MIC2182YM

MIC2182 High-Efficiency Synchronous Buck Controller Features General Description • • • • • • • • • The MIC2182 is a synchronous buck (step-down) switching regulator controller. An all N-channel synchronous architecture and powerful output drivers allow up to a 20A output current capability. The PWM and skip-mode control scheme allows efficiency to exceed 95% over a wide range of load current, making it ideal for battery powered applications, as well as high current distributed power supplies. • • • • • • • • • • • 4.5V to 32V Input Voltage Range 1.25V to 6V Output Voltage Range 95% Efficiency 300 kHz Oscillator Frequency Current Sense Blanking 5Ω Impedance MOSFET Drivers Drives N-channel MOSFETs 600 µA Typical Quiescent Current (Skip-Mode) Logic Controlled Micropower Shutdown (IQ < 0.1 µA) Current-Mode Control Cycle-by-Cycle Current Limiting Built-In Undervoltage Protection Adjustable Undervoltage Lockout Easily Synchronizable Precision 1.245V Reference Output 0.6% Total Regulation 16-Lead SOIC and SSOP Packages Frequency Foldback Overcurrent Protection Sustained Short-Circuit Protection at Any Input Voltage 20A Output Current Capability Applications • • • • • The MIC2182 operates from a 4.5V to 32V input and can operate with a maximum duty cycle of 86% for use in low- dropout conditions. It also features a shutdown mode that reduces quiescent current to 0.1 µA. The MIC2182 achieves high efficiency over a wide output current range by automatically switching between PWM and skip mode. Skip-mode operation enables the converter to maintain high efficiency at light loads by turning off circuitry pertaining to PWM operation, reducing the no-load supply current from 1.6 mA to 600 µA. The operating mode is internally selected according to the output load conditions. Skip mode can be defeated by pulling the PWM pin low which reduces noise and RF interference. The MIC2182 is available in a 16-lead SOIC (small-outline package) and SSOP (shrink small-outline package) with an operating ambient temperature range from –40°C to +85°C. DC Power Distribution Systems Notebook and Subnotebook Computers PDAs and Mobile Communicators Wireless Modems Battery-Operated Equipment  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 1 MIC2182 Package Types MIC2182 (Adjustable) 16-Lead SOIC(M) 16-Lead SSOP (SM) MIC2182 (Fixed) 16-Lead SOIC(M) 16-Lead SSOP (SM) SS 1 16 HSD SS 1 16 HSD PWM 2 15 VSW PWM 2 15 VSW COMP 3 14 BST COMP 3 14 BST SGND 4 13 LSD SGND 4 13 LSD SYNC 5 12 PGND SYNC 5 12 PGND EN/UVLO 6 FB 7 10 VIN VREF 7 10 VIN CSH 8 11 VDD EN/UVLO 6 11 VDD 9 VOUT CSH 8 9 VOUT Typical Application Circuit VIN 4.5V to 30V* D2 MIC2182-3.3YSM 10 11 SD103BWS VDD VIN R7 100k C5 0.1μF 6 2 BST 14 EN/UVLO HSD 16 PWM VSW 15 LSD 13 PGND 12 C4 1nF C3 0.1μF C2 2.2nF GND DS20006644A-page 2 R1 2k 1 SS 3 COMP CSH 8 5 SYNC VOUT 9 VREF 7 SGND 4 C9 4.7μF 16V C6 0.1μF C11 22μF 35V x2 Q2* Si4884 Q1* Si4884 L1 10μH R2 0.02 D1 B140 VOUT 3.3V/4A C7 220μF 10V x2 GND C13, 1nF * 30V maximum input voltage limit is due to standard 30V MOSFET selection. C1 0.1μF See “Application Information” section for 5V to 3.3V/10A and other circuits.  2022 Microchip Technology Inc. and its subsidiaries MIC2182 Block Diagrams Adjustable Output Voltage Version VIN CIN VDD EN/UVLO 6 VDD 11 Reference V IN 4.7μF VIN D2 VBG 1.245V 10 SS 1 VBST 14 Control Logic HSD 16 Q2 CBST 2 RCS L1 VSW PWM VOUT 15 LSD 13 COUT D1 Q1 PGND Current Limit 12 PWM Mode to Skip Mode 0.024V Skip-Mode Current Limit 0.07V Low Comp PWM OUTPUT –2%VBG Hysteresis Comp Current Sense Amp PWM CSH 8 CORRECTIVE RAMP VOUT VBG RESET SYNC 5 9 AV = 2 R1 Oscillator Error Amp FB 7 COMP 3 CCOMP SGND 100k 4 gm = 0.2mS RCOMP MIC2182 [adj.] ( ) VOUT = 1.245 1+ R2 R1 R2 VOUT(MAX) = 6.0V Fixed Output Voltage Version VIN CIN VDD EN/UVLO 6 VDD 11 Reference V IN 4.7μF VIN D2 VBG 1.245V 10 SS 1 VBST 14 Control Logic HSD 16 PWM Q2 CBST L1 VSW 2 RCS VOUT 15 LSD 13 D1 COUT Q1 PGND Current Limit 12 PWM Mode to Skip Mode 0.024V Skip-Mode Current Limit 0.07V Low Comp PWM OUTPUT –2%VBG Hysteresis Comp Current Sense Amp PWM CSH 8 CORRECTIVE RAMP VOUT VBG RESET SYNC 5 Oscillator Error Amp SGND R2 50k 3 100k gm = 0.2mS RCOMP * 82.5k for 3.3V Output 150k for 5V Output R1* COMP CCOMP 9 AV = 2 4 VREF 7 MIC2182-x.x  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 3 MIC2182 1.0 ELECTRICAL CHARACTERISTICS Absolute Maximum Ratings † Analog Supply Voltage (VIN) .....................................................................................................................................+34V Digital Supply Voltage (VDD) .......................................................................................................................................+7V Driver Supply Voltage (BST) ................................................................................................................................. VIN +7V Sense Voltage (VOUT, CSH)............................................................................................................................ 7V to –0.3V Sync Pin Voltage (VSYNC) .............................................................................................................................. 7V to –0.3V Enable Pin Voltage (VEN/UVLO) ....................................................................................................................................VIN Power Dissipation (PD) SOIC .............................................................................................................................................. 400 mW @ TA = 85°C SSOP ............................................................................................................................................. 270 mW @ TA = 85°C ESD Rating .......................................................................................................................................................... (Note 1) Operating Ratings ‡ Analog Supply Voltage (VIN) ...................................................................................................................... +4.5V to +32V † Notice: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational sections of this specification is not intended. Exposure to maximum rating conditions for extended periods may affect device reliability. Specifications are for packaged product only. ‡ Notice: The device is not guaranteed to function outside its operating ratings. Note 1: Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5 kΩ in series with 100 pF. ELECTRICAL CHARACTERISTICS Electrical Characteristics: VIN = 15V; SS = Open; VSHDN = 5V; ILOAD = 0.1A, TA = +25°C, Bold values indicate –40°C ≤ TA ≤ +85°C; unless otherwise specified. Parameter Symbol Min. Typ. Max. Units Conditions MIC2182 (Adjustable) (Note 1) Feedback Voltage Reference VREF 1.233 1.245 1.257 V — 1.220 1.245 1.270 V — 1.208 1.245 1.282 V 4.5V < VIN < 32V, full load range, 0 mV < VCSH – VOUT < 75 mV — 10 — nA — — Feedback Bias Current IFB Output Voltage Range VOUT 1.25 — 6 V Output Voltage Line Regulation ΔVO_LN — 0.03 — %/V Output Voltage Load Regulation ΔVO_LD — 0.5 — % 25 mV < (VCSH – VOUT) < 75 mV (PWM mode only) Output Voltage Total Regulation ΔVO_TOT — 0.6 — % 0 mV < (VCSH – VOUT) < 75 mV (full load range), 4.5V < VIN < 32V 3.267 3.3 3.333 V — 3.234 3.3 3.366 V — 4.5V < VIN < 32V, full load range, 0 mV < VCSH – VOUT < 75 mV MIC2182-3.3 Output Voltage VOUT 3.201 3.3 3.399 V Output Voltage Line Regulation ΔVO_LN — 0.03 — %/V Output Voltage Load Regulation ΔVO_LD — 0.5 — % DS20006644A-page 4 VIN = 4.5V to 32V, VCSH – VOUT = 50 mV VIN = 4.5V to 32V, VCSH – VOUT = 50 mV 25 mV < (VCSH – VOUT) < 75 mV (PWM mode only)  2022 Microchip Technology Inc. and its subsidiaries MIC2182 ELECTRICAL CHARACTERISTICS (CONTINUED) Electrical Characteristics: VIN = 15V; SS = Open; VSHDN = 5V; ILOAD = 0.1A, TA = +25°C, Bold values indicate –40°C ≤ TA ≤ +85°C; unless otherwise specified. Parameter Symbol Output Voltage Total Regulation ΔVO_TOT Min. Typ. Max. Units — 0.8 — % MIC2182-5.0 Output Voltage VOUT Conditions 0 mV < (VCSH – VOUT) < 75 mV (full load range), 4.5V < VIN < 32V 4.95 5.0 5.05 V — 4.90 5.0 5.10 V — 4.85 5.0 5.150 V 6.5V < VIN < 32V, full load range, 0 mV < VCSH – VOUT < 75 mV VIN = 6.5V to 32V, VCSH – VOUT = 50 mV Output Voltage Line Regulation ΔVO_LN — 0.03 — %/V Output Voltage Load Regulation ΔVO_LD — 0.5 — % 25 mV < (VCSH – VOUT) < 75 mV (PWM mode only) Output Voltage Total Regulation ΔVO_TOT — 0.8 — % 0 mV < (VCSH – VOUT) < 75 mV (full load range), 6.5V < VIN < 32V Input and VDD Supply Quiescent Current PWM Mode Quiescent Current IQ_PWM — 1.6 2.5 mA VPWM = 0V, excluding external MOSFET gate drive current Skip Mode Quiescent Current IQ_SKIP — 600 1500 µA ILOAD = 0 mA, VPWM floating (1 nF capacitor to ground) Shutdown Quiescent Current ISD — 0.1 5 µA VEN/UVLO = 0V Digital Supply Voltage VDD 4.7 — 5.3 V ILOAD = 0 mA to 5 mA VDDUV_R — 4.2 — V VDD upper threshold (turn-on threshold) VDDUV_F — 4.1 — V VDD lower threshold (turn-off threshold) Undervoltage Lockout Reference Output (Fixed Versions Only VREF 1.220 1.245 1.270 V Reference Line Regulation ΔVREF_LN — 1 — mV 6V < VIN < 32V Reference Load Regulation ΔVREF_LD — 2 — mV 0 µA < IREF < 100 µA VEN_TH Reference Voltage Enable/UVLO — 0.6 1.1 1.6 V — VENUV_TH 2.2 2.5 2.8 V — IEN — 0.1 5 µA VEN/UVLO = 5V ISS –3.5 –5 –6.5 µA VSS = 0V VILIM_TH 