LNK304-306 ® LinkSwitch-TN Family Lowest Component Count, Energy Efficient Off-Line Switcher IC Product Highlights Cost Effective Linear/Cap Dropper Replacement • Lowest cost and component count buck converter solution • Fully integrated auto-restart for short-circuit and open loop fault protection - saves external component costs • 66 kHz operation with accurate current limit - allows low cost off-the-shelf 1 mH inductor for up to 120 mA output current • Tight tolerances and negligible temperature variation • High breakdown voltage of 700 V provides excellent input surge withstand • Frequency jittering dramatically reduces EMI (~10 dB) minimizes EMI filter cost • High thermal shutdown temperature (+135 °C minimum) Much Higher Performance over Discrete Buck and Passive Solutions • Supports buck, buck-boost and flyback topologies • System level thermal overload, output short-circuit and open control loop protection • Excellent line and load regulation even with typical configuration • High bandwidth provides fast turn-on with no overshoot • Current limit operation rejects line ripple • Universal input voltage range (85 VAC to 265 VAC) • Built-in current limit and hysteretic thermal protection • Higher efficiency than passive solutions • Higher power factor than capacitor-fed solutions • Entirely manufacturable in SMD EcoSmart® – Extremely Energy Efficient • Consumes typically only 50/80 mW in self-powered buck topology at 115/230 VAC input with no load (opto feedback) • Consumes typically only 7/12 mW in flyback topology with external bias at 115/230 VAC input with no load • Meets Blue Angel, Energy Star, and EU requirements Applications • Appliances and timers • LED drivers and industrial controls Description LinkSwitch-TN is specifically designed to replace all linear and capacitor-fed (cap dropper) non-isolated power supplies in the under 360 mA output current range at equal system cost while offering much higher performance and energy efficiency. FB D + Wide Range HV DC Input BP S + DC Output LinkSwitch-TN PI-3492-111903 Figure 1. Typical Buck Converter Application (See Application Examples Section for Other Circuit Configurations). OUTPUT CURRENT TABLE(1) 230 VAC ±15% PRODUCT(4) MDCM(2) CCM(3) 85-265 VAC MDCM(2) CCM(3) LNK304P or G 120 mA 170 mA 120 mA 170 mA LNK305P or G 175 mA 280 mA 175 mA 280 mA LNK306P or G 225 mA 360 mA 225 mA 360 mA Table 1. Notes: 1. Typical output current in a non-isolated buck converter. Output power capability depends on respective output voltage. See Key Applications Considerations Section for complete description of assumptions, including fully discontinuous conduction mode (DCM) operation. 2. Mostly discontinuous conduction mode. 3. Continuous conduction mode. 4. Packages: P: DIP-8B, G: SMD-8B. Please see ordering information. LinkSwitch-TN devices integrate a 700 V power MOSFET, oscillator, simple On/Off control scheme, a high voltage switched current source, frequency jittering, cycle-by-cycle current limit and thermal shutdown circuitry onto a monolithic IC. The startup and operating power are derived directly from the voltage on the DRAIN pin, eliminating the need for a bias supply and associated circuitry in buck or flyback converters. The fully integrated auto-restart circuit safely limits output power during fault conditions such as short-circuit or open loop, reducing component count and system-level load protection cost. A local supply provided by the IC allows use of a non-safety graded optocoupler acting as a level shifter to further enhance line and load regulation performance in buck and buck-boost converters, if required. January 2004 LNK304-306 BYPASS (BP) DRAIN (D) REGULATOR 5.8 V FAULT PRESENT 49 µA AUTORESTART COUNTER CLOCK RESET + 5.8 V 4.85 V BYPASS PIN UNDER-VOLTAGE - CURRENT LIMIT COMPARATOR 6.3 V + VI - LIMIT JITTER CLOCK DCMAX OSCILLATOR FEEDBACK (FB) THERMAL SHUTDOWN 1.63 V -VTH S Q R Q LEADING EDGE BLANKING SOURCE (S) PI-2367-112503 Figure 2. Functional Block Diagram. Pin Functional Description DRAIN (D) Pin: Power MOSFET drain connection. Provides internal operating current for both start-up and steady-state operation. BYPASS (BP) Pin: Connection point for a 0.1 uF external bypass capacitor for the internally generated 5.8 V supply. FEEDBACK (FB) Pin: During normal operation, switching of the power MOSFET is controlled by this pin. MOSFET switching is terminated when a current greater than 49 µA is delivered into this