Datasheet 3.5V to 14V, 0.8A 1ch Synchronous Buck Converter Integrated MOSFET BD8312HFN Key Specifications General Description BD8312HFN can produce 1.2V, 1.8V, 3.3V, or 5V stepped-down output voltages from a power supply composed of 4 batteries, which can be Li2cell, Li3cell, or from a 5V/12V fixed power supply line. The built-in synchronous rectification switches are capable of withstanding up to15V. This IC has a flexible phase compensation system and a switching frequency of 1.5MHz allowing the use of smaller external output inductor and capacitor making the construction of a compact power supply really easy. Input Voltage Range: Output Voltage Range: Output Current: Switching Frequency: Pch FET ON-Resistance: Nch FET ON-Resistance: Standby Current: Operating Temperature Range: Package +3.5V to +14V +1.2V to +12V 0.8A(Max) 1.5MHz(Typ) 450mΩ(Typ) 300mΩ(Typ) 0μA(Typ) -25°C to +85°C W (Typ) x D (Typ) x H (Max) Features Built-In 1.0A/15V Pch/Nch Synchronous Rectification SW On-Chip Phase Compensation Device between Input and Output of Error AMP. Built-In Soft-Start Function. Built-In Timer Latch System for Short Circuit Protection Function. HSON8 2.90mm x 3.00mm x 0.60mm Application For Portable Equipments like DSC/DVC Powered by 4 Dry Batteries or Li2cell and Li3cell, or General Consumer-Equipment with 5V/12 V Lines Typical Application Circuit Input: 4.5V to 10V, output: 3.3V / 500mA VBAT=4.5V to 10V LX Figure 1. Typical Application Circuit ○Product structure：Silicon monolithic integrated circuit .www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・14・001 ○This product has no designed protection against radioactive rays 1/21 TSZ02201-0Q3Q0NZ00360-1-2 17.Feb.2015 Rev.002 BD8312HFN Pin Configuration (TOP VIEW) GND INV VCC STB VREG PVCC PGND LX Figure 2. Pin Configuration Pin Description Pin No. Pin Name Function 1 GND Ground pin 2 VCC Supply voltage input pin for control circuit 3 VREG 5V output terminal of regulator for internal circuit 4 PGND Power switch ground pin 5 LX 6 PVCC 7 STB ON/OFF pin 8 INV Error AMP input pin Power switch terminal for external coil Supply voltage input pin for power switches Block Diagram Figure 3. Block Diagram www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 2/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Description of Blocks (1) Reference This block produces the 1.0V internal reference voltage of the ERROR AMP. (2) 5V REG This block produces a 5V regulated voltage supply for the internal analog circuit. BD8312HFN is equipped with this regulator for the purpose of protecting the internal circuit from high voltages. The output of this block decreases when VCC is less than 5V, increasing the PMOS ON-Resistance and decreasing the DC/DC converter’s power efficiency and maximum output current (Please see data in Figure 15, 16, 17 and 18). (3) UVLO This circuit prevents malfunction of the internal circuit during activation of the power supply voltage or during low power supply voltage. It monitors the VCC pin voltage, turns OFF all output FET and DC/DC converter output, and resets the timer latch of the internal SCP circuit and soft-start circuit when VCC voltage becomes lower than 2.9V. Typical UVLO hysteresis is 200 mV. (4) SCP SCP is a timer latch system for short circuit protection. When the DC/DC converter is at 100% duty, the internal SCP circuit starts counting. The internal counter is in-sync with OSC so that the latch circuit is activated to turn OFF the DC/DC converter’s output after about 2.7 msec or after the counter counts about 4000 clock pulses. To reset the latch circuit, turn OFF the STB pin once, then, turn it ON again. Or, turn the power supply OFF and then ON again. (5) OSC Circuit that generates oscillating saw-tooth waveform signal with a fixed frequency of 1.5 MHz. (6) ERROR AMP The Error amplifier detects the output signal and output PWM control signals. The internal reference voltage is set at 1.0V. A primary phase compensation device of 200 pF, 62kΩ is built-in between the inverting input terminal and the output terminal of this ERROR AMP. (7) PWM COMP PWM COMP is the voltage-to-pulse-width converter for controlling the output voltage corresponding to the input voltage. It compares the internal SLOPE waveform with the ERROR AMP output voltage, then controls the pulse width of the output to the driver. (8) Soft Start This circuit prevents inrush current during startup by gradually increasing the output voltage of the DC/DC