75 100 135 mV VCSH = VOUT AV(EA) — 20 — V/V gm(EA) = 0.2 mS, RO(EA) = 100 kΩ AV(CS) — 2.0 — V/V — Oscillator Frequency fOSC 270 300 330 kHz — Maximum Duty Cycle DMAX — 86 — % — tON(MIN) — 140 250 ns VOUT = VOUT(NOMINAL) + 200 mV Enable Input Threshold UVLO Threshold Enable Input Current Soft-Start Soft-Start Source Current Current Limit Current Limit Threshold Voltage Error Amplifier Error Amplifier Voltage Gain Current Amplifier Current Sense Amplifier Gain Oscillator Section Minimum On-Time  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 5 MIC2182 ELECTRICAL CHARACTERISTICS (CONTINUED) Electrical Characteristics: VIN = 15V; SS = Open; VSHDN = 5V; ILOAD = 0.1A, TA = +25°C, Bold values indicate –40°C ≤ TA ≤ +85°C; unless otherwise specified. Parameter Symbol SYNC Threshold Level VSYNC_TH ISYNC SYNC Input Current SYNC Minimum Pulse Width SYNC Capture Range Frequency Foldback Threshold Foldback Frequency Gate Drivers Rise/Fall Time Output Driver Impedance Driver Non-overlap Time PWM Input PWM Input Source Current 1: 2: Min. Typ. Max. Units 0.7 1.3 1.9 V — — 0.1 5 µA VSYNC = 5V tSYNC(MIN) 200 — — ns fSYNC 330 — — kHz VFOLD_TH 0.75 0.95 1.15 V fFOLD — 60 — kHz tR, tF — 60 — ns RON_H — 5 8.5 RON_L — 3.5 6 tNON — 80 — ns — IPWM_SRC — –10 — µA VPWM = 0V Ω Conditions — Note 2 Measured at VOUT Pin — CLOAD = 3000 pF Source Sink VIN > 1.3 x VOUT (for the feedback voltage reference and output voltage line and total regulation). See the Oscillator and Sync section for limitations on the synchronizing signal frequency. TEMPERATURE SPECIFICATIONS (Note 1) Parameters Sym. Min. Typ. Max. Units Conditions Ambient Storage Temperature Range TS –65 — +150 °C Ambient Temperature Range TA –40 — +85 °C — Junction Temperature Range TJ –40 — +125 °C — Thermal Resistance SOIC 16-Ld JA — 100 — °C/W — Thermal Resistance SSOP 16-Ld JA — 150 — °C/W — Temperature Ranges Package Thermal Resistances Note 1: — The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction temperature and the thermal resistance from junction to air (i.e., TA, TJ, JA). Exceeding the maximum allowable power dissipation will cause the device operating junction temperature to exceed the maximum +125°C rating. Sustained junction temperatures above +125°C can impact the device reliability. DS20006644A-page 6  2022 Microchip Technology Inc. and its subsidiaries MIC2182 2.0 Note: TYPICAL PERFORMANCE CURVES The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. FIGURE 2-1: Temperature. Quiescent Current vs. FIGURE 2-4: Supply Voltage. Quiescent Current vs. FIGURE 2-2: Temperature. Quiescent Current vs. FIGURE 2-5: Regulation. VREF (Fixed Versions) Line FIGURE 2-3: Supply Voltage. Quiescent Current vs. FIGURE 2-6: Regulation. VREF (Fixed Versions) Load  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 7 MIC2182 FIGURE 2-7: Temperature. VREF (Fixed Versions) vs. FIGURE 2-10: FIGURE 2-8: VDD Line Regulation. FIGURE 2-11: Oscillator Frequency Variation vs. Temperature. FIGURE 2-9: VDD Load Regulation. FIGURE 2-12: Oscillator Frequency Variation vs. Supply Voltage. DS20006644A-page 8 VDD vs. Temperature.  2022 Microchip Technology Inc. and its subsidiaries MIC2182 FIGURE 2-13: vs. Temperature. Soft-Start Source Current FIGURE 2-14: Overcurrent Threshold Voltage vs. Temperature. FIGURE 2-16: Effect of Soft-Start Capacitor (CSS) Value on Output Voltage Waveforms During Turn-On (10A Power Supply Configuration). FIGURE 2-17: Effect of Soft-Start Capacitor (CSS) Value on Output Voltage Waveforms During Turn-On (4A Power Supply Configuration). VSW (Normal) VSW (VOUT Short) FIGURE 2-15: Current-Limit Foldback.  2022 Microchip Technology Inc. and its subsidiaries FIGURE 2-18: Normal (300 kHz Switching Frequency) and Output Short-Circuit (60 kHz) Conditions Switch Node (Pin 15) Waveforms. DS20006644A-page 9 HIGH-SIDE DRIVE VOLTAGE REFERENCED TO GROUND VGS LOW-SIDE MOSFET HIGH-SIDE MOSFET GATE-TO-SOURCE VOLTAGE IL1 (2A/div) LOW-SIDE MOSFET GATE-TO-SOURCE VOLTAGE INDUCTOR CURRENT FIGURE 2-19: VIN = 12V VOUT = 3.3V L1 = 10μH R2 = 20mΩ QTY: 2 Si4884 HIGH-SIDE MOSFETS QTY: 2 Si4884 LOW-SIDE MOSFETS 10Amps Converter Waveforms. FIGURE 2-22: Load Transient Response (4A Power Supply Configuration). VOUT VOUT VOUT VIN = 7V L1 = 3.3μH VOUT = 3.3V IOUT = 10A IOUT 2A/div PIN 16 SWITCH-NODE VOLTAGE VGS HIGH-SIDE MOSFET VSW+HSD VSW PIN 15 MIC2182 VIN = 6V VOUT = 3.3V L1 = 3.3μH R2 = 7.5mΩ IOUT 5A/div VSW 100 210 80 180 20 90 0 60 -20 30 -40 0 10x100 IL (0.5A/div) 120 PHASE PHASE (°) VSW 150 GAIN 40 300x103 GAIN (dB) 60 100x103 VOUT FIGURE 2-23: Load Transient Response (10A Power Supply Configuration). 10x103 Typical Skip-Mode 100x100 FIGURE 2-20: Waveforms. 1x103 IL (1A/div) FREQUENCY (Hz) FIGURE 2-21: Waveforms. DS20006644A-page 10 Typical PWM Mode FIGURE 2-24: Configuration). Bode Plot (4A Power Supply  2022 Microchip Technology Inc. and its subsidiaries MIC2182 180 60 150 GAIN 40 120 20 90 0 60 PHASE 0 300x103 100x103 30 10x103 10x100 -40 100x100 -20 80 EFFICIENCY (%) 80 PHASE (°) 210 1x103 GAIN (dB) 100 100 PWM Skip 60 40 VIN = 24V R2 = 15mΩ L1 = 10μH 20 1 high-side MOSFET: Si4800 1 low-side MOSFET: Si4800 0 0.01 0.1 1 4 OUTPUT CURRENT (A) FREQUENCY (Hz) FIGURE 2-25: Bode Plot (10A Power Supply Configuration). FIGURE 2-28: Efficiency at VIN = 24V, VOUT = 3.3V (4A Power Supply Configuration). 100 100 EFFICIENCY (%) 80 Skip PWM 60 40 VIN = 5V R2 = 15mΩ L1 = 10μH 20 1 high-side MOSFET: Si4800 1 low-side MOSFET: Si4800 0 0.01 0.1 1 4 OUTPUT CURRENT (A) FIGURE 2-26: Efficiency at VIN = 5V, VOUT = 3.3V (4A Power Supply Configuration). 80 EFFICIENCY (%) Skip 60 PWM 40 20 R2 = 7.5mΩ L1 = 3.3μH 2 high-side MOSFETs: Si4884 2 low-side MOSFETs: Si4884 0 0.01 0.1 1 10 OUTPUT CURRENT (A) FIGURE 2-29: Efficiency at VIN = 5V, VOUT = 3.3V (10A Power Supply Configuration). EFFICIENCY (%) 100 80 Skip PWM 60 40 VIN = 12V R2 = 15mΩ L1 = 10μH 20 1 high-side MOSFET: Si4800 1 low-side MOSFET: Si4800 0 0.01 0.1 1 4 OUTPUT CURRENT (A) FIGURE 2-27: Efficiency at VIN = 12V, VOUT = 3.3V (4A Power Supply Configuration).  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 11 MIC2182 3.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table 3-1. TABLE 3-1: PIN FUNCTION TABLE Pin Name Pin Number Description 1 SS Soft-Start (External Component): Connect external capacitor to ground to reduce inrush current by delaying and slowing the output voltage rise time. Rise time is controlled by an internal 5 µA current source that charges an external capacitor to VDD. 2 PWM PWM/Skip-Mode Select (Input): Low sets PWM-mode operation. 1 nF capacitor to ground sets automatic PWM/skip-mode selection. 3 COMP Compensation (Output): Internal error amplifier output. Connect to capacitor or series RC network to compensate the regulator control loop. 4 SGND Small Signal Ground (Return): Route separately from other ground traces to the (–) terminal of COUT. 5 SYNC Frequency Synchronization (Input): Optional. Connect to external clock signal to synchronize the oscillator. Leading edge of signal above the threshold terminates the switching cycle. Connect to SGND if unused. Enable/Undervoltage Lockout (Input): Low-level signal powers down the controller. Input below the 2.5V UVLO threshold voltage disables switching and functions as an accurate undervoltage lockout (UVLO). Input below the 1.1V enable threshold voltage forces complete micropower (< 0.1 µA) shutdown. 6 EN/UVLO 7 (Fixed) VREF Reference Voltage (Output): 1.245V output. Requires 0.1 µF capacitor to ground. 7 (Adj.) FB Feedback (Input): Regulates FB pin to 1.245V. See the Applications Information section for resistor divider calculations. Current-Sense High (Input): Current-limit comparator non-inverting input. A built-in offset of 100 mV between CSH and VOUT pins in conjunction with the current-sense resistor set the current-limit threshold level. This is also the positive input to the current sense amplifier. 8 CSH 9 VOUT 10 VIN [Battery] Unregulated Input (Input): +4.5V to +32V supply input. 11 VDD 5V Internal Linear-Regulator (Output): VDD is the external MOSFET gate drive supply voltage and an internal supply bus for the IC. Bypass to SGND with a 4.7 µF capacitor. VDD can supply up to 5 mA for external loads. 12 PGND MOSFET Driver Power Ground (Return): Connects to source of synchronous MOSFET and the (–) terminal of CIN. 13 LSD Low-Side Drive (Output): High-current driver output for external synchronous MOSFET. Voltage swing is between ground and VDD. 14 BST Boost (Input): Provides drive voltage for the high-side MOSFET driver. The drive voltage is higher than the input voltage by VDD minus a diode drop. 15 VSW Switch (Return): High-side MOSFET driver return. 16 HSD High-Side Drive (Output): High-current driver output for high-side MOSFET. This node voltage swing is between ground and VIN + 5V - Vdiode drop. DS20006644A-page 12 Current-Sense Low (Input): Output voltage feedback input and inverting input for the current limit comparator and the current sense amplifier.  