MIC33050_1205 [MICREL]

4MHz Internal Inductor PWM Buck Regulator with HyperLight Load;
MIC33050_1205
型号: MIC33050_1205
厂家: MICREL SEMICONDUCTOR    MICREL SEMICONDUCTOR
描述:

4MHz Internal Inductor PWM Buck Regulator with HyperLight Load

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MIC33050  
4MHz Internal Inductor PWM Buck  
Regulator with HyperLight Load®  
General Description  
Features  
The Micrel MIC33050 is a high-efficiency 600mA PWM  
synchronous buck (step-down) regulator with internal  
inductor featuring HyperLight Load, a patent-pending  
switching scheme that offers best-in-class light load  
efficiency and transient performance while providing very  
small external components and low output ripple at all  
loads.  
Input voltage: 2.7V to 5.5V  
600mA output current  
Fixed and adjustable output voltage options  
No external inductor required  
Ultra-fast transient response  
20µA quiescent current  
4MHz switching in PWM mode  
Low output voltage ripple  
>93% peak efficiency  
The MIC33050 also has a very-low typical quiescent  
current of 20µA and can achieve over 85% efficiency even  
at 1mA.  
>85% efficiency at 1mA  
In contrast to traditional light load schemes, the HyperLight  
Load architecture does not trade off control speed to  
obtain low standby currents and in doing so, the device  
only needs a small output capacitor to absorb the load  
transient as the powered device goes from light load to full  
load.  
Micropower shutdown  
12-pin 3mm x 3mm MLF®  
–40C to +125C junction temperature range  
Applications  
At higher loads, the MIC33050 provides a constant  
switching frequency of greater than 4MHz while providing  
peak efficiencies greater than 93%.  
Cellular phones  
Digital cameras  
The MIC33050 is available in fixed and adjustable output  
voltages and comes in a 12-pin 3mm x 3mm MLF® with a  
junction operating range of –40C to +125C.  
Data sheets and support documentation can be found on  
Micrel’s web site at: www.micrel.com.  
Portable media players  
Wireless LAN cards  
WiFi, WiMax, and WiBro modules  
USB-powered devices  
____________________________________________________________________________________________________________  
Typical Application  
HyperLight Load is a registered trademark of Micrel, Inc.  
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.  
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com  
M9999-050312-C  
May 2012  
Micrel, Inc.  
MIC33050  
Ordering Information  
Part Number  
MIC33050-CYHL  
MIC33050-4YHL  
MIC33050-GYHL  
MIC33050-SYHL  
MIC33050-AYHL  
Notes:  
Voltage  
1.0V  
Temperature Range  
–40° to +125°C  
–40° to +125°C  
–40° to +125°C  
–40° to +125°C  
–40° to +125°C  
Package  
Lead Finish  
12-Pin 3mm x 3mm MLF®  
12-Pin 3mm x 3mm MLF®  
12-Pin 3mm x 3mm MLF®  
12-Pin 3mm x 3mm MLF®  
12-Pin 3mm x 3mm MLF®  
Pb-Free  
Pb-Free  
Pb-Free  
Pb-Free  
Pb-Free  
1.2V  
1.8V  
3.3V  
ADJ  
1. Other output voltage options available. Please 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) Fixed Output  
Top View  
12-Pin 3mm x 3mm MLF® (HL) Adjustable Output  
Top View  
Pin Description  
Pin Number  
(Fixed)  
Pin Number  
(Adj)  
Pin Name  
Pin Function  
1
1
VIN  
PGND  
SW  
Supply Voltage (Input): Requires bypass capacitor-to-GND.  
Power Ground.  
2
3, 4, 5, 6  
7, 8  
2
3, 4, 5, 6  
7, 8  
Switch (Output): Internal power MOSFET output switches.  
Output after the internal inductor.  
OUT  
EN  
9
9
Enable (Input): Logic low will shut down the device, reducing the quiescent  
current to less than 4µA. Do not leave floating.  
10  
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  
FB  
Feed forward capacitor connected to out sense pin.  
11  
Feedback voltage. Connect a resistor divider from output to ground to set the  
output voltage.  
