MIC4930
Hyper Speed Control® 3A Buck Regulator
Features
General Description
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The MIC4930 is a high-efficiency, 3A synchronous
buck regulator with ultra-fast transient response
perfectly suited for supplying processor core and I/O
voltages from a 5V or 3.3V bus. The MIC4930 provides
a switching frequency up to 3.3 MHz while achieving
peak efficiencies up to 95%. An additional benefit of
high-frequency operation is very low output ripple
voltage throughout the entire load range with the use of
a small output capacitor. The MIC4930 is designed for
use with a very small inductor, down to 1 μH, and an
output ceramic capacitor as small as 10 μF without the
need for external ripple injection. A wide range of
output capacitor types and values can also be
accommodated.
Input Voltage: 2.7V to 5.5V
3A Output Current
Up To 95% Efficiency
Up To 3.3 MHz Operation
Safe Start-Up into a Pre-Biased Output
Power Good Output
Ultra-Fast Transient Response
Low Output Voltage Ripple
Low RDS(ON) Integrated MOSFET Switches
0.01 μA Shutdown Current
Thermal Shutdown and Current Limit Protection
Output Voltage as low as 0.7V
3 mm × 4 mm DFN-10L
–40°C to +125°C Junction Temperature Range
Applications
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DTVs
Set-Top Boxes
Printers
DVD Players
Distributed Power Supplies
The MIC4930 supports safe start-up into a pre-biased
output.
The MIC4930 is available in a 10-pin 3 mm × 4 mm
DFN package with an operating junction temperature
range from –40°C to +125°C. The MIC4930 is
pin-to-pin compatible with the 5A-rated MIC4950YFL.
Package Type
MIC4930
3x4 DFN
Top View
2016 Microchip Technology Inc.
PGND
1
PGND
2
9
EN
PVIN
3
8
PVIN
AVIN
4
7
PG
AGND
5
6
FB
EP
10 SW
DS20005669A-page 1
MIC4930
Typical Application Circuit
MIC4930
3x4 DFN-10L
MIC4930YFL
VIN
2.7V to 5.5V
10μF
10V
PVIN
SW
AVIN
PG
EN
PGND
GND
DS20005669A-page 2
R1
301kΩ
FB
ON
OFF
VOUT
1.8V
1μH
AGND
CF
22pF
COUT
10μF
R2
160kΩ
GND
2016 Microchip Technology Inc.
MIC4930
1.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings †
PVIN, AVIN Supply Voltage (VIN)................................................................................................................... –0.3V to +6V
SW Output Switch Voltage (VSW).................................................................................................................. –0.3V to VIN
EN, PG (VEN, VPG)........................................................................................................................................ –0.3V to VIN
FB Feedback Input Voltage (VFB) ................................................................................................................ –0.3V to VIN
ESD Protection On All Pins (Note 1) ...............................................................................................................±2 kV HBM
Operating Ratings ††
Supply Voltage (VIN) ................................................................................................................................. +2.7V to +5.5V
Enable Input Voltage (VEN) ............................................................................................................................... 0V to VIN
† Notice: Exceeding the absolute maximum ratings may damage the device.
†† 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 (Note 1)
Electrical Characteristics: Unless otherwise indicated, VIN = VEN = 3.3V; L = 1.0 μH; TA = 25°C, CIN = 10 μH,
COUT = 10 μH.
Parameters
Sym.
Min.
Typ.
Max.
Units
Supply Voltage Range
VIN
2.7
—
5.5
V
—
Undervoltage lockout
threshold
VUVLO
2.41
2.5
2.61
V
(turn-on)
Undervoltage lockout
hysteresis
VUVLOH
—
400
—
mV
—
IQ
—
0.8
2
mA
IOUT = 0 mA, FB >1.2 ×
VFB(Nominal)
Shutdown current
ISD
—
0.01
2
μA
VEN = 0V
Feedback voltage
VFB
0.609
0.625
0.640
V
—
ILIMIT
3.5
5.75
8
A
FB = 0.9V × VFB(Nominal)
Quiescent current
Current limit
Output voltage line
regulation
Note 1:
LINEREG
—
1
—
%/V
Conditions
VIN = 2.7V to 3.5V, VOUTNOM
= 1.8V,
ILOAD = 20 mA
VIN = 4.5V to 5.5V if
VOUTNOM ≥2.5V,
ILOAD = 20 mA
Specification for packaged product only.
