BD9329AEFJ : Power Management

1 Datasheet 2012 ROHM Co., Ltd. All rights reserved. TSZ22111 14 001 TSZ02201-0323 AAJ00010-1-2 to 18V, 3A 1ch Synchronous Buck Converter with Integrated FET BD9329 AEFJ General Description The BD9329 AEFJ is a synchronous step-down switching regulator with built-in two low-resistance N-Channel MOSFETs. This IC can supply continuous output current of 3A over a wide input range, and provides not only fast transient response, but also easy phase compensation because of current mode control. Features Uses Low ESR Output Ceramic Capacitors Low Standby Current 380 kHz Fixed Operating Frequency Feedback V oltage (Ta=25 C) (Ta=-25 C to +85 C) Under Voltage Protection Thermal Shutdown Over Current Protection Applications Distributed Power Systems Pre-Regulator for Linear Regulators Key Specifications I nput Voltage Range: to 18V Output Voltage Range: to (VIN x )V Output Current: (Max) Switching Frequency 380kHz(Typ) Hi-Side FET ON-Resistance: (Typ) Lo-Side FET ON-Resistance: (Typ) Standby Current: 15 A (Typ) Operating Temperature Range.

2 -40 C to +85 C Package W(Typ) D(Typ) H(Max) Typical Application Circuit R_BS protects from VIN-BST short destruction. Figure 1. Typical Application Circuit C_CO1 R_PC R_UP C_BS F 10 H C_VC1 10 F C_PC 3300pF R_DW 10k 27k 20 F C_SS F L SS EN COMP FB BST VIN GND SW Thermal Pad (to be shorted to GND) VIN = 12V VOUT = R_BS 22 HTSOP-J8 x x Product structure : Silicon monolithic integrated circuit This product has no designed protection against radioactive rays 1/ 19 BD9329 AEFJ 2012 ROHM Co., Ltd. All rights reserved. TSZ22111 15 001 TSZ02201-0323 AAJ00010-1-2 Pin Configuration Block Diagram Figure 2.

3 Pin Configuration Figure 3. Block Diagram Pin Description Pin No. Pin Name Function 1 BST High-side gate drive boost input 2 VIN Power input 3 SW Power switching output 4 GND Ground 5 FB Feedback input 6 COMP Compensation node 7 EN Enable input 8 SS Soft start control input (TOP VIEW) BST VIN SW GND FB COMP EN SS VIN VIN 2/19 BD9329 AEFJ 2012 ROHM Co., Ltd. All rights reserved. TSZ22111 15 001 TSZ02201-0323 AAJ00010-1-2 Absolute Maximum Ratings ( Ta = 25 C) Parameter Symbol Rating Unit Supply Voltage VIN 20 V Switch Voltage VSW 20 V Power Dissipation for HTSOP-J8 Pd (Note 1) W Package Thermal Resistance ja (Note 2) ja C/W Package Thermal Resistance jc (Note 2) jc C/W Operating Temperature Range Topr -40 to +85 C Storage Temperature Range Ts t g -55 to +150 C Maximum Junction Temperature Tjmax 150 C BST Voltage VBST VSW+7 V EN Voltage VEN 20 V All Other Pins VOTH 20 V (Note 1) Reduced by mW/ C over 25 C (Mount on 4-layer x x board) (Note 2) Mount on 4-layer 50mm x 30mm x application board Caution: Operating the IC over the absolute maximum ratings may damage the IC.

4 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 = -40 C to +85 C) Parameter Symbol Rating Unit Min Typ Max Supply Voltage VIN 12 18 V SW Voltage VSW - +18 V Output Current ISW3 - - 3 A Output Voltage Range VRANGE - VIN x V Electrical Characteristics (Unless otherwise specified VIN=12V Ta=25 C) Parameter Symbol Limit Unit Conditions Min Typ Max Error Amplifier Block FB Input Bias Current IFB - 2 A Feedback Voltage1 VFB1 V Voltage Follower Feedback Voltage2 VFB2 V Ta =-25 C to +85 C SW Block SW Hi-Side FET ON-R esistance RONH - - ISW= Lo-Side FET ON-R esistance RONL - - ISW= Hi/Lo-Side FET Leak Current ILEAKN - 0 10 A VIN= 18V.

5 VSW = 0V / 18V Switch Current Limit ILIMIT3 - - A Maximum Duty Cycle MDUTY - 90 - % VFB= 0V General Enable Sink Current IEN 90 180 270 A VEN= 12V Enable Threshold Voltage VEN V Under Voltage Lockout Threshold VUVLO V VIN Rising Under Voltage Lockout Hysteresis VHYS - - V Soft Start Current ISS 5 10 15 A VSS= 0V Soft Start Time tSS - 22 - ms CSS= F Operating Frequency fOSC 300 380 460 kHz Circuit Current ICC - 3 mA VFB= , VEN= 12V Standby Current IQUI - 15 27 A VEN= 0V 3/19 BD9329 AEFJ 2012 ROHM Co., Ltd. All rights reserved. TSZ22111 15 001 TSZ02201-0323 AAJ00010-1-2 Typical Performance Curves (Unless otherwise specified, VIN= 12V Ta = 25 C) Figure 7. Feedback Voltage vs Temperature Figure 4.