pin. SOURCE (S) Pin: This pin is the power MOSFET source connection. It is also the ground reference for the BYPASS and FEEDBACK pins. 2 D 1/04 P Package (DIP-8B) G Package (SMD-8B) S 1 8 S S 2 7 S BP 3 FB 4 5 D PI-3491-111903 Figure 3. Pin Configuration. LNK304-306 LinkSwitch-TN combines a high voltage power MOSFET switch with a power supply controller in one device. Unlike conventional PWM (pulse width modulator) controllers, LinkSwitch-TN uses a simple ON/OFF control to regulate the output voltage. The LinkSwitch-TN controller consists of an oscillator, feedback (sense and logic) circuit, 5.8 V regulator, BYPASS pin undervoltage circuit, over-temperature protection, frequency jittering, current limit circuit, leading edge blanking and a 700 V power MOSFET. The LinkSwitch-TN incorporates additional circuitry for auto-restart. Oscillator The typical oscillator frequency is internally set to an average of 66 kHz. Two signals are generated from the oscillator: the maximum duty cycle signal (DCMAX) and the clock signal that indicates the beginning of each cycle. The LinkSwitch-TN oscillator incorporates circuitry that introduces a small amount of frequency jitter, typically 4 kHz peak-to-peak, to minimize EMI emission. The modulation rate of the frequency jitter is set to 1 kHz to optimize EMI reduction for both average and quasi-peak emissions. The frequency jitter should be measured with the oscilloscope triggered at the falling edge of the DRAIN waveform. The waveform in Figure 4 illustrates the frequency jitter of the LinkSwitch-TN. Feedback Input Circuit The feedback input circuit at the FB pin consists of a low impedance source follower output set at 1.65 V. When the current delivered into this pin exceeds 49 µA, a low logic level (disable) is generated at the output of the feedback circuit. This output is sampled at the beginning of each cycle on the rising edge of the clock signal. If high, the power MOSFET is turned on for that cycle (enabled), otherwise the power MOSFET remains off (disabled). Since the sampling is done only at the beginning of each cycle, subsequent changes in the FB pin voltage or current during the remainder of the cycle are ignored. pin through an external resistor. This facilitates powering of LinkSwitch-TN externally through a bias winding to decrease the no-load consumption to about 50 mW. BYPASS Pin Under-Voltage The BYPASS pin under-voltage circuitry disables the power MOSFET when the BYPASS pin voltage drops below 4.85 V. Once the BYPASS pin voltage drops below 4.85 V, it must rise back to 5.8 V to enable (turn-on) the power MOSFET. Over-Temperature Protection The thermal shutdown circuitry senses the die temperature. The threshold is set at 142 °C typical with a 75 °C hysteresis. When the die temperature rises above this threshold (142 °C) the power MOSFET is disabled and remains disabled until the die temperature falls by 75 °C, at which point it is re-enabled. Current Limit The current limit circuit senses the current in the power MOSFET. When this current exceeds the internal threshold (ILIMIT), the power MOSFET is turned off for the remainder of that cycle. The leading edge blanking circuit inhibits the current limit comparator for a short time (tLEB) after the power MOSFET is turned on. This leading edge blanking time has been set so that current spikes caused by capacitance and rectifier reverse recovery time will not cause premature termination of the switching pulse. Auto-Restart In the event of a fault condition such as output overload, output short, or an open loop condition, LinkSwitch-TN enters into auto-restart operation. An internal counter clocked by the oscillator gets reset every time the FB pin is pulled high. If the FB pin is not pulled high for 50 ms, the power MOSFET switching is disabled for 800 ms. The auto-restart alternately enables and disables the switching of the power MOSFET until the fault condition is removed. 600 500 PI-3660-081303 LinkSwitch-TN Functional Description V DRAIN 5.8 V Regulator and 6.3 V Shunt Voltage Clamp The 5.8 V regulator charges the bypass capacitor connected to the BYPASS pin to 5.8 V by drawing a current from the voltage on the DRAIN, whenever the MOSFET is off. The BYPASS pin is the internal supply voltage node for the LinkSwitch-TN. When the MOSFET is on, the LinkSwitch-TN runs off of the energy stored in the bypass capacitor. Extremely low power consumption of the internal circuitry allows the LinkSwitch-TN to operate continuously from the current drawn from the DRAIN pin. A bypass capacitor value of 0.1 µF is sufficient for both high frequency decoupling and energy storage. 