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MIC23150
4MHz PWM 2A Buck Regulator with HyperLight LoadTM
General Description
The MIC23150 is a high efficiency 4MHz 2A synchronous buck regulator with HyperLight LoadTM mode. HyperLight LoadTM provides very high efficiency at light loads and ultra-fast transient response which is perfectly suited for supplying processor core voltages. An additional benefit of this proprietary architecture is very low output ripple voltage throughout the entire load range with the use of small output capacitors. The tiny 2mm x 2mm Thin MLF(R) package saves precious board space and requires only three external components. The MIC23150 is designed for use with a very small inductor, down to 0.47H, and an output capacitor as small as 2.2 F that enables a total solution size, less than 1mm height. The MIC23150 has a very low quiescent current of 23A and achieves a peak efficiency of 93% in continuous conduction mode. In discontinuous conduction mode, the MIC23150 can achieve 87% efficiency at 1mA. The MIC23150 is available in 8-pin 2mm x 2mm Thin MLF(R) package with an operating junction temperature range from -40C to +125C. Datasheets and support documentation can be found on Micrel's web site at: www.micrel.com.
Features
* * * * * * * *
HyperLight LoadTM Input voltage: 2.7V to 5.5V 2A output current Up to 93% peak efficiency 87% typical efficiency at 1mA 23A typical quiescent current 4MHz PWM operation in continuous mode Ultra fast transient response Low ripple output voltage - 14mVpp ripple in HyperLight LoadTM mode - 5mV output voltage ripple in full PWM mode Fully integrated MOSFET switches 0.01A shutdown current Thermal shutdown and current limit protection Output Voltage as low as 0.95V 8-pin 2mm x 2mm Thin MLF(R) -40C to +125C junction temperature range
* * * * * *
Applications
* Mobile handsets * Portable media/MP3 players * Portable navigation devices (GPS) * WiFi/WiMax/WiBro modules * Solid State Drives/Memory * Wireless LAN cards * Portable applications ____________________________________________________________________________________________________________
Typical Application
U1 MIC23150
VIN C1 EN L1 VOUT
100 90
Efficiency V = 1.8V OUT
VIN = 2.7V V = 3.0V IN V = 3.6V IN
VIN
SW 2mmx2mm ThinMLF SNS
C2
80 70 60
EN AGND PGND
GND
50 40 11
GND
L = 1.0H C = 4.7F OUT 0 100 1000 10000 OUTPUT CURRENT (mA)
HyperLight Load is a trademark of Micrel, Inc. MLF and MicroLeadFrame are registered trademark 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
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Micrel Inc.
MIC23150
Ordering Information
Part Number MIC23150-CYMT MIC23150-4YMT MIC23150-GYMT MIC23150-SYMT
Notes: 1. Other options available (0.95V - 3.6V). Contact Micrel Marketing for details. 2. Thin MLF is GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. 3. Thin MLF = Pin 1 identifier.
(R) (R)
Marking Code QKC QK4 QKG QKS
Nominal Output Voltage 1.0V 1.2V 1.8V 3.3V
Junction Temp. Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C
Package 8-Pin 2mm x 2mm Thin MLF(R) 8-Pin 2mm x 2mm Thin MLF(R) 8-Pin 2mm x 2mm Thin MLF 8-Pin 2mm x 2mm Thin MLF
(R) (R)
Lead Finish Pb-Free Pb-Free Pb-Free Pb-Free
Pin Configuration
SW SW EN SNS 1 2 3 4
8 7 6 5
PGND VIN VIN AGND
(Top View) 2mm x 2mm Thin MLF (MT)
Pin Description
Pin Number 1,2 3 4 5 6,7 8 Pin Name SW EN SNS AGND VIN PGND Pin Function Switch (Output): Internal power MOSFET output switches. Enable (Input): Logic high enables operation of the regulator. Logic low will shut down the device. Do not leave floating. Sense: Connect to VOUT as close to output capacitor as possible to sense output voltage. Analog Ground: Connect to central ground point where all high current paths meet (CIN, COUT, PGND) for best operation. Input Voltage: Connect a capacitor-to-ground to decouple the noise. Power Ground.
