BM1703

BM1707 BOOKLY | Alldatasheet

Document overview

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Technical content

Features

¾ Input Voltage Range: 2.5 to 5.5V ¾ Adjustable Output Voltage From 0.6V to V IN ¾ Precision Feedback Reference Voltage: 0.6V (±2%) ¾ Output Current: 2A (Max.) ¾ Up to 95% efficiency ¾ Internal Fixed PWM Frequency: 1.5MHz ¾ Low Quiescent Current: BM1703=100 μA ,BM1707=45uA ¾ No Sch ottky Diode Required ¾ Built-in Soft Start ¾ Current Mode Operation ¾ Over Temperature Protection ¾ Package: MSOP-10L (EP) and SOT23-5

Applications

¾ USB device ¾ Wireless and DSL Modems ¾ Set-top-box ¾ MID(=PAD) ¾ 3G/2G net-card Typical Application Circuit BM1703 GND SW FB / VOUT VIN RUN V 1 5.5V VIN OUT A .8V / 22.5V /

www.bookly.com BM1703/BM1707 Function Block Diagram

www.bookly.com BM1707/BM1703 Pin Descriptions M S O P - 1 0 L ( E P ) Name 10L. 5L. ddescription EN 1 1 Enable / UVLO VCC 2 4 Supply Voltage AVCC 3 Analog Supply Voltage PGOOD 4 Power Good Open Drain Output FB / VOUT 5 5 Feedback Pin AGND 6 2 Analog Ground SW 7 3 Switch Pin SW 8 Switch Pin GND 9 Ground GND 10 Ground EP 11 Exposed PA D - Must Connect to Ground Top View GND GND E N V CC AVCC PGOOD 101 SW83 SW74 AGNDFB / VOUT 65 Bottom View EP . 8V

www.bookly.com BM1703/BM1707

Ordering Information

Part Number Operating Temperature Package MOQ Description BM1703-ADgR-G1 -40°C ~ +85°C MSOP-10L (EP) 2500EA Tape & Reel BM1703-15gR-G1 -40°C ~ +85°C MSOP-10L (EP) 2500EA Tape & Reel BM1707 -40°C ~ +85°C SOT23-5 3000EA Absolute Maximum Ratings Parameter Symbol Conditions Min. Typ. Max. Unit Input Supply Voltage VIN -0.3 6 V RUN, VFB, SW Pin Voltage -0.3 VIN V P-Channel Switch Source Current (DC) 2.6 A N-Channel Switch Source Current (DC) 2.6 A Peak SW Switch Sink and Source Current (AC) 4.3 A Thermal Resistance (Junction to Ambient) θJA MSOP-10L +70 °C / W Thermal Resistance (Junction to Case) θJC MSOP-10L +10 °C / W Operating Temperature -40 +85 °C Junction Temperature +150 °C Storage Temperature -65 +150 °C Lead Temperature (soldering, 10 sec) MSOP-10L +260 °C Suggested IR Re-flow Soldering Curve

www.bookly.com BM1707/BM1703 Recommended Operating Conditions Parameter Symbol Conditions Min. Typ. Max. Unit Supply Voltage VIN 2.5 6.0 V Operating Temperature -40 +85 °C Parameter Symbol Conditions Min. Typ. Max. Unit TA=25°C 0.588 0.6 0.612 V Regulated Feedback Voltage VFB Line Regulation with VREF ΔVFB VIN=2.5V to 5.5V 0.04 0.4 % / V BM1703-1.5, IOUT=100mA 1.455 1.5 1.545 V Regulated Output Voltage VOUT BM1703-1.8, IOUT=100mA 1.746 1.8 1.845 V Output Voltage LineRegulation ΔVOUT VIN=2.5 to 5.5V 0.04 0.4 % / V RDS (ON) of P-Channel FET RDS (ON) P I SW=100mA 0.11 0.12 0.135 Ω RDS (ON) of N-Channel FET RDS(ON)N I SW =-100mA 0.12 0.13 0.14 Ω SW Leakage ILSW V RUN=0V, VIN=5V ±0.01 ±1 µA Peak Inductor Current IPK V FB=0.5V 3.3 A Shutdown, VRUN=0V 0.1 1 µA BM1703 100 µA Quiescent Current Iq BM1707 45 µA RUN Threshold VRUN -40°C~+85°C 0.3 1 1.5 V RUN Leakage Current IRUN -40°C ~+85°C ±0.01 ±1 µA Oscillator Frequency FOSC V FB=0.6V, -40°C ~+85°C 1.2 1.5 1.8 MHz

