MIC4723YMME-TR

MIC4723 3A 2MHz Integrated Switch Buck Regulator General Description Features The Micrel MIC4723 is a high efficiency PWM buck (stepdown) regulator that provides up to 3A of output current. The MIC4723 operates at 2.0MHz and has proprietary internal compensation that allows a closed loop bandwidth of over 200KHz. The low on-resistance internal p-channel MOSFET of the MIC4723 allows efficiencies over 92%, reduces external components count and eliminates the need for an expensive current sense resistor. The MIC4723 operates from 2.7V to 5.5V input and the output can be adjusted down to 1V. The devices can operate with a maximum duty cycle of 100% for use in lowdropout conditions. The MIC4723 is available in the exposed pad 12-pin 3mm x 3mm MLF® and 10-pin ePAD MSOP packages with a junction operating range from –40°C to +125°C. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. • • • • • • • • • • • • • • 2.7/3.0V to 5.5V supply voltage 2.0MHz PWM mode Output current to 3A Up to 94% efficiency 100% maximum duty cycle Adjustable output voltage option down to 1V Ultra-fast transient response Ultra-small external components Stable with a 1µH inductor and a 4.7µF output capacitor Fully integrated 3A MOSFET switch Micropower shutdown Thermal shutdown and current limit protection Pb-free 12-pin 3mm x 3mm MLF® package Pb-free 10-pin ePAD MSOP package –40°C to +125°C junction temperature range Applications • FPGA/DSP/ASIC applications • General point of load • Broadband communications • DVD/TV recorders • Point of sale • Printers/Scanners • Set top boxes • Computing peripherals • Video cards ___________________________________________________________________________________________________________ Typical Application 96 94 92 MIC4723 3.3VOUT Efficiency 4.5VIN 90 88 86 5VIN 5.5VIN 84 82 80 3A 2MHz Buck Regulator 78 76 0 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 3 MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com June 2008 M9999-060308-E Micrel, Inc. MIC4723 Ordering Information Part Number Voltage Temperature Range Package Lead Finish ® MIC4723YML Adj. –40° to +125°C 12-Pin 3x3 MLF MIC4723YMME Adj. –40° to +125°C 10-Pin ePAD MSOP Pb-Free Pb-Free Note ® MLF is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. Pin Configuration SW 1 12 SW SW 1 10 SW VIN 2 11 VIN VIN 2 9 VIN PGND 3 10 NC SGND 3 8 PGND SGND 4 9 PGOOD BIAS 4 7 PGOOD 6 EN BIAS 5 8 EN FB 6 EP FB 5 EP 7 NC 12-Pin 3mm x 3mm MLF (ML) 10-Pin ePAD MSOP (MME) Pin Description Pin Number MLF-12 Pin Number MSOP-10 1, 12 1, 10 SW Switch (Output): Internal power P-Channel MOSFET output switch. 2, 11 2, 9 VIN Supply Voltage (Input): Supply voltage for the source of the internal P-channel MOSFET and driver. Requires bypass capacitor to GND. Pin Name Pin Function 3 8 PGND Power Ground. Provides the ground return path for the high-side drive current. 4 3 SGND Signal (Analog) Ground. Provides return path for control circuitry and internal reference. 5 4 BIAS 6 5 FB Feedback. Input to the error amplifier, connect to the external resistor divider network to set the output voltage. 7, 10 — NC No Connect. Not internally connected to die. This pin can be tied to any other pin if desired. 8 6 EN Enable (Input). Logic level low, will shutdown the device, reducing the current draw to less than 5µA. 9 7 PGOOD EP EP GND June 2008 Internal circuit bias supply. Must be bypassed with a 0.1µF ceramic capacitor to SGND. Power Good. Open drain output that is pulled to ground when the output voltage is within ±7.5% of the set regulation voltage. Connect to ground. 2 M9999-060308-E Micrel, Inc. MIC4723 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) .......................................................+6V Output Switch Voltage (VSW) ..........................................+6V Output Switch Current (ISW)............................................11A Logic Input Voltage (VEN) .................................. –0.3V to VIN Storage Temperature (Ts) .........................