MIC33050_09 MICREL | Alldatasheet

Document overview

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Technical content

Features

  • Input voltage: 2.7V to 5.5V HyperLight Load™
  • 600mA output current
  • Fixed output voltage options from 0.72V to 3.3V
  • No external inductor required
  • Ultra fast transient response
  • 20µA typical quiescent current
  • 4MHz in PWM in constant current mode
  • Low voltage output ripple – 25mVpp in HyperLight Load™ mode – 3mV output voltage ripple in full PWM mode
  • >93% efficiency
  • >85% at 1mA
  • Micropower shutdown
  • 3mm x 3mm MLF ®-12L
  • –40 °C to +125°C junction temperature range

Applications

  • Cellular phones
  • Digital cameras
  • Portable media players
  • Wireless LAN cards
  • WiFi/WiMax/WiBro modules
  • USB Powered Devices Typical Application 100 1 10 100 1000 EFFICIENCY (%) OUTPUT CURRENT (mA) Efficiency VOUT = 1.8V VIN = 4.2VVIN = 3.6V VIN = 3.0V

Micrel, Inc. MIC33050 July 2009 2 M9999-070909-C

Ordering Information

Part Number Voltage Temperature Range Package Lead Finish MIC33050-CYHL 1.0V –40° to +125°C 12-Pin 3mm x 3mm MLF ® Pb-Free MIC33050-4YHL 1.2V –40° to +125°C 12-Pin 3mm x 3mm MLF ® Pb-Free MIC33050-GYHL 1.8V –40° to +125°C 12-Pin 3mm x 3mm MLF ® Pb-Free MIC33050-SYHL 3.3V –40° to +125°C 12-Pin 3mm x 3mm MLF ® Pb-Free Note: 1. Other output voltage options avail able. Contact Micrel for details. 2. MLF is a green RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. Pin Configuration 12-Pin 3mm x 3mm MLF® (HL) (Top View) Pin Description Pin Number Pin Name Pin Function 1 VIN Supply Voltage (Input): Requires bypass capacitor-to-GND. 2 PGND Power Ground. 3,4,5,6 SW Switch (Output): Inte rnal power MOSFET output switches. 7,8 OUT Output after the internal inductor.

9 EN Enable (Input): Logic low will shut down the device, reducing the quiescent

current to less than 4µA. Do not leave floating. 10 SNS Input to the error amplifier. Connect to the external resistor divider network to see the output voltage. For fixed output voltages connect VOUT (internal resistor network sets the output voltage). 11 CFF Feed forward capacitor connected to out sense pin. 12 AGND Analog ground. E-PAD HS PAD Connect to power ground.

Micrel, Inc. MIC33050 July 2009 3 M9999-070909-C Absolute Maximum Ratings(1) Operating Ratings(2) Thermal Resistance Electrical Characteristics(4) TA = 25°C with VIN = VEN = 3.6V; CFF = 560pF; COUT = 4.7µF; IOUT = 20mA unless otherwise specified. Bold values indicate –40°C< TJ < +125°C. Parameter Condition Min Typ Max Units Supply Voltage Range 2.7 5.5 V Under-Voltage Lockout Threshold (turn-on) 2. 45 2.55 2.65 V UVLO Hysteresis 100 mV Quiescent Current, Hyper LL mode IOUT = 0mA , VSNS > 1.2*VOUT nominal 20 32 µA Shutdown Current VIN = 5.5V; VEN = 0V; 0.01 4 µA Output Voltage Accuracy V IN = 3.0V, ILOAD = 20mA –2.5 +2.5 % Current Limit in PWM Mode SNS = 0.9*V NOM 0.65 1 1.7 A Output Voltage Line Regulation V IN = 3.0V to 5.5V, ILOAD = 20mA 0.5 %/V Output Voltage Load Regulation 20mA < I LOAD < 500mA, 0.3 % Maximum Duty Cycle SNS ≤ VNOM 80 89 % PWM Switch ON-Resistance ISW = 100mA PMOS ISW = -100mA NMOS 0.45 0.5 Ω Ω Frequency I LOAD = 120mA 4 MHz Soft Start Time V OUT = 90% 650 µs Enable Threshold (turn-on) 0.5 0.8 1.2 V Enable Hysteresis 35 mV Enable Input Current 0.1 2 µA Over-temperature Shutdown 165 °C Over-temperature Shutdown Hysteresis 20 °C Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 4. Specification for packaged product only.

