Ron Lenk IEEE Press 1998 Secondary Ground The GND pin should be connected to the secondary ground of the converter No Connect Pins The NC pins have no internal connection They should not have any connection to the secondary side as this may compromise the isolation
6. structure Photo Transistor The Photo transistor is the output of the FOD2741 In a normal configuration the collector will be attached to a pull up resistor and the emitter grounded There is no base connection neces sary The value of the pull up resistor and the current limiting resis tor feeding the LED must be carefully selected to account for voltage range accepted by the PWM IC and for the variation in current transfer ratio CTR of the opto isolator itself Example The voltage feeding the LED pins is 12V the volt age feeding the collector pull up is 10V and the PWM IC is the Fairchild KA1H0680 which has 5V reference If we select a 10 resistor for the LED the maximum current the LED can see is 12V 4V 10kQ 800pA The CTR of the opto isolator is a minimum of 100 so the minimum collector current of the photo transistor when the diode is full on is also 800A The collector resistor must thus be such that 10V 5V FEL lt 800 or Reottector gt 6 25 COLLECTOR select 12kQ to allow some margin 2003 Fairchild Semiconductor Corporation Page 10 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C Package Dimensions Through Hole Package Dimensions Surface Mount 0 390 9 91 0 370 9 40 P 0 270 6 86 0 250 6 35 0 270 6 86 0 250 6 35 6 ET TT LI td 0 390 9 91 0 370 9 40 0 070 1 78 0 s
7. 5 C x 10 where ATA is the rated operating free air temperature range of the device AVagre ppm C 2 The dynamic impedance is defined as IZoyrl gp When the device is operating with two external resistors see Figure 2 the total dynamic impedance of the circuit is given by R1 Zour A Zour x EE ER 2003 Fairchild Semiconductor Corporation Page 3 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C OUTPUT CHARACTERISTICS T 25 C Unless otherwise specified Parameter Test Conditions Symbol ee Collector dark current Vcg 10 V Fig 5 Emitter collector voltage breakdown lg 100 pA Collector emitter voltage breakdown Ic 1 0mA TRANSFER CHARACTERISTICS T 25 Unless otherwise e ILEp 10 mA Vcomp Current transfer ratio Voe 5 V Fig 6 100 Collector emitter 10 mA Vcomp VFB saturation voltage 2 5 mA Fig 6 SAD ISOLATION CHARACTERISTICS T 25 Unless otherwise specified Input output insulation 4596 TA 25 t 5s leakage current 3000 VDC note 1 i i i RH lt 50 TA 25 C t 1 mi Withstand insulation RH lt A min Viso 5000 voltage notes 1 Resistance input to output 500 VDC note 1 SWITCHING CHARAC
8. 62 0 070 1 78 0 045 1 14 0 045 1 14 0 016 0 41 T 0 200 5 08 0 020 0 51 MIN LA B 0 20 0 140 3 55 0 154 3 90 0 120 3 05 01022 07158 0 045 1 14 0 56 m 016 0 41 oie a 0 00 0 008 0 20 L 0 1 yo 54 TYP 0 100 2 54 TYP 0 405 10 30 MIN z lt al n z E x Lu 7 Lead Coplanarity 0 004 0 10 MAX 8 Pin Dip 7 io fo L 0 060 1 52 0 270 6 86 0 250 6 35 0 100 2 54 Ll 0 295 7 49 0 390 9 91 7 0370 940 E 0 030 0 76 3 0 070 1 78 0 415 10 54 J x 0 76 p 0 045 1 14 zd 0 200 5 08 0 004 0 10 MIN Bj 0 140 3 55 m OUOU 0 154 3 90 II 0 120 3 05 0 022 0 56 6940458 22 0 016 0 41 EE 2 2400 D 16 L 100 2 54 TYP NOTE All dimensions are in inches millimeters 2003 Fairchild Semiconductor Corporation Page 11 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C ORDERING INFORMATION Example FOD2741A X Y X Y Packaging Option T 0 4 Lead Spacing V VDE tested S Surface Mount Lead Bend SD Surface Mount Tape and Reel 1000 per reel MARKING INFORMATION Fairchild logo Device number VDE mark Note Only appears on parts ordered with VDE option See order entry table
9. Corporation Page 8 of 15 12 9 04 OPTICALLY ISOLATED ERROR AMPLIFIER FAIRCHILD SEMICONDUCTOR FOD2741B FOD2741C FOD2741A g 20 Voltage Gain vs Frequency 12 9 04 Page 9 of 15 2003 Fairchild Semiconductor Corporation FAIRCHILD SEMICONDUCTOR OPTICALLY ISOLATED ERROR AMPLIFIER FOD2741A FOD2741B FOD2741C The FOD2741 The FOD2741 is an optically isolated error amplifier It incor porates three of the most common elements necessary to make an isolated power supply a reference voltage an error amplifier and an optocoupler It is functionally equivalent to the popular KA431 shunt voltage regulator plus the CNY17F X optocoupler Powering the Secondary Side The LED pin in the FOD2741 powers the secondary side and in particular provides the current to run the LED The actual structure of the FOD2741 dictates the minimum voltage that can be applied to the LED pin The error amplifier output has a minimum of the reference voltage and the LED is in series with that Minimum voltage applied to the LED pin is thus 2 5V 1 5V 4 0V This voltage can be generated either directly from the output of the converter or else from a slaved second ary winding The secondary winding will not affect regulation as the input to the FB pin may still be taken from the output winding The LED pin needs to be fed through a current limiting