–60°C to +150°C Supply Voltage (VIN)..................................... +2.7V to +5.5V Logic Input Voltage (VEN) ....................................... 0V to VIN Junction Temperature (TJ) ........................ –40°C to +125°C Junction Thermal Resistance 3mm x 3mm MLF-12 (θJA) .................................60°C/W 3mm x 3mm MLF-12 (θJc) .................................28°C/W ePAD MSOP-10 (θJA) ........................................76°C/W ePAD MSOP-10 (θJc) ........................................28°C/W Electrical Characteristics(4) VIN = VEN = 3.6V; L = 1µH; COUT = 4.7µF; TA = 25°C, unless noted. Bold values indicate –40°C< TJ < +125°C. Parameter Condition MIC4723YML MIC4723YMME Supply Voltage Range Under-Voltage Lockout Threshold Min 2.7 3.0 2.45 (turn-on) Typ UVLO Hysteresis 2.55 Max Units 5.5 5.5 V V 2.65 V 100 Quiescent Current VFB = 0.9 * VNOM (not switching) Shutdown Current VEN = 0V [Adjustable] Feedback Voltage ± 2% (over temperature) ILOAD = 100mA 570 900 µA 2 10 µA 1.02 V 0.98 FB pin input current mV 1 3.5 nA Current Limit in PWM Mode VFB = 0.9 * VNOM 5 A Output Voltage Line Regulation VOUT > 2V; VIN = VOUT+500mV to 5.5V; ILOAD= 100mA VOUT < 2V; VIN = 2.7V to 5.5V; ILOAD= 100mA 0.07 % % Output Voltage Load Regulation 20mA < ILOAD < 3A 0.2 % Maximum Duty Cycle VFB ≤ 0.4V PWM Switch ONResistance ISW = 50mA; VFB = GND (High Side Switch) 100 % 95 200 300 mΩ mΩ MHz Oscillator Frequency 1.8 2 2.2 Enable Threshold 0.5 0.85 1.3 V Enable Hysteresis 50 Enable Input Current 0.1 2.3 µA Power Good Range ±7 ±10 % 150 250 Ω Power Good Resistance IPGOOD = 500µA mV Over-Temperature Shutdown 160 °C Over-Temperature Hysteresis 25 °C Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Specification for packaged product only. June 2008 3 M9999-060308-E Micrel, Inc. MIC4723 Typical Characteristics MIC4723 3.3V OUT Efficiency 96 4.5VIN 94 94 5VIN 92 92 86 82 84 80 78 82 76 0 80 0 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 3 MIC4723 1.8V OUT Efficiency 90 88 4.5VIN 5VIN 86 84 82 80 5.5VIN 78 76 74 72 70 68 66 64 62 60 0.5 1 1.5 2 2.5 0 OUTPUT CURRENT (A) 92 90 3VIN 88 3.3VIN 86 84 82 3.6VIN 80 78 76 74 72 70 68 66 64 0 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 3 3 MIC4723 1V OUT Efficiency 90 88 86 84 82 80 78 76 74 72 70 68 66 64 62 60 0 80 78 5VIN 72 68 76 74 5.5VIN 72 70 66 64 62 68 66 60 0 64 0 June 2008 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 90 88 5.5VIN 3 MIC4723 2.5VOUT Efficiency 3VIN 3.3VIN 3.6VIN 86 84 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 96 94 92 3VIN 3.3VIN 90 88 86 84 3.6VIN 82 80 78 76 74 72 70 68 66 0 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 84 82 4.5VIN 74 70 94 92 82 80 0 3 MIC4723 1.8V OUT Efficiency MIC4723 1.5V OUT Efficiency 76 5VIN 88 86 84 78 4.5VIN 90 5.5VIN 100 98 96 86 84 82 80 78 76 74 72 70 68 66 64 0 3 MIC4723 1.2V OUT Efficiency 5VIN 5.5VIN 3 MIC4723 1V OUT Efficiency 3VIN 3 MIC4723 1.5VOUT Efficiency 4.5VIN 5VIN 5.5VIN 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 90 88 86 3VIN 84 3.3VIN 82 80 78 76 3.6VIN 74 72 70 68 66 64 62 60 0.5 1 1.5 2 2.5 0 OUTPUT CURRENT (A) 4.5VIN 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 3 MIC4723 1.2VOUT Efficiency 3 Load Regulation 1.010 OUTPUT VOLTAGE (V) 90 88 MIC4723 2.5V OUT Efficiency 3.3VIN 3.6VIN 1.005 1.000 0.995 3.3V VIN = 3.3V 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 4 3 0.990 0 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) 3 M9999-060308-E Micrel, Inc. MIC4723 Typical Characteristics (continue) Line Regulation 1.0010 1.0008 1.010 1.008 Feedback Voltage vs. Temperature 1.0006 1.006 2.5 2.4 2.3 1.0004 1.0002 1.004 1.002 2.2 2.1 1.0000 0.9998 1.000 0.998 2.0 1.9 0.9996 0.996 0.9994 0.9992 0.994 0.992 V = 3.3V IN 0.990 20 40 60 80 TEMPERATURE (°C) 1.8 1.7 0.9990 2.7 3.2 3.7 4.2 4.7 5.2 SUPPLY VOLTAGE (V) Feedback Voltage vs. Supply Voltage 1.2 800 1.6 V = 3.3V