FOD2742A

OPTICALLY ISOLATED ERROR AMPLIFIER FOD2742A DESCRIPTION The FOD2742 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 converters. FUNCTIONAL BLOCK DIAGRAM FOD2742B FOD2742C When using the FOD2742, 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 small outline package. FEATURES • Optocoupler, precision reference and error amplifier in single package • 2.5V reference • CTR 100% to 200% • 2,500V RMS isolation • UL approval E90700, Volume 2 • VDE approval 136616 • FOD2742A: tolerance 0.5% FOD2742B: tolerance 1% FOD2742C: tolerance 2% • BSI approval 8661, 8662 • CSA approval 1113643 NC 1 8 LED C 2 7 FB E 3 6 COMP NC 4 5 GND • Low temperature coefficient 50 ppm/°C max APPLICATIONS • Power supplies regulation • DC to DC converters PIN DEFINITIONS Pin Number 1 2 3 4 5 6 7 8 Pin Name NC C E NC GND COMP FB LED Pin function description Not connected 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 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 13 8/27/03 OPTICALLY ISOLATED ERROR AMPLIFIER FOD2742A TYPICAL APPLICATION FOD2742B FOD2742C V1 FAN4803 PWM Control VO FOD2742 2 8 6 R1 3 7 R2 5 ABSOLUTE MAXIMUM RATINGS (TA = 25°C Unless otherwise specified.) Parameter Storage Temperature Operating Temperature Reflow Temperature Profile (refer to fig. 21) 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) VLED ILED VCEO VECO IC PD1 PD2 PD3 37 20 70 7 50 145 85 145 V mA V V mA mW mW mW Symbol TSTG TOPR Value -40 to +125 -25 to +85 Units °C °C Notes 1. Derate linearly from 25°C at a rate of 2.42 mW/ °C 2. Derate linearly from 25°C at a rate of 1.42 mW/ °C. 3. Derate linearly from 25°C at a rate of 2.42 mW/ °C. 4. Functional operation under these conditions is not implied. Permanent damage may occur if the device is subjected to conditions outside these ratings. © 2003 Fairchild Semiconductor Corporation Page 2 of 13 8/27/03 OPTICALLY ISOLATED ERROR AMPLIFIER FOD2742A FOD2742B FOD2742C ELECTRICAL CHARACTERISTICS (TA = 25°C Unless otherwise specified.) INPUT CHARACTERISTICS Parameter LED Forward Voltage Test Conditions (ILED = 10 mA, VCOMP = VFB) (fig. 1) ILED = 10 mA, VCOMP = VFB (fig. 1) Symbol VF VREF Device ALL A Reference Voltage Deviation of VREF over temperature Ratio of VREF variation to the output of the error amplifier Feedback Input Current Deviation of IREF over temperature Minimum Drive Current Off-state error amplifier current Error amplifier output impedance (see note 2) B C TA = -25°C to +85°C (fig. 1) VREF (DEV) ILED = 10 mA ∆VCOMP = 10V to VREF (fig. 2) ∆VCOMP = 36V to 10V ILED = 10mA, R1 = 10KΩ (fig. 3) TA = -25°C to +85°C (fig. 3) VCOMP = VFB (fig. 1) VLED = 37V, VFB = 0 (fig. 4) VCOMP = VREF, ILED = 1mA to 20mA, f ≥ 1.0 kHz ∆VREF/ ∆VCOMP IREF IREF (DEV) ILED (MIN) I(OFF) |ZOUT| ALL ALL ALL ALL ALL ALL ALL 2.482 2.470 2.450 Min. Typ. 1.20 2.495 2.495 2.500 3.5 -0.5 -0.3 2.2 1.0 0.45 0.01 0.15 Max. 1.5 2.508 2.520 2.550 17 -2.7 -2.0 4 1.2 1.0 1.0 0.5 Unit V V V V mV mV/ V µA µA mA µA Ω 1. The deviation parameters VREF(DEV) and IREF(DEV) 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, ∆VREF, is defined as: { V REF ( DEV ) /V REF ( T A = 25°C ) } × 10 ∆ V REF ( ppm/°C ) = ---------------------------------------------------------------------------------------------------∆ TA where ∆TA is the rated operating free-air temperature range of the device. 