MIC2101/02
38V, Synchronous Buck Controllers
Featuring Adaptive On-Time Control
Hyper Speed Control Family
General Description
The
Micrel MIC2101/02
are constant-frequency,
synchronous buck controllers featuring a unique adaptive
ON-time control architecture. The MIC2101/02 operates
over an input supply range from 4.5V to 38V and can be
used to supply up to 15A of output current. The output
voltage is adjustable down to 0.8V with a guaranteed
accuracy of ±1%. The device operates with programmable
switching frequency from 200kHz to 600kHz.
Micrel’s Hyper Light Load™ architecture provides the same
high-efficiency and ultra-fast transient response as the Hyper
Speed Control architecture under the medium to heavy loads,
but also maintains high efficiency under light load conditions
by transitioning to variable frequency, discontinuous-mode
operation.
The MIC2101/02 offers a full suite of protection features to
ensure protection of the IC during fault conditions. These
include undervoltage lockout to ensure proper operation
under power-sag conditions, internal soft-start to reduce
inrush current, fold-back current limit, “hiccup” mode short-
circuit protection and thermal shutdown.
All support documentation can be found on Micrel’s web
site at:
www.micrel.com.
Features
Hyper Speed Control architecture enables:
-
High Delta V operation (V
IN
= 38V and V
OUT
= 1.2V)
-
Any Capacitor stable
4.5V to 38V input voltage
0.8V reference voltage with ±1% accuracy
200kHz to 600kHz, programmable switching frequency
Hyper Light Load Control (MIC2101)
Hyper Speed Control (MIC2102)
Enable input and Power Good output
Built-in 5V regulator for single-supply operation
Programmable current limit and fold-back “hiccup”
mode short-circuit protection
5ms internal soft-start, internal compensation, and
thermal shutdown
Supports safe start-up into a pre-biased output
–40C to +125C junction temperature range
Available in 16-pin 3mm x 3mm MLF
®
package
Applications
Distributed power systems
Networking/telecom Infrastructure
Printers, scanners, graphic cards, and video cards
__________________________________________________________________________________________________________
Typical Application
MIC2101 Efficiency (V
IN
= 12V)
vs. Output Current (MIC2101)
100
90
80
5.0V
3.3V
2.5V
1.8V
1.5V
1.2V
1.0V
0.9V
0.8V
EFFICIENCY (%)
70
60
50
40
30
20
10
f
SW
= 600kHz (CCM)
MIC2101/02 Wide Input, Hyper Light Load Buck Converter
Hyper Speed Control, Hyper Light Load, and Any Capacitor are trademarks 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
100µF
470µF
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
OUTPUT CURRENT (A)
August 2012
M9999-080712-A
Micrel, Inc.
MIC2101/02
Ordering Information
Part Number
MIC2101YML
MIC2102YML
Switching
Frequency
200kHz to 600kHz
200kHz to 600kHz
Features
Hyper Light Load
Hyper Speed Control
Package
16-Pin 3mm x 3mm MLF
16-Pin 3mm x 3mm MLF
Junction
Temperature
Range
–40°C to +125°C
–40°C to +125°C
Lead Finish
Pb-Free
Pb-Free
Pin Configuration
16-Pin 3mm x 3mm MLF (ML)
(TOP VIEW)
Pin Description
Pin Number
1
2
3
Pin Name
VDD
PVDD
ILIM
Pin Function
Internal +5V Linear Regulator Output. VDD is the internal supply bus for the device. A 4.7μF ceramic
capacitor from VDD to AGND is required for decoupling. In the applications with VIN < +5.5V, VDD
should be tied to VIN to by-pass the linear regulator.
5V supply input for the low-side N-channel MOSFET driver, which can be tied to VDD externally. A
4.7μF ceramic capacitor from PVDD to PGND is recommended for decoupling.
Current Limit Setting. Connect a resistor from SW to ILIM to set the over-current threshold for the
converter.
Low-Side Drive output. High-current driver output for external low-side MOSFET of a buck converter.
