RT7736

RT7736 RICHTEK | Alldatasheet

Document overview

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Technical content

Features

 Proprietary SmartJitterTM Technology  Reducing EMI Emissions of SMPS  Output Jittering Ripple Elimination  No Load Input Power Under 100mW (RT7736G/R/L/E)  Accurate Over Load Protection  PRO Pin for External Arbitrary OVP/OTP  IC ON/OFF Control (RT7736G/R/L)  BNO Pin for Brown-In/Out (RT7736B/F)  Soft Driving for EMI Noise Reduction  High Noise Immunity  RoHS Compliant and Halogen Free Simplified Application Circuit AC Mains (90V to 265V) PRO COMP GND GATE CS RT7736 VDD Vo+ Vo-

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Ordering Information

E : SOT-23-6 Lead Plating System G : Green (Halogen Free and Pb Free) RT7736 Version (Refer to Version Table) Marking Information Note : Richtek products are :  RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020.  Suitable for use in SnPb or Pb-free soldering processes. RT7736 Version Table IFF= : Product Code DNN : Date Code RT7736GGE IFF=DNN RT7736FGE 0P= : Product Code DNN : Date Code0P=DNN 09= : Product Code DNN : Date Code RT7736LGE 09=DNN 0F=DNN RT7736EGE 0F= : Product Code DNN : Date Code 00= : Product Code DNN : Date Code RT7736BGE 00=DNN RT7736RGE 2B= : Product Code DNN : Date Code2B=DNN Version RT7736G RT7736R RT7736L RT7736E RT7736B RT7736F Frequency 65kHz 65kHz 65kHz 65kHz 65kHz 65kHz OLP Delay Time 56ms 56ms 56ms 56ms 56ms 64ms Internal OVP Auto Recovery Auto Recovery Latch Latch Auto Recovery Auto Recovery OLP & SRSP Auto Recovery Auto Recovery Auto Recovery Auto Recovery Auto Recovery Auto Recovery PRO Pin High Latch Auto Recovery Latch Latch X X PRO Pin Low Auto Recovery Auto Recovery Auto Recovery Latch X X External OTP by PRO Auto Recovery Auto Recovery Latch Latch X X External Brown-In/Out X X X X ○ ○ Part Status Active Active Active Lifebuy Active Active

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Pin Configuration (TOP VIEW) RT7736B/F SOT-23-6 GND COMP BNO GATE VDD CS RT7736G/R/L/E SOT-23-6 GND COMP PRO GATE VDD CS Pin No. Pin Name Pin Function 1 GND Ground of the controller. 2 COMP Feedback voltage input. Connect an opto-coupler to close the control loop and achieve output voltage regulation. PRO Protection input for OVP , OTP or ON/OFF control. (RT7736G/R/L/E) BNO Brown-in/out detection Input for RT7736B/F Only. 4 CS Current sense input. The current sense resistor between this pin and GND is used for current limit setting. 5 VDD Supply voltage input. The controller will be enabled when VDD exceeds V TH_ON (14.5V typ.) and disabled when VDD decreases lower than VTH_OFF (9V typ.) 6 GATE Gate driver output for external power MOSFET. Functional Pin Description The part status values are defined as below : Active : Device is in production and is recommended for new designs. Lifebuy : The device will be discontinued, and a lifetime-buy period is in effect. NRND : Not recommended for new designs. Preview : Device has been announced but is not in production. Obsolete : Richtek has discontinued the production of the device.

©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Figure 1. Block Diagram for RT7736G, RT7736R, RT7736L and RT7736E

©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Figure 2. Block Diagram for RT7736B and RT7736F The burst mode is designed to reduce switching loss. the switching will be resumed. design and transient design easier.