2022 Microchip Technology Inc. and its subsidiaries MIC2182 4.0 FUNCTIONAL DESCRIPTION 4.1 The MIC2182 is a BiCMOS, switched-mode, synchronous step-down (buck) converter controller. Current-mode control is used to achieve superior transient line and load regulation. An internal corrective ramp provides slope compensation for stable operation above 50% duty cycle. The controller is optimized for high-efficiency, high-performance DC-DC converter applications. Control Loop 4.1.1 PWM AND SKIP MODES OF OPERATION The MIC2182 operates in PWM (pulse-width modulation) mode at heavier output load conditions. At lighter load conditions, the controller can be configured to automatically switch to a pulse-skipping mode to improve efficiency. The potential disadvantage of skip mode is the variable switching frequency that accompanies this mode of operation. The occurrence of switching pulses depends on component values as well as line and load conditions. There is an external sync function that is disabled in skip mode. In PWM mode, the synchronous buck converter forces continuous current to flow in the inductor. In skip mode, current through the inductor can settle to zero, causing voltage ringing across the inductor. Pulling the PWM pin (Pin 2) low will force the controller to operate in PWM mode for all load conditions, which will improve cross regulation of transformer-coupled, multiple output configurations. The MIC2182 block diagrams are shown in the Block Diagrams section. The MIC2182 controller is divided into six functions. • Control Loop - PWM Operation - Skip-Mode Operation • Current Limit • Reference, Enable, and UVLO • MOSFET Gate Drive • Oscillator and Sync • Soft Start 4.1.2 PWM CONTROL LOOP The MIC2182 uses current-mode control to regulate the output voltage. This method senses the output voltage (outer loop) and the inductor current (inner loop). It uses inductor current and output voltage to determine the duty cycle of the buck converter. Sampling the inductor current removes the inductor from the control loop, which simplifies compensation. VIN CIN VDD Reference VDD 11 VIN 4.7F VIN D2 VBG 1.245V 10 CONTROL LOGIC AND PULSE-WIDTH MODULATOR VBST 14 HSD 16 Q2 CBST L1 VSW RCS VOUT 15 LSD 13 PWM Mode to Skip Mode COUT D1 Q1 PGND 12 Q R LOW FORCES SKIP MODE S 0.024V Current Sense Amp PWM COMPARATOR CSH 8 VOUT CORRECTIVE RAMP VBG RESET AV = 2 9 R1 Oscillator Error Amp FB 7 COMP CCOMP 3 100k gm = 0.2mS RCOMP ( V OUT = 1.245V 1 + R1 R2 R2 ) MIC2182 [adj.] PWM Mode FIGURE 4-1: PWM Operation.  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 13 MIC2182 access to the output of the error amplifier and allows the use of external components to stabilize the voltage loop. A block diagram of the MIC2182 PWM current-mode control loop is shown in Figure 4-1 and the PWM mode voltage and current waveforms are shown in Figure 4-3. The inductor current is sensed by measuring the voltage across the resistor, RCS. A ramp is added to the amplified current-sense signal to provide slope compensation, which is required to prevent unstable operation at duty cycles greater than 50%. 4.1.3 SKIP-MODE CONTROL LOOP This control method is used to improve efficiency at light output loads. At light output currents, the power drawn by the MIC2182 is equal to the input voltage times the IC supply current (IQ). At light output currents, the power dissipated by the IC can be a significant portion of the total output power, which lowers the efficiency of the buck converter. The MIC2182 draws less supply current in skip mode by disabling portions of the control and drive circuitry when the IC is not switching. The disadvantage of this method is greater output voltage ripple and variable switching frequency. A transconductance amplifier is used for the error amplifier, which compares an attenuated sample of the output voltage with a reference voltage. The output of the error amplifier is the COMP (compensation) pin, which is compared to the current-sense waveform in the PWM block. When the current signal becomes greater than the error signal, the comparator turns off the high-side drive. The COMP pin (Pin 3) provides A block diagram of the MIC2182 skip mode is shown in Figure 4-2. Skip mode voltage and current waveforms are shown in Figure 4-4. VIN CIN VDD Reference VDD 11 VIN 4.7F VIN D2 VBG 1.245V 10 CONTROL LOGIC AND SKIP-MODE LOGIC VBST 14 HSD 16 Q2 CBST L1 VSW LOW-SIDE DRIVER ONE SHOT RCS VOUT 15 LSD 13 COUT D1 Q1 PGND 12 Q R S Skip-Mode Current Limit 0.07V Low Comp ONE SHOT –2%VBG Hysteresis Comp 1% VBG LOW FORCES PWM MODE Current Sense Amp CSH 8 VOUT AV = 2 9 R1 FB 7 MIC2182 [adj.] Skip Mode FIGURE 4-2: DS20006644A-page 14 ( V OUT = 1.245V 1 + R1 R2 ) R2 Skip-Mode Operation.  2022 Microchip Technology Inc. and its subsidiaries MIC2182 VIN VSW 0V ILOAD IL1 0A VDD Reset Pulse 0V VIN + VDD VHSD 0V VDD VLSD FIGURE 4-3: 0V PWM-Mode Timing. VDD VHSD 0V VDD VLSD 0V VIN VSW VOUT 0V IL(PKMAX)_SKIP IL1 0A Vone-shot VDD 0V VOUT +1% VNOMINAL –1% 0V IOUT FIGURE 4-4: 0A Skip-Mode Timing. A hysteretic comparator is used in place of the PWM error amplifier and a current-limit comparator senses the inductor current. A one-shot starts the switching cycle by momentarily turning on the low side MOSFET to insure the high-side drive boost capacitor, CBST, is fully charged. The high-side MOSFET is turned on and current ramps up in the inductor, L1. The high-side drive is turned off when either the peak voltage on the input of the current-sense comparator exceeds the threshold, typically 35 mV, or the output voltage rises above the hysteretic threshold of the output voltage comparator. Once the high-side MOSFET is turned off, the load current discharges the output capacitor, causing VOUT to fall. The cycle repeats when VOUT falls below the lower threshold, –1%.  2022 Microchip Technology Inc. and its subsidiaries The maximum peak inductor current in Skip Mode depends on the skip-mode current-limit threshold and the value of the current-sense resistor, RCS. EQUATION 4-1: 35mV I L(PKMAX)_SKIP = -------------R CS Figure 4-5 shows the improvement in efficiency that skip mode makes at lower output currents. DS20006644A-page 15 MIC2182 EQUATION 4-3: 100 P WM 35mV I OUT  MAXSKIP  = 0.5  -------------R CS EFFICIENCY (%) 80 S kip 60 40 20 0 0.01 0.1 1 10 OUTPUT CURRENT (A) FIGURE 4-5: 4.1.4 100 Efficiency. SWITCHING FROM PWM TO SKIP MODE The current sense amplifier in Figure 4-1 monitors the average voltage across the current-sense resistor. The controller will switch from PWM to skip mode when the average voltage across the current-sense resistor drops below approximately 12 mV if the PWM/Skip mode selection is set to automatic. This is shown in Figure 4-6. The average output current at this transition level for is calculated below. The PWM pin (Pin 2) is the PWM/Skip mode selection pin. When the PWM pin is logic level low, the device is set in forced PWM operation. A capacitor (typically 1 nF) connected across the PWM pin and ground sets the device to automatic PWM/Skip selection according to the output current level. The capacitor on the PWM pin (Pin 2) is discharged when the IC transitions from skip to PWM mode. This forces the IC to remain in PWM mode for a fixed period of time. The added delay prevents unwanted switching between PWM and skip mode. The capacitor is charged with a 10 µA current source on Pin 2. The threshold on Pin 2 is 2.5V. The delay for a typical 1 nF capacitor is: EQUATION 4-4: C PWM  V TH_MODESEL t DELAY = ------------------------------------------------------- = I PWM_SRC EQUATION 4-2: 1nF  2.5V ---------------------------- = 250s 10A Where: 0.012V I OUT  MINPWM  = ----------------R CS 0.012V = Threshold Voltage of the Internal Comparator RCS = Current-Sense Resistor Value 4.1.5 Where: CPWM = Capacitor connected to Pin 2. VTH_MODESEL = Mode selection threshold voltage (2.5V typ.) IPWM_SRC = PWM pin source current (10 µA typ.) 4.2 SWITCHING FROM SKIP TO PWM MODE The frequency of occurrence of the skip-mode current pulses increase as the output current increases until the hysteretic duty cycle reaches full CCM duty cycle (continuous pulses). Increasing the current past this point will cause the output voltage to drop. The low limit comparator senses the output voltage when it drops below 2% of the set output and automatically switches the converter to PWM mode. The inductor current in skip mode is a triangular wave shape a minimum value of 0 and a maximum value of 35 mV/RCS (see Figure 4-7). The maximum average output current in skip mode is the average value of the inductor waveform: DS20006644A-page 16 Current Limit The current-limit circuit operates during PWM mode. The output current is detected by the voltage drop across the external current-sense resistor (RCS in the Block Diagrams). The current-limit threshold voltage is 100 mV +35 mV/–25 mV. The current-sense resistor must be sized using the minimum current-limit threshold voltage. The external components must be designed to withstand the maximum current limit. The current-sense resistor value is calculated by the equation below: EQUATION 4-5: 75mV R CS  -------------------------I OUT  MAX  Where: IOUT(MAX) = Target maximum output current.  