The DL driving voltage swings from ground to VDD. Adding a small resistor between DL pin and the
gate of the low-side N-channel MOSFET can slow down the turn-on and turn-off speed of the
MOSFET.
Power Ground. PGND is the return path for the buck converter power stage. The PGND pin
connects to the sources of low-side N-Channel external MOSFET, the negative terminals of input
capacitors, and the negative terminals of output capacitors. The return path for the power ground
should be as small as possible and separate from the signal ground (AGND) return path.
Switching Frequency Adjust input. Tie this pin to VIN to operate at 600kHz and place a resistor
divider to reduce the frequency.
4
DL
5
PGND
6
FREQ
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M9999-080712-A
Micrel, Inc.
MIC2101/02
Pin Configuration (Continued)
Pin Number
7
Pin Name
DH
Pin Function
High-Side Drive Output. High-current driver output for external high-side MOSFET of a buck
converter. The DH driving voltage is floating on the switch node voltage (V
SW
). Adding a small
resistor between DH pin and the gate of the high-side N-channel MOSFET can slow down the turn-
on and turn-off speed of the MOSFET.
Switch Node and Current-Sense input. High current output driver return. The SW pin connects
directly to the switch node. Due to the high-speed switching on this pin, the SW pin should be
routed away from sensitive nodes. The SW pin also senses the current by monitoring the voltage
across the low-side MOSFET during OFF time. In order to sense the current accurately, connect the
low-side MOSFET drain to the SW pin using a Kelvin connection.
No Connection.
Voltage supply input for the high-side N-channel MOSFET driver, which can be powered by a
bootstrapped circuit connected between VDD and SW, using a Schottky diode and a 0.1μF ceramic
capacitor. Adding a small resistor at BST pin can slow down the turn-on speed of the high-side
MOSFET.
Signal ground for VDD and the control circuitry, which is connected to thermal pad electronically.
The signal ground return path should be separate from the power ground (PGND) return path.
Feedback Input. Input to the transconductance amplifier of the control loop. The FB pin is regulated
to 0.8V. A resistor divider connecting the feedback to the output is used to set the desired output
voltage.
Power Good Output. Open drain output, an external pull-up resistor to VDD or external power rails
is required.
Enable Input. A logic signal to enable or disable the buck converter operation. The EN pin is CMOS
compatible. Logic high enables the device, logic low shutdowns the regulator. In the disable mode,
the VDD supply current for the device is minimized to 0.7mA typically.
Supply Voltage. The VIN operating voltage range is from 4.5V to 38V. A 1μF ceramic capacitor from
VIN to AGND is required for decoupling.
Exposed Pad. Connect the EPAD to PGND plain on the PCB to improve the thermal performance.
8
SW
9, 11
10
NC
BST
12
13
14
15
16
EP
AGND
FB
PG
EN
VIN
ePad
August 2012
3
M9999-080712-A
Micrel, Inc.
MIC2101/02
Absolute Maximum Ratings
(1)
V
IN
................................................................
0.3V
to +40V
V
DD
, V
PVDD
........................................................
0.3V
to +6V
V
SW
, V
FREQ
, V
ILIM
, V
EN
............................
0.3V
to (V
IN
+0.3V)
V
BST
to V
SW
........................................................
0.3V
to 6V
V
BST
................................................................
0.3V
to 46V
V
PG
.....................................................
0.3V
to (V
DD
+ 0.3V)
V
FB
.....................................................
0.3V
to (V
DD
+ 0.3V)
PGND to AGND ...........................................
0.3V
to +0.3V
Junction Temperature .............................................. +150°C
Storage Temperature (T
S
) .........................
65C
to +150C
Lead Temperature (soldering, 10s) ............................ 260°C
ESD Rating
(2)
................................................. ESD Sensitive
Operating Ratings
(3)
Supply Voltage (V
IN
) .......................................... 4.5V to 38V
Enable Input (V
EN
) .................................................. 0V to V
IN
V
SW
, V
FREQ
, V
ILIM
, V
EN
............................................. 0V to V
IN
Junction Temperature (T
J
) ........................