Micrel, Inc. MIC33050 July 2009 4 M9999-070909-C Typical Characteristics 100 1 10 100 1000 EFFICIENCY (%) OUTPUT CURRENT (mA) Efficiency VOUT = 3.3V VIN = 5.0V VIN = 4.2V VIN = 5.5V 100 1 10 100 1000 EFFICIENCY (%) OUTPUT CURRENT (mA) Efficiency VOUT = 1.8V VIN = 4.2VVIN = 3.6V VIN = 3.0V 100 1 10 100 1000 EFFICIENCY (%) OUTPUT CURRENT (mA) Efficiency VOUT = 1.2V VIN = 2.7V VIN = 3.6V VIN = 4.2V 100 1 10 100 1000 EFFICIENCY (%) OUTPUT CURRENT (mA) Efficiency VOUT = 1.0V VIN = 2.7V VIN = 3.6V VIN = 4.2V L = 1uH Quiescent Current vs. Temperature 20 40 60 80 TEMPERATURE (°C) VIN = 3.6V VOUT = 1.8V 2.7 INPUT VOLTAGE (V) Quiescent Current vs. Input Voltage VOUT = 1.8V No Load 2.5 3.0 3.5 4.0 4.5 5.0 5.5 Switching Frequency vs. Temperature 20 40 60 80 TEMPERATURE (°C) VIN = 3.6V VOUT = 1.8V Load = 150mA 2.5 3.0 3.5 4.0 4.5 5.0 5.5 2.7 INPUT VOLTAGE (V) Switching Frequency vs. Input Voltage VOUT = 1.8V Load = 150mA 0.60 0.62 0.64 0.66 0.68 0.70 0.72 0.74 0.76 0.78 0.80 Feedback Voltage vs. Temperature 20 40 60 80 TEMPERATURE (°C) VIN = 3.6V VOUT = 1.8V No Load 1.70 1.75 1.80 1.85 1.90 Output Voltage vs. Temperature 20 40 60 80 TEMPERATURE (°C) VIN = 3.6V VOUT = 1.8V No Load 1.70 1.75 1.80 1.85 1.90 2.7 INPUT VOLTAGE (V)INPUT VOLTAGE (V) Output Voltage vs. Input Voltage Load = 20mA 1.70 1.75 1.80 1.85 1.90 0 100 200 300 400 500 600 OUTPUT CURRENT (mA) Output Voltage vs. Output Current VIN = 3.6V

Micrel, Inc. MIC33050 July 2009 5 M9999-070909-C Functional Characteristics

Micrel, Inc. MIC33050 July 2009 6 M9999-070909-C Functional Characteristics (continued)

Micrel, Inc. MIC33050 July 2009 7 M9999-070909-C Functional Diagram MIC33050 Simplified Block Diagram

Micrel, Inc. MIC33050 July 2009 8 M9999-070909-C Functional Description VIN VIN provides power to the MOSFETs for the switch mode regulator section and to the analog supply circuitry. Due to the high switching speeds, it is recommended that a 2.2µF or greater capacitor be plac ed close to VIN and the power ground (PGND) pin for bypassing. Refer to the layout recommendations for details. EN The enable pin (EN) controls the on and off state of the device. A high logic on the enable pin activates the regulator, while a low logic deactivates it. MIC33050 features built-in soft-start circuitry that reduces in-rush current and prevents the output voltage from overshooting at start up. Do not leave floating. 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 rout ed away from sensitive nodes such as the CFF pin. OUT The output pin (OUT) is the output voltage pin following the internal inductor of the dev ice. Connect an output filter capacitor equal to 2.2µF or greater to this pin. SNS The SNS pin is needed to sense the output voltage at the output filter capacitor. In order for the control loop to monitor the output voltage accura tely it is good practice to sense the output voltage at the positive side of the output filter capacitor where voltage ripple is smallest. CFF The CFF pin is connected to the SNS pin of MIC33050 with a feed-forward capacitor of 560pF. The CFF pin itself is compared with the internal reference voltage (V REF) of the device and provides the co ntrol path to control the output. VREF is equal to 0.72V. The CFF pin is sensitive to noise and should be place away from the SW pin. Refer to the layout recommendations for details. PGND Power ground (PGND) is the ground path for high current. The current loop for the power ground should be as small as possible and separate from the Analog ground (AGND) loop. Refer to the layout recommendations for more details. AGND Signal ground (AGND) is the ground path for the biasing and control circuitry. The current loop for the signal ground should be separate from the Power ground (PGND) loop. Refer to the layout recommendations for more details.