12  
12  
AGND  
ePad  
Analog ground.  
EP  
EP  
Exposed Heatsink Pad. Connect to power ground for best thermal performance.  
M9999-050312-C  
May 2012  
2
Micrel, Inc.  
MIC33050  
Absolute Maximum Ratings(1)  
Operating Ratings(2)  
Supply Voltage (VIN).........................................................6V  
Output Switch Voltage (VSW)............................................6V  
Output Switch Current (ISW)..............................................2A  
Logic Input Voltage (VEN) ..................................0.3V to VIN  
Storage Temperature Range (Ts)..............65°C to +150°C  
ESD Rating(3)................................................. ESD Sensitive  
Supply Voltage (VIN)......................................... 2.7V to 5.5V  
Logic Input Voltage (VEN)…………………………-0.3V to VIN  
Junction Temperature (TJ) ..................–40°C TJ +125°C  
Thermal Resistance  
3mm x 3mm MLF®-12 (JA)................................60°C/W  
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.  
2.7  
Typ.  
Max.  
5.5  
Units  
V
Supply Voltage Range  
Undervoltage Lockout Threshold  
UVLO Hysteresis  
(turn-on)  
2.45  
2.55  
100  
20  
2.65  
V
mV  
µA  
µA  
%
Quiescent Current, Hyper LL mode  
Shutdown Current  
IOUT = 0mA ; VSNS > 1.2*VOUT nominal  
VIN = 5.5V; VEN = 0V  
32  
4
0.01  
Output Voltage Accuracy  
Current Limit in PWM Mode  
Output Voltage Line Regulation  
Output Voltage Load Regulation  
Feedback Voltage  
VIN = 3.0V; ILOAD = 20mA  
SNS = 0.9*VNOM  
–2.5  
0.65  
+2.5  
1.7  
1
A
VIN = 3.0V to 5.5V; ILOAD = 20mA  
20mA < ILOAD < 500mA,  
VIN = 3.0V; IOUT = 20mA  
0.5  
0.3  
400  
89  
%/V  
%
390  
80  
410  
mV  
%
Maximum Duty Cycle  
SNS VNOM  
ISW = 100mA PMOS  
ISW = -100mA NMOS  
ILOAD = 120mA  
0.45  
0.5  
PWM Switch ON-Resistance  
Frequency  
4
MHz  
µs  
Soft-Start Time  
VOUT = 90%  
(turn-on)  
650  
0.8  
35  
Enable Threshold  
Enable Hysteresis  
Enable Input Current  
Over-temperature Shutdown  
0.5  
1.2  
2
V
mV  
µA  
C  
0.1  
165  
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.  
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kin series with 100pF.  
4. Specification for packaged product only.  
M9999-050312-C  
May 2012  
3
Micrel, Inc.  
MIC33050  
Typical Characteristics  
Efficiency VOUT = 1.2V  
Efficiency VOUT = 3.3V  
Efficiency VOUT = 1.8V  
100  
90  
80  
70  
60  
50  
100  
100  
90  
80  
70  
60  
50  
VIN = 4.2V  
90  
VIN = 3.0V  
VIN = 2.7V  
80  
VIN = 5.0V  
VIN = 5.5V  
VIN = 4.2V  
VIN = 3.6V  
70  
60  
50  
VIN = 4.2V  
VIN = 3.6V  
1
10  
100  
1000  
1
10  
100  
1000  
1
10  
100  
1000  
OUTPUT CURRENT (mA)  
OUTPUT CURRENT (mA)  
OUTPUT CURRENT (mA)  
Quiescent Current vs.  
Temperature  
Quiescent Current vs. Input  
Voltage  
Efficiency VOUT = 1.0V  
40  
30  
20  
10  
0
100  
90  
50  
45  
40  
35  
30  
25  
20  
15  
10  
5
VIN = 2.7V  
80  
70  
VIN = 4.2V  
V
V
IN = 3.6V  
OUT = 1.8V  
V
V
IN = 3.6V  
OUT = 1.8V  
60 VIN = 3.6V  
No Load  
L = 1uH  
100  
OUTPUT CURRENT (mA)  
0
50  
1
10  
1000  
2.7  
3.2  
3.7  
4.2  
4.7  
5.2  
-40  
-20  
0
20  
40  
60  
80  
100 120  
INPUT VOLTAGE (V)  
TEMPERATURE (°C)  
Switching Frequency vs. Input  
Voltage  
Switching Frequency vs.  