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Absolute Maximum Ratings(1)
Supply Voltage (VIN) . ..............................................6V Sense (VSNS).. ..................................................................6V Output Switch Voltage (VSW) ............................................6V Enable Input Voltage (VEN).. ..............................-0.3V to VIN Storage Temperature Range .. ...............-65C to +150C ESD Rating(3) ..................................................................2kV
Operating Ratings(2)
Supply Voltage (VIN)... ................................2.7V to 5.5V Enable Input Voltage (VEN) .. ............................0V to VIN Junction Temperature Range (TJ)... ....-40C TJ +125C Thermal Resistance 2mm x 2mm Thin MLF-8 (JA) ...........................90C/W
Electrical Characteristics(4)
TA = 25C; VIN = VEN = 3.6V; L = 1.0H; COUT = 4.7F unless otherwise specified. Bold values indicate -40C TJ +125C, unless noted.
Parameter Supply Voltage Range Under-Voltage Lockout Threshold Under-Voltage Lockout Hysteresis Quiescent Current Shutdown Current Output Voltage Accuracy Current Limit Output Voltage Line Regulation Output Voltage Load Regulation PWM Switch ON-Resistance Switching Frequency SoftStart Time Enable Threshold Enable Input Current Over-temperature Shutdown Over-temperature Shutdown Hysteresis
Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 4. Specification for packaged product only.
Condition (turn-on) IOUT = 0mA , SNS > 1.2 * VOUT Nominal VEN = 0V; VIN = 5.5V VIN = 3.6V if VOUTNOM < 2.5V, ILOAD = 20mA VIN = 4.5V if VOUTNOM 2.5V, ILOAD = 20mA SNS = 0.9*VOUTNOM VIN = 3.6V to 5.5V if VOUTNOM < 2.5V, ILOAD = 20mA VIN = 4.5V to 5.5V if VOUTNOM 2.5V, ILOAD = 20mA 20mA < ILOAD < 500mA, VIN = 3.6V if VOUTNOM < 2.5V 20mA < ILOAD < 500mA, VIN = 5.0V if VOUTNOM 2.5V ISW = 100mA PMOS ISW = -100mA NMOS IOUT = 120mA VOUT = 90% Turn-On
Min 2.7 2.45
Typ 2.55 75 23 0.01
Max 5.5 2.65 40 5 +2.5
Units V V mV A A % A %/V %/A MHz s
-2.5 2.2 3.4 0.3 0.75 0.150 0.110 4 115 0.5 0.8 0.1 160 20
1.2 2
V A C C
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Typical Characteristics
OUT 100 VIN = 3.0V VIN = 2.7V
Efficiency = 1.8V V
VIN = 3.6V
100 90 EFFICIENCY (%) 80 70 60
Efficiency = 3.3V V
OUT
90 80 70 60 50
VIN = 4.2V EFFICIENCY (%)
100 95 90 85 80 75 70 65 60 55 50 0.1
Efficiency with Various Inductors
L = 0.68H L = 1.0H
EFFICIENCY (%)
L = 1.5H
L = 2.2H
VIN = 4.2V VIN = 5.0V
VIN = 5.5V
VIN = 5.0V V
IN
= 5.5V
V V
IN
= 3.6V = 1.8V
40 0.1
L = 1.0H COUT = 4.7F 1 10 100 1000 10000 OUTPUT CURRENT (mA)
50 L = 1.0H = 4.7F C OUT 40 0.1 1 10 100 1000 10000 OUTPUT CURRENT (mA)
OUT
COUT = 4.7F 1 10 100 1000 10000 OUTPUT CURRENT (mA)
QUIESCENT CURRENT (A)
3.4 3.2 3.0 2.8 2.6 2.4
30 25 20 15
OUTPUT VOLTAGE (V)
CURRENT LIMIT (A)
4.0 3.8 3.6
Current Limit vs. Input Voltage
40 35
Quiescent Current vs. Input Voltage
2 1.95 1.9 1.85 1.8
Output Voltage vs. Input Voltage
25C 125C
Load = 200mA Load = 600mA
-40C
1.75 Load = 1000mA Load = 1500mA 1.7 1.65 1.6 2.7 3.2 3.7 4.2 4.7 5.2 INPUT VOLTAGE (V) 5.7
L = 1.0H 2.2 C = 4.7F OUT 2.0 2.7 3.2 3.7 4.2 4.7 5.2 INPUT VOLTAGE (V)