40C
to +125C
Junction Thermal Resistance
3mm x 3mm MLF-16 (
JA
) ....................... 50.8°C/W
3mm x 3mm MLF-16 (
JC
) ....................... 25.3°C/W
Electrical Characteristics
(4)
V
IN
= 12V, V
OUT
=1.2V; V
BST
– V
SW
= 5V; T
A
= 25°C, unless noted.
Bold
values indicate
40°C
≤
T
J
≤
+125°C.
Parameter
Power Supply Input
Input Voltage Range (V
IN
)
(5)
Quiescent Supply Current (MIC2101)
Quiescent Supply Current (MIC2102)
Shutdown Supply Current
V
FB
= 1.5V
V
FB
= 1.5V
SW unconnected, V
EN
= 0V
4.5
400
2.1
0.1
38
750
3
10
V
µA
mA
µA
Condition
Min.
Typ.
Max.
Units
VDD Supply
VDD Output Voltage
VDD UVLO Threshold
VDD UVLO Hysteresis
Load Regulation
Reference
Feedback Reference Voltage
FB Bias Current
Enable Control
EN Logic Level High
EN Logic Level Low
EN Hysteresis
EN Bias Current
Oscillator
Switching Frequency
Maximum Duty Cycle
Minimum Duty Cycle
Minimum Off-Time
V
FB
> 0.8V
140
V
FREQ
= V
IN
V
FREQ
= 50%V
IN
400
600
300
85
0
200
260
750
kHz
%
%
ns
V
EN
= 12V
200
6
30
1.8
0.6
V
V
mV
µA
T
J
= 25°C (±1.0%)
40°C
≤
T
J
≤
125°C (±2%)
V
FB
= 0.8V
0.792
0.784
0.8
0.8
5
0.808
0.816
500
V
nA
I
DD
= 0 to 40mA
0.6
V
IN
= 7V to 38V, I
DD
= 10mA
V
DD
rising
4.8
3.8
5.2
4.2
400
2
3.6
5.4
4.6
V
V
mV
%
August 2012
4
M9999-080712-A
Micrel, Inc.
MIC2101/02
Electrical Characteristics
(4)
(Continued)
V
IN
= 12V, V
OUT
= 1.2V; V
BST
– V
SW
= 5V; T
A
= 25°C, unless noted.
Bold
values indicate
40°C
≤
T
J
≤
+125°C.
Parameter
Condition
Min.
Typ.
Soft-Start
Soft-Start time
Short-Circuit Protection
Current-Limit Threshold
Short-Circuit Threshold
Current-Limit Source Current
Short-Circuit Source Current
FET Drivers
DH, DL Output Low Voltage
DH, DL Output High Voltage
DH On-Resistance, High State
DH On-Resistance, Low State
DL On-Resistance, High State
DL On-Resistance, Low State
SW, BST Leakage Current
Power Good (PG)
PG Threshold Voltage
PG Hysteresis
PG Delay Time
PG Low Voltage
Thermal Protection
Over-Temperature Shutdown
Over-Temperature Shutdown Hysteresis
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
3. The device is not guaranteed to function outside operating range.
4. Specification for packaged product only.
5. The application is fully functional at low V
DD
(supply of the control section) if the external MOSFETs have low voltage V
TH
.
Max.
Units
5
V
FB
= 0.79V
V
FB
= 0V
V
FB
= 0.79V
V
FB
= 0V
I
SINK
= 10mA
V
PVDD
0.1V
I
SOURCE
= 10mA
or
V
BST
0.1V
2.1
1.8
1.8
1.2
3.3
3.3
3.3
2.3
50
Sweep V
FB
from Low to High
Sweep V
FB
from High to Low
Sweep V
FB
from Low to High
V
FB
< 90% x V
NOM
, I
PG
= 1mA
T
J
Rising
85
90
6
100
70
160
7
200
95
30
23
60
27
14
7
80
37
0
9
100
47
0.1
ms
mV
mV
µA
µA
V
V
Ω
Ω
Ω
Ω
µA
%V
OUT
%V
OUT
µs
mV
°C
°C
August 2012
5
M9999-080712-A
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