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Leading Edge Blanking (LEB) To prevent unexpectedly gate switching interruption from the initial spike on CS pin, the LEB delay is designed to block this spike at the beginning of gate switching. Gate Driver A totem pole gate driver is designed to meet both EMI and efficiency requirements in low power applications. An internal pull-low circuit is activated after pretty low V DD to prevent external MOSFET from accidentally turning on during UVLO. PRO Pin (RT7736G/R/L/E) The RT7736G/R/L/E features a PRO pin, and it can be applied for external arbitrary OVP or OTP applications (RT7736G/R/L/E), and also can be applied for IC ON/OFF control (RT7736G/R/L). BNO Pin (RT7736B/F) The RT7736B/F features a BNO pin, and it can be applied for external arbitrary brown-in/out. The BNO pin is connected to the AC line input or bulk capacitor with a resistive divider to achieve brown-in/out protection. Cycle-by-Cycle Current Limit This is a basic but very useful function and it can be implemented easily in current mode controller. Over-Load Protection In over load conditions, long time current limit will lead to system thermal stress problem. To further protect the system, the RT7736 is designed with a proprietary prolonged turn-off period during hiccup. The power loss and temperature during OLP will be averaged to an acceptable level over the ON/OFF cycle. CS Pin Open Protection When the CS pin is opened, the controller will shut down after a few cycles. Over-Voltage Protection Output voltage can be roughly sensed by the VDD pin. If the sensed voltage reaches V OVP threshold, the controller will shut down after deglitch delay. The controller will resume once the fault is removed. Feedback Open and Opto-Coupler Short If the output voltage feedback loop is open or the opto- coupler is shorted, the OVP/OLP function will be triggered depending on which one occurs first. Secondary Rectifier Short Protection The current spike during secondary rectifier short test is extremely high because of the saturated main transformer. Meanwhile, the transformer acts like a leakage inductance. During high line, the current in power MOSFET is sometimes too high for OLP delay time. To offer better and easier protection design, the RT7736 will shut down after a few of cycles before fuse is impacted. Output Short Protection The RT7736 implements output short protection by detecting GATE width with delay time. It could minimize the power loss and temperature during output short, especially at high line input voltage.

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Electrical Characteristics

Recommended Operating Conditions (Note 4) Absolute Maximum Ratings (Note 1)  Power Dissipation, PD @ TA = 25°C  Package Thermal Resistance (Note 2)  ESD Susceptibility (Note 3) (VDD = 15V, T A = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit VDD Section VDD Over-Voltage Protection Level V OVP 26 27 28 V VDD Zener Clamp V Z 29 -- -- V On Threshold Voltage VTH_ON 13.5 14.5 15.5 V Off Threshold Voltage VTH_OFF 8.5 9 9.5 V Disable Brown-in Detection to Avoid Start-up Failed VDD_BNI 11 12 13 V VDD Holdup Mode Entry Point VDD_ET VCOMP < 1.3V 9.5 10 10.5 V VDD Holdup Mode Ending Point VDD_ED VCOMP < 1.3V 10 10.5 11 V Latch-off Clamping Voltage VDD_LH -- 5.5 -- V Threshold Voltage for Latch-off Release VLH_OFF -- 5 -- V Start-up Current I DD_ST VDD < VTH_ON  0.1V, TA = 40°C to 80°C -- 5 10 A Latch-off Operating Current IDD_LH TA = 40°C to 80°C 2 -- 10 A Operating Supply Current IDD_OP1 VDD = 15V, GATE pin open, VCOMP = 2.5V -- 1 -- mA Operating Supply Current IDD_OP2 VDD = 15V, GATE pin open, VCOMP = 1.7V -- 0.9 -- mA IDD Sinking Current of Waiting Brown-in After Start-up IDD_BNI For RT7736B/F; V DD = 15V, GATE and COMP pin open 100 150 200 A