5.7
10 Not Switching L = open 5 = 1.2V x V V OUT NOM 0 2.7 3.2 3.7 4.2 4.7 5.2 INPUT VOLTAGE (V)
5.7
OUTPUT VOLTAGE (V)
1.9 1.85 1.8 1.75 1.7 1.65 1.6 2.7 3.2 3.7 4.2 4.7 5.2 INPUT VOLTAGE (V) 5.7 Load = 10mA Load = 100mA Load = 1mA
1
IN
V V
IN
IN
= 3.6V
= 4.2V
OUTPUT VOLTAGE (V)
1.95
SWITCHING FREQUENCY (MHz)
2
Output Voltage vs. Input Voltage
10 V
Switching Frequency vs Output Current
= 3.0V
1.9 1.88
Output Voltage vs Output Current
V = 5.5V IN 1.86 V = 4.2V V = 3.6V 1.84 IN IN 1.82 1.8 1.78 V
IN
0.1 L = 1.0H = 1.8V V
OUT
= 2.7V
0.01
C 0.001 1
OUT
= 4.7F
10 100 1000 10000 OUTPUT CURRENT (mA)
1.76 L = 1.0H 1.74 V = 1.8V OUT 1.72 C = 4.7F OUT 1.7 0.1 1 10 100 1000 10000 OUTPUT CURRENT (mA)
Switching Frequency vs. Temperature
SWITCHING FREQUENCY (MHz) 4.5 4.4 4.3 4.2 4.1 4.0 3.9 V = 3.6V 3.8 IN L =1.0H 3.7 C = 4.7F 3.6 OUT LOAD = 120mA 3.5 0 20 -40 -20 OUTPUT VOLTAGE (V) 1.85 1.84 1.83 1.82 1.81 1.80 1.79 1.78
Output Voltage vs. Temperature
ENABLE THRESHOLD (V)
1.2 1.0 0.8 0.6 0.4
Enable Thresold vs. Temperature
ENABLE ON
VIN = 2.7V VIN = 3.6V VIN = 5.5V
ENABLE OFF
40
60
80
100
120
0
20
40
60
80
100
120
-40
-20
20
40
60
80
0
100
TEMPERATURE (C)
TEMPERATURE (C)
TEMPERATURE (C)
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120
-40
-20
L =1.0H 1.77 C = 4.7F OUT 1.76 LOAD = 120mA 1.75
L = 1.0H 0.2 COUT = 4.7F 0
Micrel Inc.
MIC23150
Functional Characteristics
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MIC23150
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MIC23150
Functional Characteristics (cont.)
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Functional Characteristics (cont.)
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Functional Diagram
VIN
EN UVLO CONTROL LOGIC Timer & Softstart Gate Drive SW
Reference
Current Limit ERROR COMPARATOR ZERO 1 ISENSE PGND SNS
AGND
Figure 1. Simplified MIC23150 Functional Block Diagram
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Functional Description
VIN The input supply (VIN) provides power to the internal MOSFETs for the switch mode regulator along with the internal control circuitry. The VIN operating range is 2.7V to 5.5V so an input capacitor, with a minimum voltage rating of 6.3V, is recommended. Due to the high switching speed, a minimum 2.2F bypass capacitor placed close to VIN and the power ground (PGND) pin is required. Refer to the layout recommendations for details. EN A logic high signal on the enable pin activates the output voltage of the device. A logic low signal on the enable pin deactivates the output and reduces supply current to 0.01A. MIC23150 features built-in soft-start circuitry that reduces in-rush current and prevents the output voltage from overshooting at start up. Do not leave the EN pin floating. SW The switch (SW) connects directly to one end of the inductor and provides the current path during switching cycles. The other end of the inductor is connected to the load, SNS pin and output capacitor. Due to the high speed switching on this pin, the switch node should be routed away from sensitive nodes whenever possible.
