MIC38300
HELDO®
3A High-Effici ency Low Dropout Regulator
HELDO is a registered trademark of Micrel, Inc.
MLF and MicroLead Frame 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
April 10, 2013
Revision 5.0
General Description
The MIC38300 is a 3A peak, 2.2A continuous output
current step down converter. This is the first device in a
new generation of HELDO® (High-Efficiency Low Dropout)
regulators th at provide the benef its of an L DO i n res pe c t to
ease of use, fast transient performance, high PSRR, and
low noise while offering the efficiency of a switching
regulator.
As output voltages move lower, the output noise and
transient response of a switching regulator become an
increasing challenge for designers. By combining a
switcher whose output is slaved to the input of a high-
performance LDO, high efficiency is achieved with a clean
low noise output. The MIC38300 is designed to provide
less than 5mV of peak to peak noise and over 70dB of
PSRR at 1kHz. Furthermore, the architecture of the
MIC38300 is optimized for fast load transients that allow
maintenanc e of les s than 3 0m V of output voltage de vi ation
even during ul tra-f as t load steps, making the MIC38300 an
ideal choice for low-voltage ASICs and other digital ICs.
The MIC38300 features a fully-integrated switching
regulator and LDO combo, operates with input voltages
from 3.0V to 5.5V input, and offers adjustable output
voltages down to 1.0V.
The MIC38300 is offered in the small 28-pin 4mm × 6mm
× 0.9mm MLF® package and can operate from –40°C to
+125°C.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
HELDO®
Features
• 3A peak output current
• 2.2A continuous operating current
• Input voltage range: 3.0V to 5.5V
• Adjustab le output volta ge down to 1.0V
• Output noise less than 5mV
• Ultra-fast transient performance
• Unique switcher plus LDO architecture
• Fully-integrated MOSFET switches
• Micro-power shutdown
• Easy upgrade from LDO as power dissipation becomes
an issue
• Thermal shutdown and current-limit protection
• 4mm × 6mm × 0.9mm MLF package
Applications
• Point-of-load applications
• Networking, server, industrial power
• Wireless base-stations
• Sensitive RF applications
Typical Application
Micrel, Inc.
MIC38300
April 10, 2013
2 Revision 5.0
Ordering Information
Part Number Output Current Voltage
(1)
Junction Temperature Range Package
MIC38300HYHL 3.0A Adjustable –40°C to +125°C Pb-Free 28-Pin 4mm × 6mm M LF
Note:
1. Other voltages are available. Contact Micrel for details.
Pin Configuration
28-Pin 4mm × 6m m MLF (ML)
(Top View)
Pin Description
Pin Number
MIC38300HYHL Pin Name Pin Name
1, 2, 3, 4, 5 SWO Switch (Output): This is the output of the PFM Switcher.
6, 23, 24, 25, 26, 27 , 28 SW Switch Node: Attach external resistor from LPF to increase hysteretic frequency.
7, 22 ePAD Exposed heat-sink pad. Connect externally to PGND.
8 AVIN Analog Supply Voltage: Supply for the anal og contr ol circ uitry. Require s bypa ss capac itor
to ground. Nominal bypass capacitor is 1µF.
9 LPF Low Pass Filter: Attach external resistor from SW to increase hysteretic frequency.
10 AGND Analog Ground.
11 FB Feedback: Input to the error amplifier. Connect to the external resistor divider network to
set the output voltage.
SW
5
1
SW
SW
SW
SW
2
3
4
10
6
7
8
9
24
28
27
26
25
23
11
19
22
21
20
18
1613 14 15 1712
SW
SWO
SWO
SWO
SWO
SWO
SW
FB
ePAD
AVIN
LPF
AGND PGND
ePAD
PGND
PGND
EN
PVIN
LDOOUT
LDOOUT
LDOIN
LDOIN
PVIN
Micrel, Inc.
MIC38300
April 10, 2013
3 Revision 5.0
Pin Description (Continued)
Pin Number
MIC38300HYHL Pin Name Pin Name
12, 13 LDOOUT LDO Output: Output of voltage regulator. Place capacitor to ground to bypass the output
voltage. Nominal bypa ss capa citor is 10µ F.