6 Circuit Current vs Input Voltage (No Switching) Figure 5. Standby Current vs Input Voltage (Shutdown Mode) Figure 6. Input Bias Current vs Feedback Voltage ICC (mA) VIN [V] ICC ( A) VIN [V] IFB ( A) VFB [V] Temp [ C] 4/19 BD9329 AEFJ 2012 ROHM Co., Ltd. All rights reserved. TSZ22111 15 001 TSZ02201-0323 AAJ00010-1-2 Typical Performance Curves - continued Figure 8. Hi-Side, Low-Side FET ON-Resistance vs Temperature Figure 9. Operating Frequency vs Temperature Figure 10. STEP-Down Efficiency vs IO (VIN= 12V VOUT= L=10 H) Figure 11. Soft Start Time vs CSS RON ( ) Temp [ C] 360365370375380385390-40-20020406080 TEMP ( C)FOSC (kHz)fOSC (kHz) Temp [ C] Efficiency IO [mA] Soft Start Time [ms] CSS [ F] 5/19 BD9329 AEFJ 2012 ROHM Co.

7 , Ltd. All rights reserved. TSZ22111 15 001 TSZ02201-0323 AAJ00010-1-2 Typical Waveforms Figure 12. Over Current Protection (VOUT is shorted to GND) Figure 13. Transient Response (VIN= 12V, VOUT= , L= 10 H, COUT =22 F, IOUT= ) Figure 15. Transient Response (VIN= 12V, VOUT= , L= 10 H, COUT =22 F, IOUT = ) Figure 14. Output Ripple Voltage (VIN= 12V, VOUT= , L= 10 H, COUT =22 F, IOUT= ) IOUT 6/19 BD9329 AEFJ 2012 ROHM Co., Ltd. All rights reserved. TSZ22111 15 001 TSZ02201-0323 AAJ00010-1-2 Typical Waveforms - continued Figure 17. Start-U p Waveform (VIN= 12V, VOUT= , L= 10 H, CSS= F) Figure 16. Output Ripple Voltage (VIN= 12V, VOUT= , L= 10 H, COUT =22 F, IOUT= ) tSS 7/19 BD9329 AEFJ 2012 ROHM Co.

8 , Ltd. All rights reserved. TSZ22111 15 001 TSZ02201-0323 AAJ00010-1-2 Application Information 1. Typical Application Circuit R_BS protect from VIN-BST short destruction. Figure 18. Typical Application Circuit Symbol Maker Part No Input Capacitor C_VC1 TDK C3225JB1E106K 10 F/25V Output Capacitor C_CO1 TDK C3216JB1C106M 10 F/16V Inductor L TDK SLF10165-100M3R8 10 C_BS F VOUT = R_BS 22 VIN = 12V C_CO1 R_UP 10 H C_VC1 10 F C_PC 3300pF R_DW 10k 27k 20 F C_SS F L SS EN COMP- FB BST VIN GND SW Thermal Pad (to be shorted to GND) R_PC 8/19 BD9329 AEFJ 2012 ROHM Co., Ltd. All rights reserved. TSZ22111 15 001 TSZ02201-0323 AAJ00010-1-2 2. Block Operation (1) VREG This block generates a constant voltage for DC/DC boosting.

9 (2) VREF This block generates an internal reference voltage of (Typ). (3) TSD/UVLO TSD (Thermal shutdown)/UVLO (Under Voltage Lockout) protection block. The TSD circuit shuts down the IC at high temperature. The UVLO circuit shuts down the IC when the VIN voltage is low. (4) Error Amp Block (ERR) This block compares the reference voltage and the feedback voltage from the output. The output voltage of this block, which is connected to COMP pin, determines the switching duty cycle. At the time of startup, since the soft-start is operated by the SS pin voltage, the COMP pin voltage is limited to the SS pin voltage. (5) Oscillator Block (OSC) This block generates the oscillating frequency. (6) SLOPE Block This block generates the triangular waveform with the use of the clock created by OSC.

10 The generated triangular waveform is sent to the PWM comparator. (7) PWM Block The COMP pin voltage output of the error amp is compared with the SLOPE block's triangular waveform to determine the switching duty. Since the switching duty cycle is limited by the maximum duty ratio which is determined internally, 100% duty cycle cannot be achieved. (8) DRV Block This is the A DC/DC driver block that accepts signal from the PWM block to drive the Power FETs. (9) OCP Block OCP (Over Current Protection) block. The current that flows through the FETs is detected, and OCP starts when it reaches (min). After OCP detection, switching is turned OFF and the SS capacitor is discharged. OCP is self-recovery type (not latch). (10) Soft-Start Circuit This circuit prevents output voltage overshoot or inrush current by making the output voltage rise gradually while restricting the current at the time of startup.