400 300 200 100 0 68 kHz 64 kHz 20 0 In addition, there is a 6.3 V shunt regulator clamping the BYPASS pin at 6.3 V when current is provided to the BYPASS Time (µs) Figure 4. Frequency Jitter. D 1/04 3 LNK304-306 R1 13.0 kΩ 1% RF1 8.2 Ω 2W 85-265 VAC L2 1 mH D3 1N4007 D4 1N4007 FB D C4 4.7 µF 400 V C5 4.7 µF 400 V BP C1 100 nF R3 2.05 kΩ 1% S LinkSwitch-TN LNK304 C3 10 µF 35 V L1 1 mH 280 mA D1 UF4005 D2 1N4005GP 12 V, 120 mA C2 100 µF 16 V R4 3.3 kΩ RTN Figure 5. Universal Input, 12 V, 120 mA Constant Voltage Power Supply Using LinkSwitch-TN. Applications Example A 1.44 W Universal Input Buck Converter The circuit shown in Figure 5 is a typical implementation of a 12 V, 120 mA non-isolated power supply used in appliance control such as rice cookers, dishwashers or other white goods. This circuit may also be applicable to other applications such as night-lights, LED drivers, electricity meters, and residential heating controllers, where a non-isolated supply is acceptable. The input stage comprises fusible resistor RF1, diodes D3 and D4, capacitors C4 and C5, and inductor L2. Resistor RF1 is a flame proof, fusible, wire wound resistor. It accomplishes several functions: a) Inrush current limitation to safe levels for rectifiers D3 and D4; b) Differential mode noise attenuation; c) Input fuse should any other component fail short-circuit (component fails safely open-circuit without emitting smoke, fire or incandescent material). The power processing stage is formed by the LinkSwitch-TN, freewheeling diode D1, output choke L1, and the output capacitor C2. The LNK304 was selected such that the power supply operates in the mostly discontinuous-mode (MDCM). Diode D1 is an ultra-fast diode with a reverse recovery time (trr) of approximately 75 ns, acceptable for MDCM operation. For continuous conduction mode (CCM) designs, a diode with a trr of ≤35 ns is recommended. Inductor L1 is a standard off-theshelf inductor with appropriate RMS current rating (and acceptable temperature rise). Capacitor C2 is the output filter capacitor; its primary function is to limit the output voltage ripple. The output voltage ripple is a stronger function of the ESR of the output capacitor than the value of the capacitor itself. To a first order, the forward voltage drops of D1 and D2 are identical. Therefore, the voltage across C3 tracks the output voltage. The voltage developed across C3 is sensed and regulated via the resistor divider R1 and R3 connected to U1’s FB pin. The values of R1 and R3 are selected such that, at the desired output voltage, the voltage at the FB pin is 1.65 V. 4 D 1/04 PI-3757-112103 Regulation is maintained by skipping switching cycles. As the output voltage rises, the current into the FB pin will rise. If this exceeds IFB then subsequent cycles will be skipped until the current reduces below IFB. Thus, as the output load is reduced, more cycles will be skipped and if the load increases, fewer cycles are skipped. To provide overload protection if no cycles are skipped during a 50 ms period, LinkSwitch-TN will enter auto-restart, limiting the average output power to approximately 6% of the maximum overload power. Due to tracking errors between the output voltage and the voltage across C3 at light load or no load, a small pre-load may be required (R4). For the design in Figure 5, if regulation to zero load is required, then this value should be reduced to 2.4 kΩ. Key Application Considerations LinkSwitch-TN Design Considerations Output Current Table Data sheet maximum output current table (Table 1) represents the maximum practical continuous output current for both mostly discontinuous conduction mode (MDCM) and continuous conduction mode (CCM) of operation that can be delivered from a given LinkSwitch-TN device under the following assumed conditions: 1) Buck converter topology. 2) The minimum DC input voltage is ≥70 V. The value of input capacitance should be large enough to meet this criterion. 3) For CCM operation a KRP* of 0.4. 4) Output voltage of 12 VDC. 5) Efficiency of 75%. 