converter.. Soft-start time is in-sync with the internal OSC so that the output voltage of the DC/DC converter reaches the set voltage after about 8000 oscillations. (9) PRE DRIVER/TIMING CONTROL CMOS inverter circuit for driving the built-in synchronous rectification Pch/Nch FET switch. The synchronous rectification OFF time for preventing feed through is about 25 nsec. (10) STBY_IO Voltage applied on STB pin (7 pin) controls the ON/OFF state of the IC. The IC is turned ON when a voltage of 2.5V or higher is applied and turned OFF when the terminal is open or 0V is applied. A pull-down resistor which is approximately 400kΩ is built-in. (11) Pch/Nch FET SW Built-in synchronous rectification FET for switching the coil current of the DC/DC converter. The switch is a combination of a Pch FET rated at 15V with RON of 450mΩ and a Nch FET also rated at 15V with Ron of 300mΩ. Since the current rating of this FET is 1.0A, the output current including the ripple current of the coil should not exceed this limit. www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 3/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Absolute Maximum Ratings Parameter Symbol Maximum Applied Power Voltage Maximum Input Current Power Dissipation Rating Unit VCC, PVCC 15 V IINMAX 1.0 A Pd 0.63 (Note 1) W Operating Temperature Range Topr -25 to +85 °C Storage Temperature Range Tstg -55 to +150 °C +150 °C Junction Temperature Tjmax t (Note 1) When used at Ta = 25°C or more and installed on a 70x70x1.6 mm board, the rating is reduced by 5.04mW/°C. Caution: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over the absolute maximum ratings. Recommended Operating Conditions (Ta = 25°C) Parameter Symbol Rating Unit Power Supply Voltage VCC 3.5 to 14 V Output Voltage VOUT 1.2 to 12 V Electrical Characteristics (Unless otherwise specified, Ta = 25°C, VCC = 7.4V) Parameter Symbol Limit Min Typ Max Unit Conditions [Low Voltage Input Malfunction Preventing Circuit] Detection Threshold Voltage VUV - 2.9 3.2 V ΔVUVHY 100 200 300 mV fOSC 1.38 1.5 1.62 MHz VREG 4.65 5.0 5.35 V INV Threshold Voltage VINV 0.99 1.00 1.01 V Input Bias Current IINV -50 0 +50 nA Soft-Start Time tSS 3.2 5.3 7.4 msec DMAX - - PMOS ON-Resistance RONP - 450 600 mΩ NMOS ON-Resistance RONN - 300 420 mΩ Leak Current ILEAK -1 0 +1 µA Operation VSTBH 2.5 - 11 V No-Operation VSTBL RSTB -0.3 - +0.3 V 250 400 700 kΩ VCC Pin ISTB1 - - 1 µA PVCC Pin ISTB2 - - 1 µA Circuit Current at Operation VCC ICC1 - 600 900 µA VINV=1.2V Circuit Current at Operation PVCC ICC2 - 30 50 µA VINV=1.2V Hysteresis Range VREG monitor [Oscillator] Oscillation Frequency [Regulator] Output Voltage [Error AMP] VCC=12.0V , VINV=6.0V [PWM Comparator] LX Max Duty 100 (Note 1) % [Output] [STB] STB Pin Control Voltage STB Pin Pull-Down Resistance [Circuit Current] Standby Current (Note 1) 100% is MAX Duty as behavior of a PWM comparator. wherein High side PMOS is 100% at ON state because the same or less input voltage than output voltage is supplied. This causes the SCP to activate and stop the operation of the DC/DC converter . www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 4/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Typical Performance Curves 1.02 1.02 1.01 1.01 INV Threshold [V] INV Threshold [V] (Unless otherwise specified, Ta = 25°C, VCC = 7.4V） 1.00 0.99 0.98 1.00 0.99 0.98 -40 -20 0 20 40 60 80 100 120 0 5 10 VCC [V] Temperature [°C] Figure 4. INV Threshold vs Temperature Figure 5. INV Threshold vs Power Supply Voltage 5.3 8 7 5.2 5 VREG [V] VREG Voltage [V] 6 5.1 5.0 4.9 4 3 2 4.8 1 4.7 0 -40 0 40 80 120 0 Temperature [°C] 4 6 8 10 12 14 VCC [V] Figure 6. VREG Output vs Temperature www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 2 Figure 7. VREG Output vs Power Supply Voltage 5/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Typical Performance Curves – continued 1.7 1.7 1.6 1.6 Frequency [MHz] Frequency [MHz] (Unless otherwise specified, Ta = 25°C, VCC = 7.4V) 1.5 1.4 1.5 1.4 1.3 1.3 -40 0 40 Temperature [°C] 80 3 120 Hysteresis width ID=500mA UVLO release voltage 0.20 3.10 0.15 2.90 0.10 UVLO detection voltage 2.70 0.05 2.50 Hysteresis Voltage Vhys [V] Nch ON-Resistance [mΩ] UVLO Threshold [V] 15 500 0.25 0.00 0 12 Figure 9. Frequency vs Power Supply Voltage 3.50 -40 9 VCC [V] Figure 8. Frequency vs Temperature 3.30 6 40 80 300 200 100 120 -40 0 40 80 120 Temperature [°C] Environmental Temperature Ta [°C] Figure 10. UVLO Threshold vs Environmental