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Parameter Symbol Test Conditions Min Typ Max Unit IDD Sinking Current IDD_ARP During entering auto recovery protection 300 400 500 A Oscillator Section Normal PWM Frequency f OSC VCOMP > VBS_ET 60 65 70 kHz Maximum Duty Cycle DCY MAX 70 75 80 % Minimum Burst Switching Green Mode Frequency fBS_MIN 18.5 22 25.5 kHz PWM Frequency Jittering Range f -- ±6 -- % PWM Frequency Jittering Period T JIT -- 16 -- ms Frequency Variation Versus VDD Deviation fDV V DD = 9V to 23V -- -- 2 % Frequency Variation Versus Temperature Deviation fDT T A = 30°C to105°C -- -- 5 % COMP Input Section Open Loop Voltage VCOMP_OP COMP pin open 5 5.2 5.4 V Short Circuit Current of COMP I ZERO V COMP = 0V 0.24 0.29 0.34 mA Delay Time of COMP Open-loop Protection TOLP f OSC = 65kHz RT7736G/R/L/E/B -- 56 -- ms RT7736F -- 64 -- Burst Switching Green Mode Entry Voltage VBS_ET 2.3 2.35 2.4 V Burst Switching Green Mode Ending Voltage VBS_ED 2.1 2.15 2.2 V Delay Time of Output Short Protection TD_OSP fOSC = 65kHz, RT7736G/R/L/E/B -- 8 -- ms Current Sense Section Maximum Current Limit V CS_MAX (Note 5) 1.05 1.1 1.15 V Leading Edge Blanking Time T LEB (Note 5) 150 250 350 ns Internal Propagation Delay Time T PD (Note 5) -- 100 -- ns Minimum On-Time T ON_MIN 250 350 450 ns Detection On-Time of Output Short Protection TON_OSP fOSC = 65kHz, RT7736G/R/L/E/B (Note 6) 0.7 1.1 1.5 s GATE Section Rising Time T R V DD = 15V, CL = 1nF -- 60 -- ns Falling Time T F V DD = 15V, CL = 1nF -- 40 -- ns Gate Output Clamping Voltage V CLAMP V DD = 23V -- 13.5 -- V PRO Interface Section (RT7736G/R/L/E) Pull High Threshold VTH_H 1.75 1.8 1.85 V Pull Low OTP Threshold VTH_OTP 0.47 0.5 0.53 V Pull Low Threshold VTH_L 0.25 0.3 0.35 V

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Note 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 in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. Note 2. θ JA is measured in natural convection (still air) at T A = 25°C with the component mounted on a low effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. Leading edge blanking time and internal propagation delay time are guaranteed by design. Note 6. Guaranteed by design. Parameter Symbol Test Conditions Min Typ Max Unit Open Loop Voltage VPRO_OP PRO pin open -- 1.3 -- V Internal Bias Current I BIAS 90 100 110 A Pull High Sinking Current I SIN -- -- 500 A Delay Time of OTP by PRO T D_OTP f OSC = 65kHz -- 56 -- ms BNO Interface Section (RT7736B/F) Brown-In Threshold VBNI_TH 0.96 1 1.04 V Brown-Out Threshold VBNO_TH 0.81 0.85 0.89 V De-bounce Time of VBNO_TH T D_BNO f OSC = 65kHz RT7736B -- 56 -- ms RT7736F -- 24 -- Over-Temperature Protection (OTP) Section Over-Temperature Protection T OTP On Chip OTP (Note 6) -- 140 -- C

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Typical Operating Characteristics IDD_ST vs. VDD 0369 1 2 1 5 VDD (V) IDD_ST (µA) IDD_ST vs. Temperature - 5 0 - 2 50 2 55 07 5 1 0 0 1 2 5 Temperature (°C) IDD_ST (µA) VTH_ON vs. Temperature 13.0 13.5 14.0 14.5 15.0 15.5 16.0 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) VTH_ON (V) VOVP vs. Temperature 26.00 26.25 26.50 26.75 27.00 27.25 27.50 27.75 28.00 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) VOVP (V) VTH_OFF vs. Temperature 8.0 8.5 9.0 9.5 10.0 -50 -25 0 25 50 75 100 125 Temperature (°C) VTH_OFF (V) VDD_LH & VLH_OFF vs. Temperature 4.8 5.0 5.2 5.4 5.6 5.8 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) VDD_LH & VLH_OFF (V) VDD_LH VLH_OFF

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. fOSC vs. VDD 63.0 63.5 64.0 64.5 65.0 65.5 66.0 66.5 67.0 10 13 16 19 22 25 VDD (V) fOSC (kHz) fOSC vs. Temperature - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) fOSC (kHz) IDD_LH vs. Temperature - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) IDD_LH (µA) IDD_BNI vs. Temperature 120 140 160 180 200 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) IDD_BNI (µA) IDD_ARP vs. Temperature 325 350 375 400 425 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) IDD_ARP (µA) fBS_MIN vs. Temperature -50 -25 0 25 50 75 100 125 Temperature (°C) fBS_MIN (kHz)