6) A catch/freewheeling diode with trr ≤75 ns is used for MDCM operation and for CCM operation, a diode with trr ≤35 ns is used. 7) The part is board mounted with SOURCE pins soldered to a sufficient area of copper to keep the SOURCE pin temperature at or below 100 °C. *KRP is the ratio of ripple to peak inductor current. LNK304-306 LinkSwitch-TN RF1 D1 L2 D FB D2 R4 + BP AC INPUT C4 C5 S S S S C1 R3 C2 DC OUTPUT D1 D4 Optimize hatched copper areas ( L1 C3 ) for heatsinking and EMI. PI-3750-112103 Figure 6. Recommended Printed Circuit Layout for LinkSwitch-TN in a Buck Converter Configuration. LinkSwitch-TN Selection and Selection Between MDCM and CCM Operation Select the LinkSwitch-TN device, freewheeling diode and output inductor that gives the lowest overall cost. In general, MDCM provides the lowest cost and highest efficiency converter. CCM designs require a larger inductor and ultra-fast (trr <35 ns) freewheeling diode in all cases. It is lower cost to use a larger LinkSwitch-TN in MDCM than a smaller LinkSwitch-TN in CCM because of the additional external component costs of a CCM design. However, if the highest output current is required, CCM should be employed following the guidelines below. Topology Options LinkSwitch-TN can be used in all common topologies, with or without an opto-coupler and reference to improve output voltage tolerance and regulation. Table 2 provide a summary of these configurations. For more information see the Application Note – LinkSwitch-TN Design Guide. Component Selection Referring to Figure 5, the following considerations may be helpful in selecting components for a LinkSwitch-TN design. Freewheeling Diode D1 Diode D1 should be an ultra-fast type. For MDCM, reverse recovery time trr ≤75 ns should be used at a temperature of 70 °C or below. Slower diodes are not acceptable, as continuous mode operation will always occur during startup, causing high leading edge current spikes, terminating the switching cycle prematurely, and preventing the output from reaching regulation. If the ambient temperature is above 70 °C then a diode with trr ≤35 ns should be used. For CCM an ultra-fast diode with reverse recovery time trr ≤35 ns should be used. A slower diode may cause excessive leading edge current spikes, terminating the switching cycle prematurely and preventing full power delivery. Fast and slow diodes should never be used as the large reverse recovery currents can cause excessive power dissipation in the diode and/or exceed the maximum drain current specification of LinkSwitch-TN. Feedback Diode D2 Diode D2 can be a low-cost slow diode such as the 1N400X series, however it should be specified as a glass passivated type to guarantee a specified reverse recovery time. To a first order, the forward drops of D1 and D2 should match. Inductor L1 Choose any standard off-the-shelf inductor that meets the design requirements. A “drum” or “dog bone” “I” core inductor is recommended with a single ferrite element due to to its low cost and very low audible noise properties. The typical inductance value and RMS current rating can be obtained from the LinkSwitch-TN design spreadsheet available within the PI Expert design suite from Power Integrations. Choose L1 greater than or equal to the typical calculated inductance with RMS current rating greater than or equal to calculated RMS inductor current. Capacitor C2 The primary function of capacitor C2 is to smooth the inductor current. The actual output ripple voltage is a function of this capacitor’s ESR. To a first order, the ESR of this capacitor should not exceed the rated ripple voltage divided by the typical current limit of the chosen LinkSwitch-TN. D 1/04 5 LNK304-306 TOPOLOGY High-Side Buck – Direct Feedback BASIC CIRCUIT SCHEMATIC FB BP S D + KEY FEATURES + LinkSwitch-TN VIN 1) 2) 3) 4) Output referenced to input Positive output (VO) with respect to -VIN Step down – VO < VIN Low cost direct feedback (±10% typ.) VO PI-3751-121003 High-Side Buck – Optocoupler Feedback BP FB + D S + LinkSwitch-TN VO VIN PI-3752-121003 Low-Side Buck – Optocoupler Feedback + LinkSwitch-TN VO VIN BP FB D PI-3753-111903 + LinkSwitch-TN VF + VIN D R= FB VF PI-3754-112103 IO BP S D + LinkSwitch-TN VIN VO + PI-3755-121003 300 Ω RSENSE = 2 kΩ FB + D BP 2V IO RSENSE IO S LinkSwitch-TN VIN 10 µF 50 V 100 nF PI-3779-120803 Table 2. Common Circuit Configurations Using LinkSwitch-TN. 6 D 1/04 Output referenced to input Negative output (VO) with respect to +VIN Step down – VO < VIN Optocoupler feedback - Accuracy only limited by reference choice - Low cost non-safety rated opto - No pre-load required - Ideal for driving LEDs FB S High-Side Buck Boost – Constant Current LED Driver 1) 2) 3) 4) IO BP High-Side Buck Boost – Direct Feedback Output referenced to input Positive output (VO) with respect to -VIN Step down – VO < VIN Optocoupler feedback - Accuracy only limited by reference choice - Low cost non-safety rated opto - No pre-load required 5) Minimum no-load consumption + S Low-Side Buck – Constant Current LED Driver 1) 2) 3) 4) 1) 2) 3) 4) 5) Output referenced to input Negative output (VO) with respect to -VIN Step up/down – VO > VIN or VO < VIN Low cost direct feedback (±10% typ.) Fail-safe – output is not subjected to input voltage if the internal MOSFET fails 6) Ideal for driving LEDs - better accuracy and temperature stability than Low-side Buck constant current LED driver LNK304-306 TOPOLOGY Low-Side Buck Boost – Optocoupler Feedback BASIC CIRCUIT SCHEMATIC KEY FEATURES + LinkSwitch-TN VO VIN BP S FB D + PI-3756-111903 1) 2) 3) 4) Output referenced to input Positive output (VO) with respect to +VIN Step up/down – VO > VIN or VO < VIN Optocoupler feedback - Accuracy only limited by reference choice - Low cost non-safety rated opto - No pre-load required 5) Fail-safe – output is not subjected to input voltage if the internal MOSFET fails 6) Minimum no-load consumption Table 2 (cont). Common Circuit Configurations Using LinkSwitch-TN. Feedback Resistors R1 and R3 The values of the resistors in the resistor divider formed by R1 and R3 are selected to maintain 1.65 V at the FB pin. It is recommended that R3 be chosen as a standard 1% resistor of 2 kΩ. This ensures good noise immunity by biasing the feedback network with a current of approximately 0.8 mA. Feedback Capacitor C3 Capacitor C3 can be a low cost general purpose capacitor. It provides a “sample and hold” function, charging to the output voltage during the off time of LinkSwitch-TN. Its value should be 10 µF to 22 µF; smaller values cause poorer regulation at light load conditions. Pre-load Resistor R4 In high-side, direct feedback designs where the minimum load is <3 mA, a pre-load resistor is required to maintain output regulation. This ensures sufficient inductor energy to pull the inductor side of the feedback capacitor C3 to input return via D2. The value of R4 should be selected to give a minimum output load of 3 mA. In designs with an optocoupler the Zener or reference bias current provides a 1 mA to 2 mA minimum load, preventing “pulse bunching” and increased output ripple at zero load. LinkSwitch-TN Layout Considerations In the buck or buck-boost converter configuration, since the SOURCE pins in LinkSwitch-TN are switching nodes, the copper area connected to SOURCE should be minimized to minimize EMI within the thermal constraints of the design. In the boost configuration, since the SOURCE pins are tied to DC return, the copper area connected to SOURCE can be maximized to improve heatsinking. The loop formed between the LinkSwitch-TN, inductor (L1), freewheeling diode (D1), and output capacitor (C2) should be kept as small as possible. The BYPASS pin capacitor C1 (Figure 6) should be located physically close to the SOURCE (S) and BYPASS (BP) pins. To minimize direct coupling from switching nodes, the LinkSwitch-TN should be placed away from AC input lines. It may be advantageous to place capacitors C4 and C5 in-between LinkSwitch-TN and the AC input. The second rectifier diode D4 is optional, but may be included for better EMI performance and higher line surge withstand capability. Quick Design Checklist As with any power supply design, all LinkSwitch-TN designs should be verified for proper functionality on the bench. The following minimum tests are recommended: 1) Adequate DC rail voltage - check that the minimum DC input voltage does not fall below 70 VDC at maximum load, minimum input voltage. 2) Correct Diode Selection – UF400x series diodes are recommended only for designs that operate in MDCM at an ambient of 70 °C or below. For designs operating in continuous conduction mode (CCM) and/or higher ambients, then a diode with a reverse recovery time of 35 ns or better, such as the BYV26C, is recommended. 3) Maximum drain current - verify that the peak drain current is below the data sheet peak drain specification under worstcase conditions of highest line voltage, maximum overload (just prior to auto-restart) and highest ambient temperature. 