SNS The sense (SNS) pin is connected to the output of the device to provide feedback to the control circuitry. The SNS connection should be placed close to the output capacitor. Refer to the layout recommendations for more details. AGND The analog 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. PGND The power ground pin is the ground path for the high current in PWM mode. The current loop for the power ground should be as small as possible and separate from the analog ground (AGND) loop as applicable. Refer to the layout recommendations for more details.
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MIC23150 in inductance. Ensure the inductor selected can handle the maximum operating current. When saturation current is specified, make sure that there is enough margin so that the peak current does not cause the inductor to saturate. Peak current can be calculated as follows:
1 - VOUT /VIN I PEAK = IOUT + VOUT 2 x f x L
Application Information
The MIC23150 is a high performance DC-to-DC step down regulator offering a small solution size. Supporting an output current up to 2A inside a tiny 2mm x 2mm Thin MLF(R) package, the IC requires only three external components while meeting today's miniature portable electronic device needs. Using the HyperLight LoadTM switching scheme, the MIC23150 is able to maintain high efficiency throughout the entire load range while providing ultra-fast load transient response. The following sections provide additional device application information. Input Capacitor A 2.2F ceramic capacitor or greater should be placed close to the VIN pin and PGND pin for bypassing. A TDK C1608X5R0J475K, size 0603, 4.7F ceramic capacitor is recommended based upon performance, size and cost. A X5R or X7R temperature rating is recommended for the input capacitor. Y5V temperature rating capacitors, aside from losing most of their capacitance over temperature, can also become resistive at high frequencies. This reduces their ability to filter out high frequency noise. Output Capacitor The MIC23150 is designed for use with a 2.2F or greater ceramic output capacitor. Increasing the output capacitance will lower output ripple and improve load transient response but could also increase solution size or cost. A low equivalent series resistance (ESR) ceramic output capacitor such as the TDK C1608X5R0J475K, size 0603, 4.7F ceramic capacitor is recommended based upon performance, size and cost. Both the X7R or X5R temperature rating capacitors are recommended. The Y5V and Z5U temperature rating capacitors are not recommended due to their wide variation in capacitance over temperature and increased resistance at high frequencies. Inductor Selection When selecting an inductor, it is important to consider the following factors (not necessarily in the order of importance): * * * * Inductance Rated current value Size requirements DC resistance (DCR)
As shown by the calculation above, the peak inductor current is inversely proportional to the switching frequency and the inductance; the lower the switching frequency or the inductance the higher the peak current. As input voltage increases, the peak current also increases. The size of the inductor depends on the requirements of the application. Refer to the Typical Application Circuit and Bill of Materials for details. DC resistance (DCR) is also important. While DCR is inversely proportional to size, DCR can represent a significant efficiency loss. Refer to the Efficiency Considerations. Compensation The MIC23150 is designed to be stable with a 0.47H to 2.2H inductor with a minimum of 2.2F ceramic (X5R) output capacitor. Duty Cycle The typical maximum duty cycle of the MIC23150 is 80%. Efficiency Considerations Efficiency is defined as the amount of useful output power, divided by the amount of power supplied.
V xI Efficiency % = OUT OUT V xI IN IN x 100
The MIC23150 is designed for use with a 0.47H to 2.2H inductor. For faster transient response, a 0.47H inductor will yield the best result. For lower output ripple, a 2.2H inductor is recommended. Maximum current ratings of the inductor are generally given in two methods; permissible DC current and saturation current. Permissible DC current can be rated either for a 40C temperature rise or a 10% to 20% loss February 2009 11
Maintaining high efficiency serves two purposes. It reduces power dissipation in the power supply, reducing the need for heat sinks and thermal 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 I2R. Power is dissipated in the high side switch during the on cycle. Power loss is equal to the high side MOSFET RDSON multiplied by the Switch Current squared. During the off cycle, the low side Nchannel MOSFET conducts, also dissipating power. Device operating current also reduces efficiency. The product of the quiescent (operating) current and the supply voltage represents another DC loss. The current required driving the gates on and off at a constant 4MHz frequency and the switching transitions make up the switching losses.