Temperature  
Feedback Voltage vs.  
Temperature  
5.5  
5
5.50  
5.00  
4.50  
4.00  
3.50  
3.00  
2.50  
0.5  
0.48  
0.46  
0.44  
0.42  
0.4  
4.5  
4
0.38  
0.36  
0.34  
0.32  
0.3  
3.5  
3
V
V
IN = 3.6V  
OUT = 1.8V  
V
V
IN = 3.6V  
OUT = 1.8V  
V
V
IN = 3.6V  
OUT = 1.8V  
No Load  
Load = 150mA  
Load = 150mA  
2.5  
-40  
-20  
0
20  
40  
60  
80  
100 120  
2.70  
3.20  
3.70  
4.20  
4.70  
5.20  
-40  
-20  
0
20  
40  
60  
80  
100 120  
TEMPERATURE (°C)  
INPUT VOLTAGE (V)  
TEMPERATURE (°C)  
M9999-050312-C  
May 2012  
4
Micrel, Inc.  
MIC33050  
Typical Characteristics (Continued)  
Output Voltage vs. Temperature  
Output Voltage  
vs. Output Current  
Output Voltage vs. Input  
Voltage (V)  
1.9  
1.90  
1.85  
1.80  
1.75  
1.70  
1.9  
1.85  
1.85  
1.8  
1.8  
V
V
IN = 3.6V  
OUT = 1.8V  
1.75  
1.7  
1.75  
1.7  
No Load  
Load = 20mA  
V
= 3.6V  
IN  
0
100 200 300 400 500 600  
OUTPUT CURRENT (mA)  
-40  
-20  
0
20  
40  
60  
80  
100 120  
2.7  
3.2  
3.7  
4.2  
4.7  
5.2  
TEMPERATURE (°C)  
INPUT VOLTAGE (V)  
M9999-050312-C  
May 2012  
5
Micrel, Inc.  
MIC33050  
Functional Characteristics  
M9999-050312-C  
May 2012  
6
Micrel, Inc.  
MIC33050  
Functional Characteristics (Continued)  
M9999-050312-C  
May 2012  
7
Micrel, Inc.  
MIC33050  
Functional Diagram  
MIC33050 Fixed Output Block Diagram  
MIC33050 Adjustable Output Block Diagram  
M9999-050312-C  
May 2012  
8
Micrel, Inc.  
MIC33050  
Functional Description  
VIN  
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 (VREF) of  
the device and provides the control path to control the  
output. VREF is equal to 400mV. The CFF pin is sensitive to  
noise and should be place away from the SW pin. Refer to  
the layout recommendations for details.  
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 placed close to VIN and the power  
ground (PGND) pin for bypassing. Refer to the PCB  
Layout Recommendations for details.  
EN  
FB  
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.  
The feedback pin is provided for the adjustable output  
version. An external resistor divider network is connected  
from the output and is compared to the internal 400mV  
internal reference voltage within the control loop.  
The output voltage, of the circuit below, may be calculated  
via the following equation:  
SW  
The pins at the switch node, SW, connect directly to the  
internal inductor which provides the switching current  
necessary to operate in PWM mode. Due to the high-  
speed switching on this pin, the switch node should be  
routed away from sensitive nodes such as the CFF and FB  
pins.  
R1  
VOUT 0.4V1   
R2  
OUT  
The OUT pin is for the output voltage following the internal  
inductor of the device. Connect an output filter capacitor  
equal to 2.2µF or greater to this pin.  
SNS  
The sense pin, SNS, is needed to sense the output voltage  
at the output filter capacitor. In order for the control loop to  
monitor the output voltage accurately it is good practice to  
sense the output voltage at the positive side of the output  
filter capacitor where voltage ripple is smallest.  
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 PCB 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 PGND loop. Refer to the PCB  
Layout Recommendations for more details.  