2016 Microchip Technology Inc.
DS20005669A-page 3
MIC4930
ELECTRICAL CHARACTERISTICS (CONTINUED)(Note 1)
Electrical Characteristics: Unless otherwise indicated, VIN = VEN = 3.3V; L = 1.0 μH; TA = 25°C, CIN = 10 μH,
COUT = 10 μH.
Parameters
Sym.
Min.
Typ.
Max.
Units
Conditions
20 mA < ILOAD < 500 mA,
VIN = 3.6V if VOUTNOM < 2.5V
—
Output voltage load
regulation
PWM switch ON
resistance
Maximum turn-on time
0.3
—
%
LOADREG
%
20 mA < ILOAD < 500 mA,
VIN = 5.0V if
VOUTNOM ≥ 2.5V
20 mA < ILOAD < 3A,
VIN = 3.6V
if VOUTNOM < 2.5V
—
1
—
RDSON-P
—
30
—
RDSON-N
—
25
—
ISW = 1A N-Channel
MOSFET
—
665
—
VIN = 4.5V, VFB = 0.5V
—
1000
—
—
1120
—
mΩ
tON
ns
20 mA < ILOAD < 3 mA,
VIN = 5.0V
if VOUTNOM ≥ 2.5V
ISW = 1A P-Channel
MOSFET
VIN = 3.0V, VFB = 0.5V
VIN = 2.7V, VFB = 0.5V
Minimum turn-off time
tOFF
—
176
—
ns
VIN = 3.0V, VFB = 0.5V
Soft-start time
tSOFT-ON
—
500
—
μs
VOUT = 90% of VOUTNOM
Enable threshold
VEN
0.5
0.8
1.2
V
Turn-on
Enable input current
IEN
0.1
1
μA
—
Power Good threshold
VOUTPG
82
88
94
%
Rising
Power Good hysteresis
VOUTPGH
—
7
—
%
—
Overtemperature
shutdown
TSD
150
°C
—
Overtemperature
shutdown hysteresis
TSDH
20
°C
—
Note 1:
Specification for packaged product only.
DS20005669A-page 4
2016 Microchip Technology Inc.
MIC4930
TEMPERATURE SPECIFICATIONS (Note 1)
Parameters
Sym.
Min.
Typ.
Max.
Units
Conditions
Storage Temperature
TS
–65
—
+150
°C
—
Junction Operating Temperature
TJ
–40
—
+125
°C
—
JA
—
35
—
°C/W
—
Temperature Ranges
Package Thermal Resistances
Thermal Resistance, DFN-10Ld
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.
2016 Microchip Technology Inc.
DS20005669A-page 5
MIC4930
2.0
TYPICAL PERFORMANCE CURVES
Note:
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.
100
10
90
CURRENT LIMIT (A)
EFFICIENCY (%)
95
VIN = 5V
VOUT = 3.3V
85
80
75
70
8
6
4
VOUT = 1.8V
2
65
60
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
2.5
3.0
FIGURE 2-1:
Current.
Efficiency vs. Output
FIGURE 2-4:
Voltage.
4.0
4.5
5.0
5.5
Current Limit vs. Input
8
100
CURRENT LIMIT (A)
VIN = 3.3V
VOUT = 1.8V
95
EFFICIENCY (%)
3.5
INPUT VOLTAGE (V)
OUTPUT CURRENT (A)
90
85
VIN = 5.0V
VOUT = 1.8V
80
75
70
VIN = 3.3V
VOUT = 1.8V
6
VIN = 5V
VOUT = 1.8V
4
2
65
0
60
0.0
0.5
1.0
1.5
2.0
2.5
0.0
3.0
0.1
OUTPUT CURRENT (A)
FIGURE 2-2:
Current.
Efficiency vs. Output
FIGURE 2-5:
Voltage.
0.3
0.4
0.5
Current Limit vs. Feedback
3.0
100
LINE REGULATION (%/V)
V = 3.3V
VOUT = 1.8V
95
EFFICIENCY (%)
0.2
FEEDBACK VOLTAGE (V)
90
85
VIN = 5.0V
VOUT = 1.8V
80
75
70
2.0
1.0
0.0
VOUT = 1.8V
IOUT = 0A
-1.0
65
-2.0
60
0.0
0.5
FIGURE 2-3:
Current.
