1/4 STRUCTURE Silicon Monolithic Integrated Circuit TYPE Single Channel Series Regulator Driver IC PRODUCT SERIES BD3520FVM FEATURES ・Ｎon Rush Current on Start up (NRCS) ・N channel MOSFET driver ・Output Voltage : 1.2V （±1%） ○ ABSOLUTE MAXIMUM RATINGS（Ta=25℃） Parameter Supply Voltage Symbol VCC Limit 7 Drain Voltage (VIN) VD 7 Enable Input Voltage Ven 7 Power Dissipation Operating Temperature Range Storage Temperature Range Maximum Junction Temperature Pd Unit *1 V V V 437.5 *2 mW Topr -10～+100 ℃ Tstg -55～+150 ℃ Tjmax +150 ℃ *1 Operating temperature range should not exceed Tjmax=150℃ *2 Pd derating at 3.5mW/℃ for temperature above Ta=25℃ ○ RECOMMENDED OPERATING CONDITIONS（Ta=25℃） PARAMETER Supply Voltage SYMBOL MIN MAX UNIT VCC 4.5 5.5 V Drain Voltage（VIN） VD 1.2 5.5 V Enable Input Voltage Ven -0.3 5.5 V CNRCS 0.001 1 uF Capacitor on NRCS Terminal ★ This product is not designed for protection against radioactive rays. REV. A 2/4 ○ ELECTRICAL CHARACTERISTICS （Unless otherwise specified,Ta=25℃ VCC=5V VIN=3.3V Ven=3V） LIMIT PARAMETER SYMBOL MIN TYP ICC 0.85 Bias Current IST 0 Shut Down Mode Current Vo1 1.188 1.200 Output Voltage 1 Output Voltage 2 Line Regulation Load Regulation [Enable] High Level Enable Input Voltage Low Level Enable Input Voltage Enable pin Input Current [Source Voltage] VS Input Bias Current VS Standby Current [Output MOSFET Driver] MOSFET Driver Source Current MOSFET Driver Sink Current [UVLO] VCC UVLO VCC UVLO Hysterisis VD UVLO [Drain Voltage Sensing] VD Input bias Current [NRCS/SCP] NRCS Charge Current SCP Charge Current SCP Discharge Current SCP Threshold Voltage Short Detect Voltage NRCS Stand-by Voltage (※) MAX 1.7 10 1.212 UNIT mA uA V CONDITIONS Ven=0V Io=50mA Vcc=4.5V to 5.5V , Ta=-10℃ to 100℃(※) VCC=4.5V to 5.5V Io=0 to 3A Vo2 1.176 1.200 1.224 V Reg.l Reg.L - 0.1 0.5 0.5 10 %/V mV Enhi 2 - Vcc V Enlow -0.3 - 0.8 V Ien - 7 10 uA Ven=3V ISBIAS ISSTB 150 1.2 - 2.4 - mA mA VS=1V Ven=0V IGSO 2 3 4 mA VFB=1.1V,VGATE=2.5V IGSI 2 3 4 mA VFB=1.3V,VGATE=2.5V VccUVLO Vcchys VDUVLO 4.20 100 Vo×0.6 4.35 160 Vo×0.7 4.50 220 Vo×0.8 V mV V Vcc:Sweep up Vcc:Sweep down VD:Sweep up Ivd 10 16 22 uA Inrcs Iscpch IscpDi Vscp Voscp VSTB 14 20 26 14 20 26 0.3 1.2 1.3 1.4 Vo×0.3 Vo×0.35 Vo×0.4 50 Design Guarantee REV. A uA uA mA V V mV VNRCS=0.5V VNRCS=0.5V VNRCS=0.5V 3/4 ○ PHYSICAL DIMENSIONS D 3 5 0 2 1PIN MARK Lot No. (UNIT:mm) MSOP8 ○ BLOCK DIAGRAM ○ Pin number Pin name VCC C1 VCC 4 UVLO2 EN 3 Enable + - Reference Block VD VD UVLO LATCH UVLO1 C2 UVLO1 VREF EN G NRCS 0.65V 0.65V VS 0.65V + VO 6 C4 5 TSD NRCS 7 TSD SCP UVLO1 UVLO2 EN Thermal Protection VIN 8 SCP VFB SCP NRCS 2 1 NRCS GND C3 REV. A PIN No. 1 2 3 4 5 6 7 8 PIN Name NRCS GND EN VCC VFB VS G VD 4/4 ○NOTES FOR USE (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) Absolute maximum range Although the quality of this product is rigorously controlled, and circuit operation is guaranteed within the operation ambient temperature range, the device may be destroyed when applied voltage or operating temperature exceeds its absolute maximum rating. Because the failure mode (such as short mode or open mode) cannot be identified in this instance, it is important to take physical safety measures such as fusing if a specific mode in excess of absolute rating limits is considered for implementation. Ground potential Make sure the potential for the GND pin is always kept lower than the potentials of all other pins, regardless of the operating mode, including transient conditions. Thermal Design Provide sufficient margin in the thermal design to account for the allowable power dissipation (Pd) expected in actual use. Using in the strong electromagnetic field Use in strong electromagnetic fields may cause malfunctions. ASO Be sure that the output transistor for this IC does not exceed the absolute maximum ratings or ASO value. Thermal Protection Circuit A thermal shutdown circuit (T.S.D) is built into the IC to prevent damage due to overheating. Therefore, all the outputs are turned off when the T.S.D circuit is activated. (This IC latches output to off mode when the temperature recedes to the specified level. To release latch mode, EN or UVLO is re-operated.) However, the T.S.D circuit is used only for extreme conditions, and the regulator circuit should still be designed for the IC not to exceed Tj(max)=150℃. GND pattern When both a small-signal GND and