2022 Microchip Technology Inc. and its subsidiaries MIC2182 The maximum current limit is: EQUATION 4-6: I LIM  MAX  135mV = ----------------R CS The current-sense pins CSH (Pin 8) and VOUT (Pin 9) are noise sensitive due to the low signal level and high input impedance. The PCB traces should be short and routed close to each other. A small (1 nF to 0.1 µF) capacitor across the pins will attenuate high frequency switching noise. When the peak inductor current exceeds the current-limit threshold, the current-limit comparator, in the Block Diagrams, turns off the high-side MOSFET for the remainder of the cycle. The output voltage drops as additional load current is pulled from the converter. When the output voltage reaches approximately 0.95V, the circuit enters frequency-foldback mode and the oscillator frequency will drop to 60 kHz while maintaining the peak inductor current equal to the FIGURE 4-6: nominal 100 mV across the external current-sense resistor. This limits the maximum output power delivered to the load under a short circuit condition. 4.3 Reference, Enable, and UVLO Circuits The output drivers are enabled when the following conditions are satisfied: • The VDD voltage (Pin 11) is greater than its undervoltage threshold (typically 4.2V) • The voltage on the enable pin is greater than the enable UVLO threshold (typically 2.5V) The internal bias circuit generates a 1.245V bandgap reference voltage for the voltage error amplifier and a 5V VDD voltage for the gate drive circuit. The reference voltage in the fixed-output-voltage versions of the MIC2182 is buffered and brought to Pin 7. The VREF pin should be bypassed to GND (Pin 4) with a 0.1 µF capacitor. The adjustable version of the MIC2182 uses Pin 7 for output voltage sensing. A decoupling capacitor on Pin 7 is not used in the adjustable output voltage version. Minimum PWM-Mode Load Inductor Current for PWM Operation. Inductor IOUT(MAXSKIP) Current 0A FIGURE 4-7: 35mV THRESHOLD ACROSS RCS. Maximum Skip-Mode-Load Inductor Current. The enable pin (Pin 6) has two threshold levels, allowing the MIC2182 to shut down in a low current mode, or turn off output switching in UVLO mode. An enable pin voltage lower than the shutdown threshold turns off all the internal circuitry and reduces the input current to typically 0.1 µA. If the enable pin voltage is between the shutdown and UVLO thresholds, the internal bias, VDD, and reference voltages are turned on. The soft-start pin is forced low by an internal discharge MOSFET. The output drivers are inhibited from switching and remain in a low state. Raising the enable voltage above the UVLO threshold of 2.5V allows the soft-start capacitor to charge and enables the output drivers. Either of two UVLO conditions will pull the soft-start capacitor low.  2022 Microchip Technology Inc. and its subsidiaries • When the VDD drops below 4.1V • When the enable pin drops below the 2.5V threshold 4.4 MOSFET Gate Drive The MIC2182 high-side drive circuit is designed to switch an N-channel MOSFET. Referring to the Block Diagrams, a bootstrap circuit, consisting of D2 and CBST, supplies energy to the high-side drive circuit. Capacitor CBST is charged while the low-side MOSFET is on and the voltage on the VSW pin (Pin 15) is approximately 0V. When the high-side MOSFET driver is turned on, energy from CBST is used to turn the high-side MOSFET on. As the MOSFET turns on, the voltage on the VSW pin increases to approximately VIN. Diode D2 is reversed biased and voltage at the BST pin DS20006644A-page 17 The drive voltage is derived from the internal 5V VDD bias supply. The nominal low-side gate drive voltage is 5V and the nominal high-side gate drive voltage is approximately 4.5V due the voltage drop across D2. A fixed 80 ns delay between the high-side and low-side driver transitions is used to prevent current from simultaneously flowing unimpeded through both MOSFETs. Oscillator and Sync The SYNC input (Pin 5) allows the MIC2182 to synchronize with an external clock signal. The rising edge of the sync signal generates a reset signal in the oscillator, which turns off the low-side gate drive output. The high-side drive then turns on, restarting the switching cycle. The sync signal is inhibited when the controller operates in skip mode or during frequency foldback. The sync signal frequency must be greater than the maximum specified free running frequency of the MIC2182. If the synchronizing frequency is lower, double pulsing of the gate drive outputs will occur. When not used, the sync pin must be connected to ground. Figure 4-8 shows the timing between the external sync signal (trace 2), the low-side drive (trace 1) and the high-side drive (trace R1). There is a delay of approximately 250 ns between the rising edge of the external sync signal and turnoff of the low-side MOSFET gate drive. Some concerns of operating at higher frequencies are: • Higher power dissipation in the internal VDD regulator. This occurs because the MOSFET gates require charge to turn on the device. The average current required by the MOSFET gate increases with switching frequency. This increases the power dissipated by the internal VDD regulator. Figure 4-9 and Figure 4-10 shows the total gate charge which can be driven by the MIC2182 over the input voltage range, for different values of switching frequency. The total gate charge includes both the high-side and low-side MOSFETs. The larger SOIC package is capable of dissipating more power than the SSOP package and can drive larger MOSFETs with higher gate drive requirements. DS20006644A-page 18 FIGURE 4-8: Sync Waveforms. • Reduced maximum duty cycle due to switching transition times and constant delay times in the controller. As the switching frequency increased, the switching period decreases. The switching transition times and constant delays in the MIC2182 start to become noticeable. The effect is to reduce the maximum duty cycle of the controller. This will cause the minimum input to output differential voltage (dropout voltage) to increase. 100 S OIC 80 GATE CHARGE (nC) The internal oscillator is free running and requires no external components. The nominal oscillator frequency is 300 kHz. If the output voltage is below approximately 0.95V, the oscillator operates in a frequency-foldback mode and the switching frequency is reduced to 60 kHz. TIME 60 300kHz 40 400kHz 20 0 500kHz 0 4 8 12 16 20 24 28 32 SUPPLY VOLTAGE (V) FIGURE 4-9: SOIC Package Device MOSFET Gate Charge Driving Ability vs. Input Voltage. 100 S S OP 80 GATE CHARGE (nC) 4.5 SYNC SIGNAL floats high while continuing to keep the high-side MOSFET on. When the low-side switch is turned back on, CBST is recharged through D2. LOW-SIDE HIGH-SIDE DRIVE DRIVE MIC2182 60 300kHz 40 400kHz 20 500kHz 0 0 4 8 12 16 20 24 28 32 SUPPLY VOLTAGE (V) FIGURE 4-10: SSOP Package Device MOSFET Gate Charge Driving Ability vs. Input Voltage.  2022 Microchip Technology Inc. and its subsidiaries MIC2182 4.6 Soft-Start Soft start reduces the power supply input surge current at startup by controlling the output voltage rise time. The input surge appears while the output capacitance is charged up. A slower output rise time will draw a lower input surge current. Soft start may also be used for power supply sequencing. The soft-start voltage is applied directly to the PWM comparator. A 5 µA internal current source is used to charge up the soft-start capacitor. The capacitor is discharged when either the enable voltage drops below the UVLO threshold (2.5V) or the VDD voltage drops below the UVLO level (4.1V). Minimum Pulse Width The MIC2182 has a specified minimum pulse width. This minimum pulse width places a lower limit on the minimum duty cycle of the buck converter. When the MIC2182 is operating in forced PWM mode (Pin 2 low) and when the output current is very low or zero, there is a limit on the ratio of VOUT/VIN. If this limit is exceeded, the output voltage will rise above the regulated voltage level. A minimum load is required to prevent the output from rising up. This will not occur for output voltages greater than 3V. Figure 4-12 should be used as a guide when the MIC2182 is forced into PWM-only mode. The actual maximum input voltage will depend on the exact external components used (MOSFETs, inductors, etc.). 35 30 25 20 15 10 0 1 2 3 4 OUTPUT VOLTAGE (V) 5 6 FIGURE 4-12: Max. Input Voltage in Forced-PWM Mode. This restriction does not occur when the MIC2182 is set to automatic mode (Pin 2 connected to a capacitor) since the converter operates in skip mode at low output current. VSS VOUT The part switches at a minimum duty cycle when the soft-start pin voltage is less than 0.4V. This maintains a charge on the bootstrap capacitor and insures high-side gate drive voltage. As the soft-start voltage rises above 0.4V, the duty cycle increases from the minimum duty cycle to the operating duty cycle. The oscillator runs at the foldback frequency of 60 kHz until the output voltage rises above 0.95V. Above 0.95V, the switching frequency increases to 300 kHz (or the synced frequency), causing the output voltage to rise a greater rate. The rise time of the output is dependent on the soft-start capacitor, output capacitance, output voltage, and load current. The oscilloscope photo in Figure 4-11 show the output voltage and the soft-start pin voltage at startup. 4.7 INPUT VOLTAGE (V) It is recommended that the user limits the maximum synchronized frequency to 600 kHz. If a higher synchronized frequency is required, it may be possible and will be design dependent. TIME FIGURE 4-11: Startup Waveforms.  