Temperature (UVLO Threshold) www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 400 6/21 Figure11. Nch FET ON-Resistance vs Temperature TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Typical Performance Curves – continued (Unless otherwise specified, Ta = 25°C, VCC = 7.4V） 600 800 ID=500mA ID=500mA Pch ON-Resistance [mΩ] Nch ON-Resistance [mΩ] 500 400 300 200 600 400 200 100 0 0 3 6 9 12 -40 15 40 80 120 Temperature [ºC] VCC [V] Figure 13. Pch FET ON-Resistance vs Temperature Figure 12. Nch FET ON-Resistance vs VCC 1000 3.0 ID=500mA 2.5 800 PMOS ON-Resistance [Ω] Pch ON-Resistance [mΩ] 0 600 400 Ta=25 ºC 2.0 Ta=-25 ºC 1.5 1.0 200 0.5 0 0.0 3 6 9 12 0.0 15 1.0 2.0 IO [A] VCC [V] Figure 15. Pch FET ON-Resistance vs IO (VCC=3.5V) Figure 14. Pch FET ON-Resistance vs VCC www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 Ta=85 ºC 7/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Typical Performance Curves – continued 3.0 3.0 2.5 2.5 PMOS ON-Resistance [Ω] PMOS ON-Resistance [Ω] (Unless otherwise specified, Ta = 25°C, VCC = 7.4V） 2.0 Ta=25 ºC Ta=85 ºC 1.5 1.0 Ta=-25 ºC 0.5 0.0 2.0 Ta=85 ºC Ta=25 ºC 1.5 1.0 Ta=-25 ºC 0.5 0.0 0.0 1.0 2.0 0.0 1.0 2.0 IO [A] IO [A] Figure 16. Pch FET ON Resistance vs IO (VCC=4.0V) Figure 17. Pch FET ON-Resistance vs IO (VCC=4.5V) 3.0 2.5 2.0 ON 2.0 STB Voltage [V] PMOS ON-Resistance [Ω] 2.5 1.5 1.0 1.5 0.5 OFF 0.0 1.0 0.0 1.0 2.0 -50 IO [A] 50 Ta [°C] 100 150 Figure 19. STB Threshold vs Temperature Figure 18. Pch FET ON-Resistance vs IO (VCC=5.0V) www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 0 8/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Typical Performance Curves- continued 1000 1000 800 800 600 600 ICC [µA] ICC [µA] (Unless otherwise specified, Ta = 25°C, VCC = 7.4V) 400 400 200 200 0 0 -40 0 40 80 0 120 2 4 6 8 10 12 Temperature [ºC] VCC [V] Figure 20. Circuit current ICC vs Temperature Figure 21. Circuit current ICC vs VCC www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 9/21 14 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Application Information 1. Example of Application Input: 4.5V to 10V, Output: 3.3V / 500mA VBAT =4.5V to 10V VBAT=4.5～10V 1μ F 1µF GRM188B11A105KA61 （Murata） GND INV VCC STB ON/OFF 10pF PVCC VREG 10kΩ 3.3V/500mA 1μ F 1µF GRM188B11A105KA61 （Murata） LX Lx PGND 4.7μ 47µHH 1098AS-4R7M（TOKO） 200kΩ 51kΩ 10μ F 10µF GRM31CB11A106KA01 （Murata） 22kΩ Figure 22. Reference Application Diagram 2. Reference Application Data 1 100 3.35 3.33 VCC=4.5V VCC=4.5V Output Voltage [V] Output Voltage [V] 80 VCC=7.5V 60 40 VCC=5.5V 3.31 VCC=5.5V 20 3.27 0 3.25 1 10 100 1 1000 Output Current [mA] 10 100 1000 Output Current [mA] Figure 23. Power Conversion Efficiency (VOUT = 3.3V) www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 VCC=7.5V 3.29 Figure 24. Load Regulation (VOUT = 3.3V) 10/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN 3. Reference Application Data 2 (Input 4.5V, 6.0V, 8.4V, 10V, Output 3.3V ) 180 60 180 Phase 120 40 120 20 60 20 60 0 0 0 0 Gain -20 -60 -40 -120 100 1000 10000 100000 Gain -180 1000000 -20 -60 -40 -120 -60 -180 100 Frequency [Hz] 100000 1000000 Figure 26. Frequency Response 2 (VCC =6.0V, IO=250mA) Gain [dB] Phase [deg] Gain [dB] 10000 Frequency [Hz] Figure 25. Frequency Response 1 (VCC=4.5V, IO=250mA) Frequency [Hz] Frequency [Hz] Figure 27. Frequency Response 3 (VCC=8.4V, IO =250mA) www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 1000 Phase [deg] -60 Gain [dB] 40 Phase [deg] Gain [dB] Phase Figure 28. Frequency Response 4 (VCC=10V, IO=250mA) 11/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 Phase [deg] 60 BD8312HFN Frequency [Hz] Frequency [Hz] Gain [dB] Phase [deg] Figure 30. Frequency Response 6 (VCC=6.0V, IO =500mA) Phase [deg] Gain [dB] Figure 29. Frequency Response 5 (VCC=4.5V, IO =500mA) Frequency [Hz] Frequency [Hz] Figure 32. Frequency Response 8 (VCC=10V, IO =500mA) Figure 31. Frequency Response 7 (VCC=8.4V, IO =500mA) www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 Phase [deg] Gain [dB] Phase [deg] Gain [dB] Reference Application Data 2 - continued (Input 4.5V, 6.0V, 8.4V, 10V, Output 3.3V ) 12/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN 4. Reference Board Pattern (1) The heat sink on the rear should be a GND trace of low impedance and at the same potential with the PGND trace. (2) It is recommended to install a GND pin not directly connected to the PGND, as shown in the picture above. (3) Make the patterns for VBAT, LX and PGND as wide as possible since these paths carry large current. 