RY2121

RY2121 1CH ADJ Current-Limited Power Distribution Switch Features • • Single-Channel Power Distribution Switch Programmable Current Limit in 0.4A~2A Output Current • • • • Enable polarity: Active High 2.4V to 5.5V Supply Range Under-Voltage Lockout -40°C to +85°C Ambient Temperature Range • • • • • • • Accurate Current Limit 15μA Quiescent Current 80mΩ MOSFET Thermal-Shutdown Protection Built-In Soft Start Reverse Current Blocking (No Body Diode) Available in SOT23-5 Package • • • • ONT Boxes USB Ports and Hubs, Laptops, and Desktops Smartphone and PDA MiniPCI Accessories Applications • • • • Set-Top Boxes Wi-Fi Router/AP USB 3G Datacard/ USB Dongle High-Definition Digital TVs General Description The RY2121 Power Distribution Switch features internal current limiting to prevent damage to host devices due to faulty load conditions. The RY2121 develops ultra-low on-resistance switch with programmable current limiting to protect the power source from over current and short circuit conditions. It integrates the over temperature protection and discharges the output capacitor during the shutdown. In case the output is pulled higher than the input voltage under the shutdown, the RY2121 can block the current flowing from the output to the input. The RY2121 is available in SOT23-5 package. Typical Application Circuit VIN CIN IN ON/ OFF VOUT OUT EN SET GND COUT RSET Basic Application Circuit Email: support@rychip.com ©RYCHIP Semiconductor Inc. http://www.rychip.com Page 1 / 9 RY2121 1CH ADJ Current-Limited Power Distribution Switch Pin Description Pin Configuration TOP VIEW OUT 1 GND 2 SET 3 5 IN 4 EN SOT23-5 Top Marking: MEYLL (device code: ME, Y=year code, LL= lot number code) Pin Description Pin Name Function 1 OUT Output Pin. 2 GND Ground Pin. 3 SET Current limit programming Pin. Connect a resistor RSET from this pin to GND to program the current limit. 4 EN ON/OFF control. Pull high to enable IC, Do not float. 5 IN Power Supply Pin Order Information Marking Part No. Model Description Package T/R Qty MEYLL 70702013 RY2121 RY2121 1CH Current Limited IC, VIN 2.4VSOT23-5 5.5V, ILIM ADJ, Active High, SOT23-5 3000PCS Email: support@rychip.com ©RYCHIP Semiconductor Inc. http://www.rychip.com Page 2 / 9 RY2121 1CH ADJ Current-Limited Power Distribution Switch Absolute Maximum Ratings (1) (2) (3) All Pins Voltage ……………...……………………...………….…………………..……..………...… -0.3V to +6V Operating Virtual Junction (TJ) ……………...………......……………….……..……..………..… -40°C to +150°C Ambient Temperature Operating Range (TA) …………………..…………………………………... -40°C to +85°C Storage Temperature Range (TS) …………………………………...……………………………... -55°C to +150°C Lead Temperature (Soldering, 10s) (TL) ………………………..…………………………………………... +260°C Junction-to-ambient thermal resistance (RθJA) …………………...…………..…………..…………….…. 200°C/W Junction-to-case thermal resistance (RθJC) ……………..……….………………………...…………….… 130°C/W Note 1: Exceeding these ratings may damage the device. Note 2: The device is not guaranteed to function outside of its operating conditions. Note 3: θJA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Pin 2 of SOT23-5 packages is the case position for θJC measurement. Recommended Operating Conditions Input Voltage Pin …….………....…………..……………………….……………..……..……....… +2.4V to +5.5V All Other Pins …………...…….…...…………..……….……………………..………..........……....… 0V to +5.5V Junction Temperature Range (Tj) …………..………………………………………………….….. -40°C to +125°C Ambient Temperature Range (TA) ………...………………..………………………..……………... -40°C to +85°C Electrical Characteristics(4) (VIN = 5V, CL=1μF, per channel, TA = 25°C unless otherwise specified) Parameter Symbol Input Voltage Range VIN Shutdown Input Current ISHDN Open load, IC Disabled 0.6 Quiescent Supply Current IQ Open load, IC Enabled 20 μA FET RON RDS(ON)1 80 mΩ ENB Rising Threshold VENB(H) ENB Falling Threshold VENB(L) ENB Leakage IENB IN UVLO Threshold VIN,UVLO IN UVLO Hysteresis VIN,HYS ILIM Over Current Limit Turn-ON Time (5) Turn-OFF Time (5) Test Conditions Min Typ. 2.4 Max Unit 5.5 V 1 μA 1.2 V VENB=5.5V 0.8 V 1 μA 2.3 V 0.1 RSET=6.8kΩ 0.75 1.0 V 1.25 A ILIM(MIN) 0.4 A ILIM(MAX) 2 A TON RL=10Ω, CL=1uF 120 μS TOFF RL=10Ω, CL=1μF 10 μS OUT Shutdown Discharge Resistance RDIS 150 Ω Thermal Shutdown Temperature TSD 130 ℃ Thermal Shutdown Hysteresis THYS 20 ℃ Email: support@rychip.com ©RYCHIP Semiconductor Inc. http://www.rychip.com Page 3 / 9 RY2121 1CH ADJ Current-Limited Power Distribution Switch Note 4: The device is not guaranteed to function outside its operating conditions. Note 5: Measured from (50%) EN signal to (90%) output signal. Typical Performance Characteristics (6) (7) Note 6: Performance waveforms are tested on the evaluation board. Note 7: VIN = 5V, COUT = 1µF, RSET = 6.8kΩ, TA = +25ºC, unless otherwise noted. VEN tr 90% VoUT 10% 90% 50% 50% tf ton 10% toff 90% VoUT 10% Figure 1 Tr, Tf, Ton, Toff waveforms Turn on Delay vs. Input Voltage Turn off Delay vs. Input Voltage Supply Current, Output Enabled vs. Input Voltage VEN=5V，RLOAD=5Ω VEN=5V，RLOAD=5Ω Supply