DS20005669A-page 6
1.0
1.5
2.0
2.5
3.0
Efficiency vs. Output
2.7
3.0
3.3
3.6
INPUT VOLTAGE (V)
FIGURE 2-6:
Voltage.
Line Regulation vs. Input
2016 Microchip Technology Inc.
MIC4930
.
4
QUIESCENT CURRENT (mA)
LINE REGULATION (%/V)
3.0
2.0
1.0
0.0
VOUT = 1.8V
IOUT = 0A
-1.0
-2.0
4.50
4.75
5.00
5.25
VFB > 1.2 x VFB(NOM)
IOUT = 0A
3
2
1
0
5.50
2.5
3.0
FIGURE 2-7:
Voltage.
3.5
4.0
4.5
5.0
5.5
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Line Regulation vs. Input
FIGURE 2-10:
Voltage.
Quiescent Current vs. Input
.
1.82
OUTPUT VOLTAGE (V)
LINE REGULATION (%/V)
3.0
2.0
1.0
0.0
VOUT = 1.8V
IOUT = 1A
-1.0
VIN = 3.3V
VOUT = 1.8V
1.81
1.80
1.79
1.78
-2.0
1.77
2.7
3.0
3.3
3.6
0.0
0.5
FIGURE 2-8:
Voltage.
Line Regulation vs. Input
OUTPUT VOLTAGE (V)
LINE REGULATION (%/V)
2.0
2.5
3.0
2.52
2.0
1.0
0.0
VOUT = 1.8V
IOUT = 1A
-1.0
2.51
VIN = 5V
VOUT = 2.5V
2.50
2.49
2.48
2.47
2.46
4.75
5.00
5.25
5.50
INPUT VOLTAGE (V)
FIGURE 2-9:
Voltage.
1.5
FIGURE 2-11:
Output Voltage (VIN = 3.3V)
vs. Output Current.
3.0
-2.0
4.50
1.0
OUTPUT CURRENT (A)
INPUT VOLTAGE (V)
Line Regulation vs. Input
2016 Microchip Technology Inc.
0.0
0.5
1.0
1.5
2.0
2.5
OUTPUT CURRENT (A)
3.0
FIGURE 2-12:
Output Voltage (VIN = 5V)
vs. Output Current.
DS20005669A-page 7
MIC4930
3.60
SWITCHING FREQUENCY (MHz)
FEEDBACK VOLTAGE (V)
0.635
0.630
0.625
0.620
0.615
VIN = 3.3V
VOUT = 1.8V
IOUT = 0A
0.610
0.605
-50
-20
FIGURE 2-13:
Temperature.
10
40
70
100
TEMPERATURE (°C)
3.20
2.40
VIN = 3.3V
VOUT = 1.8V
2.00
1.60
1.20
0.0
130
Feedback Voltage vs.
VIN = 5.0V
VOUT = 1.8V
2.80
0.5
FIGURE 2-16:
Output Current.
1.0
1.5
2.0
2.5
OUTPUT CURRENT (A)
3.0
Switching Frequency vs.
SWITCHING FREQUENCY (MHz)
3.60
3.20
2.80
VIN = 5.0V
VOUT = 1.2V
2.40
2.00
VIN = 3.3V
VOUT = 1.2V
1.60
1.20
0.0
Switching Frequency vs.
FIGURE 2-14:
Temperature.
0.5
FIGURE 2-17:
Output Current.
1.0
1.5
2.0
2.5
OUTPUT CURRENT (A)
3.0
Switching Frequency vs.
SWITCHING FREQUENCY (MHz)
3.20
2.80
VIN = 3.0V
VOUT = 1.2V
IOUT = 0A
VIN = 5.0V
VOUT = 3.3V
2.40
VIN
(1V/div)
2.00
VOUT
(500mV/div)
1.60
PG
(2V/div)
1.20
0.0
0.5
FIGURE 2-15:
Output Current.
DS20005669A-page 8
1.0
1.5
2.0
2.5
OUTPUT CURRENT (A)
3.0
Switching Frequency vs.
Time (2ms/div)
FIGURE 2-18:
VIN Soft Turn-On.
2016 Microchip Technology Inc.
MIC4930
VIN = 3.0V
VOUT = 1.2V
IOUT = 0A
EN
(2V/div)
EN
(2V/div)
VOUT
(1V/div)
VOUT
(500mV/div)
PG
(2V/div)
PG
(1V/div)
IL
(500mA/div)
Time (2ms/div)
FIGURE 2-19:
Enable Turn-On (No Load).