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 19 MIC2182 5.0 APPLICATIONS INFORMATION 5.1 Inductor Selection Values for inductance, peak, and RMS currents are required to select the output inductor. The input and output voltages and the inductance value determine the peak to peak inductor ripple current. Generally, higher inductance values are used with higher input voltages. Larger peak to peak ripple currents will increase the power dissipation in the inductor and MOSFETs. Larger output ripple currents will also require more output capacitance to smooth out the larger ripple current. Smaller peak to peak ripple currents require a larger inductance value and therefore a larger and more expensive inductor. A good compromise between size, loss and cost is to set the inductor ripple current to be equal to 20% of the maximum output current. The inductance value is calculated by the equation below: EQUATION 5-1: V OUT   V IN  MAX  – V OUT  L = -----------------------------------------------------------------------------------V IN  MAX   f SW  0.2  I OUT  MAX  Where: fSW = Switching frequency 0.2 = Ratio of AC ripple current to maximum DC output current. VIN(MAX) = Maximum input voltage IOUT(MAX) = Maximum DC output current The peak-to-peak inductor current (AC ripple current) is: EQUATION 5-2: V OUT   V IN  MAX  – V OUT  I L  PP  = ------------------------------------------------------------------V IN  MAX   f SW  L The peak inductor current is equal to the average output current plus one half of the peak to peak inductor ripple current. DS20006644A-page 20 EQUATION 5-3: I L  PK  = I OUT  MAX  + 0.5  I L  PP  The RMS inductor current is used to calculate the I2 x R losses in the inductor. EQUATION 5-4: 1 I L  PP  2 I L  RMS  = I OUT  MAX   1 + ------  -------------------------- 12  I OUT  MAX  Maximizing efficiency requires the proper selection of core material and minimizing the winding resistance. The high frequency operation of the MIC2182 requires the use of ferrite materials for all but the most cost sensitive applications. Lower cost iron powder cores may be used but the increase in core loss will reduce the efficiency of the buck converter. This is especially noticeable at low output power. The winding resistance decreases efficiency at the higher output current levels. The winding resistance must be minimized although this usually comes at the expense of a larger inductor. The power dissipated in the inductor is equal to the sum of the core and copper losses. At higher output loads, the core losses are usually insignificant and can be ignored. At lower output currents, the core losses can be a significant contributor. Core loss information is usually available from the magnetics vendor. Copper loss in the inductor is calculated by the equation below: EQUATION 5-5: 2 P LOSS  Cu  = I L  RMS   R WINDING The resistance of the copper wire, RWINDING, increases with temperature. The value of the winding resistance used should be at the operating temperature.  2022 Microchip Technology Inc. and its subsidiaries MIC2182 EQUATION 5-6: The maximum power dissipated in the sense resistor is: R WINDING  HOT  = R WINDING  20C    1 + 0.0042   T HOT – T 20C   EQUATION 5-9: 2 P D  RCS  = I OVERCURRENT  MAX   R CS Where: THOT = Temperature of the wire under operating load T20°C = Ambient room temperature RWINDING(20°C) = Room temperature winding resistance (usually specified by the manufacturer) 5.2 Current-Sense Resistor Selection Low inductance power resistors, such as metal film resistors should be used. Most resistor manufacturers make low inductance resistors with low temperature coefficients, designed specifically for current-sense applications. Both resistance and power dissipation must be calculated before the resistor is selected. The value of RCS is chosen based on the maximum output current and the minimum current-limit threshold voltage level. The power dissipated is based on the maximum peak current limit at the maximum current-limit threshold voltage. EQUATION 5-7: 75mV R CS  -------------------------I OUT  MAX  5.3 MOSFET Selection External N-channel logic-level power MOSFETs must be used for the high-side and low-side switches. The MOSFET gate-to-source drive voltage of the MIC2182 is regulated by an internal 5V VDD regulator. Logic-level MOSFETs, whose operation is specified at VGS = 4.5V must be used. It is important to note the on-resistance of a MOSFET increases with increasing temperature. A 75°C rise in junction temperature will increase the channel resistance of the MOSFET by 50% to 75% of the resistance specified at 25°C. This change in resistance must be accounted for when calculating MOSFET power dissipation. Total gate charge is the charge required to turn the MOSFET on and off under specified operating conditions (VDS and VGS). The gate charge is supplied by the MIC2182 gate drive circuit. At 300 kHz switching frequency and above, the gate charge can be a significant source of power dissipation in the MIC2182. At low output load, this power dissipation is noticeable as a reduction in efficiency. The average current required to drive the high-side MOSFET is: EQUATION 5-10: The maximum overcurrent at current-limit threshold voltage is: the maximum EQUATION 5-8: 135mV I OVERCURRENT  MAX  = ----------------R CS I GHS  AVG  = Q G  f SW Where: IGHS(AVG) = Average High-Side MOSFET Gate Current QG = Total Gate Charge for the High-Side MOSFET Taken from Manufacturer’s Data Sheet with VGS = 5V fSW = Switching Frequency The low-side MOSFET is turned on and off at VDS = 0 because the freewheeling diode is conducting during this time. The switching losses for the low-side MOSFET is usually negligible. Also, the gate drive  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 21 MIC2182 current for the low-side MOSFET is more accurately calculated using CISS at VDS = 0V instead of gate charge. The gate drive current for the low-side MOSFET: EQUATION 5-11: I GLS  AVG  = C ISS  V GS  f SW Where: CISS = Input capacitance of the low-side MOSFET at VDS = 0V. EQUATION 5-13: Where: P D  SW  = P CONDUCTION + P AC PCONDUCTION = ISW(RMS)2 x RDS(ON) PAC = PAC(OFF) + PAC(ON) RDS(ON) = On-Resistance of the MOSFET Switch ISW(RMS) = RMS current of the MOSFET switch Because the current from the gate drive comes from the input voltage, the power dissipated in the MIC2182 due to gate drive is: Making the assumption the turn-on and turn-off transition times are equal, the transition time can be approximated by: EQUATION 5-12: EQUATION 5-14: C ISS  V GS + C OSS  V IN t T = ------------------------------------------------------------IG P D  GDRV  = V IN   I GHS  AVG  + I GLS  AVG   Where: PD(GDRV) = Power Dissipated Due to Gate Drive Where: CISS and COSS are Measured at VDS = 0V A convenient figure of merit for switching MOSFETs is the on-resistance times the total gate charge (RDS(ON) x QG). Lower numbers translate into higher efficiency. Low gate-charge logic-level MOSFETs are a good choice for use with the MIC2182. Power dissipation in the MIC2182 package limits the maximum gate drive current. Refer to Figure 4-9 and Figure 4-10 for the MIC2182 gate drive limits. Parameters that are important to MOSFET switch selection are: • Voltage rating • On-resistance • Total gate charge The voltage rating of the MOSFETs are essentially equal to the input voltage. A safety factor of 20% should be added to the VDS(max) of the MOSFETs to account for voltage spikes due to circuit parasitics. The power dissipated in the switching transistor is the sum of the conduction losses during the on-time (PCONDUCTION) and the switching losses that occur during the period of time when the MOSFETs turn on and off (PAC). DS20006644A-page 22 IG = Gate Drive Current (1A for the MIC2182) The total high-side MOSFET switching loss is: EQUATION 5-15: P AC  SWHS  =  V IN + V D   I L  AVG   t T  f SW Where: IL(AVG) = Average inductor current tT = Switching transition time typically 20 ns to 50 ns) VD = Freewheeling diode drop, typically 0.5V fSW = Switching frequency, normally 300 kHz Because the low-side MOSFET body diode is forward biased before the low-side MOSFET is turned on and after the low-side MOSFET is turned off, this keeps the voltage across the low-side MOSFET to about 0.5V during switching transitions, the low-side MOSFET switching losses are negligible and can be ignored.  