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. IDD_OP1 vs. Temperature 650 700 750 800 850 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) IDD_OP1 (µA) IDD_OP2 vs. Temperature 650 700 750 800 850 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) IDD_OP2 (µA) VCOMP_OP vs. Temperature 5.1 5.2 5.3 5.4 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) VCOMP_OP (V) IZERO vs. Temperature 270 280 290 300 310 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) IZERO (µA) TOLP vs. Temperature - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) TOLP (ms) RT7736G/R/L/E/B TOLP vs. Temperature -50 -25 0 25 50 75 100 125 Temperature (°C) TOLP (ms) RT7736F

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. VTH_H vs. Temperature 1.70 1.75 1.80 1.85 1.90 -50 -25 0 25 50 75 100 125 Temperature (°C) VTH_H (V) tR vs. Temperature - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) tR (ns) tF vs. Temperature -50 -25 0 25 50 75 100 125 Temperature (°C) tF (ns) IBIAS vs. Temperature 102 106 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) IBIAS (µA) VCLAMP vs. Temperature 11.5 12.5 13.5 14.5 15.5 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) VCLAMP (V) TD_BNO vs. Temperature -50 -25 0 25 50 75 100 125 Temperature (°C) TD_BNO (ms) RT7736F

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. VBNI_TH vs. Temperature 0.90 0.95 1.00 1.05 1.10 - 5 0 - 2 50 2 55 07 5 1 0 0 1 2 5 Temperature (°C) VBNI_TH (V) VBNO_TH vs. Temperature 0.75 0.80 0.85 0.90 0.95 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) VBNO_TH (V) VTH_OTP vs. Temperature 0.40 0.45 0.50 0.55 0.60 -50 -25 0 25 50 75 100 125 Temperature (°C) VTH_OTP (V) VTH_L vs. Temperature 0.20 0.25 0.30 0.35 0.40 -50 -25 0 25 50 75 100 125 Temperature (°C) VTH_L (V)

www.richtek.com ©Copyright 2019 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Figure 5. Frequency Jittering Range During Green Mode : General PWM Controller vs. RT7736

Application Information

The RT7736 series applies RICHTEK proprietary SmartJitterTM technology. In order to reduce switching loss for lower power consumption during light load or no load, general PWM controllers have green mode function according to the feedback voltage V COMP. The output power equation is : 1C O M Po_DCM COMP p s COMP CS Where LP is the magnetizing inductance of the transformer, RCS is the current sense resistor, VCOMP is the feedback voltage of the COMP pin. fS is the switching frequency of the power switch, η is the conversion efficiency, and x1 is a constant coefficient. Output power is a function of feedback voltage V COMP. Frequency jittering technique is typically used to improve EMI problems in general PWM controllers, and the frequency jittering period is based on PWM switching frequency. When the system enters green mode, a output power relationship is formed between the feedback voltage V COMP and the PWM switching frequency, and a new stable equilibrium point is eventually reached after back-and-forth adjustments. It limits the frequency jittering range is limited and the improving EMI function is poor, as shown in Figure 5. The innovative SmartJitter TM technology not only helps reduce EMI emissions of SMPS when the system entering green mode, but also eliminates output jittering ripple. Accurate Over-Load Protection and Tight Current Limit Tolerance Generally, the saw current limit is applied to low cost flyback controllers because of simple design. The RT7736 series applies with RICHTEK proprietary technology through well foundry control, design and test/trim mode in final test. Therefore, the current limit tolerance is tight enough to make design and mass production easier, and it provides accurate over-load protection. Jittering Freq. fs mean = 64.85kHz Jittering Range = 6.3% Normal Operating General PWM Controller Jittering Freq. fs mean = 42.99kHz Jittering Range = 3.3% General PWM Controller Green Mode Jittering Freq. fs mean = 42.58kHz Jittering Range = 7.7% RT7736 Green Mode Jittering Freq. fs mean = 64.61kHz Jittering Range = 6.0% RT7736 Normal Operating

www.richtek.com Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnish ed by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringeme nts of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of R ichtek or its subsidiaries. Outline Dimension A e b B D C H L Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.889 1.295 0.031 0.051 A1 0.000 0.152 0.000 0.006 B 1.397 1.803 0.055 0.071 b 0.250 0.560 0.010 0.022 C 2.591 2.997 0.102 0.118 D 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 H 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 SOT-23-6 Surface Mount Package