4) Thermal check – at maximum output power, minimum input voltage and maximum ambient temperature, verify that the LinkSwitch-TN SOURCE pin temperature is 100 °C or below. This figure ensures adequate margin due to variations in RDS(ON) from part to part. A battery powered thermocouple D 1/04 7 LNK304-306 meter is recommended to make measurements when the SOURCE pins are a switching node. Alternatively, the ambient temperature may be raised to indicate margin to thermal shutdown. 8 D 1/04 In a LinkSwitch-TN design using a buck or buck boost converter topology, the SOURCE pin is a switching node. Oscilloscope measurements should therefore be made with probe grounded to a DC voltage, such as primary return or DC input rail, and not to the SOURCE pins. The power supply input must always be supplied from an isolated source (e.g. via an isolation transformer). LNK304-306 ABSOLUTE MAXIMUM RATINGS(1,5) DRAIN Voltage ....................................... - 0.3 V to 700 V Peak DRAIN Current (LNK304) ....... 400 mA (750 mA)(2) Peak DRAIN Current (LNK305) ..... 800 mA (1500 mA)(2) Peak DRAIN Current (LNK306) ... 1400 mA (2600 mA)(2) FEEDBACK Voltage ................................... - 0.3 V to 9 V FEEDBACK Current ............................................. 100 mA BYPASS Voltage .......................................... -0.3 V to 9 V Storage Temperature ................................ -65 °C to 150 °C Operating Junction Temperature(3) ........... -40 °C to 150 °C Lead Temperature(4) ................................................ 260 °C Notes: 1. All voltages referenced to SOURCE, TA = 25 °C. 2. The higher peak DRAIN current is allowed if the DRAIN to SOURCE voltage does not exceed 400 V. 3. Normally limited by internal circuitry. 4. 1/16” from case for 5 seconds. 5. Maximum ratings specified may be applied, one at a time, without causing permanent damage to the product. Exposure to Absolute Maximum Rating conditions for extended periods of time may affect product reliability. THERMAL IMPEDANCE Thermal Impedance: P/G Package: Notes: (θJA) ........ 70 °C/W(2); 60 °C/W(3) 1. Measured on pin 2 (SOURCE) close to plastic interface. (θJC)(1) .......................... 11 °C/W 2. Soldered to 0.36 sq. inch (232 mm2), 2oz. (610 g/m2) copper clad. 3. Soldered to 1 sq. inch (645 mm2), 2oz. (610 g/m2) copper clad. Conditions Parameter Symbol SOURCE = 0 V; TJ = -40 to 125 °C See Figure 7 (Unless Otherwise Specified) Min Typ Max 62 66 70 Units CONTROL FUNCTIONS Average Output Frequency fOSC Maximum Duty Cycle DCMAX S2 Open 66 69 72 % IFB TJ = 25 °C 30 49 68 µA VFB IFB = 49 µA 1.54 1.65 1.76 V IS1 VFB ≥2 V (MOSFET Not Switching) See Note A 160 220 µA LNK304 200 260 LNK305 220 280 LNK306 250 310 FEEDBACK Pin Turnoff Threshold Current FEEDBACK Pin Voltage DRAIN Supply Current IS2 TJ = 25 °C Peak-Peak Jitter FEEDBACK Open (MOSFET Switching) See Notes A, B 4 kHz µA D 1/04 9 LNK304-306 Conditions Parameter Symbol SOURCE = 0 V; TJ = -40 to 125 °C See Figure 7 (Unless Otherwise Specified) Min Typ Max Units CONTROL FUNCTIONS (cont.) ICH1 BYPASS Pin Charge Current ICH2 VBP = 0 V TJ = 25 °C See Note C LNK304 -5.5 -3.3 -1.8 LNK305 -7.5 -4.6 -2.5 LNK306 -7.5 -4.6 -2.5 VBP = 4 V TJ = 25 °C See Note C LNK304 -3.8 -2.3 -1.0 LNK305 -4.5 -3.3 -1.5 LNK306 -4.5 -3.3 -1.5 mA BYPASS Pin Voltage VBP 5.55 5.8 6.10 V BYPASS Pin Voltage Hysteresis VBPH 0.8 0.95 1.2 V BYPASS Pin Supply Current IBPSC 68 See Note D µA CIRCUIT PROTECTION di/dt = 65 mA/µs TJ = 25 °C Current Limit ILIMIT (See Note E) 240 257 275 di/dt = 415 mA/µs TJ = 25 °C 271 308 345 di/dt = 75 mA/µs TJ = 25 °C 350 375 401 di/dt = 500 mA/µs TJ = 25 °C di/dt = 95 mA/µs TJ = 25 °C di/dt = 610 mA/µs TJ = 25 °C Minimum On Time tON(MIN) Leading Edge Blanking Time tLEB Thermal Shutdown Temperature TSD Thermal Shutdown Hysteresis TSHD 10 D 1/04 TJ = 25 °C See Note F See Note G LNK304 mA LNK305 396 450 504 450 482 515 508 578 647 LNK304 280 360 475 LNK305 360 460 610 LNK306 400 500 675 170 215 135 142 LNK306 75 ns ns 150 °C °C LNK304-306 Conditions Parameter Symbol Typ Max TJ = 25 °C 24 27.6 TJ = 100 °C 38 44.2 TJ = 25 °C 12 13.8 TJ = 100 °C 19 22.1 TJ = 25 °C 7 8.1 TJ = 100 °C 11 12.9 SOURCE = 0 V; TJ = -40 to 125 °C See Figure 7 (Unless Otherwise Specified) Min Units OUTPUT LNK304 ID = 25 mA On-State Resistance RDS(ON) LNK305 ID = 35 mA LNK306 ID = 45 mA OFF-State Drain Leakage Current IDSS Breakdown Voltage BVDSS Rise Time tR Fall Time tF VBP = 6.2 V, VFB ≥2 V, VDS = 560 V, TJ = 125 °C LNK305 50 70 LNK306 90 VBP = 6.2 V, VFB ≥2 V TJ = 25 °C 700 µA V 50 ns 50 ns Measured in a