5. Selection of Parts for Application (1) Inductor A shielded inductor with low DCR (direct resistance component) that satisfies the current rating (current value, Ipeak as shown in the equation below) is recommended. Inductor values affect inductor ripple current, which causes output ripple. Ripple current can be reduced as the coil L value becomes larger and the switching frequency becomes higher. Ipeak IOUT I L / 2 IL Figure 33. Inductor Current ‧ ‧ ‧ (1) [ A] V IN VOUT VOUT 1 L V IN f Δ Δ IILL ‧ ‧ ‧ (2) [ A] where η is the Efficiency. ∆IL is the Output ripple current. f is the Switching frequency. As a guide, inductor ripple current should be set at about 20% to 50% of the maximum input current. Note: Current flowing in the coil that is larger than the coil’s rating will bring the coil into magnetic saturation, which may lead to lower efficiency or output oscillation. Select an inductor with an adequate margin so that the peak current does not exceed the rated current of the coil. (2) Output Capacitor A ceramic capacitor with low ESR is recommended for the output in order to reduce output ripple. There must be an adequate margin between the maximum rating and output voltage of the capacitor, taking the DC bias property into consideration. Output ripple voltage is acquired by the following equation. VPP I L 1 I L RESR 2 f CO [V ] ‧ ‧ ‧ (3) Setting must be performed so that output ripple is within the allowable ripple voltage. www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 13/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN (3) Output Voltage Setting The internal reference voltage of the ERROR AMP is 1.0V. Output voltage is acquired by Equation (4). V OUT VOUT ERROR AMP R R11 INV VO ( R1 R2 ) R2 RR2 2 1.0 [V ] ‧ ‧ ‧ (4) VVREF REF 1.0V 1.0V Figure 34. Setting of Voltage Feedback Resistance (4) DC/DC Converter Frequency Response Adjustment System Condition for stable application. The condition for feedback system stability under negative feedback is that the phase delay is 135° or less when gain is 1 (0dB). Since DC/DC converter application is sampled according to the switching frequency, the bandwidth G BW of the whole system (frequency at which gain is 0 dB) must be controlled to be equal to or lower than 1/10 of the switching frequency. In summary, the conditions necessary for the DC/DC converter are: - Phase delay must be 135° or lower when gain is 1 (0 dB). Bandwidth GBW (frequency when gain is 0 dB) must be equal to or lower than 1/10 of the switching frequency. To satisfy those two conditions, R1, R2, R3, CS and RS in Figure 35 should be set as follows. (a) R1, R2, R3 BD8312HFN incorporates phase compensation devices of R4=62kΩ and C2=200pF. C2 and R1, R2, and R3 values decide the primary pole that determines the bandwidth of DC/DC converter. VOUT R1 Cs Inside of IC R4 C2 Rs FB Primary pole point frequency fp R2 1 R1 R2 2 A R3 C2 R R 1 2 R3 ・・・・(5) Figure 35. Example of Phase Compensation setting DC/DC converter DC Gain DC Gain A where: A is the Error AMP Gain 5 About 100dB = 10 B is the Oscillator amplification = 0.5 VIN is the Input voltage VOUT is the Output voltage 1 VIN B VO ・・・・(6) Using Equations (5) and (6), the frequency fSW of point 0 dB under limitation of the bandwidth of the DC gain at the primary pole point is as shown below. f SW fp DC Gain 1 1 VIN R1 R 2 R B VO 2 C2 R1 R2 3 ・・・・(7) It is recommended that fSW should be approximately10kHz. When load response is difficult, it may be set at approximately 20kHz. In Equation (7), R1 and R2, which determines the voltage value, will be in the order of several hundred kΩ. If an appropriate resistance value this high is not available and routing may cause noise, the use of R3 enables easy setting. www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 14/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN (b) Cs and Rs Setting For DC/DC converter, the 2nd dimension pole point is caused by the coil and capacitor as expressed by the following equation. f LC 1 ・・・・(8) 2 LCout Cout: Output Capacitor This secondary pole causes a phase rotation of 180°. To secure the stability of the system, put a zero point in 2 places to perform compensation. Zero point by built-in CR Zero point by CS f Z1 1 13kHz ・・・・(9) 2R4C2 fZ2 1 2 R1 R3 C S ・・・・(10) Setting fZ2 frequency to be half to two times as large as fLC provides an appropriate phase margin. It is desirable