2022 Microchip Technology Inc. and its subsidiaries MIC2182 5.3.1 RMS CURRENT AND MOSFET POWER DISSIPATION CALCULATION Under normal operation, the high-side MOSFET’s RMS current is greatest when VIN is low (maximum duty cycle). The low-side MOSFET’s RMS current is greatest when VIN is high (minimum duty cycle). However, the maximum stress to the MOSFETs occurs during short circuit conditions, where the output current is equal to IOVERCURRENT(MAX). (See the Current-Sense Resistor Selection section). The calculations below are for normal operation. To calculate the stress under short circuit conditions, substitute IOVERCURRENT(MAX) for IOUT(MAX). Use the formula below to calculate duty cycle D under short circuit conditions. EQUATION 5-16: EQUATION 5-19: V OUT D = -----------------  V IN Where: = Efficiency of the Converter Converter efficiency depends on component parameters, which have not yet been selected. For design purposes, an efficiency of 90% can be used for VIN less than 10V and 85% can be used for VIN greater than 10V. The efficiency can be more accurately calculated once the design is complete. If the assumed efficiency is grossly inaccurate, a second iteration through the design procedure can be made. For the high-side switch, the conduction power loss is: D SHORTCIRCUIT = 0.063 – 1.8  10 –3  V IN EQUATION 5-20: 2 The RMS value of the high-side switch current is: EQUATION 5-17: 2 I SWHS  RMS  =  2 I L  PP   D   I OUT  MAX  + -------------------- 12   P COND  SWHS  = R DSON  HS   I SWHS  RMS  Where: RDSON(HS) = High-side MOSFET ON-Resistance Because the AC switching losses for the low-side MOSFET is near zero, the total power dissipation of the low-side MOSFET is: EQUATION 5-21: P D  SWLS  = P COND  SWLS  = R DSON  LS   I SWLS  RMS  The RMS value of the low-side switch current is: EQUATION 5-18: 2 Where: RDSON(LS) = Low-side MOSFET ON-Resistance The total power dissipation for the high-side MOSFET is: I SWLS  RMS  = 2  2 I L  PP    1 – D    I OUT  MAX  + -------------------- 12   Where: EQUATION 5-22: P D  SWHS  = P COND  SWHS  + P AC  SWHS  D = Duty Cycle of the Converter  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 23 MIC2182 External Schottky Diode An external freewheeling diode is used to keep the inductor current flow continuously while both MOSFETs are turned off during dead time. This dead time prevents current from flowing unimpeded through both MOSFETs and is typically 80 ns The diode conducts twice during each switching cycle. Although the average current through this diode is small, the diode must be able to handle the peak current. less power than the body diode. The lack of a reverse recovery mechanism in a Schottky diode causes less ringing and less power loss. Depending on the circuit components and operating conditions, an external Schottky diode will give a 1/2% to 1% improvement in efficiency. Figure 5-1 illustrates the difference in noise on the VSW pin with and without a Schottky diode. WITH WITHOUT FREEWHEELING DIODE FREEWHEELING DIODE 5.4 EQUATION 5-23: I D  AVG  = I OUT  2  80ns  f SW The reverse voltage requirement of the diode is: TIME EQUATION 5-24: V DIODE  RRM  = V IN The power dissipated by the Schottky diode is: EQUATION 5-25: P DIODE = I D  AVG   V F Where: VF = Forward Voltage at the Peak Diode Current The external freewheeling Schottky diode, D1, is not necessary for circuit operation since the low-side MOSFET contains a parasitic body diode. The external diode will improve efficiency and decrease high frequency noise. If the MOSFET body diode is used, it must be rated to handle the peak and average current. The body diode has a relatively slow reverse recovery time and a relatively high forward voltage drop. The power lost in the diode is proportional to the forward voltage drop of the diode. As the high-side MOSFET starts to turn on, the body diode becomes a short circuit for the reverse recovery period, dissipating additional power. The diode recovery and the circuit inductance will cause ringing during the high-side MOSFET turn-on. FIGURE 5-1: Switch Output Noise With and Without Schottky Diode. 5.5 Output Capacitor Selection The output capacitor values are usually determined by the capacitors ESR (equivalent series resistance). Voltage rating and RMS current capability are two other important factors in selecting the output capacitor. Recommended capacitors are tantalum, low-ESR aluminum electrolytics, and OS-CON. The output capacitor’s ESR is usually the main cause of output ripple. The maximum value of ESR is calculated by: EQUATION 5-26: V OUT ESR COUT  -----------------I L  PP  Where: ΔVOUT = Peak-to-peak output voltage ripple ΔIL(PP) = Peak-to-peak inductor ripple current An external Schottky diode conducts at a lower forward voltage preventing the body diode in the MOSFET from turning on. The lower forward voltage drop dissipates DS20006644A-page 24  2022 Microchip Technology Inc. and its subsidiaries MIC2182 The total output ripple is a combination of output ripple voltages due to the ESR and the output capacitance. The total ripple is calculated below: EQUATION 5-27: V OUT = EQUATION 5-30: V IN = I L  PK   ESR CIN Where: ESRCIN = ESR of input capacitor. 2 I L  PP  2  ------------------------------------- +  I L  PP   ESR COUT   8  C OUT  f SW Where: COUT = Output capacitance value fSW = Switching frequency ESRCOUT = ESR of output capacitor The input capacitor must be rated for the input current ripple. The RMS value of input capacitor current is determined at the maximum output current. Assuming the peak to peak inductor ripple current is low: EQUATION 5-31: The voltage rating of capacitor should be twice the output voltage for a tantalum and 20% greater for an aluminum electrolytic or OS-CON. I CIN  RMS   I OUT  MAX   D   1 – D  The output capacitor RMS current is calculated below: The power dissipated in the input capacitor is: EQUATION 5-28: EQUATION 5-32: I COUT  RMS  I L  PP  = ----------------12 2 P DISS  CIN  = I CIN  RMS   ESR CIN The power dissipated in the output capacitor is: EQUATION 5-29: 5.7 2 P DISS  COUT  = I COUT  RMS   ESR COUT 5.6 Voltage Setting Components The MIC2182-3.3 and MIC2182-5.0 ICs contain internal voltage dividers that set the output voltage. The MIC2182 adjustable version requires two resistors to set the output voltage as shown in Figure 5-2. Input Capacitor Selection The input capacitor should be selected for ripple current rating and voltage rating. Tantalum input capacitors may fail when subjected to high inrush currents, caused by turning the input supply on. Tantalum input capacitor voltage rating should be at least twice the maximum input voltage to maximize reliability. Aluminum electrolytic, OS-CON, and multilayer polymer film capacitors can handle the higher inrush currents without voltage derating. The input voltage ripple will primarily depend on the input capacitors ESR. The peak input current is equal to the peak inductor current, so:  2022 Microchip Technology Inc. and its subsidiaries R1 Error Amp FB 7 R2 VREF 1.245V MIC2182 [adj.] FIGURE 5-2: Configuration. Voltage Divider DS20006644A-page 25 MIC2182 The output voltage is determined by the equation: EQUATION 5-33: To maximize efficiency at light loads: V OUT = V REF   1 + R1 -------  R2 Where: VREF for the MIC2182 is typically 1.245V A typical value of R1 can be between 3 kΩ and 10 kΩ. If R1 is too large, it may allow noise to be introduced into the voltage feedback loop. If R1 is too small in value, it will decrease the efficiency of the buck converter, especially at low output loads. Once R1 is selected, R2 can be calculated using: EQUATION 5-34: V REF  R1 R2 = -------------------------------V OUT – V REF 5.7.1 The reference voltage and R2 set the current through the voltage divider. EQUATION 5-35: V REF I DIVIDER = -----------R2 The power dissipated by the divider resistors is: EQUATION 5-36: 5.8 • Use a low gate-charge MOSFET or use the smallest MOSFET, which is still adequate for maximum output current. • Allow the MIC2182 to run in skip mode at lower currents. • Use a ferrite material for the inductor core, which has less core loss than an MPP or iron powder core. Under heavy output loads, the significant contributors to power loss are (in approximate order of magnitude): • • • • • Resistive on-time losses in the MOSFETs Switching transition losses in the MOSFETs Inductor resistive losses Current-sense resistor losses Input capacitor resistive losses (due to the capacitor’s ESR) To minimize power loss under heavy loads: VOLTAGE DIVIDER POWER DISSIPATION P DIVIDER =  R1 + R2   I DIVIDER • Supply current to the MIC2182 • MOSFET gate-charge power (included in the IC supply current) • Core losses in the output inductor 2 Efficiency Calculation and Considerations • Use logic-level, low on-resistance MOSFETs. Multiplying the gate charge by the on-resistance gives a figure of merit, providing a good balance between low and high load efficiency. • Slow transition times and oscillations on the voltage and current waveforms dissipate more power during turn-on and turnoff of the MOSFETs. A clean layout will minimize parasitic inductance and capacitance in the gate drive and high current paths. This will allow the fastest transition times and waveforms without oscillations. Low gate-charge MOSFETs will transition faster than those with higher gate-charge requirements. • For the same size inductor, a lower value will have fewer turns and therefore, lower winding resistance. However, using too small of a value will require more output capacitors to filter the output ripple, which will force a smaller bandwidth, slower transient response and possible instability under certain conditions. • Lowering the current-sense resistor value will decrease the power dissipated in the resistor. However, it will also increase the overcurrent limit and will require larger MOSFETs and inductor components. • Use low-ESR input capacitors to minimize the power dissipated in the capacitors ESR. Efficiency is the ratio of output power to input power. The difference is dissipated as heat in the buck converter. Under light output load, the significant contributors are: DS20006644A-page 26  2022 Microchip Technology Inc. and its subsidiaries MIC2182 5.9 Decoupling Capacitor Selection 5.10 The 4.7 µF decoupling capacitor is used to minimize noise on the VDD pin. The placement of this capacitor is critical to the proper operation of the IC. It must be placed right next to the pins and routed with a wide trace. The capacitor should be a good quality tantalum. An additional 