MIC2168A
1MHz PWM Synchronous Buck-Control IC
General Description
The MIC2168A is a high-efficiency, simple to use 1MHz
PWM synchronous buck-control IC housed in a small
MSOP-10 package. The MIC2168A allows compact
DC/DC solutions with a minimal external component count
and cost.
The MIC2168A operates from a 3V to 14.5V input, without
the need of any additional bias voltage. The output voltage
can be precisely regulated down to 0.8V. The adaptive all
N-Channel MOSFET drive scheme allows efficiencies over
95% across a wide load range.
The MIC2168A senses current across the high-side N-
Channel MOSFET, eliminating the need for an expensive
and lossy current-sense resistor. Current limit accuracy is
maintained by a positive temperature coefficient that tracks
the increasing R
DS(ON)
of the external MOSFET. Further
cost and space are saved by the internal in-rush-current
limiting and digital soft-start.
The MIC2168A is identical to the MIC2168 with the
exception that the MIC2168A increases the overcurrent
blanking time from 80ns (typ.) to 120ns (typ.)
The MIC2168A is available in a 10-pin MSOP package,
with a wide junction operating range of –40°C to +125°C.
Datasheets and support documentation are available on
Micrel’s web site at:
www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
3V to 14.5V input voltage range
Adjustable output voltage down to 0.8V
Up to 95% efficiency
1MHz PWM operation
Adjustable current-limit senses high-side N-Channel
MOSFET current
No external current sense resistor
Adaptive gate drive increases efficiency
Ultra-fast response with hysteretic transient recovery
mode
Overvoltage protection protects the load in fault
conditions
Dual mode current limit speeds up recovery time
Hiccup mode short-circuit protection
Internal soft-start
Small-size MSOP 10-pin package
Applications
•
•
•
•
•
•
•
Point-of-load DC/DC conversion
Set-top boxes
Graphic cards
LCD power supplies
Telecom power supplies
Networking power supplies
Cable modems and routers
Typical Application
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 22, 2015
Revision 3.0
Micrel, Inc.
MIC2168A
Ordering Information
Part Number
MIC2168AYMM
Frequency
1MHz
Junction Temperature Range
–40° to +125°C
Package
10-Pin MSOP Pb-Free
Pin Configuration
10-Pin MSOP (MM)
(Top View)
Pin Description
Pin Number
1
2
Pin Name
VIN
VDD
Pin Function
Supply Voltage (Input): 3V to 14.5V.
5V Internal Linear Regulator (Output): VDD is the external MOSFET gate drive supply voltage
and an internal supply bus for the IC. When VIN is <5V, this regulator operates in dropout mode.
Current Sense / Enable (Input): Current-limit comparator noninverting input. The current limit is
sensed across the MOSFET during the ON time. The current can be set by the resistor in series
with the CS pin.
Compensation (Input): Dual function pin. Pin for external compensation. If this pin is pulled below
0.2V, with the reference fully up, the device shuts down (50μA typical current draw).
Feedback (Input): Input to error amplifier. Regulates error amplifier to 0.8V.
Ground (Return).
Low-Side Drive (Output): High-current driver output for external synchronous MOSFET.
Switch (Return): High-side MOSFET driver return.
High-Side Drive (Output): High-current output-driver for the high-side MOSFET. When VIN is
between 3.0V to 5V, 2.5V threshold-rated MOSFETs should be used. At VIN > 5V, 5V threshold
MOSFETs should be used.
Boost (Input): Provides the drive voltage for the high-side MOSFET driver. The gate-drive voltage
is higher than the source voltage by VIN minus a diode drop.
3
CS
4
5
6
7
8
9
COMP
FB
GND
LSD
VSW
HSD
10
BST
April 22, 2015
2
Revision 3.0
Micrel, Inc.
MIC2168A
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .................................................. +15.5V
Bootstrapped Voltage (V
BST
). ................................... V
IN
+5V
Junction Temperature (T
J
) ..................–40°C ≤ T
J
≤ +125°C
Storage Temperature (T
S
) ......................... –65°C to +150°C
Operating Ratings
(2)
Supply Voltage (V
IN
) ...................................... +3V to +14.5V
Output Voltage Range............................. 0.8V to V
IN
× D
MAX
Package Thermal Resistance
10-Pin MSOP (θ
JA
) ........................................... 180°C/W
Electrical Characteristics
(3)
T
J
= 25°C, V
IN
= 5V, unless otherwise specified. Bold values indicate –40°C < T
J
< +125°C.
Parameter
Feedback Voltage Reference
Feedback Voltage Reference
Feedback Bias Current
Output Voltage Line Regulation
Output Voltage Load Regulation
Output Voltage Total Regulation
Oscillator Section
Oscillator Frequency
Maximum Duty Cycle (D
MAX
)
Minimum On-Time
(4)
Input and V
DD
Supply
PWM Mode Supply Current
V
CS
= V
IN
–0.25V; V
FB
= 0.7V
(output switching but excluding external MOSFET
gate current.)
V
COMP/EN
=0V
0.1
C
COMP
= 100nF
V
IN
≥ 6V
4.7
1.6
3
mA
900
90
30
60
ns
1000
1100
kHz
3V ≤ V
IN
≤ 14.5V; 1A ≤ I
OUT
≤ 10A; (V
OUT
= 2.5V)
(4)
(± 1%)
(± 2% over temp)
Condition
Min.
0.792
0.784
Typ.
0.8
0.8
30
0.03
0.5
0.6
Max.
0.808
0.816
100
Units
V
V
nA
%/V
%
%
Shutdown Quiescent Current
VCOMP Shutdown Threshold
VCOMP Shutdown Blanking
Period
Digital Supply Voltage (V
DD
)
Error Amplifier
DC Gain
Transconductance
Soft Start
Soft-Start Current
Current Sense
CS Overcurrent Trip Point
Temperature Coefficient
Notes:
50
0.25
4
5
150
0.4
µA
V
ms
5.3
V
70
1
dB
ms
After timeout of internal timer.
(See “Soft-Start” section.)
8.5
µA
V
CS
= V
IN
–0.25V
160
200
+1800
240
µA
ppm/°C
1. Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating
the device outside of its operating ratings. The maximum allowable power dissipation is a function of the maximum junction temperature, T
J(max)
, the
junction-to-ambient thermal resistance, θ
JA
, and the ambient temperature, T
A
. The maximum allowable power dissipation will result in excessive die
temperature, and the regulator will go into thermal shutdown.
2. Devices are ESD sensitive, handling precautions required.
3. Specification for packaged product only.
4. Guaranteed by design.
April 22, 2015
3
Revision 3.0
Micrel, Inc.
MIC2168A
Electrical Characteristics (Continued)
T
J
= 25°C, V
IN
= 5V, unless otherwise specified.
Bold
values indicate –40°C < T
J
< +125°C.
Parameter
Output Fault Correction Thresholds
Upper Threshold, V
FB_OVT
Lower Threshold, V
FB_UVT
Gate Drivers
Rise/Fall Time
Output Driver Impedance
Into 3000pF at V
IN
> 5V
Source, V
IN
= 5V
Sink, V
IN
= 5V
Source, V
IN
= 3V
Sink, V
IN
= 3V
Driver Non-Overlap Time
Note 4
10
20
30
6
6
10
10
ns
Ω
Ω
Ω
Ω
ns
(relative to V
FB
)
(relative to V
FB
)
+3
-3
%
%
Condition
Min.
Typ.
Max.
Units
April 22, 2015
4
Revision 3.0
Micrel, Inc.
MIC2168A
Typical Characteristics
April 22, 2015
5
Revision 3.0
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