TS4305 SEMTECH | Alldatasheet
Document overview
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- PDF pages: 13
Technical content
Features
- Current-sense control for low or high-side synchronous rectifiers
- Rectifier turn on/off thresholds set with external resistors
- Minimum ON and OFF time to minimize GATE turn- on oscillation
- UVLO configurable to 9V or 4V
- Wide supply range 4.5V to 24V
- Gate drive internally limited to 5V or 10V
- 2A sink, 1A source gate drive
- 2mm x 2mm DFN-8 & 4mm x 5mm SOIC-8 packages
- Product is lead-free, Halogen Free, RoHS / WEEE compliant
Applications
- LLC converters
- Flyback converters
Description
TS4305 is a synchronous rectifier controller for AC -DC power supply’s secondary side rectification. Specifications
- Drives low or high side N-channel MOSFET
- Sync-FET control based on current sensing in low or high-side sense resistor
- -40°C to +125°C T J operation
- Operation to 24V
- 2A/1A sink/source gate drive
- 5 V or 10V gate drive capability
- 100ns propagation delay between current sense to GATE drive
- 180μA (typical) quiescent current in low power mode
- Under voltage lock out protection
- Over temperature shut down (TSD) protection Typical Application Circuit Vout GND Cvccbypass Flyback Converter Controller ISENSE VSS VCC AC DRIVE Snubber CS_GND CS VDD _BYP HI ISET GATE VCC GND TS4305 Rsense 22Ω Ciset Rfeedback Rgain Rhyst 1Meg FB Vout feedback Cbypass
Final Datasheet Rev 2.0 August 29, 2017 2 of 13 Semtech Pin Configuration DFN-8 (Top View) SOIC-8 (Top View) Pin Configuration DFN-8/SOIC-8 Pin # Pin Name Function Description
1 CS_GND Current Sense Current sense resistor high- side terminal
2 CS Current Sense Current sense resistor low-side terminal
3 VDD_BYP Power Bypass External bypass capacitor fo r internal 5V VDD supply
4 HI Vendor Test Mode Tie to VCC through 1Meg resis tor
5 GND Ground Circuit Common
6 VCC Power Input Supply voltage
7 GATE FET Gate Drive Gate drive, regulated voltage swing
8 ISET Current Sense Output Current sense in voltag e form using Rfeedback
Final Datasheet Rev 2.0 August 29, 2017 3 of 13 Semtech Functional Block Diagram Functional Diagram Configured in QR Flyback application
Final Datasheet Rev 2.0 August 29, 2017 4 of 13 Semtech Absolute Maximum Ratings Over operating free–air temperature range unless otherwise noted (1, 2) Parameter Value Unit VCC -0.3 to 26 V GATE -0.3 to 12 V ISET, CS, HI, VDD_BYP -0.3 to 5.5 V Electrostatic Discharge – Human Body Model +/-2k V Electrostatic Discharge – Charge Device Model +/-500 V Reflow or solder Temperature (soldering, 10 seconds) 260 °C (1) Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute–maximum–rated conditions for extended periods may affect device reliability. (2) All voltage values are with respect to GND. Thermal Characteristics DFN-8 Symbol Parameter Value Unit θJA Thermal Resistance Junction to Air (1) 70 °C/W TSTG Storage Temperature Range -65 to 150 °C TJ MAX Maximum Junction Temperature 150 °C TA Operating Ambient Temperature Range -20 to 85 °C TJ Operating Junction Temperature Range -20 to 125 °C (1) Assumes 8LD DFN mounted on a 4-layer FR4 2S2P JEDEC board as per JESD51-7 with 13.5 inch 2 of 1 oz Cu. Thermal Characteristics SOIC-8 Symbol Parameter Value Unit θJA Thermal Resistance Junction to Air (1) 153 °C/W TSTG Storage Temperature Range -65 to 150 °C TJ MAX Maximum Junction Temperature 150 °C TA Operating Ambient Temperature Range -40 to 85 °C TJ Operating Junction Temperature Range -40 to 125 °C (1) Assumes 8LD SOIC mounted on a 1-layer FR4 2S2P JEDEC board as per JESD51-7 with 13.5 inch 2 of 1 oz Cu. Recommended Operating Conditions Symbol Parameter Min Typ Max Unit VCC Input Operating Voltage 4.5 24 V CS dv/dt CS Input Slew Rate 10 V/ms CS Input CS Input voltage with respect to GND 100 mV CVCCBYP1 VCC Bypass Capacitor , appropriate voltage rating per VCC 10 µF CVCCBYP2 VCC Bypass Capacitor , appropriate voltage rating per VCC 10 pF Cbyp Internal 5V VDD Bypass Capacitor 1 µF Fswitch Maximum Gate Drive Switching Frequency 150 kHz
Final Datasheet Rev 2.0 August 29, 2017 5 of 13 Semtech
Electrical Characteristics