www.bookly.com BM1707/BM1703 Typical Operating Characteristics (TA= 25°C, VIN=3.6V, unless otherwise noted) Supply Current vs. VIN 120 122 124 126 128 130 132 134 136 138 140 2 2.5 3 3.5 4 4.5 5 5.5 6 V IN (V) Supply Current (uA) 85℃ 25℃ -45℃ VFB=0.5V Supply Current vs. VIN 22 . 533 . 544 . 555 . 56 VIN (V) Supply Current (uA) 85℃ 25℃ -45℃ VFB=0.65V Line Regulation 0.585 0.59 0.595 0.6 0.605 0.61 22 . 533 . 544 . 555 . 56 VIN (V) Reference Voltage (V) TA=25℃ Supply Current vs. VIN 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 2 2.5 3 3.5 4 4.5 5 5.5 6 VIN (V) Supply Current (uA) 85℃ 25℃ -45℃ Shutdown Reference Voltage vs. Temperature 0.595 0.596 0.597 0.598 0.599 0.6 0.601 0.602 - 6 0 - 5 0 - 4 0 - 3 0 - 2 0 - 1 00 1 02 03 04 05 06 07 08 09 0 Temperature ( Reference Voltage (V) VIN=3.6V Frequency vs. VIN 1.45 1.46 1.47 1.48 1.49 1.5 1.51 1.52 1.53 1.54 1.55 22 . 533 . 544 . 555 . 56 V IN (V) Frequency (MHz) TA=25℃ SWITCH LEAKAGE vs. INPUT VOLTAGE 0.2 0.4 0.6 0.8 1.2 1234567 V IN (V) SWITCH LEAKAGE(nA) SYNCHRONOU MAIN SWITCH TA=25℃ Frequency vs. Temerature 1.47 1.475 1.48 1.485 1.49 1.495 1.5 1.505 1.51 1.515 1.52 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 Temperature(℃) Frequency (MHz) VIN =3.6V

www.bookly.com BM1703/BM1707 Function Description Control Loop The BM1703 is a high efficiency current mode synchronous buck regulator. Both the main (P-channel MOSFET) and synchronous (N-channel MOSFET) switches are built internally. With current mode operation, the PWM duty is controll ed both by the error amplifier output and the peak inductor current. At the beginning of each cycle, the oscillator turn on the P-MOSFET switch to source current from V IN to SW output. Then, the chip starts to compare the inductor current with the error amplifier output. Once the inductor current is larger than the error amplifier output, the P-MOSFET switch is turned off. When the load current increases, the feedback voltage FB will slightly drop. This causes the error amplifier to output a higher current level until the prior mentioned peak inductor current reach the same level. The output voltage then can be sustained at the same. When the top P-MOSFET switch is off, the botto m synchronous N-MOSFET switch is turned on. Once the inductor current reverses, both top and bottom MOSFET will be turn off to leave the SW pin into high impedance state. The BM1703’s current mode control loop also includes slope compensation to suppress sub-harmonic oscillations at high duty cycles. This slope compensation is achieved by adding a compensation ramp to the inductor current signal. LDO Mode The BM1703’s maximum duty cycle can reach 100%. That means the driver’s main switch is turn on through out whole clock cycle. Once the duty reaches 100%, the feedback path no longer controls the output voltage. The output voltage will be the input voltage minus the main switch voltage drop. Over Current Protection BM1703 limits the peak main switch current cycle by cycle. When over current occurs, chip will turn off the main switch and turn the synchronous switch on until next cycle. Short Circuit Protection When the FB pin is drop below 300mV , the chip will tri-state the output pin SW automatically. After 300us rest to avoid over heating, chip will re-initiate PWM operation with soft start. Power Good The power good function is an open-drain output. Connects 100kΩ pull up resistor to VIN to obtain a PGOOD voltage. The PGOOD pin will output high immediately after the output voltage arrives 90% of setting output voltage. The PGOOD pin will output high with delay time. Connect to AGND if no used. Thermal Protection BM1703 will shutdown automatically when the internal junction temperature reaches 125 ℃ to protect both the part and the system.