to set Rs at about 1/20 of (R1+R3) to cancel any phase boosting at high frequencies. These pole points are summarized in the figure below. The actual frequency property is different from the ideal calculation because of part constants. If possible, check the phase margin with a frequency analyzer or network analyzer. Otherwise, check for the presence or absence of ringing by load response waveform and also check for the presence or absence of oscillation under a load of an adequate margin. (9) (10) (7) (8) Figure 36. Example of DC/DC Converter Frequency Property （Measured with FRA5097 by NF Corporation） www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 15/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN I/O Equivalent Circuit STB INV VCC VCC VREG VCC VCC STB VREG INV VREG LX, PGND, PVCC VCC VCC PVCC PVCC VCC VCC VREG VREG Lx LX PGND PGND Figure 37. I/O Equivalent Circuit www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 16/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Operational Notes 1. Reverse Connection of Power Supply Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity when connecting the power supply, such as mounting an external diode between the power supply and the IC’s power supply pins. 2. Power Supply Lines Design the PCB layout pattern to provide low impedance supply lines. Separate the ground and supply lines of the digital and analog blocks to prevent noise in the ground and supply lines of the digital block from affecting the analog block. Furthermore, connect a capacitor to ground at all power supply pins. Consider the effect of temperature and aging on the capacitance value when using electrolytic capacitors. 3. Ground Voltage Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition. 4. Ground Wiring Pattern When using both small-signal and large-current ground traces, the two ground traces should be routed separately but connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal ground caused by large currents. Also ensure that the ground traces of external components do not cause variations on the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance. 5. Thermal Consideration Should by any chance the power dissipation rating be exceeded the rise in temperature of the chip may result in deterioration of the properties of the chip. In case of exceeding this absolute maximum rating, increase the board size and copper area to prevent exceeding the Pd rating. 6. Recommended Operating Conditions These conditions represent a range within which the expected characteristics of the IC can be approximately obtained. The electrical characteristics are guaranteed under the conditions of each parameter. 7. Inrush Current When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power supply. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of connections. 8. Operation Under Strong Electromagnetic Field Operating the IC in the presence of a strong electromagnetic field may cause the IC to malfunction. 9. Testing on Application Boards When testing the IC on an application board, connecting a capacitor directly to a low-impedance output pin may subject the IC to stress. Always discharge capacitors completely after each process or step. The IC’s power supply should always be turned off completely before connecting or removing it from the test setup during the inspection process. To prevent damage from static discharge, ground the IC during assembly and use similar precautions during transport and storage. 10. Inter-pin Short and Mounting Errors Ensure that the direction and position are correct when mounting the IC on the PCB. Incorrect mounting may result in damaging the IC. Avoid nearby pins being shorted to each other especially to ground, power supply and output pin. Inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins during assembly to name a few. www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 17/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Operational Notes – continued 11. Unused Input Pins Input pins of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance and extremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small charge acquired in this way is enough to produce a significant effect on the conduction through the transistor and cause unexpected operation of the IC. So unless otherwise specified, unused input pins should be connected to the power supply or ground line. 12. Regarding the Input Pin of the