Typical Buck Converter Application DRAIN Supply Voltage Output Enable Delay Output Disable Setup Time LNK304 Ω 50 tEN tAR Auto-Restart Duty Cycle DCAR 10 See Figure 9 tDST Auto-Restart ON-Time V TJ = 25 °C See Note H µs 0.5 µs 50 ms 6 % D 1/04 11 LNK304-306 NOTES: A. Total current consumption is the sum of IS1 and IDSS when FEEDBACK pin voltage is ≥2 V (MOSFET not switching) and the sum of IS2 and IDSS when FEEDBACK pin is shorted to SOURCE (MOSFET switching). B Since the output MOSFET is switching, it is difficult to isolate the switching current from the supply current at the DRAIN. An alternative is to measure the BYPASS pin current at 6 V. C. See Typical Performance Characteristics section Figure 14 for BYPASS pin start-up charging waveform. D. This current is only intended to supply an optional optocoupler connected between the BYPASS and FEEDBACK pins and not any other external circuitry. E. For current limit at other di/dt values, refer to Figure 13. F. This parameter is guaranteed by design. G. This parameter is derived from characterization. H. Auto-restart on time has the same temperature characteristics as the oscillator (inversely proportional to frequency). 470 Ω 5W 2 MΩ D S1 FB S2 BP 50 V S S S S 150 V 0.1 µF PI-3490-111903 Figure 7. LinkSwitch-TN General Test Circuit. DCMAX t2 (internal signal) tP t1 HV 90% 90% FB DRAIN VOLTAGE t D= 1 t2 VDRAIN tEN 10% 0V t = P 1 fOSC PI-3707-112503 PI-2048-033001 Figure 8. LinkSwitch-TN Duty Cycle Measurement. 12 D 1/04 Figure 9. LinkSwitch-TN Output Enable Timing. LNK304-306 Typical Performance Characteristics 1.0 PI-2680-012301 1.2 Output Frequency (Normalized to 25 °C) PI-2213-012301 1.0 0.8 0.6 0.4 0.2 0.9 0 -50 -25 0 25 50 75 100 125 150 -50 -25 Junction Temperature (°C) 0.8 Normalized di/dt di/dt = 1 di/dt = 6 0.4 0.2 0 -50 100 125 PI-3710-112103 1.2 1.0 0.8 0.6 LNK304 LNK305 LNK306 0.4 Normalized di/dt = 1 65 mA/µs 75 mA/µs 95 mA/µs Normalized Current Limit = 1 257 mA 375 mA 482 mA 0.2 0 0 50 100 1 150 2 3 4 5 6 Normalized di/dt Temperature (°C) Figure 13. Current Limit vs. di/dt. PI-2240-012301 7 6 5 4 3 2 1 0 400 350 DRAIN Current (mA) Figure 12. Current Limit vs. Temperature at Normalized di/dt. BYPASS Pin Voltage (V) 75 1.4 Normalized Current Limit 1.0 0.6 50 Figure 11. Frequency vs. Temperature. PI-3709-111203 Current Limit (Normalized to 25 °C) 1.2 25 Junction Temperature (°C) Figure 10. Breakdown vs. Temperature. 1.4 0 PI-3661-090303 Breakdown Voltage (Normalized to 25 °C) 1.1 25 °C 300 100 °C 250 200 150 Scaling Factors: LNK304 1.0 LNK305 2.0 LNK306 3.4 100 50 0 0 0.2 0.4 0.6 0.8 Time (ms) Figure 14. BYPASS Pin Start-up Waveform. 1.0 0 2 4 6 8 10 12 14 16 18 20 DRAIN Voltage (V) Figure 15. Output Characteristics. D 1/04 13 LNK304-306 Typical Performance Characteristics (cont.) PI-3711-110303 Drain Capacitance (pF) 1000 100 Scaling Factors: LNK304 1.0 LNK305 2.0 LNK306 3.4 10 1 0 100 200 300 400 500 600 Drain Voltage (V) Figure 16. COSS vs. Drain Voltage. PART ORDERING INFORMATION LinkSwitch Product Family TN Series Number Package Identifier G Plastic Surface Mount DIP P Plastic DIP Package/Lead Options LNK 304 G - TL Blank TL 14 D 1/04 Standard Configurations Tape & Reel, 1 k pcs minimum, G Package only LNK304-306 DIP-8B ⊕ D S .004 (.10) Notes: 1. Package dimensions conform to JEDEC specification MS-001-AB (Issue B 7/85) for standard dual-in-line (DIP) package with .300 inch row spacing. 2. Controlling dimensions are inches. Millimeter sizes are shown in parentheses. 3. Dimensions shown do not include mold flash or other protrusions. Mold flash or protrusions shall not exceed .006 (.15) on any side. 4. Pin locations start with Pin 1, and continue counter-clockwise to Pin 8 when viewed from the top. The notch and/or dimple are aids in locating Pin 1. Pin 6 is omitted. 5. Minimum metal to metal spacing at the package body for the omitted lead location is .137 inch (3.48 mm). 6. Lead width measured at package body. 7. Lead spacing measured with the leads constrained to be perpendicular to plane T. -E- .240 (6.10) .260 (6.60) Pin 1 -D- .367 (9.32) .387 (9.83) .125 (3.18) .145 (3.68) .057 (1.45) .068 (1.73) (NOTE 6) .015 (.38) MINIMUM -TSEATING PLANE .100 (2.54) BSC .008 (.20) .015 (.38) .120 (3.05) .140 (3.56) .300 (7.62) BSC (NOTE 7) .300 (7.62) .390 (9.91) .048 (1.22) .053 (1.35) .014 (.36) .022 (.56) ⊕ T E D S .010 (.25) M P08B PI-2551-041003 SMD-8B ⊕ D S .004 (.10) -E- .372 (9.45) .388 (9.86) ⊕ E S .010 (.25) .240 (6.10) .260 (6.60) Pin 1 .100 (2.54) (BSC) -D- .367 (9.32) .387 (9.83) .057 (1.45) .068 (1.73) (NOTE 5) .125 (3.18) .145 (3.68) .032 (.81) .037 (.94) .048 (1.22) .053 (1.35) Notes: 1. Controlling dimensions are inches. Millimeter sizes are shown in parentheses. 