M9999-082908-A
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Efficiency = 1.8V V
VIN = 2.7V
MIC23150 the error comparator turns the PMOS off for a minimumoff-time until the output drops below the threshold. 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, the MIC23150 works in pulse frequency modulation (PFM) to regulate the output. As the output current increases, the off-time decreases, thus provides more energy to the output. This switching scheme improves the efficiency of MIC23150 during light load currents by only switching when it is needed. As the load current increases, the MIC23150 goes into continuous conduction mode (CCM) and switches at a frequency centered at 4MHz. The equation to calculate the load when the MIC23150 goes into continuous conduction mode may be approximated by the following formula:
(V - VOUT ) x D I LOAD > IN 2L x f
100 90 EFFICIENCY (%) 80 70 60 50 40 0.1
OUT VIN = 3.0V
VIN = 3.6V
VIN = 4.2V VIN = 5.0V
VIN = 5.5V
L = 1.0H COUT = 4.7F 1 10 100 1000 10000 OUTPUT CURRENT (mA)
Figure 2. Efficiency Under Load
The figure above shows an efficiency curve. From no load to 100mA, efficiency losses are dominated by quiescent current losses, gate drive and transition losses. By using the HyperLight LoadTM mode, the MIC23150 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-Source 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: PDCR = IOUT2 x DCR From that, the loss in efficiency due to inductor resistance can be calculated as follows:
As shown in the previous equation, the load at which MIC23150 transitions from HyperLight LoadTM mode to PWM mode is a function of the input voltage (VIN), output voltage (VOUT), duty cycle (D), inductance (L) and frequency (f). As shown in Figure 3, as the Output Current increases, the switching frequency also increases until the MIC23150 goes from HyperLight LoadTM mode to PWM mode at approximately 120mA. The MIC23150 will switch at a relatively constant frequency around 4MHz once the output current is over 120mA.
SW Frequency vs Output Current
V 1
IN
10 SW FREQUENCY (MHz)
VOUT x IOUT Efficiency Loss = 1 - V OUT x IOUT + PDCR
x 100
= 3.0V
V V
IN
IN
= 3.6V
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. HyperLight LoadTM Mode MIC23150 uses a minimum on and off time proprietary control loop (patented by Micrel). 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. This increases the output voltage. If the output voltage is over the regulation threshold, then
= 4.2V
0.1 L = 4.7H VOUT = 1.8V C 0.001 1
OUT
0.01
= 4.7F
10 100 1000 10000 OUTPUT CURRENT (mA)
Figure 3. SW Frequency vs. Output Current
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MIC23150 Typical Application Circuit
U1 MIC23150
VIN C1 EN L1
VIN
SW 2mmx2mm ThinMLF SNS
VOUT
C2
EN AGND PGND
GND
GND
Bill of Materials
Item C1, C2 L1 U1
Notes:
1. TDK: www.tdk.com 2. Coilcraft: www.coilcraft.com 3. Micrel, Inc.: www.micrel.com
Part Number C1608X5R0J475K VLS3010T-1R0N1R9 VLS4012T-1R0N1R6 DO2010-102ML MIC23150-xYMT
Manufacturer TDK(1) TDK TDK
(1) (1) (2)
Description 4.7F Ceramic Capacitor, 6.3V, X5R, Size 0603 1H, 1.9A, 60m, L3.0mm x W3.0mm x H1.0mm 1H, 2.8A, 50m, L4.0mm x W4.0mm x H1.2mm 1H, 1.8A, 162m, L2.0mm x W2.0mm x H1.0mm 4MHz 2A Buck Regulator with HyperLight LoadTM Mode
Qty. 2 1 1
Coilcraft
Micrel, Inc.(3)
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PCB Layout Recommendations
Thin MILF Top Layer
Thin MLF Bottom Layer
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Package Information
8-Pin 2mm x 2mm Thin MLF
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.
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(c) 2008 Micrel, Incorporated.

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