VIN = 3.0V
VOUT = 1.2V
IOUT = 1A
EN
(2V/div)
Time (4ms/div)
FIGURE 2-22:
Rising).
VOUT RIPPLE
(10mV/div)
IL
(200mA/div)
VOUT
(500mV/div)
PG
(2V/div)
Enable Turn-On (1A Load).
VIN = 3.0V
VOUT = 1.2V
IOUT = 1A
EN
(2V/div)
VOUT
(500mV/div)
PG
(2V/div)
Time (200ns/div)
FIGURE 2-23:
(IOUT = 0A).
Switching Waveforms
VOUT
(10mV/div)
IL
(500mA/div)
VIN = 3.0V
VOUT = 1.2V (AC-Coupled)
IOUT = 1A
SW Node
(2V/div)
Time (100μs/div)
FIGURE 2-21:
VIN = 3.0V
VOUT = 1.2V (AC-Coupled)
IOUT = 0A
SW Node
(2V/div)
Time (100μs/div)
FIGURE 2-20:
1.4V Pre-Bias Start-Up (EN
Enable Turn-Off (1A Load).
2016 Microchip Technology Inc.
Time (200ns/div)
FIGURE 2-24:
(IOUT = 1A).
Switching Waveforms
DS20005669A-page 9
MIC4930
VOUT
(10mV/div)
IL
(1A/div)
VOUT
(200mV/div)
VIN = 3.0V
VOUT = 1.2V (AC-Coupled)
IOUT = 3A
IOUT
(1A/div)
SW Node
(2V/div)
Time (20μs/div)
Time (200ns/div)
FIGURE 2-25:
(IOUT = 3A).
VIN = 3.0V
VOUT = 1.2V (AC-Coupled)
COUT = 10μF
Switching Waveforms
FIGURE 2-28:
(IOUT = 3A).
Load Transient Response
VOUT
(10mV/div)
IL
(2A/div)
VIN = 3.0V
VOUT = 1.2V (AC-Coupled)
RLOAD = 0.25Ω
SW Node
(2V/div)
Time (200ns/div)
FIGURE 2-26:
(Current Limit).
VOUT
(200mV/div)
Switching Waveforms
VIN = 3.0V
VOUT = 1.2V (AC-Coupled)
COUT = 10μF
IOUT
(1A/div)
Time (20μs/div)
FIGURE 2-27:
(IOUT = 1.5A).
DS20005669A-page 10
Load Transient Response
2016 Microchip Technology Inc.
MIC4930
3.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1:
PIN FUNCTION TABLE
3X4 DFN
Symbol
1, 2, EP
PGND
Power Ground.
3, 8
PVIN
Power input voltage: Connect a 10μF ceramic capacitor between PVIN and PGND
for input decoupling. Pins 3 and 8 are internally connected inside the package.
4
AVIN
Analog input voltage: Connect a 1μF ceramic capacitor between AVIN and AGND
to decouple the noise for the internal reference and error comparator.
5
AGND
Analog ground input: Connect to a quiet ground plane for best operation. Do not
route power switching currents on the AGND net. Connect AGND and PGND nets
together at a single point.
6
FB
Feedback (input): Connect an external divider between VOUT and AGND to
program the output voltage.
7
PG
Power Good (output): Open-drain output. A pull-up resistor from this pin to a
voltage source is required to detect an output power-is-good condition.
9
EN
Enable (input): Logic high enables operation of the regulator. Logic low will shut
down the device. Do not leave floating.
10
SW
Switch (output): Internal power MOSFET output switches.
2016 Microchip Technology Inc.
Description
DS20005669A-page 11
MIC4930
4.0
FUNCTIONAL DESCRIPTION
4.1
PVIN
The power input (PVIN) pin provides power to the
internal MOSFETs for the switch mode regulator
section of the MIC4930. The input supply operating
range is from 2.7V to 5.5V. A low-ESR ceramic
capacitor of at least 10 μF is required to bypass from
PVIN to (power) GND. See the Application Information
section for further details.
4.2
AVIN
The analog power input (AVIN) pin provides power to
the internal control and analog supply circuitry. Careful
layout should be considered to ensure that
high-frequency switching noise caused by PVIN is
reduced before reaching AVIN. Always place a 1 μF
minimum ceramic capacitor very close to the IC
between the AVIN and AGND pins. For additional
high-frequency switching noise attenuation, RC
filtering can be used (R = 10Ω).