IC This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated. P-N junctions are formed at the intersection of the P layers with the N layers of other elements, creating a parasitic diode or transistor. For example (refer to figure below): When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode. When GND > Pin B, the P-N junction operates as a parasitic transistor. Parasitic diodes inevitably occur in the structure of the IC. The operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. Therefore, conditions that cause these diodes to operate, such as applying a voltage lower than the GND voltage to an input pin (and thus to the P substrate) should be avoided. Resistor Transistor (NPN) Pin A Pin B C E Pin A N P+ P N N P+ N Pin B B Parasitic Elements N P+ N P N P+ B N C E Parasitic Elements P Substrate P Substrate GND GND Parasitic Elements GND Parasitic Elements GND N Region close-by Figure 38. Example of monolithic IC structure 13. Thermal Shutdown Circuit(TSD) This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always be within the IC’s power dissipation rating. If however the rating is exceeded for a continued period, the junction temperature (Tj) will rise which will activate the TSD circuit that will turn OFF all output pins. When the Tj falls below the TSD threshold, the circuits are automatically restored to normal operation. Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from heat damage. www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 18/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Ordering Information B D 8 3 1 H 2 Part Number F N - Package HFN: HSON8 TR Packaging and forming specification TR: Embossed tape and reel Marking Diagram HSON8 (TOP VIEW) Part Number Marking BD8 LOT Number 3 1 2 1PIN MARK www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 19/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Physical Dimension, Tape and Reel information Package Name www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 HSON8 20/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 BD8312HFN Revision History Date Revision 26.Nov.2014 17.Feb.2015 001 002 Changes New Release Correction of the writing. www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 21/21 TSZ02201-0Q3Q0NZ00360-1-2 17. Feb.2015 Rev.002 Datasheet Notice Precaution on using ROHM Products 1. Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment, OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you (Note 1) , transport intend to use our Products in devices requiring extremely high reliability (such as medical equipment equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance. Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific Applications. (Note1) Medical Equipment Classification of the Specific Applications JAPAN USA EU CHINA CLASSⅢ CLASSⅡb CLASSⅢ CLASSⅢ CLASSⅣ CLASSⅢ 2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which a failure or malfunction of our Products may cause. The following are examples of safety measures: [a] Installation of protection circuits or other protective devices to improve system safety [b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. Our Products are designed and manufactured for use under standard conditions and not under any special or extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any special or extraordinary environments or conditions. If you intend to use our Products under any special or extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be necessary: [a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents [b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust [c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves [e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items [f] Sealing or coating our Products with resin or other coating materials [g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning residue after soldering [h] Use of the Products in places subject to dew condensation 4. The Products are not subject to radiation-proof design. 5. Please verify and confirm characteristics of the final or mounted products in using the Products. 6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied, confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect product performance and reliability. 7. De-rate Power Dissipation (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual ambient temperature. 8. Confirm that operation temperature is within the specified range described in the product specification. 