M9999-050312-C  
May 2012  
9
Micrel, Inc.  
MIC33050  
Applications Information  
Input Capacitor  
Efficiency VOUT = 1.8V  
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 reduces their ability to filter out  
high frequency noise.  
100  
90  
80  
70  
60  
50  
VIN = 3.0V  
VIN = 4.2V  
VIN = 3.6V  
Output Capacitor  
The MIC33050 was designed for use with a 2.2µF or  
greater ceramic output capacitor. 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.  
1
10  
100  
1000  
OUTPUT CURRENT (mA)  
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.  
Compensation  
The MIC33050 is designed to be stable with an internal  
inductor with a minimum of 2.2µF ceramic (X5R) output  
capacitor.  
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:  
Efficiency Considerations  
Efficiency is defined as the amount of useful output power,  
divided by the amount of power supplied.  
VOUT IOUT  
VIN IIN  
Efficiency (%)   
100  
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.  
L
PD = IOUT2 × DCR  
From that, the loss in efficiency due to inductor resistance  
can be calculated as follows;  
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 square of the  
Switch Current. 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 required driving  
the gates on and off at a constant 4MHz frequency and the  
switching transitions make up the switching losses.  
VOUT IOUT  
VOUT IOUT LPD  
Efficiency Loss (%) 1  
100  
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.  
M9999-050312-C  
May 2012  
10  
Micrel, Inc.  
MIC33050  
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 the 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 increases, the switching frequency  
increases. This improves the 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:  
(V VOUT ) D  
IN  
ILOAD  
2L f  
M9999-050312-C  
May 2012  
11  
Micrel, Inc.  
MIC33050  
MIC33050 Typical Application Circuit (Fixed Output)  
Bill of Materials  
Item  
C1, C2  
C3  
Part Number  
C1608X5R0J475K  
C1608C0G1H561J  
CRCW0603100KFKEA  
Manufacturer  
TDK(1)  
Description  
4.7µF Ceramic Capacitor, 6.3V, X5R, Size 0603  
560pF Ceramic Capacitor, 50V, NPO, Size 0603  
100k, Tolerance 1%, Size 0603  
Qty  
2
TDK(1)  
Vishay(2)  
1
R1  
1
4MHz Internal Inductor PWM Buck Regulator with  
HyperLight Load® Mode  
U1  
MIC33050-xYHL  
Micrel, Inc. (3)  
1
Notes:  
1. TDK: www.tdk.com.  
2. Vishay: www.vishay.com.  
3. Micrel, Inc: www.micrel.com.  
M9999-050312-C  
May 2012  
12  
Micrel, Inc.  
MIC33050  
MIC33050 Typical Application Circuit (Adjustable)  
Bill of Materials  
Item  
C1, C2  
C3  
Part Number  
Manufacturer  
TDK(1)  
Description  
Qty  
2
C1608X5R0J475K  
C1608C0G1H121J  
CRCW0603100KFKEA  
CRCW0603348KFKEA  
4.7µF Ceramic Capacitor, 6.3V, X5R, Size 0603  
120pF Ceramic Capacitor, 50V, NPO, Size 0603  
100k, Tolerance 1%, Size 0603  
TDK(1)  
Vishay(2)  
Vishay(2)  
1
R1, R3  
R2  
2
348k, Tolerance 1%, Size 0603  
1
4MHz Internal Inductor PWM Buck Regulator with  
HyperLight Load®  
U1  
MIC33050-AYHL  
Micrel, Inc. (3)  
1
Notes:  
1. TDK: www.tdk.com  
2. Vishay: www.vishay.com  
3. Micrel, Inc: www.micrel.com  
M9999-050312-C  
May 2012  
13  
Micrel, Inc.  
MIC33050  
PCB Layout Recommendations (Fixed)  
Top Layer  
Bottom Layer  
M9999-050312-C  
May 2012  
14  
Micrel, Inc.  
MIC33050  
PCB Layout Recommendations (Adjustable)  
Top Layer  
Bottom Layer  
M9999-050312-C  
May 2012  
15  
Micrel, Inc.  
MIC33050  
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.  
M9999-050312-C  
May 2012  
16  

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