2. Dimensions shown do not include mold flash or other protrusions. Mold flash or protrusions shall not exceed .006 (.15) on any side. .420 3. Pin locations start with Pin 1, and continue counter-clock .046 .060 .060 .046 Pin 8 when viewed from the top. Pin 6 is omitted. 4. Minimum metal to metal .080 spacing at the package body Pin 1 for the omitted lead location is .137 inch (3.48 mm). .086 5. Lead width measured at .186 package body. .286 6. D and E are referenced Solder Pad Dimensions datums on the package body. .004 (.10) .009 (.23) .004 (.10) .012 (.30) .036 (0.91) .044 (1.12) 0°- 8° G08B PI-2546-080703 D 1/04 15 LNK304-306 Revision Notes Date C Release Final Data Sheet. 12/03 D Corrected Minimum On Time. 1/04 For the latest updates, visit our Web site: www.powerint.com PATENT INFORMATION Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it convey any license under its patent rights or the rights of others. The products and applications illustrated herein (including circuits external to the products and transformer construction) may be covered by one or more U.S. and foreign patents or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A complete list of Power Integrations’ patents may be found at www.powerint.com. LIFE SUPPORT POLICY POWER INTEGRATIONS' PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF POWER INTEGRATIONS. As used herein: 1. Life support devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and 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 to the user. 2. A critical component is 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. The PI logo, TOPSwitch, TinySwitch, LinkSwitch and EcoSmart are registered trademarks of Power Integrations. PI Expert and DPA-Switch are trademarks of Power Integrations. ©Copyright 2004, Power Integrations WORLD HEADQUARTERS Power Integrations 5245 Hellyer Avenue San Jose, CA 95138, USA. Main: +1-408-414-9200 Customer Service: Phone: +1-408-414-9665 Fax: +1-408-414-9765 e-mail: [email protected] CHINA (SHENZHEN) Power Integrations International Holdings, Inc. Rm# 1705, Bao Hua Bldg. 1016 Hua Qiang Bei Lu Shenzhen Guangdong, 518031, China Phone: +86-755-8367-5143 Fax: +86-755-8377-9610 e-mail: [email protected] ITALY Power Integrations S.r.l. Via Vittorio Veneto 12, Bresso Milano, 20091, Italy Phone: +39-028-928-6001 Fax: +39-028-928-6009 e-mail: [email protected] SINGAPORE (ASIA PACIFIC HEADQUARTERS) Power Integrations, Singapore 51 Newton Road #15-08/10 Goldhill Plaza Singapore, 308900 Phone: +65-6358-2160 Fax: +65-6358-2015 e-mail: [email protected] AMERICAS Power Integrations 4335 South Lee Street, Suite G Buford, GA 30518, USA Phone: +1-678-714-6033 Fax: +1-678-714-6012 e-mail: [email protected] GERMANY Power Integrations GmbH Rueckerstrasse 3 D-80336, Muenchen, Germany Phone: +49-895-527-3910 Fax: +49-895-527-3920 e-mail: [email protected] JAPAN Power Integrations, K.K. Keihin-Tatemono 1st Bldg. 12-20 Shin-Yokohama 2-Chome, Kohoku-ku, Yokohama-shi, Kanagawa 222-0033, Japan Phone: +81-45-471-1021 Fax: +81-45-471-3717 e-mail: [email protected] TAIWAN Power Integrations International Holdings, Inc. 5F-1, No. 316, Nei Hu Rd., Sec. 1 Nei Hu Dist. Taipei, Taiwan 114, R.O.C. Phone: +886-2-2659-4570 Fax: +886-2-2659-4550 e-mail: [email protected] CHINA (SHANGHAI) Power Integrations International Holdings, Inc. Rm 807, Pacheer Commercial Centre 555 Nanjing West Road Shanghai, 200041, China Phone: +86-21-6215-5548 Fax: +86-21-6215-2468 e-mail: [email protected] INDIA (TECHNICAL SUPPORT) Innovatech 261/A, Ground Floor 7th Main, 17th Cross, Sadashivanagar Bangalore 560080 Phone: +91-80-5113-8020 Fax: +91-80-5113-8023 e-mail: [email protected] APPLICATIONS HOTLINE World Wide +1-408-414-9660 APPLICATIONS FAX World Wide +1-408-414-9760 16 D 1/04 KOREA Power Integrations International Holdings, Inc. 8th Floor, DongSung Bldg. 17-8 Yoido-dong, Youngdeungpo-gu, Seoul, 150-874, Korea Phone: +82-2-782-2840 Fax: +82-2-782-4427 e-mail: [email protected] UK (EUROPE & AFRICA HEADQUARTERS) Power Integrations (Europe) Ltd. 1st Floor, St. James’s House East Street Farnham Surrey GU9 7TJ United Kingdom Phone: +44 (0) 1252-730-140 Fax: +44 (0) 1252-727-689 e-mail: [email protected]