www.bookly.com BM1707/BM1703

Application Information

The input capacitor must be connected to the VIN pin and GND pin of BM1703 to maintain steady input voltage and filter out t he pulsing input current. The voltage rating of input capacitor must be greater than maximum input voltage plus ripple voltage. In switch mode, the input current is discontinuo us in a buck converter. The source current waveform of the high-side MOSFET is a square wa ve. To prevent large voltage transients, a low ESR input capacitor sized for the maximum RMS current must be used. The RMS value of input capacitor current can be calculated by: ⎛ −= IN O IN O MAX _ ORMS V V1V VI I can be seen that when VO is half of VIN, CIN is under the worst current stress. The worst current stres ductor Selection nductor is selected based on the desired ripple current. Large inductance gives low in It s on CIN is IO_MAX/2. In The value of the i ductor ripple current and small inductance result in high ripple current. However, the larger value inductor has a larger physical size, higher series resistance, and/or lower saturation current. In experience, the value is to allow the peak-to-pea k ripple current in the inductor to be 10%~20% maximum load current. The inductance value can be calculated by: [] IN OO INO O IN V ) V V (V ) V V (L −=−= OIN L V I %) 20 ~ % 10 ( 2 f V I f× ×Δ × The inductor ripple current can be calculated by: ⎡ − × = Δ OO L V1VI ⎦ ⎣× INV L f Choose an inductor that does not saturate u nder the worst-case load conditions, which is the load current plus half the peak-to-peak induct or ripple current, even at the highest operating temperature. The peak inductor current is: ILΔ+ =I IO_ LPEAK The inductors in different shape and style are available from manufacturers. Shielded inductors are small and radiate less EMI issue. But they cost more than unshielded inductors. The choice depends on EMI requirement, price and size.

www.bookly.com BM1703 /BM1707 Inductor Value (µH) Dimensions (mm) Component Supplier Model 2.2 8.3×8.3×4.5 FENG-JUI TPRH8D43-2R2M 2.2 10.3×10.3×4.0 FENG-JUI TPRH10D40-2R2M 3.3 8.3×8.3×4.5 FENG-JUI TPRH8D43-3R3M 3.3 10.3×10.3×4.0 FENG-JUI TPRH10D40-3R3M 4.7 8.3×8.3×4.5 FENG-JUI TPRH8D43-4R7M 4.7 10.3×10.3×4.0 FENG-JUI TPRH10D40-4R7M Output Capacitor Selection The output capacitor is required to maintain t he DC output voltage. Low ESR capacitors are preferred to keep the output voltage ripple low. In a buck converter circuit, output ripple voltage is determined by inductor value, switching frequency, output capacitor value and ESR. The output ripple is determined by: × ×+× Δ = Δ OUT COUTL O C f 8 1ESR I V Where f = operating frequency, COUT= output capacitance and ΔIL = ripple current in the inductor. For a fixed output voltage, the output ripple is highest at maximum input voltage since ΔIL increases with input voltage. Capacitor Value Case Size Component Supplier Model 10μF 0805 Taiyo Yuden JMK212BJ106MG 10μF 0805 TDK C12012X5ROJ106K 22μF 0805 1206 TDK C2012JB0J226M Using Ceramic Input and Output Capacitors Care must be taken when ceramic capacitors are used at the input and the output. When a ceramic capacitor is used at the input and the power is supplied by a wall adapter through long wires, a load step at the output can induce ringing at the input, VIN. At best, this ringing can couple to the output and be mistaken as loop instability. At worst, a sudden inrush current through the long wires can potentially cause a voltage spike at V IN, which may large enough to damage the part. When choosing the input and output ceramic capacitors, choose the X5R or X7R specification. Their dielectrics have the best temperature and voltage characteristics of all the ceramics for a given value and size. Output Voltage Programming In the adjustable version, the output voltage is set using a resistive voltage divider from the output voltage to FB. The output voltage is: ⎛ + = O R R1 V 6 . 0 V