high current GND are present, single-point grounding (at the set standard point) is recommended, in order to separate the small-signal and high current patterns, and to be sure the voltage change stemming from the wiring resistance and high current does not cause any voltage change in the small-signal GND. In the same way, care must be taken to avoid wiring pattern fluctuations in any connected external component GND. Output Capacitor (C4) Mount an output capacitor between VS and GND for stability purposes. The output capacitor is for the open loop gain phase compensation and reduces the output voltage load regulation. If the capacitor value is not large enough, the output voltage may oscillate. And if the equivalent series resistance (ESR) is too large, the output voltage rise/drop increases during a sudden load change. A 220uF polymer capacitor is recommended. However, the stability depends on the characteristics of temperature, load, the gate capacitance of the external MOSFET, and the mutual conductance (gm). And if a small ESR capacitor such as a ceramic capacitor is utilized (several kind of capacitors are utilized in parallel), the output voltage may oscillate due to lack of phase margin. In this case, measures can be taken by adding a capacitor and a resistor in series with this capacitor between the gate of MOSFET and GND. Please confirm operation across a variety of temperature, load conditions, and MOSFET characteristics. Input Capacitor (C1, C2) The input capacitor reduces the output impedence of the voltage supply source connected in the VCC and VIN. If the output impedence of this power supply increases, the input voltage (VCC,VIN) may become unstable. This may result in the output voltage oscillation or lowering ripple rejection. A low ESR 10uF capacitor with minimal susceptibility to temperature is preferable, but stability depends on power supply characteristics, the substrate wiring pattern, and the parasitic capacitor between Gate and Drain of MOSFET. Please confirm operation across a variety of temperature, load, and MOSFET conditions. NRCS (Non Rush Current on Start-up) Setting（C3） The NRCS function is built in this IC to prevent rush current from going through the load (VIN to Vo) for start-up. The constant current comes from the NRCS pin when EN is high or UVLO function is deactivated. Temporary reference voltage is made proportional to time due to current charge the NRCS pin capacitor and make output voltage start up proportional to this reference volatge. Timer latch short circuit protection function is built in this IC (NRCS is also working at the same time.) to protect the breakdown of the power MOSFET caused by rush current when the output is shorted to GND. This function becomes active when the output voltage level goes under by 30% of specified Vout. The constant current comes from the NRCS pin in this case. When the reference voltage made by the current charge of the NRCS pin hits 1.3V (Typ.), the gate voltage becomes low. To obtain a stable SCP delay time, a capacitor (B) with susceptiblity to temperature is recommended. Input Terminal (VCC,VD,EN) The EN, VD, and VCC are isolatetd. The UVLO protects incorrect operation when the voltage level of VD and VCC are low. The output becomes high when these pins reach the individual threshold level independent of the start-up pin order. However, if VIN shut down while the IC works under the normal operation, SCP function becomes active and latches the status. And the output does not come back active even though VIN goes up high again. In this case, start VCC or EN up again to deactivate this latch function. Maximum Output Current (Maximum Load) (Example) The maximum output current of the power supply utilizing the IC depends OUTPUT PIN on external MOSFET. The MOSFET should be chosen based on a required power supply characteristics for an actual application. Please add a protection diode when a large inductance component is connected to the output terminal, and reverse-polarity power is possible at startup or in output OFF condition. REV. A Notice Notes No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. The content specified herein is subject to change for improvement without notice. The content specified herein is for the purpose of introducing ROHM's products (hereinafter "Products"). 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