1 µF ceramic capacitor may be necessary when driving large MOSFETs with high gate capacitance. Incorrect placement of the VDD decoupling capacitor will cause jitter or oscillations in the switching waveform and large variations in the overcurrent limit. A single schematic diagram, shown in Figure 5-3, can be used to build power supplies ranging from 3A to 10A at the common output voltages of 1.8V, 2.5V, 3.3V, and 5V. Components that vary, depending upon output current and voltage, are listed in Table 5-3 through Table 5-6. Power supplies larger than 10A can also be constructed using the MIC2182 by using larger power-handling components. Figure 2-16 through Figure 2-29 provide useful information about the actual performance of some of these circuits. A 0.1 µF ceramic capacitor is required to decouple the VIN. The capacitor should be placed near the IC and connected directly to between Pin 10 (VIN) and Pin 12 (PGND). VIN VIN D2 MIC2182 SD103BWS VDD C5 0.1μF R7 100k BST EN/UVLO HSD PWM C2 2.2nF R1 2k TABLE 5-1: TABLE 5-2: Q2 (table) L1 (table) R2 (table) VOUT D1 (table) C7 (table) PGND COMP CSH SYNC VOUT C12 0.1μF 50V GND C13, 1nF VREF SGND GND FIGURE 5-3: C11 (table) Q1 (table) LSD SS C9 4.7μF 16V VSW C4 1nF C3 0.1μF C6 0.1μF Components Selection of Predesigned Circuits C1 0.1μF 50V Basic Circuit Diagram for use with Table 5-3 through Table 5-6. SPECIFICATIONS FOR FIGURE 5-3 & TABLE 5-3 THROUGH TABLE 5-6 Specification Limit Switching Frequency Ripple 1% of Output Voltage Max. Ambient Temp. +85°C Short-Circuit Capability Continuous Switching Frequency 300 kHz COMPONENT SUPPLIERS Manufacturer Website Address Microchip Technology Inc. www.microchip.com Kyocera AVX www.kyocera-avx.com Central Semiconductor www.centralsemi.com Eaton www.eaton.com Infineon www.infineon.com Vishay www.vishay.com Sumida www.sumida.com  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 27 MIC2182 TABLE 5-3: COMPONENTS FOR 5V OUTPUT Reference 3A (6.5V to 30V) Part No./Desc. 4A (6.5V to 30V) Part No./Desc. 5A (6.5V to 30V) Part No./Desc. 10A (6.5V to 30V) Part No./Desc. C7 Qty: 2 TPSE227M010R0100 Kyocera AVX, 220µF 10V, 0.1Ω ESR, Output filter capacitor Qty: 2 TPSE227M010R0100 Kyocera AVX, 220µF 10V, 0.1Ω ESR, Output filter capacitor Qty: 2 TPSE227M010R0060 Kyocera AVX, 220µF 10V, 0.06Ω ESR, Output filter capacitor Qty: 2 TPSV337M010R0060 Kyocera AVX, 330µF 10V, 0.06Ω ESR, Output filter capacitor C11 Qty: 2 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 3 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 4 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 4 TPSV107M020R0085 Kyocera AVX, 100µF 20V, 0.085Ω ESR, Input filter capacitor D1 Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B330, Vishay, Freewheeling diode L1 Qty: 1 CDRH125NP-100MC, Qty: 1 CDRH127NP-100MC, Qty: 1 CDRH127NP-100MC, Qty: 1 UP4B-3R3, Sumida, 10µH 4A, Sumida, 10µH 5A, Sumida, 10µH 5A, Eaton, 3.3µH 11A, Output inductor Output inductor Output inductor Output inductor Q1 Qty: 1 Si4800BDY, Vishay, Low-side MOSFET Qty: 1 Si4800BDY, Vishay, Low-side MOSFET Qty: 1 Si4884BDY, Vishay, Low-side MOSFET Qty: 2 Si4884BDY, Vishay, Low-side MOSFET Q2 Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 1 Si4884BDY, Vishay, High-side MOSFET Qty: 2 Si4884BDY, Vishay, High-side MOSFET R2 Qty: 1 WSL2010R0250F, Vishay, 0.025, 1%, 0.5W, Current sense resistor Qty: 1 WSL2010R0200F, Vishay, 0.02, 1%, 0.5W, Current sense resistor Qty: 1 WSL2512R0150F, Vishay, 0.015, 1%, 1W, Current sense resistor Qty: 2 WSL2512R0150F, Vishay, 0.015, 1%, 1W, Current sense resistor U1 MIC2182-5.0YSM or MIC2182-5.0YM MIC2182-5.0YSM or MIC2182-5.0YM MIC2182-5.0YSM or MIC2182-5.0YM MIC2182-5.0YM TABLE 5-4: COMPONENTS FOR 3.3V OUTPUT Reference 3A (6.5V to 30V) Part No./Desc. 4A (6.5V to 30V) Part No./Desc. 5A (6.5V to 30V) Part No./Desc. 10A (6.5V to 30V) Part No./Desc. C7 Qty: 2 TPSE227M010R0100 Kyocera AVX, 220µF 10V, 0.1Ω ESR, Output filter capacitor Qty: 2 TPSE227M010R0100 Kyocera AVX, 220µF 10V, 0.1Ω ESR, Output filter capacitor Qty: 2 TPSE227M010R0060 Kyocera AVX, 220µF 10V, 0.06Ω ESR, Output filter capacitor Qty: 2 TPSV477M006R0055 Kyocera AVX, 470µF 6.3V, 0.055Ω ESR, Output filter capacitor C11 Qty: 2 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 2 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 3 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 3 TPSV227M016R0075 Kyocera AVX, 220µF 16V, 0.075Ω ESR, Input filter capacitor D1 Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B330, Vishay, Freewheeling diode L1 Qty: 1 CDRH125NP-100MC, Qty: 1 CDRH127NP-100MC, Qty: 1 CDRH127NP-100MC, Qty: 1 UP4B-3R3, Sumida, 10µH 4A, Sumida, 10µH 5A, Sumida, 10µH 5A, Eaton, 3.3µH 11A, Output inductor Output inductor Output inductor Output inductor Q1 Qty: 1 Si4800BDY, Vishay, Low-side MOSFET Qty: 1 Si4800BDY, Vishay, Low-side MOSFET Qty: 1 Si4800BDY, Vishay, Low-side MOSFET Qty: 2 Si4884BDY, Vishay, Low-side MOSFET Q2 Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 2 Si4884BDY, Vishay, High-side MOSFET R2 Qty: 1 WSL2010R0250F, Vishay, 0.025, 1%, 0.5W, Current sense resistor Qty: 1 WSL2010R0200F, Vishay, 0.02, 1%, 0.5W, Current sense resistor Qty: 1 WSL2512R0150F, Vishay, 0.015, 1%, 1W, Current sense resistor Qty: 2 WSL2512R0150F, Vishay, 0.015, 1%, 1W, Current sense resistor U1 MIC2182-3.3YSM or MIC2182-3.3YM MIC2182-3.3YSM or MIC2182-3.3YM MIC2182-3.3YSM or MIC2182-3.3YM MIC2182-3.3YM DS20006644A-page 28  2022 Microchip Technology Inc. and its subsidiaries MIC2182 TABLE 5-5: COMPONENTS FOR 2.5V OUTPUT Reference 3A (6.5V to 30V) Part No./Desc. 4A (6.5V to 30V) Part No./Desc. 5A (6.5V to 30V) Part No./Desc. 10A (6.5V to 30V) Part No./Desc. C7 Qty: 2 TPSE227M010R0100 Kyocera AVX, 220µF 10V, 0.1Ω ESR, Output filter capacitor Qty: 2 TPSE227M010R0100 Kyocera AVX, 220µF 10V, 0.1Ω ESR, Output filter capacitor Qty: 2 TPSE227M010R0060 Kyocera AVX, 220µF 10V, 0.06Ω ESR, Output filter capacitor Qty: 2 TPSV477M006R0055 Kyocera AVX, 470µF 6.3V, 0.055Ω ESR, Output filter capacitor C11 Qty: 2 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 2 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 2 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 3 TPSV227M016R0075 Kyocera AVX, 220µF 16V, 0.075Ω ESR, Input filter capacitor D1 Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B330, Vishay, Freewheeling diode L1 Qty: 1 CDRH125NP-100MC, Qty: 1 CDRH127NP-100MC, Qty: 1 CDRH127NP-100MC, Qty: 1 UP4B-3R3, Sumida, 10µH 4A, Sumida, 10µH 5A, Sumida, 10µH 5A, Eaton, 3.3µH 11A, Output inductor Output inductor Output inductor Output inductor Q1 Qty: 1 Si4800BDY, Vishay, Low-side MOSFET Qty: 1 Si4884BDY, Vishay, Low-side MOSFET Qty: 1 Si4884BDY, Vishay, Low-side MOSFET Qty: 2 Si4884BDY, Vishay, Low-side MOSFET Q2 Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 2 Si4884BDY, Vishay, High-side MOSFET R2 Qty: 1 WSL2010R0250F, Vishay, 0.025, 1%, 0.5W, Current sense resistor Qty: 1 WSL2010R0200F, Vishay, 0.02, 1%, 0.5W, Current sense resistor Qty: 1 WSL2512R0150F, Vishay, 0.015, 1%, 1W, Current sense resistor Qty: 2 WSL2512R0150F, Vishay, 0.015, 1%, 1W, Current sense resistor U1 MIC2182YSM or MIC2182YM MIC2182YSM or MIC2182YM MIC2182YSM or MIC2182YM MIC2182YM TABLE 5-6: COMPONENTS FOR 1.8V OUTPUT Reference 3A (6.5V to 30V) Part No./Desc. 4A (6.5V to 30V) Part No./Desc. 5A (6.5V to 30V) Part No./Desc. 10A (6.5V to 30V) Part No./Desc. C7 Qty: 2 TPSE227M010R0100 Kyocera AVX, 220µF 10V, 0.1Ω ESR, Output filter capacitor Qty: 2 TPSE227M010R0100 Kyocera AVX, 220µF 10V, 0.1Ω ESR, Output filter capacitor Qty: 2 TPSE227M010R0060 Kyocera AVX, 220µF 10V, 0.06Ω ESR, Output filter capacitor Qty: 2 TPSV477M006R0055 Kyocera AVX, 470µF 6.3V, 0.055Ω ESR, Output filter capacitor C11 Qty: 2 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 2 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 2 TPSE226M035R0300 Kyocera AVX, 22µF 35V, 0.3Ω ESR, Input filter capacitor Qty: 2 TPSV227M016R0075 Kyocera AVX, 220µF 16V, 0.075Ω ESR, Input filter capacitor D1 Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B140, Vishay, Freewheeling diode Qty: 1 B330, Vishay, Freewheeling diode L1 Qty: 1 CDRH125NP-100MC, Qty: 1 CDRH127NP-100MC, Qty: 1 CDRH127NP-100MC, Qty: 1 UP4B-3R3, Sumida, 10µH 4A, Sumida, 10µH 5A, Sumida, 10µH 5A, Eaton, 3.3µH 11A, Output inductor Output inductor Output inductor Output inductor Q1 Qty: 1 Si4800BDY, Vishay, Low-side MOSFET Qty: 1 Si4884BDY, Vishay, Low-side MOSFET Qty: 1 Si4884BDY, Vishay, Low-side MOSFET Qty: 2 Si4884BDY, Vishay, Low-side MOSFET Q2 Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 1 Si4800BDY, Vishay, High-side MOSFET Qty: 2 Si4884BDY, Vishay, High-side MOSFET R2 Qty: 1 WSL2010R0250F, Vishay, 0.025, 1%, 0.5W, Current sense resistor Qty: 1 WSL2010R0200F, Vishay, 0.02, 1%, 0.5W, Current sense resistor Qty: 1 WSL2512R0150F, Vishay, 0.015, 1%, 1W, Current sense resistor Qty: 2 WSL2512R0150F, Vishay, 0.015, 1%, 1W, Current sense resistor U1 MIC2182YSM or MIC2182YM MIC2182YSM or MIC2182YM MIC2182YSM or MIC2182YM MIC2182YM  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 29 MIC2182 5.11 PCB Layout and Checklist PCB layout is critical to achieve reliable, stable and efficient performance. A ground plane is required to control EMI and minimize the inductance in power and signal return paths. The following guidelines should be followed to insure proper