4.3
EN
A logic high signal on the enable (EN) pin activates the
output of the switch. A logic low on EN deactivates the
output and reduces the supply current to a nominal
0.01 μA. Do not leave this pin floating.
4.4
4.5
PGND
The power ground (PGND) pin is the ground return
terminal for the high current in the switching node SW.
The current loop for the PGND should be as short as
possible and kept separate from the AGND net
whenever applicable.
4.6
PG
The power-is-good (PG) pin is an open-drain output
that indicates logic high when the output voltage is
typically above 88% of its steady-state voltage. A
pull-up resistor of 10 kΩ or greater should be
connected from PG to VOUT, or to another voltage
source less than or equal to the input voltage.
4.7
FB
To program the output voltage, an external resistive
divider network is connected to this pin from the output
voltage to AGND, as shown in the Typical Application
Circuit, and is compared to the internal 0.625V
reference within the regulation loop. The formula in
Equation 4-1 is used to program the output voltage.
EQUATION 4-1:
R1
V OUT = V REF 1 + -------
R2
SW
The switch (SW) pin connects directly to one side of the
inductor and provides the current path during switching
cycles. The other end of the inductor is connected to
the load and output capacitor. Due to the high speed
switching on this pin, the switch node should be routed
away from sensitive nodes whenever possible to avoid
unwanted injection of noise.
TABLE 4-1:
RECOMMENDED FEEDBACK
RESISTOR VALUES
VOUT
R1
R2
1.0V
120k
180k
1.2V
274k
294k
1.5V
316k
226k
1.8V
301k
160k
2.5V
316k
105k
3.3V
309k
71.5k
The feed-forward capacitor (CF in the Typical
Application Circuit) is typically in the range of 22 pF to
39 pF. The MIC4930 features an internal ripple
injection network, whose current is injected into the FB
node and integrated by CF. Thus, the waveform at FB
is approximately a triangular ripple. The size of CF
dictates the amount of ripple amplitude at the FB node.
Smaller values of CF yield higher FB ripple amplitudes
and better stability, but also somewhat degrade line
regulation and transient response.
DS20005669A-page 12
2016 Microchip Technology Inc.
MIC4930
4.8
Hyper Speed Control®
MIC4930 uses an ON- and OFF-time proprietary
ripple-based control loop that features three different
timers:
• Minimum ON Time
• Maximum ON Time
• Minimum OFF Time
When the required duty cycle is very low, the required
OFF time is typically far from the minimum OFF time
limit (about 176 ns typically). In this case, the MIC4930
operates by delivering a determined ON time at each
switching cycle, depending on the input voltage. A new
ON time is invoked by the error comparator when the
FB voltage falls below the regulation threshold. In this
mode, the MIC4930 operates as an adaptive
constant-ON-time ripple controller with nearly constant
switching frequency. Regulation takes place by
controlling the valley of the FB ripple waveform.
When higher duty cycles are required, regulation can
no longer be maintained by decreasing the OFF time
below the minimum OFF time limit. When this limit is
reached, the OFF time is no longer reduced, and the
MIC4930 smoothly transitions to an ON-time
modulation mode. In the ON-time modulation region,
frequency reduces with the increase of the required
ON-time / duty cycle, and regulation finally takes place
on the peak of the FB ripple waveform.
Note that because of the shift of the regulation
threshold between different modes, line regulation
might suffer when the input voltage and/or duty cycle
variations force the MIC4930 to switch form one
regulation mode to the other. In applications where
wide input voltage variations are expected, ensure that
the line regulation is adequate for the intended
application.
2016 Microchip Technology Inc.
DS20005669A-page 13
MIC4930
5.0
APPLICATION INFORMATION
The MIC4930 is a highly efficient, 3A synchronous
buck regulator ideally suited for supplying processor
core and I/O voltages from a 5V or 3.3V bus.
5.1
Input Capacitor
A 10 μF ceramic capacitor or greater should be placed
close to the PVIN pin and PGND pin for bypassing. A
X5R or X7R temperature rating is recommended for the
input capacitor. Take into account C vs. bias effect in
order to estimate the effective capacitance and the
input ripple at the VIN voltage.
5.2
Inductor Selection
When selecting an inductor, it is important to consider
the following factors:
•
•
•
•
•
Peak current can be calculated by using Equation 5-1.