10. EMICONDUCTOR FOD2741A FOD2741B FOD2741C 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 2 A critical component in any component of a life support which a are intended for surgical implant into the body or device or system whose failure to perform can be b support or sustain life and c whose failure to perform reasonably expected to cause the failure of the life support when properly used in accordance with instructions for use device or system or to affect its safety or effectiveness provided in the labeling can be reasonably expected to result in a significant injury of the user 2003 Fairchild Semiconductor Corporation Page 15 of 15 12 9 04
11. OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C DESCRIPTION The FOD2741 Optically Isolated Amplifier consists of the popular KA431 precision programmable shunt reference and an optocoupler The optocoupler is a gallium arsenide GaAs light emitting diode optically coupled to a silicon phototransistor It comes in 3 grades of reference voltage tolerance 2 1 and 0 5 The Current Transfer Ratio CTR ranges from 100 to 200 It also has an outstanding temperature coefficient of 50 ppm C It is primarily intended for use as the error amplifier reference voltage optocoupler function in isolated ac to dc power supplies and dc dc con verters When using the FOD2741 power supply designers can reduce the component count and save space in tightly packaged designs The tight tolerance reference eliminates the need for adjustments in many applications The device comes in a 8 pin dip white package FEATURES Optocoupler precision reference and error amplifier in single package 2 5V reference CTR 100 to 200 5 000V RMS isolation UL approved E90700 Volume 2 CSA approval 1296837 VDE approval 40002463 BSI approval 8702 8703 Low temperature coefficient 50 ppm C max FOD2741A tolerance 0 5 FOD2741B tolerance 1 FOD2741C tolerance 2 APPLICATIONS Power supplies regulation DC to DC converters PIN DEFINITIONS NC Not connected
12. Phototransistor Collector Phototransistor Emitter Not connected Ground Error Amplifier Compensation This pin is the output of the error amplifier Voltage Feedback This pin is the inverting input to the error amplifier 1 2 3 4 5 6 7 8 Anode LED This pin is the input to the light emitting diode The compensation network must be attached between pins 6 and 7 2003 Fairchild Semiconductor Corporation Page 1 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C TYPICAL APPLICATION FAN4803 PWM Control FOD2741 ABSOLUTE MAXIMUM RATINGS T 25 C Unless otherwise specified Parameter Symbol Vawe nee s Temperature M to 125 Operating Temperature ToPR 25 to 85 Lead Solder Temperature 260 for 10 sec Input Voltage Input DC Current Collector Emitter Voltage Emitter Collector Voltage Collector Current Input Power Dissipation note 1 Transistor Power Dissipation note 2 Total Power Dissipation note 3 Notes 1 Derate linearly from 25 at a rate of 2 42 mW C 2 Derate linearly from 25 at a rate of 1 42 mW 3 Derate linearly from 25 at a rate of 2 42 mW 4 Functional operation under these conditions is not implied Permanent damage may occur if the d
13. TERISTICS T 25 Unless otherwise specified Parameter Test Conditions Bandwidth Fig 7 Common mode transient 0 mA Vem 10 Vpp immunity at output high RL 2 2 Fig 8 note 2 Common mode transient 1 10 mA Vem 10 immunity at output low RL 2 2 Fig 8 note 2 Notes 1 Device is considered as a two terminal device Pins 1 2 3 and 4 are shorted together and Pins 5 6 7 and 8 are shorted together 2 Common mode transient immunity at output high is the maximum tolerable positive dVcm dt on the leading edge of the com mon mode impulse signal Vcm to assure that the output will remain high Common mode transient immunity at output low is the maximum tolerable negative dVcm dt on the trailing edge of the common pulse signal Vcm to assure that the output will remain low Typ 2003 Fairchild Semiconductor Corporation Page 4 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C LED a E u 8 12 AT 8 2 2 Ve v K K 3 Zm E VT i Vu 1T Uk Vcomp VREF R2 Veer 5 l 1 5 1 PE FIG 1 Vngr min TEST CIRCUIT FIG 2 AVnge AVcowP TEST CIRCUIT lag
14. evice is subjected to conditions outside these ratings 2003 Fairchild Semiconductor Corporation Page 2 of 15 12 9 04 OPTICALLY ISOLATED FAIRCHILD ERROR AMPLIFIER SEMICONDUCTOR FOD2741A FOD2741B FOD2741C ELECTRICAL CHARACTERISTICS T 25 C Unless otherwise specified INPUT CHARACTERISTICS Sa ee LED Forward Voltage 10 mA VcoMP Vrp fig 1 1 2 482 2 495 2 508 Reference Voltage li gp 10 mA Vcomp VFB VREF 2 470 2 495 2 520 2 450 2 500 2 550 Deviation of over TA 25 C to 85 VREF DEV temperature Ratio of Vpgr variation to the AVcomp 10V to AVper ILED 10mA output of the error amplifier AVcomp 36V to 10V Vcomp Feedback Input Current 10 R4 10kQ fig 3 IREF Deviation of Iggp over temperature 25 C to 85 IREF DEV Minimum Drive Current Vcomp Vre fig 1 lLED MIN Off state error amplifier current Vi Ep 37V Vep 0 fig 4 Error amplifier output impedance Vcomp 1mA to 20mA IZgu1l see note 2 f2 1 0 kHz oUF 1 The deviation parameters and Inge pev are defined as the differences between the maximum and minimum values obtained over the rated temperature range The average full range temperature coefficient of the reference input voltage AVngg is defined as Vneripev Vaer TA 2

FAIRCHILD SEMICONDUCTOR FOD2741A FOD2741B FOD2741C Manual(1)

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