Current, Output Disabled vs. Static Drain-Source On-State Input to Output Voltage vs. Input Voltage Resistance vs. Input Voltage Load Current VEN = 0V VEN = 5V，ILOAD=0.5A VEN = 5V Email: support@rychip.com ©RYCHIP Semiconductor Inc. VEN = 5V http://www.rychip.com Page 4 / 9 RY2121 1CH ADJ Current-Limited Power Distribution Switch Current Limit vs. Input Voltage Threshold Trip Current vs. Current Limit vs. RSET Input Voltage Turn on Delay Rise Time Turn off Delay Fall Time Threshold Trip Current with Ramped Load Enabled Device VEN = 5V，RLOAD=5Ω 1Ω Load Connected to Enabled Device Email: support@rychip.com ©RYCHIP Semiconductor Inc. Short Circuit Current，Device Enabled Current Limit vs. RSET into Short ILIM=0.4~1.5A http://www.rychip.com Page 5 / 9 RY2121 1CH ADJ Current-Limited Power Distribution Switch Function Block Diagram UVLO REVERSE CURRENT BLOCKING CURRENT SENSE LOGIC AMPLIFER IN EN OUT － SET ＋ ＋ VREF － THERMAL SENSE GND Figure 2 Function Block Diagram Email: support@rychip.com ©RYCHIP Semiconductor Inc. http://www.rychip.com Page 6 / 9 RY2121 1CH ADJ Current-Limited Power Distribution Switch Functions Description Current Limit The RY2121 provides a constant current limit that can be programmed by an external resistor. Once the device reaches its current limit threshold, the internal circuit regulates the gate voltage to hold the current in the power MOSFET constant. Below table can be taken as a reference to choose RSET to set the current limit threshold. RSET (kΩ) Typical Current Limit (mA) 5.1 1500 5.6 1420 6.8 1180 7.5 1080 8.2 980 9.1 880 10 820 11 760 12 700 13 640 15 580 16 540 18 510 20 480 30 340 43 238 51 202 68 160 82 128 100 94 150 56 180 52 200 48 Table 1 Current Limit Threshold Setting Over Current When the load exceeds trip current (minimum threshold current triggering constant-current mode) or short circuited, RY2121 switches into to constant-current mode (current limit value). RY2121 will be shut down only if the overcurrent condition stays long enough to trigger thermal protection. Trigger overcurrent protection for different overload conditions occurring in applications: 1) The output has been shorted or overloaded before the device is enabled or input applied. RY2121 detects the short or overload and immediately switches into a constant-current mode. 2) A short or an overload occurs after the device is enabled. The device switches into constant current mode after the current-limit circuit has been tripped (reached the trip current threshold). However, high current may flow for a Email: support@rychip.com ©RYCHIP Semiconductor Inc. http://www.rychip.com Page 7 / 9 RY2121 1CH ADJ Current-Limited Power Distribution Switch short period of time before the current-limit circuit can react. 3) Output current has been gradually increased beyond the recommended operating current. The load current rises until the trip current threshold is reached or until the thermal limit of the device is exceeded. Once the trip threshold has been reached, the device switches into its constant-current mode. Thermal Protection If the current limit block starts to regulate the output current, the power loss on power MOSFET will cause the IC temperature rise. The die temperature is internally monitored until the thermal limit is reached. Once this temperature is reached, the switch will turn off to allow the chip to cool until the over temperature fault remove. The over temperature threshold is 130℃ and hysteresis is 20℃. Under-voltage Lockout (UVLO) This circuit is used to monitor the input voltage to ensure that the RY2121 is operating correctly. This UVLO circuit also ensures that there is no operation until the input voltage reaches the minimum spec. Reverse Current Blocking In case the output is pulled higher than the input voltage under the shutdown, the RY2121 can block the current flowing from the output to the input. This prevents damage to devices on the input side of the RY2121 by preventing significant current from sinking into the input capacitance. Output Discharge RY2121 has output discharge function. It can discharge the output capacitor by internal pulldown resistance during shutdown. Email: support@rychip.com ©RYCHIP Semiconductor Inc. http://www.rychip.com Page 8 / 9 RY2121 1CH ADJ Current-Limited Power Distribution Switch Package Description SOT23-5 2.80 3.00 0.95 BSC 0.60 TYP 1.20 TYP EXAMPLE TOP MARK AAAAA 1.50 2.60 1.70 3.00 2.60 TYP PIN 1 TOP VIEW RECOMMENDED PAD LAYOUT GAUGE PLANE 0.25 BSC 0.90 1.30 1.45 MAX SEATING PLANE 0.30 0.50 0.95 BSC FRONT VIEW 0.00 0.15 0° ~8° 0.30 0.55 0.09 0.20 SIDE VIEW NOTE: 1. CONTROL DIMENSION IS IN INCHES. DIMENSION IN BRACKET IS IN MILLIMETERS. 2. PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. 3. PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. 4. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.004" INCHES MAX. 5. DRAWING CONFORMS TO JEDEC MS-012, VARIATION BA. 6. DRAWING IS NOT TO SCALE. Email: support@rychip.com ©RYCHIP Semiconductor Inc. http://www.rychip.com Page 9 / 9