IN 1.5 20 40 60 80 TEMPERATURE (°C) Quiescent Current vs. Supply Voltage 115 110 105 600 0.8 500 100 95 400 0.6 90 85 80 300 0.4 200 0.2 VEN = VIN 0 0 1 2 3 4 5 SUPPLY VOLTAGE (V) RDSON vs. Temperature 160 140 100 0 0 1.2 R DSON vs. Supply Voltage 120 700 1.0 Frequency vs. Temperature VEN = VIN 1 2 3 4 5 SUPPLY VOLTAGE (V) Enable Threshold vs. Supply Voltage 6 75 70 2.7 1.2 1.0 1.0 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 3.2 3.7 4.2 4.7 5.2 SUPPLY VOLTAGE (V) Enable Threshold vs. Temperature 120 100 80 60 40 20 VIN = 3.3V VIN = 3.3V 0 June 2008 20 40 60 80 TEMPERATURE (°C) 0 2.7 3.2 3.7 4.2 4.7 SUPPLY VOLTAGE (V) 5 0 20 40 60 80 TEMPERATURE (°C) M9999-060308-E Micrel, Inc. MIC4723 Functional Characteristics June 2008 6 M9999-060308-E Micrel, Inc. MIC4723 Functional Diagram VIN VIN P-Channel Current Limit BIAS HSD SW SW PWM Control EN Enable and Control Logic Bias, UVLO, Thermal Shutdown Soft Start FB EA 1.0V PGOOD 1.0V PGND SGND MIC4723 Block Diagram June 2008 7 M9999-060308-E Micrel, Inc. MIC4723 Pin Description SW The switch (SW) pin connects directly to the inductor and provides the switching current necessary to operate in PWM mode. Due to the high speed switching on this pin, the switch node should be routed away from sensitive nodes. This pin also connects to the cathode of the free-wheeling diode. VIN Two pins for VIN provide power to the source of the internal P-channel MOSFET along with the current limiting sensing. The VIN operating voltage range is from 2.7V to 5.5V for the MIC4723YML or 3.0V to 5.5V for the MIC4723YMME. Due to the high switching speeds, a 10µF capacitor is recommended close to VIN and the power ground (PGND) for each pin for bypassing. Please refer to layout recommendations. PGOOD Power good is an open drain pull down that indicates when the output voltage has reached regulation. When power good is low, then the output voltage is within ±10% of the set regulation voltage. For output voltages greater or less than 10%, the PGOOD pin is high. This should be connected to the input supply through a pull up resistor. A delay can be added by placing a capacitor from PGOOD to ground. BIAS The bias (BIAS) provides power to the internal reference and control sections of the MIC4723. A 10Ω resistor from VIN to BIAS and a 0.1µF from BIAS to SGND is required for clean operation. EN The enable pin provides a logic level control of the output. In the off state, supply current of the device is greatly reduced (typically 100MHz bandwidth is more than sufficient for most power supplies (which includes both linear and switching) and are more common and significantly cheaper than the injection transformers previously mentioned. The one disadvantage to using the op-amp injection method; is the supply voltages need to below the maximum operating voltage of the op-amp. Also, the maximum output voltage for driving 50Ω inputs using the MIC922 is 3V. For measuring higher output voltages, 1MΩ input impedance is required for the A and R channels. Remember to always measure the output voltage with an oscilloscope to ensure the measurement is working properly. You should see a single sweeping sinusoidal waveform without distortion on the output. If there is distortion of the sinusoid, reduce the amplitude of the source signal. You could be overdriving the feedback causing a large signal response. Figure 7. Transformer Injection A 50Ω resistor allows impedance matching from the network analyzer source. This method allows the DC loop to maintain regulation and allow the network analyzer to insert an AC signal on top of the DC voltage. The network analyzer will then sweep the source while monitoring A and R for an A/R measurement. While this is the most common method for measuring the gain and phase of a power supply, it does have significant limitations. First, to measure low frequency gain and phase, the transformer needs to be high in inductance. This makes frequencies