9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in this document. Precaution for Mounting / Circuit board design 1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product performance and reliability. 2. In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products, please consult with the ROHM representative in advance. For details, please refer to ROHM Mounting specification Notice-PGA-E © 2015 ROHM Co., Ltd. All rights reserved. Rev.001 Datasheet Precautions Regarding Application Examples and External Circuits 1. If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the characteristics of the Products and external components, including transient characteristics, as well as static characteristics. 2. You agree that application notes, reference designs, and associated data and information contained in this document are presented only as guidance for Products use. Therefore, in case you use such information, you are solely responsible for it and you must exercise your own independent verification and judgment in the use of such information contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such information. Precaution for Electrostatic This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron, isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control). Precaution for Storage / Transportation 1. Product performance and soldered connections may deteriorate if the Products are stored in the places where: [a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [b] the temperature or humidity exceeds those recommended by ROHM [c] the Products are exposed to direct sunshine or condensation [d] the Products are exposed to high Electrostatic 2. Even under ROHM recommended storage condition, solderability of products out of recommended storage time period may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is exceeding the recommended storage time period. 3. Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads may occur due to excessive stress applied when dropping of a carton. 4. Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of which storage time is exceeding the recommended storage time period. Precaution for Product Label QR code printed on ROHM Products label is for ROHM’s internal use only. Precaution for Disposition When disposing Products please dispose them properly using an authorized industry waste company. Precaution for Foreign Exchange and Foreign Trade act Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign trade act, please consult with ROHM in case of export. Precaution Regarding Intellectual Property Rights 1. All information and data including but not limited to application example contained in this document is for reference only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any other rights of any third party regarding such information or data. 2. ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the Products with other articles such as components, circuits, systems or external equipment (including software). 3. No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to manufacture or sell products containing the Products, subject to the terms and conditions herein. Other Precaution 1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM. 2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of ROHM. 3. In no event shall you use in any way whatsoever the Products and the related technical information contained in the Products or this document for any military purposes, including but not limited to, the development of mass-destruction weapons. 4. The proper names of companies or products described in this document are trademarks or registered trademarks of ROHM, its affiliated companies or third parties. Notice-PGA-E © 2015 ROHM Co., Ltd. All rights reserved. Rev.001 Datasheet General Precaution 1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents. ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny ROHM’s Products against warning, caution or note contained in this document. 2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s representative. 3. The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or concerning such information. Notice – WE © 2015 ROHM Co., Ltd. All rights reserved. Rev.001 Datasheet BD8312HFN - Web Page Buy Distribution Inventory Part Number Package Unit Quantity Minimum Package Quantity Packing Type Constitution Materials List RoHS BD8312HFN HSON8 3000 3000 Taping inquiry Yes