EQUATION 5-1:
1 – V OUT V IN
I PEAK = I OUT + V OUT ------------------------------------ 2 f L
Output Capacitor
The MIC4930 is designed for use with a 10 μF or
greater ceramic output capacitor. Increasing the output
capacitance will lower output ripple and improve load
transient response. A low equivalent series resistance
(ESR) ceramic output capacitor is recommended
based upon performance, size, and cost. Ceramic
capacitors with X5R or X7R temperature ratings are
recommended.
5.3
Also pay attention to the inductor saturation
characteristic in current limit. The inductor should not
heavily saturate even in current limit operation,
otherwise the current might instantaneously run away
and reach potentially destructive levels. Typically,
ferrite-core inductors exhibit an abrupt saturation
characteristic, while powdered-iron or composite
inductors have a soft-saturation characteristic.
Inductance
Rated current value
Size requirements
DC resistance (DCR)
Core losses
The MIC4930 is designed for use with a 1 μH to 2.2 μH
inductor. For faster transient response, a 1 μH inductor
will yield the best result. For lower output ripple, a 2.2
μH inductor is recommended.
Inductor current ratings are generally given in two
methods: permissible DC current, and saturation
current. Permissible DC current can be rated for a 20°C
to 40°C temperature rise. Saturation current can be
rated for a 10% to 30% loss in inductance. Ensure that
the nominal current of the application is well within the
permissible DC current ratings of the inductor, also
depending on the allowed temperature rise. Note that
the inductor permissible DC current rating typically
does not include inductor core losses. These are a very
important contribution to the total inductor core loss
and temperature increase in high-frequency DC-to-DC
converters, since core losses increase with at least the
square of the excitation frequency. For more accurate
core loss estimation, it is recommended to refer to
manufacturers’ datasheets or websites.
When saturation current is specified, make sure that
there is enough design margin, so that the peak current
does not cause the inductor to enter saturation.
DS20005669A-page 14
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 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 subsection.
5.4
Efficiency Considerations
Efficiency is defined as the amount of useful output
power, divided by the amount of power supplied. (See
Typical Performance Curves section).
EQUATION 5-2:
V OUT I OUT
Efficiency% = --------------------------------- 100
V I
IN
IN
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 N-channel MOSFET conducts, also dissipating
power. The 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 high frequency and the switching transitions make
up the switching losses.
At the higher currents for which the MIC4930 is
designed, 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
2016 Microchip Technology Inc.
MIC4930
RDSON. This improves efficiency by reducing DC
losses in the device. All but the inductor losses are
inherent to the device. In that 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 in Equation 5-3.
The injected ripple is:
EQUATION 5-5:
1
V FB PP = V IN K div D 1 – D -------------------f SW
Where:
EQUATION 5-3:
2
P DCR = I OUT DCR
From that, the loss in efficiency due to inductor DCR
and core losses (PCORE) can be calculated as in
Equation 5-4.
EQUATION 5-4:
VIN =
Power stage input voltage
D=
Duty cycle; VOUT/VIN
fSW =
Switching frequency
τ=
(R1//R2//Rinj) × CF
with Kdiv given by:
EQUATION 5-6:
Efficiency Loss (%) =
V OUT I OUT
1 – ------------------------------------------------------------------------------ 100
V
I
+P
+P
OUT
5.5
OUT
DCR
R1//R2
K div = -----------------------------------R INJ + R1//R2
CORE
External Ripple Injection
The MIC4930 control loop is ripple-based, and relies on
an internal ripple injection network to generate enough
ripple amplitude at the FB pin when negligible output
voltage ripple is present. The internal ripple injection
network is typically sufficient when recommended
R1-R2 and CF values are used. The FB ripple
amplitude should fall in the 20 mV to 100 mV range.
In Equation 5-5 and Equation 5-6, it is assumed that
the time constant associated with CF must be greater
than the switching period.
EQUATION 5-7:
1
T
-------------------- = --- « 1
f SW
If significantly lower divider resistors and/or higher CF
values are used, the amount of internal ripple injection
may not be sufficient for stable operation. In this case,
external ripple injection is needed. This is
accomplished by connecting a series Rinj-Cinj circuit
between the SW and the FB pins, as shown in
SW
Rinj
MIC4930
R1
VOUT
CF
COUT
Cinj
FB
PGND
R2
AGND
GND
GND
FIGURE 5-1:
External Ripple Injection.