2. The dynamic impedance is defined as |ZOUT| = ∆VCOMP/∆ILED. When the device is operating with two external resistors (see Figure 2), the total dynamic impedance of the circuit is given by: ∆V R1 Z OUT, TOT = ------- ≈ Z OUT × 1 + ------∆I R2 6 © 2003 Fairchild Semiconductor Corporation Page 3 of 13 8/27/03 OPTICALLY ISOLATED ERROR AMPLIFIER FOD2742A FOD2742B FOD2742C OUTPUT CHARACTERISTICS (TA = 25°C Unless otherwise specified.) Parameter Collector dark current Emitter-collector voltage breakdown Collector-emitter voltage breakdown Test Conditions (VCE = 10 V) (Fig. 5) (IE = 100 µA) (IC = 1.0mA) Symbol ICEO BVECO BVCEO 7 70 Min Typ 1 10 120 Max 50 Unit nA V V TRANSFER CHARACTERISTICS (TA = 25°C Unless otherwise specified.) Parameter Current transfer ratio Collector-emitter saturation voltage Test Conditions (ILED = 10 mA, VCOMP = VFB, VCE = 5 V) (Fig. 6) Symbol CTR Min 100 Typ 140 0.16 Max 200 0.4 Unit % V (ILED = 10 mA, VCOMP = VFB, VCE (SAT) IC = 2.5 mA) (Fig. 6) ISOLATION CHARACTERISTICS (TA = 25°C Unless otherwise specified.) Parameter Input-output insulation leakage current Withstand insulation voltage Resistance (input to output) Test Conditions (RH = 45%, TA = 25°C, t = 5s, VI-O = 3000 VDC) (note. 1) (RH 6.25K Ω ; R COLLECTOR select 12KΩ to allow some margin. Feedback Output voltage of a converter is determined by selecting a resistor divider from the regulated output to the FB pin. The FOD2742 attempts to regulate its FB pin to the reference voltage, 2.5V. The ratio of the two resistors should thus be: R TOP V OUT ------------------------- = -------------- – 1 R BOTTOM V REF The absolute value of the top resistor is set by the input offset current of 5.2µA. To achieve 0.5% accuracy, the resistance of RTOP should be: V OUT – 2.5 ---------------------------- > 1040 µ A R TOP © 2003 Fairchild Semiconductor Corporation Page 10 of 13 8/27/03 OPTICALLY ISOLATED ERROR AMPLIFIER FOD2742A Package Dimensions FOD2742B FOD2742C Footprint Drawing 0.164 (4.16) 0.144 (3.66) 0.024 (0.61) 1 0.202 (5.13) 0.182 (4.63) SEATING PLANE 0.060 (1.52) 0.275 (6.99) 0.155 (3.94) 0.143 (3.63) 0.123 (3.13) 0.010 (0.25) 0.006 (0.16) 0.021 (0.53) 0.011 (0.28) 0.008 (0.20) 0.003 (0.08) 0.050 (1.27) TYP 0.244 (6.19) 0.224 (5.69) 0.050 (1.27) Lead Coplanarity : 0.004 (0.10) MAX ORDERING INFORMATION Option R1 R1V R2 R2V Order Entry Identifier R1 R1V R2 R2V Tape and reel (500 units per reel) VDE0884, Tape and reel (500 units per reel) Tape and reel (2,500 units per reel) VDE0884, Tape and reel (2,500 units per reel) Description MARKING INFORMATION Definitions 1 2742A V 3 4 2 6 1 2 3 4 Fairchild logo Device number VDE mark (Note: Only appears on parts ordered with VDE option – See order entry table) One digit year code Two digit work week ranging from ‘01’ to ‘53’ Assembly package code X YY S 5 5 6 © 2003 Fairchild Semiconductor Corporation Page 11 of 13 8/27/03 OPTICALLY ISOLATED ERROR AMPLIFIER FOD2742A Carrier Tape Specifications FOD2742B FOD2742C 8.0 ± 0.10 3.50 ± 0.20 0.30 MAX 4.0 ± 0.10 2.0 ± 0.05 Ø1.5 MIN 1.75 ± 0.10 5.5 ± 0.05 8.3 ± 0.10 12.0 ± 0.3 5.20 ± 0.20 0.1 MAX 6.40 ± 0.20 Ø1.5 ± 0.1/-0 User Direction of Feed Reflow Profile 300 Temperature (°C) 250 200 150 100 50 0 0 0.5 1 1.5 2 2.5 245°C peak 230°C, 10–30 s Time above 183°C, 120–180 sec Ramp up = 2–10°C/sec • Peak reflow temperature: 245°C (package surface temperature) • Time of temperature higher than 183°C for 120–180 seconds • One time soldering reflow is recommended 3.5 4 4.5 3 Time (Minute) © 2003 Fairchild Semiconductor Corporation Page 12 of 13 8/27/03 OPTICALLY ISOLATED ERROR AMPLIFIER FOD2742A FOD2742B FOD2742C 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. 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. © 2003 Fairchild Semiconductor Corporation Page 13 of 13 8/27/03