TJ = 25°C for typical, TJ = -40°C to 125°C, unless otherwise noted Symbol Parameter Condition Min Typ Max Unit Current Sense Amplifier VREF 2.0V Comparator reference TJ=0°C to +85°C 1.99 2 2.01 V TJ=-40°C to +125°C 1.95 2 2.05 V Supply VCC Supply voltage 4.5 24 V Isupply Quiescent supply current CS amp = Off during lockout time period 180 300 µA VLGC Internal LV supply for logic 5 V TSD Thermal shutdown temperature (1) 135 °C Under Voltage Lock Out VUVLO_ON UV Turn On Threshold (VCC) 10V Gate Drive 8 9 10 V 5V Gate Drive 3.7 4.2 4.7 V VUVLO_OFF UV Turn Off Threshold (VCC) 10V Gate Drive 7.5 8.5 9.5 V 5V Gate Drive 3.4 3.9 4.4 V VUVLO_hyst UVLO hysteresis 10V Gate Drive 0.35 1.0 V 5V Gate Drive 0.25 0.65 V Gate Drive VGATE Gate drive voltage 10V Gate Drive , VCC > 1 3V 7.75 10 13 V 5V Gate Drive, VCC > 13V 4.3 5 6.5 V RDRVHI Gate drive source resistance VCC>13V, Gate=10V, T J=25°C, IL=50mA 7.2 17 Ω VCC= 4.5 V, Gate=5V, T J=25°C , IL=100mA 8.1 11 Ω RDRVLO Gate drive sink resistance VCC>13 V, Gate =10V, T J=25°C 2.1 3.1 Ω VCC= 4.5 V, Gate=5V, T J=25°C 1.9 2.9 Ω tprop_dly Propagation delay from CS to GATE -20mV step, R sense =5mΩ, R gain =5Ω, R feedback =10kΩ 53 ns Ton_ pulse Minimum gate ON pulse width 0.8 1.3 1.8 µs Toff blanking Minimum gate OFF blanking width 1.0 2.3 4.6 µs (1) Not tested in production
Final Datasheet Rev 2.0 August 29, 2017 6 of 13 Semtech Detailed Description of Operation TS4305 is intended for use on the secondary side of a power supply to drive a synchronous MOSFET. Unli ke traditional synchronous MOSFET controllers, the TS4305 uses an architecture that synchronizes the rectification FE T with the secondary- side current as opposed to the secondary side volta ge. Because secondary side current and voltage are not necessarily in phase, the zero current detection method yields to a more efficient operation as opposed to operation with voltage detection only. Synchronous Rectifier Control The TS4305 uses a current mirror in conjunction wit h a high-sensitivity, low-offset voltage op-amp spe cifically designed for sensing voltages near the low-side supply rail. This op-amp operates over a small range of input voltage suited specifically for converting the voltage across a low-ohmic sense resistor to current. The equivalent circuit is shown below with typical values for external components: In the above figure, the syncFET current flows through an external 5mΩ. There is also an external gain resistor Rgain = 5Ω and a feedback resistor Rfeedback = 10kΩ. The amplifie r inside the TS4305 holds the voltage at the CS pin close to the GND pin over a small operating range in which isync_FET is positive. Over this operating range, the voltag e at ISET will be equal to (isync_FET x5mΩ)x(10kΩ/5Ω). TS4305 contains a comparator that compares the volt age at ISET to an internal reference which is set t o 2.0V at T J=25 °C. In the example shown above, when VREF = 2V, the curren t trip level would be 200mA. This level can be adju sted by changing Rsense, Rgain, and Rfeedback. A hysteresis resistor can also be connected between the gate drive output and ISET to provide hysteres is in the ON/OFF trip values. In this case, the gate turn on is expected when I sync_FET is greater than: Isync ≳ 2 ∗ (||ℎ Using the example values Rgain = 5Ω, Rsense=5mΩ, Rfeedback = 10kΩ, Rhysteresis=100kΩ, Isync ≳ 220#$. TS4305
Final Datasheet Rev 2.0 August 29, 2017 7 of 13 Semtech The gate will turn off when I sync_FET falls below the level according to: Isync && ≲ () 2.0 − + − 2.0 ℎ , ∗ - Which yields Isync && ≲ 120#$ using the same example values with the Vgate=10V gate drive option. If the signal frequency on the ISET pin is above approximately 200kHz at 27°C (~150kHz at -40°C and ~300kHz at 125°C), the gate driver output will latch low to prevent the synchronous FET from operating. This condition is maintained until VCC is power cycled. TS4305 can also be configured for sensing voltages on the high-side supply rail. One possible impleme ntation can be accomplished by powering TS4305 through an auxiliar y winding and diode-capacitor filter as shown below . Alternative charge pump schemes can also be contemplated. High-side Rectification with auxiliary winding and diode-capacitor filter to power TS4305