www.bookly.com BM1707/BM1703 VOUT (V) R1 (Ω) R2 (Ω) C3 (F) 0.6 200k Not Used Not Used 1.2 200k 200k 10p 1.5 300k 200k 10p 1.8 200k 100k 10p 2.5 270k 85k 10p 3.3 306k 68k 10p The recommended resistor value is summarized above. PC Board Layout Checklist 1. The power traces, consisting of the GND, SW and V IN trace should be kept short, direct and wide. 2. Place C IN near VIN pin as closely as possible to maintain input voltage steady and filter out the pulsing input current. 3. The resistive divider R 1 and R2 must be connected to FB pin directly and as closely as possible. 4. FB is a sensitive node. Please keep it away from switching node, SW. A good approach is to route the feedback trace on another PCB layer and have a ground plane between the top and feedback trace routing layer. This reduces EM I radiation on to the DC-DC converter its own voltage feedback trace. 5. Keep the GND plates of C IN and C OUT as close as possible. Then connect this to the ground plane (if one is used) with several vias. This reduces ground plane noise by preventing the switching currents from circulating through the ground plane. It also reduces ground bounce by giving it a low impedance ground connection. Suggested Layout for MSOP-10L

3 BM1703

www.bookly.com BM1707/ BM1703 Typical Application BM 1703 GND SW V CC PGOOD 1 10GNDEN 2 9 GND L 200K 100K C 2 22UF 1 3.3U H/2.2A C 3 10 pF C 1 22UF SW AGND AV CC

8 VV IN OUT

/ V 5 V DFN - 10L/ MSOP -10L 2. / 5.5V 21.8 A 100K VIN 2.5V TO 5.5V CIN 4.7µF COUT 10µF RF1 470K RF2 150K L 2.2µH VOUT=2.5V 4 3 VDD SW GND RUN FB APW7101 BM1707 SOT23-5

www.bookly.com BM1707/BM1703 ILOAD: 100mA~2A I LOAD: 500mA~2A Ch1:VOUT C h 4 : IS W Ch1:VOUT Ch4: I SW EN On waveform (VOUT: 1 . 8 V ) E f f i c i e n c y ( VOUT: 1.8V) 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00 2.7V 3.6V 4.2V Ch1:EN Ch2: SW Ch3:VOUT Ch4:ISW PGOOD waveform (VOUT: 1.8V) Ch1:EN Ch2: VOUT Ch3:PGOOD

www.bookly.com BM1707/BM1703 P a c k a g e O u t l i n e M S O P - 1 0 L ( E P ) U N I T : m m Symbols Min. (mm) Max. (mm) A 1.100 A1 0.000 0.150 A2 0.750 0.950 b 0.170 0.270 c 0.080 0.230 D 3.000 BSC. E 4.900 BSC. E1 3.000 BSC. e 0.500 BSC. L 0.400 0.800 L1 0.950 REF. θ° 0° 8° MSOP-10L (EP) Exposed PAD Dimensions: Symbols Min. (mm) Max. (mm) E2 1.715 REF D1 1.600 REF Note: 1. Package dimensions are in compliance with JEDEC outline: MO-187 BA-T. 2. Dimension “D” does not include molding flash, protrusions or gate burrs. 3. Dimension “E1” does not include inter-lead flash or protrusions.