SC4620MLTRT Semtech, SC4620MLTRT Datasheet
SC4620MLTRT
Specifications of SC4620MLTRT
Related parts for SC4620MLTRT
SC4620MLTRT Summary of contents
Page 1
... MLPQ-20 packages- WEEE and RoHS compliant Applications Low Voltage Distributed DC-DC Converters Telecommunication Power Supplies Portable Equipment xDSL C11 C11 PVIN SYNC/ PGOOD VCC C3 C3 SC4620 SC4620 SS ISET FS COMP R11 R3 R11 SC4620 2 1 Vout www.semtech.com ...
Page 2
... B 20Pin MLPQ A θ = 29°C/W; θ 2008 Semtech Corp Ordering Information SC4620MLTRT SC4620EVB-MLPQ 16 PGND 15 Notes: (1) Available in tape and reel only. A reel contains 3,000 devices for MLPQ-20 PGND package. (2) Available in lead-free package only. Device is WEEE and RoHS compliant. AGND VCC 2.5°C/W. ...
Page 3
... Input Voltage Operating Range Ambient Temperature Range Junction Temperature Max. Output Current Electrical Characteristics Unless otherwise specified =SYNC/EN=3.3V Parameter Power Supply Start Threshold Voltage, UVLO Hysteresis Voltage, UVLO Supply Current, Shutdown Supply Current, Operating 2008 Semtech Corp. Symbol Symbol Conditions OUTMAX =51.1KΩ, R =27.4KΩ ...
Page 4
... Error Amplifier Open Loop Voltage Gain (1) Error Amplifier Unity Gain Bandwidth Output Voltage Slew Rate, COMP Source Output Current, COMP Sink Output Current, COMP Output Voltage High, COMP 2008 Semtech Corp. =51.1KΩ, R =27.4KΩ -40°C to 85°C. OSC ISET A Symbol ...
Page 5
... Power Switches High-Side P-MOSFET Low Side N-MOSFET Power Good PGood Voltage Low PGood Leakage Current PGood Delay Time (1) PGood High Window Note: (1) Guaranteed by design. 2008 Semtech Corp. =51.1KΩ, R =27.4KΩ -40°C to 85°C. OSC ISET A Symbol Conditions FB = 0.6V, I COMP V 0 ° ...
Page 6
... Figure 1. Start Shutdown by Vin Test condition: 5Vin, 1Vo, Io=0A 5V/DIV 5V/DIV 0.5V/DIV 5V/DIV 5ms/DIV Transient response Figure 3. Shutdown by V 40mV/DIV 1A/DIV 20us/DIV Figure 5. Transient Response 2.5A 2008 Semtech Corp OUT V Vin IN SS 5V/DIV SS 5V/DIV V Vout OUT 0.5V/DIV PGOOD ...
Page 7
... Room Temperature DSON 130 2.5Vin 120 3.3Vin 110 100 1.5 I (A) OUT Io(A) Figure 11. High-Side P-MOSFET 2008 Semtech Corp. Test condition: 5Vin, 1Vout , 1V IN OUT 0.6V/DIV V Vout OUT 5.0V/DIV SS SS 3V/DIV V Vphase PHASE Figure 8. Thermal Shutdown Protection@0A Sync Signal SYNC ...
Page 8
... I (A) OUT Figure 13. Loading Regulation 2008 Semtech Corp. VOUT 5Vin 1.4 1.6 1.8 2.0 Figure 14. Over Current Setting versus R 8 SC4620 OCP Trip 3.3Vin 2.5Vin R (KΩ) ISET ISET www ...
Page 9
... It senses the output voltage through an external divider. 13 AGND Analog signal ground. 14,15 PGND Power ground. 16,17,18 PH Switching nodes THERMAL Pad for heatsinking purposes only. Connect to ground plane using multiple vias. Not electrically PAD connected internally. 2008 Semtech Corp. Pin Functions 9 SC4620 www.semtech.com ...
Page 10
... POWER MANAGEMENT Block Diagram VCC BANDGAP BANDGAP AGND VREF SOFT START SS FB COMP SD SYNC/EN OSC FB FS CLOCK 1.1VREF 0.9VREF 2008 Semtech Corp. ASYNCHRONOUS START UP 0.5V THERMAL SHUTDOWN UVLO ERROR OPAMP PWM BLOCK PWM LOGIC SHOOT- THRU PROTECTION 10 SC4620 + - TOP GATE ...
Page 11
... An external capacitor is necessary for the soft start function and is connected from SS pin to AGND. 2008 Semtech Corp. During start up or restart, A typical 4µA sourcing current charges the capacitor and then the voltage of capacitor ramp up the error amp reference slowly. ...
Page 12
... Figure11). As Vin drops gradually and close to Vout, the buck regulator will go into 100% duty cycle ratio. A matter needing 2008 Semtech Corp. attention is internal high side PMOS has minimum off time limitation and is related to duty cycle rate. makes the working duty cycle perform at randon with the output ripple increasing and a poor transient response ...
Page 13
... DI = ratio of the peak to peak inductor current to the maximum output load current. The peak to peak inductor current is: 2008 Semtech Corp. After the required inductor value is selected, the proper selection of the core material is based on the peak inductor current and efficiency requirements. The core ...
Page 14
... The SC4620 has an internal error amplifier and requires the compensation network to connect among the COMP pin and FB pin, GND, and the output as shown in Figure 17. The compensation network includes C1, C2, R1, R7, R8 and C8 used to program the output voltage ac- cording to: 2008 Semtech Corp ...
Page 15
... M ⋅ ⋅ ⋅ ⋅ where G = PWM gain. PWM V = 1.0V, ramp peak to valley voltage of SC4620. M 2008 Semtech Corp. The design guidelines for the SC4620 applications are as follows ⋅ The compensated loop gain will be as given as show in Figure 18 ⋅ ⋅ C ⋅ ...
Page 16
... The size of the vias as the connection between multiple layers should not be too large or solder may seep through 2008 Semtech Corp. the big vias to the bottom layer during the re-flow process. ) should be close to ...
Page 17
... D C 1Vout@2.5A 270pF 270pF 2.32k 2.32k 22uF 22uF B (2) MLB-160808-0600R-S2 MLB-160808-0600R-S2 VIN=5V Vout=1V/2.5A Switching Frequency=550kHz L1: TOKO D104C(919AS-1R8N) A R12: Multilayer chip inductors; Input/Output Capacitors: Panasonic ECJ33YBOJ226M(22uF/6.3V) 5 2008 Semtech Corp 10R 10R 10k 10k 10k 10k 1nF 1nF 1uF 1uF 2.2pF 2.2pF C1 ...
Page 18
... POWER MANAGEMENT Operation PCB Layout PCB Layout Component Side (TOP) (TOP layer) (IN1 layer) 2008 Semtech Corp. (Bottom layer) (IN2 layer) 18 SC4620 www.semtech.com ...
Page 19
... COMPANY'S MANUFACTURING GUIDELINES ARE MET. 2. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. Contact Information Phone: (805) 498-2111 Fax: (805) 498-3804 2008 Semtech Corp SEATING PLANE ...