Final Datasheet Rev 2.0 August 29, 2017 8 of 13 Semtech Application Schematic Component Schematic Value Notes R1 1Meg Ω HI pin tie off to VCC R3 2Ω Gate resistor R8 10 Ω Snubber resistor, sized for proper power RCS 5m Ω Sense resistor RG 5.1 Ω Rgain resistor RISET 10k Ω Iset resistor RHYS 100k Ω Hysteresis resistor C1 1μF Internal 5V filter capacitor C2 10 μF 25V VCC filter capacitor C3 22pF 25V VCC filter capacitor C5 10 μF 25V VCC filter capacitor C6 1nF Snubber capacitor, rated for proper Vds Q1 Power NMOS, with proper Vds rating D1 100V schottky diode U1 TS4305 DFN/SOIC, 5V or 10V Gate Drive
Final Datasheet Rev 2.0 August 29, 2017 9 of 13 Semtech Package Drawing: 2.0 x 2.0 mm MLPD(DFN), 8 lead Package Marking: 2.0 x 2.0 mm MLPD(DFN), 8 lead b bbb aaa N L e D DIM A 0.30 0.18 0.25 0.40 0.20 0.08 0.10 0.30 2.00
0.50 BSC
0.05 1.00 DIMENSIONS MIN 0.00 NOM 0.80 0.02 (0.20) 0.90 CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). NOTES: 2.00 PIN 1 INDICATOR (LASER MARK) SEATING PLANE C BA aaa C N E 2.10 2.10 1.90 1.90 D e/2 e bxN bbb C A B COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. 2. D1 1.55 1.70 1.80 E1 0.75 0.90 1.00 D/2 E/2 E A LxN
Final Datasheet Rev 2.0 August 29, 2017 10 of 13 Semtech Landing Pattern: 2.0 x 2.0 mm MLPD(DFN), 8 lead 0.70 2.70 (2.00) 1.30 0.30 0.50 THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. NOTES: DIMENSIONS P Z X Y C G DIM MILLIMETERS FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD3. H 1.70 K 0.90 P X 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). (C) G Y Z P/2 H K
Final Datasheet Rev 2.0 August 29, 2017 11 of 13 Semtech Package Drawing: SOIC-8
Final Datasheet Rev 2.0 August 29, 2017 12 of 13 Semtech Package Marking: SOIC-8 T45 yyww xxxxx Top Mark TS4305ASTRT (SOIC 8 lead): T45 = Part Number yyww = Date Code xxxxx = Semtech Lot No. 43B yyww xxxxx Top Mark TS4305BSTRT (SOIC 8 lead): 43B = Part Number yyww = Date Code xxxxx = Semtech Lot No. Landing Pattern: SOIC-8
Ordering Information
Device Part Number Description Package TS4305AMLTRT 5V Gate Drive, 8ms lockout period MLPD(DFN)-8 2x2mm Tape & Reel (3,000 parts/reel) TS4305BMLTRT 10V Gate Drive, 8ms lockout period MLPD(DFN)-8 2x2mm Tape & Reel (3,000 parts/reel) TS4305ASTRT 5V Gate Drive, 8ms lockout period SOIC-8 Tape & Reel (2,500 parts/reel) TS4305BSTRT 10V Gate Drive, 8ms lockout period SOIC-8 Tape & Reel (2,500 parts/reel)
Final Datasheet Rev 2.0 August 29, 2017 13 of 13 Semtech IMPORTANT NOTICE Information relating to this product and the application or design described herein is believed to be reliable, however such information is provided as a guide only and Semtech assumes no liability for any errors in this document, or for the application or design described herein. Semtech reserves the right to make changes to the product or this document at any time without notice. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. Semtech warrants performance of its products to the specifications applicable at the time of sale, and all sales are made in accordance with Semtech’s standard terms and conditions of sale. SEMTECH PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHOR IZED OR WARRANTED TO BE SUITABLE FOR USE IN LIFE- SUPPORT APPLICATIONS, DEVICES OR SYSTEMS, OR IN NUC LEAR APPLICATIONS IN WHICH THE FAILURE COULD BE REASONABLY EXPECTED TO RESULT IN PERSONAL INJURY, L OSS OF LIFE OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. INCLUSION OF SEMTECH PRODUCTS IN SUCH APPLI CATIONS IS UNDERSTOOD TO BE UNDERTAKEN SOLELY AT TH E CUSTOMER’S OWN RISK. Should a customer purchase or use Semtech products for any such unauthorized application, the customer shall indemnify and hold Semtech and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs damages and attorney fees which could arise. The Semtech name and logo are registered trademarks of the Semtech Corporation. All other trademarks and trade names mentioned may be marks and names of Semtech or their respective companies. Semtech reserves the right to make changes to, or discontinue any products described in this document without further notice. Semtech makes no warranty, representation or guarantee, express or implied, regarding the suitability of its products for any particular purpose. All rights reserved. © Semtech 2017 Contact Information Semtech Corporation
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