14, 15 LDOIN LDO Input: Connec t to SW output. Requires a bypass capacitor to ground. Nominal
bypass capacit or is 10µF.
16, 17 PVIN Input Supply Voltage (Input): Requires bypass capacitor to GND. Nominal bypas s
capacitor is 10µF.
18 EN Enable (Input): Lo gic low will shut down the device, reducing the quiescent current to less
than 50µA. This pin can also be used as an undervoltage lockout function by connecting a
resistor divider from EN/UVLO pin to VIN and GND. It should be not left open.
19, 20, 21 PGND Power Ground.
Micrel, Inc.
MIC38300
April 10, 2013
4 Revision 5.0
Absolute Maximum Ratings(1)
Supply Voltage (VIN) ......................................................... 6V
Output Switc h Voltage (VSW) ............................................ 6V
LDO Output Voltage (VOUT) .............................................. 6V
Logic Input Voltage (VEN) ................................. –0.3V to VIN
Power Dissip ati on .................................. Internally Limited(3)
Storage Temperature (TS) ...................–65°C ≤ TJ ≤ +150°C
ESD Rating(4) ............................................................... 1.5kV
Operating Ratings(2)
Supply voltage (VIN) ......................................... 3.0V to 5.5V
Junction Temperature Range ........... –40°C ≤ TJ ≤ +125°C
Enable Input Voltage (VEN) ..................................... 0V to VIN
Package Thermal Resistance
4mm × 6mm MLF-28 (θJA) ................................ 24°C/W
Electrical Characteristics(5)
TA = 25°C with VIN = VEN = 5V; IOUT = 10mA, VOUT = 1.8V. Bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted.
Parameter Conditions Min. Typ. Max. Units
Supply Voltage Range (AVIN, PVIN) 3.0 5.5 V
Undervoltage Lockout Threshold Turn-on 2.85 V
UVLO Hysteresis 100 mV
Quiescent Current IOUT = 0A, Not switching, open loop 1 mA
Turn-On Time VOUT to 95% of nominal 200 500 µs
Shutdown Current VEN = 0V 30 50 µA
Feedback Voltage ±2.5% 0.975 1 1.025 V
Feedback Current 5 nA
Dropout Voltage (VIN – VOUT) ILOAD = 2.2A; VOUT = 3V 0.85 1.2 V
Current Limit VFB = 0.9 × VNOM 3 5 A
Output Voltage Load Regulation VOUT = 1.8V, 10mA to 2.2A 0.3 1 %
Output Voltage Line Regulation VOUT = 1.8V, VIN from 3.0V t o 5.5V 0.35 0.5 %/V
Output Ripple ILOAD = 1.5A, COUTLDO = 20µF, COUTSW = 20µF
LPF = 25kΩ 2 mV
Over-Temperature Shutdown 150 °C
Over-Temperature Shutdown Hysteresis 15 °C
Enable Input(6)
Enable Input Threshold Regulator enable 0.90 1 1.1 V
Enable Hys teresis 20 100 200 mV
Enable Input Current 0.03 1 µA
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guarant eed to function outside its operat i ng rating.
3. The maxim um allowable power dissi pation of any TA (ambient temperature) is PD(max) = (TJ(max) – TA) / θJA. Exceeding the maximum all owable power
dissipati on will result in excessi ve die tem perat ure, and the regulat or will go into thermal shutdown.
4. Devices are ESD sensitive. Handling prec autions recommended. Human body model, 1.5kΩ in series with 100pF.
5. Specific at i on for packaged product only.
6. Enable pin shoul d not be left open.
Micrel, Inc.
MIC38300
April 10, 2013
5 Revision 5.0
Typical Characteris tics
VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, RLPF = 25kΩ, IOUT = 100mA, unless noted.