2016 Microchip Technology Inc.
DS20005669A-page 15
MIC4930
6.0
PACKAGING INFORMATION
6.1
Package Marking Information
10-Lead FDFN*
XXX
XXXX
NNN
Legend: XX...X
Y
YY
WW
NNN
e3
*
Example
MIC
4930
123
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.
DS20005669A-page 16
2016 Microchip Technology Inc.
MIC4930
10 Lead DFN 4 mm × 3 mm Package (Flip Chip) Outline & Recommended Land Pattern
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging.
2016 Microchip Technology Inc.
DS20005669A-page 17
MIC4930
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging.
DS20005669A-page 18
2016 Microchip Technology Inc.
MIC4930
APPENDIX A:
REVISION HISTORY
Revision A (November 2016)
• Converted Micrel document MIC4930 to Microchip data sheet template DS20005669A.
• Minor grammatical text changes throughout.
2016 Microchip Technology Inc.
DS20005669A-page 19
MIC4930
NOTES:
DS20005669A-page 20
2016 Microchip Technology Inc.
MIC4930
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
XX
Device
Temperature
Range
Package
Examples:
a)
MIC4930YFL:
Hyper Speed Control® 3A Buck Regulator
Device:
MIC4930:
Temperature
Range:
Y
=
–40C to +125C
Packages:
FL
=
10-Pin 3 mm x 4 mm FQFN
2016 Microchip Technology Inc.
Note 1:
Hyper Speed Control®
3A Buck Regulator,
–40°C to +125°C
Temperature Range,
10LD FQFN
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.
DS20005669A-page 21
MIC4930
NOTES:
DS20005669A-page 22
2016 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like 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.
MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR
IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION,
INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR
FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip
devices in life support and/or safety applications is entirely at
the buyer’s risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims,
suits, or expenses resulting from such use. No licenses are
conveyed, implicitly or otherwise, under any Microchip
intellectual property rights unless otherwise stated.
Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
Trademarks
The Microchip name and logo, the Microchip logo, AnyRate, AVR,
AVR logo, AVR Freaks, BeaconThings, BitCloud, CryptoMemory,
CryptoRF, dsPIC, FlashFlex, flexPWR, Heldo, JukeBlox, KEELOQ,
KEELOQ logo, Kleer, LANCheck, LINK MD, maXStylus,
maXTouch, MediaLB, megaAVR, MOST, MOST logo, MPLAB,
OptoLyzer, PIC, picoPower, PICSTART, PIC32 logo, Prochip
Designer, QTouch, RightTouch, SAM-BA, SpyNIC, SST, SST
Logo, SuperFlash, tinyAVR, UNI/O, and XMEGA are registered
trademarks of Microchip Technology Incorporated in the U.S.A.
and other countries.
ClockWorks, The Embedded Control Solutions Company,
EtherSynch, Hyper Speed Control, HyperLight Load, IntelliMOS,
mTouch, Precision Edge, and Quiet-Wire are registered
trademarks of Microchip Technology Incorporated in the U.S.A.
Adjacent Key Suppression, AKS, Analog-for-the-Digital Age, Any
Capacitor, AnyIn, AnyOut, BodyCom, chipKIT, chipKIT logo,
CodeGuard, CryptoAuthentication, CryptoCompanion,
CryptoController, dsPICDEM, dsPICDEM.net, Dynamic Average
Matching, DAM, ECAN, EtherGREEN, In-Circuit Serial
Programming, ICSP, Inter-Chip Connectivity, JitterBlocker,
KleerNet, KleerNet logo, Mindi, MiWi, motorBench, MPASM, MPF,
MPLAB Certified logo, MPLIB, MPLINK, MultiTRAK, NetDetach,
Omniscient Code Generation, PICDEM, PICDEM.net, PICkit,
PICtail, PureSilicon, QMatrix, RightTouch logo, REAL ICE, Ripple
Blocker, SAM-ICE, Serial Quad I/O, SMART-I.S., SQI,
SuperSwitcher, SuperSwitcher II, Total Endurance, TSHARC,
USBCheck, VariSense, ViewSpan, WiperLock, Wireless DNA, 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.
Silicon Storage Technology is a registered trademark 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.
© 2016, Microchip Technology Incorporated, All Rights Reserved.
ISBN: 978-1-5224-1100-0
2016 Microchip Technology Inc.
DS20005669A-page 23
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DS20005669A-page 24
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