operation of the circuit. • Signal and power grounds should be kept separate and connected at only one location. Large currents or high di/dt signals that occur when the MOSFETs turn on and off must be kept away from the small signal connections. • The connection between the current-sense resistor and the MIC2182 current-sense inputs (Pins 8 and 9) should have separate traces, routed from the terminals directly to the IC pins. The traces should be routed as closely as possible to each other and their length should be minimized. Avoid running the traces under the inductor and other switching components. A 1 nF to 0.1 µF capacitor placed between Pins 8 and 9 will help attenuate switching noise on the current sense traces. This capacitor should be placed close to Pins 8 and 9. • When the high-side MOSFET is switched on, the critical flow of current is from the input capacitor through the MOSFET, inductor, sense resistor, output capacitor, and back to the input capacitor. These paths must be made with short, wide pieces of trace. It is good practice to locate the ground terminals of the input and output capacitors close to each other. DS20006644A-page 30 • When the low-side MOSFET is switched on, current flows through the inductor, sense resistor, output capacitor, and MOSFET. The source of the low-side MOSFET should be located close to the output capacitor. • The freewheeling diode, D1 in the Block Diagrams, conducts current during the dead time, when both MOSFETs are off. The anode of the diode should be located close to the output capacitor ground terminal and the cathode should be located close to the input side of the inductor. • The 4.7 µF capacitor, which connects to the VDD terminal (Pin 11) must be located right at the IC. The VDD terminal is very noise sensitive and placement of this capacitor is very critical. Connections must be made with wide trace. The capacitor may be located on the bottom layer of the board and connected to the IC with multiple vias. • The VIN bypass capacitor should be located close to the IC and connected between Pins 10 and 12. Connections should be made with a ground and power plane or with short, wide trace.  2022 Microchip Technology Inc. and its subsidiaries MIC2182 6.0 PACKAGING INFORMATION 6.1 Package Marking Information 16-Lead SSOP* (Fixed) Example 2182 -5.0YSM 7BF2 XXXX -X.XXXX WNNN 16-Lead SOIC* (Fixed) Example XXXX -X.XXX WNNN 2182 -5.0YM 264L Legend: XX...X Y YY WW NNN e3 * 16-Lead SSOP* (Adj.) Example XXX XXXXXXX WNNN MIC 2182YSM 3D4X 16-Lead SOIC* (Adj.) Example XXX XXXXXX WNNN MIC 2182YM 8SR6 Product code or customer-specific information Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week ‘01’) Alphanumeric traceability code Pb-free JEDEC® designator for Matte Tin (Sn) This package is Pb-free. The Pb-free JEDEC designator ( e3 ) can be found on the outer packaging for this package. ●, ▲, ▼ Pin one index is identified by a dot, delta up, or delta down (triangle mark). Note: In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information. Package may or may not include the corporate logo. Underbar (_) and/or Overbar (‾) symbol may not be to scale. Note: If the full seven-character YYWWNNN code cannot fit on the package, the following truncated codes are used based on the available marking space: 6 Characters = YWWNNN; 5 Characters = WWNNN; 4 Characters = WNNN; 3 Characters = NNN; 2 Characters = NN; 1 Character = N  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 31 MIC2182 16-Lead SOIC Package Outline and Recommended Land Pattern Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging. DS20006644A-page 32  2022 Microchip Technology Inc. and its subsidiaries MIC2182 16-Lead SSOP Package Outline and Recommended Land Pattern Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging.  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 33 MIC2182 NOTES: DS20006644A-page 34  2022 Microchip Technology Inc. and its subsidiaries MIC2182 APPENDIX A: REVISION HISTORY Revision A (February 2022) • Converted Micrel document MIC2182 to Microchip data sheet DS20006644A. • Minor text changes throughout.  2022 Microchip Technology Inc. and its subsidiaries DS20006644A-page 35 MIC2182 NOTES: DS20006644A-page 36  2022 Microchip Technology Inc. and its subsidiaries MIC2182 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, contact your local Microchip representative or sales office. PART NO. –X.X Device Output Voltage X XX –XX Package Media Type Junction Temperature Range Device: MIC2182: High-Efficiency Synchronous Buck Controller Output Voltage: = Adjustable -3.3 = 3.3V -5.0 = 5.0V Junction Temperature Range: Y Package: M = SM = Media Type: = 48/Tube (M, SOIC) = 77/Tube (SM, SSOP) TR = 1,000/Reel (SM, SSOP) TR = 2,500/Reel (M, SOIC) = Examples: a) MIC2182YM: High Efficiency Synchronous Buck Controller, ADJ Output Voltage, –40°C to +125°C Junction Temperature Range, RoHS Compliant, 16-Lead SOIC (.150 in) Package, 48/Tube b)MIC2182-3.3YM: High Efficiency Synchronous Buck Controller, 3.3V Output Voltage, –40°C to +125°C Junction Temperature Range, RoHS Compliant, 16-Lead SOIC (.150 in) Package, 48/Tube c) MIC2182-5.0YM-TR: High Efficiency Synchronous Buck Controller, 5.0V Output Voltage, –40°C to +125°C Junction Temperature Range, RoHS Compliant, 16-Lead SOIC (.150 in) Package, 2500/Reel d) MIC2182YSM: High Efficiency Synchronous Buck Controller, ADJ Output Voltage, –40°C to +125°C Junction Temperature Range, RoHS Compliant, 16-Lead SSOP (5.3 mm) Package, 77/Tube e) MIC2182-3.3YSM High Efficiency Synchronous Buck Controller, 3.3V Output Voltage, –40°C to +125°C Junction Temperature Range, RoHS Compliant, 16-Lead SSOP (5.3 mm) Package, 77/Tube f) MIC2182-5.0YSM-TR: High Efficiency Synchronous Buck Controller, 5.0V Output Voltage, –40°C to +125°C Junction Temperature Range, RoHS Compliant, 16-Lead SSOP (5.3 mm) Package, 1000/Reel –40°C to +125°C (RoHs Compliant) 16-Lead SOIC (.150in) 16-Lead SSOP (5.3mm) Note 1:  2022 Microchip Technology Inc. and its subsidiaries Tape and Reel identifier only appears in the catalog part number description. This identifier is used for ordering purposes and is not printed on the device package. Check with your Microchip Sales Office for package availability with the Tape and Reel option. DS20006644A-page 37 MIC2182 NOTES: DS20006644A-page 38  2022 Microchip Technology Inc. and its subsidiaries Note the following details of the code protection feature on Microchip products: • Microchip products meet the specifications contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is secure when used in the intended manner, within operating specifications, and under normal conditions. • Microchip values and aggressively protects its intellectual property rights. Attempts to breach the code protection features of Microchip product is strictly prohibited and may violate the Digital Millennium Copyright Act. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of its code. Code protection does not mean that we are guaranteeing the product is “unbreakable”. Code protection is constantly evolving. Microchip is committed to continuously improving the code protection features of our products. This publication and the information herein may be used only with Microchip products, including to design, test, and integrate Microchip products with your application. Use of this information in any other manner violates these terms. Information regarding device applications is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. Contact your local Microchip sales office for additional support or, obtain additional support at https:// www.microchip.com/en-us/support/design-help/client-supportservices. THIS INFORMATION IS PROVIDED BY MICROCHIP "AS IS". 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Adjacent Key Suppression, AKS, Analog-for-the-Digital Age, Any Capacitor, AnyIn, AnyOut, Augmented Switching, BlueSky, BodyCom, CodeGuard, CryptoAuthentication, CryptoAutomotive, CryptoCompanion, CryptoController, dsPICDEM, dsPICDEM.net, Dynamic Average Matching, DAM, ECAN, Espresso T1S, EtherGREEN, GridTime, IdealBridge, In-Circuit Serial Programming, ICSP, INICnet, Intelligent Paralleling, Inter-Chip Connectivity, JitterBlocker, Knob-on-Display, maxCrypto, maxView, memBrain, Mindi, MiWi, MPASM, MPF, MPLAB Certified logo, MPLIB, MPLINK, MultiTRAK, NetDetach, NVM Express, NVMe, Omniscient Code Generation, PICDEM, PICDEM.net, PICkit, PICtail, PowerSmart, PureSilicon, QMatrix, REAL ICE, Ripple Blocker, RTAX, RTG4, SAM-ICE, Serial Quad I/O, simpleMAP, SimpliPHY, SmartBuffer, SmartHLS, SMART-I.S., storClad, SQI, SuperSwitcher, SuperSwitcher II, Switchtec, SynchroPHY, Total Endurance, TSHARC, USBCheck, VariSense, VectorBlox, VeriPHY, ViewSpan, WiperLock, XpressConnect, and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. The Adaptec logo, Frequency on Demand, Silicon Storage Technology, Symmcom, and Trusted Time are registered trademarks of Microchip Technology Inc. in other countries. GestIC is a registered trademark of Microchip Technology Germany II GmbH & Co. KG, a subsidiary of Microchip Technology Inc., in other countries. All other trademarks mentioned herein are property of their respective companies. © 2022, Microchip Technology Incorporated and its subsidiaries. All Rights Reserved. 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