0
10
20
30
40
50
60
70
80
90
10 100 1k 10k 100k
FREQUENCY (Hz)
MIC38300 PSRR
1.780
1.785
1.790
1.795
1.800
1.805
1.810
1.815
1.820
00.5 1.0 1.5 2.0 2.5 3.0
LOAD CURRENT (A)
Load Regulation
VIN = 3.3V
VOUT = 1.8V
COUT = 10µF
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
012345INPUT VOLTAGE (V)
Output Voltage
vs. Input Voltage
VOUT = 1.8V
COUT = 10µF
10mA
2A
1.72
1.74
1.76
1.78
1.80
1.82
1.84
1.86
1.88
Output Voltage
vs. Temperature
20 40 60 80
TEMPERATURE (°C)
VIN = 3.3V
COUT = 10µF
IOUT = 10mA
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
-40 10 60 110 160 210
TEMPERATURE (°C)
Thermal Shutdown
VIN = 3.3V
VOUT = 1.8V
COUT = 10µF
0
10
20
30
40
50
60
70
80
90
00.5 1.0 1.5 2.0 2.5 3.0
LOAD CURRENT (A)
MIC38300 Efficiency
VIN = 5V
VOUT = 3.3V
COUT = 10µF
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
00.5 1.0 1.5 2.0 2.5 3.0
LOAD CURRENT (A)
Dropout Voltage
vs. Load Current
VIN = 3.3V
COUT = 20µF
RLPF
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Dropout Voltage
vs. Temperature
20 40 60 80
TEMPERATURE (°C)
VOUT = 4V
COUT = 20µF
2A
1A
3.5
3.7
3.9
4.1
4.3
4.5
4.7
4.9
5.1
5.3
5.5
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
INPUT VOLTAGE (V)
Current Limit
vs. Input Voltage
VOUT = 1V
COUT = 20µF
RLPF
Micrel, Inc.
MIC38300
April 10, 2013
6 Revision 5.0
Typical Characteristics (Continued)
VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, RLPF = 25kΩ, IOUT = 100mA, unless noted.
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
Enable Threshold
VOUT = 1.8V
COUT = 10µF
0
10
20
30
40
50
60
33.5 44.5 55.5
OPERATING CURRENT (mA)
INPUT VOLTAGE (V)
Operating Current
vs. Input Voltage
V
OUT
= 1.8V
C
OUT
= 10µF
0
0.5
1
1.5
2
2.5
3
10 100 1000
SWITCH FREQUENCY (MHz)
RLPF RESISTANCE (kohms)
Switch Frequency vs.
RLPF Resistance (3.3V-1.0V)
10mA
500mA
1A
1.5A
2A
0
0.5
1
1.5
2
2.5
3
10 100 1000
SWITCH FREQUENCY (MHz)
RLPF RESISTANCE (kohms)
Switch Frequency vs.
RLPF Resistance (3.3V-1.8V)
10mA
500mA
1A 1.5A
2A
0
0.5
1
1.5
2
2.5
3
10 100 1000
SWITCH FREQUENCY (MHz)
RLPF RESISTANCE (kohms)
Switch Frequency vs.
RLPF Resistance (5.0V-1.0V)
10mA
500mA
1A
1.5A
2A
0
0.5
1
1.5
2
2.5
3
10 100 1000
SWITCH FREQUENCY (MHz)
RLPF RESISTANCE (kohms)
Switch Frequency vs.
RLPF Resistance (5.0V-1.8V)
10mA 500mA
1A
1.5A 2A
0
0.5
1
1.5
2
2.5
3
10 100 1000
SWITCH FREQUENCY (MHz)
RLPF RESISTANCE (kohms)
Switch Frequency vs.
RLPF Resistance (5.0V-2.5V)
10mA
500mA
1A
1.5A 2A
0
0.5
1
1.5
2
2.5
3
3.5
-40 -20 020 40 60 80
MAX OUTPUT CURRENT (A)
AMBIENT TEMPERATURE (°C)
Max Output Current @ 110°C
Case Temp (1.0V VOUT)
5.5V
3.3V
5.0V
0
0.5
1
1.5
2
2.5
3
3.5
-40 -20 020 40 60 80
MAX OUTPUT CURRENT (A)
AMBIENT TEMPERATURE (°C)
Max Output Current @ 110°C
Case Temp (1.2V VOUT)
5.5V
3.3V
5.0V
Micrel, Inc.