Micrel, Inc. MIC33050 July 2009 9 M9999-070909-C Applications Information Input Capacitor A minimum of 2.2µF ceramic capacitor should be placed close to the VIN pin and PGND pin for bypassing. X5R or X7R dielectrics are recommended for the input capacitor. Y5V dielectrics, aside from losing most of their capacitance over temperature, they also become resistive at high frequencies. This redu ces their ability to filter out high frequency noise. Output Capacitor The MIC33050 was designed for use with a 2.2µF or greater ceramic output capacito r. A low equivalent series resistance (ESR) ceramic output capacitor either X7R or X5R is recommended. Y5V and Z5U dielectric capacitors, aside from the undesirable effect of their wide variation in capacitance over temperature, become resistive at high frequencies. Compensation The MIC33050 is designed to be stable with an internal inductor with a minimum of 2.2µF ceramic (X5R) output capacitor. Efficiency Considerations Efficiency is defined as the amount of useful output power, divided by the amount of power supplied. 100IV IV% Efficiency ININ OUTOUT ×⎟⎟ Maintaining high efficiency serves two purposes. It reduces power dissipation in the power supply, reducing the need for heat sinks and ther mal design considerations and it reduces consumption of current for battery powered applications. Reduced current draw from a battery increases the devices operating time and is critical in hand held devices. There are two types of losses in switching converters; DC losses and switching losses. DC losses are simply the power dissipation of I 2R. Power is dissipated in the high side switch during the on cycle. Power loss is equal to the high side MOSFET R DSON multiplied by the Switch Current2. During the off cycle, the low side N-channel MOSFET conducts, also dissipating power. Device operating current also reduces efficiency. The product of the quiescent (operating) current and the supply voltage is another DC loss. The current re quired driving the gates on and off at a constant 4MHz frequency and the switching transitions make up the switching losses. 100 1 10 100 1000 EFFICIENCY (%) OUTPUT CURRENT (mA) Efficiency VOUT = 1.8V VIN = 4.2VVIN = 3.6V VIN = 3.0V The Figure above shows an efficiency curve. From 1µA to 100mA, efficiency losses are dominated by quiescent current losses, gate drive and transition losses. By using the HyperLight Load™ mode, the MIC33050 is able to maintain high efficiency at low output currents. Over 100mA, efficiency loss is dominated by MOSFET RDSON and inductor losses. Higher input supply voltages will increase the Gate-to-Sour ce threshold on the internal MOSFETs, thereby reducing the internal RDSON. This improves efficiency by reducing DC losses in the device. All but the inductor losses are inherent to the device. In which case, inductor selection becomes increasingly critical in efficiency calculations. As the inductors are reduced in size, the DC resistance (DCR) can become quite significant. The DCR losses can be calculated as follows; L PD = IOUT 2 × DCR From that, the loss in efficiency due to inductor resistance can be calculated as follows; 100LIV IV1Loss Efficiency PDOUTOUT OUTOUT × ×−= Efficiency loss due to DCR is minimal at light loads and gains significance as the load is increased. Inductor selection becomes a trade-off between efficiency and size in this case.

Micrel, Inc. MIC33050 July 2009 10 M9999-070909-C HyperLight Load™ Mode The MIC33050 uses a minimum on and off time proprietary control loop. When the output voltage falls below the regulation threshold, the error comparator begins a switching cycle that turns the PMOS on and keeps it on for the duration of the minimum-on-time. When the output voltage is over t he regulation threshold, the error comparator turns the PMOS off for a minimum-off- time. The NMOS acts as an ideal rectifier that conducts when the PMOS is off. Using a NMOS switch instead of a diode allows for lower voltage drop across the switching device when it is on. The asynchronous switching combination between the PMOS and the NMOS allows the control loop to work in discontinuous mode for light load operations. In discontinuous mode, MIC33050 works in pulse frequency modulation (PFM) to regulate the output. As the output current increas es, the switching frequency increases. This improves t he efficiency of the MIC33050 during light load currents. As the load current increases, the MIC33050 goes into continuous conduction mode (CCM) at a constant frequency of 4MHz. The equation to calculate the load when the MIC33050 goes into continuous conduction mode may be approximated by the following formula: ×−= f2L D)V(VI OUTIN LOAD

Micrel, Inc. MIC33050 July 2009 11 M9999-070909-C MIC33050 Typical Application Circuit Bill of Materials Item Part Number Manufacturer Description Qty C1, C2 C1608X5R0J475K TDK (1) 4.7µF Ceramic Capacitor, 6.3V, X5R, Size 0603 2 C3 C1608C0G1H561J TDK (1) 560pF Ceramic Capacitor, 50V, NPO, Size 0603 1 U1 MIC33050-xYHL Micrel, Inc. (2) 4MHz Internal Inductor PWM Buck Regulator with HyperLight Load™ Mode 1 Notes: 1. TDK: www.tdk.com 2. Micrel, Inc: www.micrel.com

Micrel, Inc. MIC33050 July 2009 12 M9999-070909-C PCB Layout Recommendations Top Layer Bottom Layer

Micrel, Inc. MIC33050 July 2009 13 M9999-070909-C

Package Information

12-Pin 3mm x 3mm MLF® (ML) MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2007 Micrel, Incorporated.