MIC38300
April 10, 2013
7 Revision 5.0
Typical Characteristics (Continued)
VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, RLPF = 25kΩ, IOUT = 100mA, unless noted.
0
0.5
1
1.5
2
2.5
3
3.5
-40 -20 020 40 60 80
MAX OUTPUT CURRENT (A)
AMBIENT TEMPERATURE (°C)
Max Output Current @ 110°C
Case Temp (1.8V VOUT)
5.5V
5.0V
0
0.5
1
1.5
2
2.5
3
3.5
-40 -20 020 40 60 80
MAX OUTPUT CURRENT (A)
AMBIENT TEMPERATURE (°C)
Max Output Current @ 110°C
Case Temp (2.5V VOUT)
5.5V
5.0V
Micrel, Inc.
MIC38300
April 10, 2013
8 Revision 5.0
Functional Characteristics
VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, Inductor = 470nH; RLPF = 25kΩ, IOUT = 100mA, unless noted.
Micrel, Inc.
MIC38300
April 10, 2013
9 Revision 5.0
Functional Diagram
Micrel, Inc.
MIC38300
April 10, 2013
10 Revision 5.0
EMI Performance
VOUT =1.8V, IOUT = 1.2A.
EMI Test
−
Horizontal Front
EMI Test
−
Vertical Front
Additional components to MIC38150 Evaluation Board (Performance similar to MIC38300):
1. Input Ferrite Bead Inductor. Part number: BLM21AG102SN1D.
2. 0.1µF and 0.01µF ceramic bypass capacitors on PVIN, SW, SWO, and LDOOUT pins.
Micrel, Inc.
MIC38300
April 10, 2013
11 Revision 5.0
Application Information
Enable Input
The MIC3830 0 featur es a TT L/CMOS com patible pos itive
logic enable input for on/off control of the device. High
enables the regulator while low disables the regulator. In
shutdown the regulator consumes very little current (only
a few microamperes of leakage). For simple applications
the enable (EN) can be connected to VIN (IN).
Input Capacitor
PVIN provides power to the MOSFETs for the switch
mode regulator section and the gate drivers. Due to the
high s witch ing s pee ds , a 1 0µ F c apacit or is r ec om mended
close to PVIN and the power ground (PGND) pin for
bypassing.
Analog VIN (AVIN) provides power to the analog supply
circuitry. Careful layout should be considered to ensure
high-frequency switching noise caused by PVIN is
reduced before reaching AVIN. A 1µF capacitor as close
to AVIN as possible is recommended.
Output Capacitor
The MIC38300 requires an output capacitor for stable
operation. As a µCap LDO, the MIC38300 can operate
with cer am ic output ca pacit ors of 10µF or gr eater. Val ues
of greater than 10µF improve transient response and
noise reduction at high frequency. X7R/X5R dielectric-
type ceramic capacitors are recommended because of
their superior temperature performance. X7R-type
capacitors change capacitance by 15% over their
operating temperature range and are the most stable
type of ceramic capacitors. Larger output capacitances
can be achieved by placing tantalum or aluminum
electrolytics in parallel with the ceramic capacitor. For
example, a 100µF electrolytic in parallel with a 10µF
ceramic can provide the transient and high frequency
noise performance of a 100µF ceramic at a significantly
lower cost. Specific undershoot/overshoot performance
will depend on both the values and ESR/ESL of the
capacitors.
For less than 5mV noise performance at higher current
loads, 20µF capacitors are recommended at LDOIN and
LDOOUT.
Low Pass Filter Pin
The MIC38300 features a Low Pass Filter (LPF) pin for
adjusting the switcher frequency. By tuning the
frequency, the user can further improve output ripple
without losing efficiency. Adjusting the frequency is
accomplished by connecting a resistor between the LPF
and SW pins. A small value resistor would increase the
frequency while a larger value resistor decreases the
frequency. Recommended RLPF value is 25kΩ. Please
see Typical Characteristics section for more details.
Adjustable Regulator Design
The adjustable MIC38300 output voltage can be
programmed from 1V to 5 .0V using a r esis tor divider f rom
output to the FB pin. Resistors can be quite large, up to
100kΩ because of the very high input impedance and low
bias current of the sense amplifier. For large value
resistors (>50kΩ) R1 should be bypassed by a small
capacitor (CFF = 0.1µF bypass capacitor) to avoid
instability due to phase lag at the ADJ/SNS input.
Figure 1. Adjustable Regulator with Resistors
The output resistor divider values are calculated by
Equation 1:
+= 1
2R1R
V1V
OUT
Eq. 1
Efficiency Con siderations
Efficiency is defined as the amount of useful output
power, divided by the amount of power supplied.
100
IV IV
%_Efficiency ININ
OUTOUT ×
×
×
=
Eq. 2
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 a pplicat ions . Reduce d curr ent draw f rom
a battery increases the devices operating time and is
critical in handhe ld de vices .
Micrel, Inc.
MIC38300
April 10, 2013
12 Revision 5.0
There ar e t wo t ypes of loss es in switching con ver t ers ; DC
losses and switching losses. DC losses are simply the
power dissipation of I2R. Power is dissipated in the high
side switch dur i ng the o n cyc le. P o wer loss is equa l to the
high-side MOSFET RDSON multiplied by 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.
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, reducing the internal RDDSON. This improves
eff iciency by reduc ing DC los ses in the device. All bu t the
inductor l osses are inher ent to the d evice. In which c ase,
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 3:
L_PD = IOUT2 × DCR Eq. 3
From that, the loss in ef f iciency due t o induc tor res is tan ce
can be calculated as in Equation 4:
100
P_L
IV IV
1Loss
_Efficiency DOUT
OUT
OUT
OUT ×
+×
×
−=
Eq. 4
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.
Current-Sharing Circuit
Figure 2 allows two MIC38300 HELDO regulators to
share the load current equally. HELDO1 senses the
output voltage at the load, on the other side of a current
sense resistor. As the load changes, a voltage equal to
the output voltage, plus the load current times the sense
resistor, is developed at the VOUT terminal of HELDO1.
The op-amp (MIC7300) inverting pin senses this voltage
and compares it to the voltage on the VOUT terminal of
HELDO2.
If the current through the current sense of HELDO2 is
less than the current through the current sense of
HELDO1, the in vert ing pin wil l be at a higher vo ltage t han
the non-inverting pin and the op-amp will drive the FB of
HELDO2 low. The low voltage sensed on HELDO2 FB
pin will drive the output up until the output voltage of
HELDO2 matches the output voltage of HELDO1. Since
VOUT will remain constant and both HELDO VOUT
terminals and sense resistances are matched, the output
currents will be shared equally.
Micrel, Inc.
MIC38300
April 10, 2013
13 Revision 5.0
Figure 2. Current-Sharing Circuit for 6A Output
Micrel, Inc.
MIC38300
April 10, 2013
15 Revision 5.0
Recommended Landing Pattern
LP # HMLF46T-28LD-LP-1
All units are in mm
Tolerance ±0.05, if not noted
Red circles indicate Thermal Vias. Size should be .300mm − .350mm in d iam eter and it sho uld be conne cte d to
GND plane for maximum thermal performance.
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
Micrel makes no represent ations or warranties with respec t t o the accuracy or completeness of the information furnished in this data sheet. This
informat i on is not intended as a warranty and Micrel does not assume responsibilit y for its use. Micrel reserves the right to change circuitry,
specificat i ons and descript i ons at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, t o any intellectual
property rights is granted by this document. Except as provided in Micrel’s term s and condit i ons of sale for such products, Micrel assumes no liabil ity
whatsoever, and Micrel disclaims any express or implied warranty relating to t he sale and/or use of Micrel products including liabil it y or warranties
relating to fitness for a partic ular purpose, merchant abi lit y, or inf ri ngem ent of any patent, copyright or other intel l ect ual propert y ri ght .
Micrel Products are not designed or authorized for use as components in life support applianc es, devic es or syst ems where malf unct i on of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devic es or syst ems 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 u
se in life support appliances, devices or syst ems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Mic rel for any damages resulting from such use or sale.
© 2007 Micrel, Incorporated.
