MIC2169
Micrel
MIC2169
500kHz PWM Synchronous Buck Control IC
General Description
The MIC2169 is a high-efficiency, simple to use 500kHz PWM
synchronous buck control IC housed in a small MSOP-10
package. The MIC2169 allows compact DC/DC solutions
with a minimal external component count and cost.
The MIC2169 operates using a 3V to 14.5V input, without
the need for 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 MIC2169 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
via a positive temperature coefficient that tracks the increas-
ing R
DS(ON)
of the external MOSFET. Additional cost and
space are saved by the internal in-rush-current limiting and
digital soft-start.
The MIC2169 is available in a 10-pin MSOP package, with a
wide junction operating range of –40°C to +125°C.
All support documentation can be found on Micrel’s web site
at: www.micrel.com.
Features
•
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•
•
•
•
•
•
•
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3V to 14.5V input voltage range
Adjustable output voltage down to 0.8V
Up to 95% efficiency
500kHz PWM operation
Adjustable current limit senses high-side N-Channel
MOSFET current
No external current-sense resistor
Adaptive gate drive increases efficiency
Fast transient response
– Externally compensated
Overvoltage protection protects the load in fault
conditions
Dual mode current limit speeds up recovery time
Hiccup mode short-circuit protection
Small size MSOP 10-lead package
Point-of-load DC/DC conversion
Set-top boxes
Graphic cards
LCD power supplies
Telecom power supplies
Networking power supplies
Cable modems and routers
Applications
Typical Application
V
IN
= 5V
SD103BWS
100μF
4.7μF
VDD
BST
CS
HSD
VSW
1kΩ
IRF7821
2.5μH
VIN
MIC2169
3.3V
10kΩ
150μF x 2
3.24kΩ
COMP/EN
150pF
4kΩ
100nF
GND
LSD
FB
IRF7821
EFFICIENCY (%)
0.1μF
100
95
90
85
80
75
70
65
60
55
50
MIC2169 Efficiency
V
IN
= 5V
V
OUT
= 3.3V
0
2
4
6 8 10 12 14 16
I
LOAD
(A)
MIC2169 Adjustable Output 500kHz Converter
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
March 2009
1
M9999-032409
MIC2169
Micrel
Ordering Information
Part Number
MIC2169BMM
Pb-Free Part Number
MIC2169YMM
Frequency
500kHz
Junction Temp. Range
–40°C to +125°C
Package
10-lead MSOP
Pin Configuration
VIN 1
VDD 2
CS 3
COMP 4
FB 5
10 BST
9 HSD
8 VSW
7 LSD
6 GND
10-Pin MSOP (MM)
Pin Description
Pin Number
1
2
Pin Name
VIN
VDD
Pin Function
Supply Voltage (Input): 3V to 14.5V.
5V Internal Linear Regulator (Output): V
DD
is the external MOSFET gate
drive supply voltage and an internal supply bus for the IC. When V
IN
is <5V,
this regulator operates in dropout mode.
Current Sense (Input): Current-limit comparator noninverting input. The cur-
rent 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): Pin for external compensation. .
Feedback (Input): Input to error amplifier. Regulates error amplifier to 0.8V.
Ground (Return).
Low-Side Drive (Output): High-current driver output for external synchro-
nous MOSFET.
Switch (Return): High-side MOSFET driver return.
High-Side Drive (Output): High-current output-driver for the high-side MOS-
FET. When V
IN
is between 3.0V to 5V, 2.5V threshold MOSFETs should be
used. At V
IN
> 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 V
IN
minus a
diode drop.
3
CS
4
5
6
7
8
9
COMP
FB
GND
LSD
VSW
HSD
10
BST
M9999-032409
2
March 2009
MIC2169
Micrel
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) ................................................... 15.5V
Booststrapped 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
θ
JA
10-lead MSOP ............................................. 180°C/W
Electrical Characteristics
(3)
T
J
= 25°C, V
IN
= 5V;
bold
values indicate –40°C < T
J
< +125°C; unless otherwise specified.
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
Minimum On-Time
(4)
Input and V
DD
Supply
PWM Mode Supply Current
Digital Supply Voltage (V
DD
)
Error Amplifier
DC Gain
Transconductance
Soft-Start
Soft-Start Current
Current Sense
CS Over Current Trip Point
Temperature Coefficient
ppm/°C
Output Fault Correction Thresholds
Upper Threshold, V
FB_OVT
Lower Threshold, V
FB_UVT
Notes:
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.
Condition
(± 1%)
(± 2% over temp)
Min
0.792
0.784
Typ
0.8
0.8
30
0.03
0.5
Max
0.808
0.816
100
Units
V
V
nA
%/V
%
%
3V
≤
V
IN
≤
14.5V; 1A
≤
I
OUT
≤
10A; (V
OUT
= 2.5V)
(4)
450
92
0.6
500
30
550
60
3
5.3
kHz
%
ns
mA
V
dB
ms
μA
V
CS
= V
IN
–0.25V; V
FB
= 0.7V (output switching but excluding
external MOSFET gate current.)
V
IN
≥
6V
4.7
1.5
5
70
1
After timeout of internal timer. See
“Soft-Start”
section.
V
CS
= V
IN
–0.25V
160
8.5
200
+1800
240
μA
(relative to V
FB
)
(relative to V
FB
)
+3
–3
%
%
March 2009
3
M9999-032409
MIC2169
Micrel
Electrical Characteristics
(5)
Parameter
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
Notes:
5. Specification for packaged product only.
6. Guaranteed by design.
Condition
Min
Typ
30
Max
Units
ns
6
6
10
10
10
20
Ω
Ω
Ω
Ω
ns
Note 6
M9999-032409
4
March 2009
MIC2169
Micrel
Typical Characteristics
V
IN
= 5V
PWM Mode Supply Current
vs. Temperature
PWM Mode Supply Current
vs. Supply Voltage
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
1.3
1.1
0.9
0.7
0.5
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
2.0
QUIESCENT CURRENT (mA)
0.8010
0.8005
V
FB
Line Regulation
1.5
0.8000
I
DD
(mA)
V
FB
(V)
1.0
0.5
0.7995
0.7990
0.7985
0
5
10
SUPPLY VOLTAGE (V)
15
0.7980
0
5
V
IN
(V)
10
15
0.804
0.802
V
DD
(V)
V
DD
REGULATOR VOLTAGE (V)
0.806
V
FB
vs. Temperature
6
5
4
3
2
1
0
0
V
DD
Line Regulation
5.02
5.00
4.98
4.96
4.94
4.92
4.90
0
V
DD
Load Regulation
V
FB
(V)
0.800
0.798
0.796
0.794
0.792
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
5
V
IN
(V)
10
15
5
10 15 20 25
LOAD CURRENT (mA)
30
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
V
DD
Line Regulation
vs. Temperature
FREQUENCY VARIATION (%)
V
DD
LINE REGULATION (%)
FREQUENCY (kHz)
550
540
530
520
510
Oscillator Frequency
vs. Temperature
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
0
Oscillator Frequency
vs. Supply Voltage
500
490
480
470
460
450
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
5
V
IN
(V)
10
15
4
Current Limit Foldback
260
240
Overcurrent Trip Point
vs. Temperature
3
V
OUT
(V)
I
CS
(
μA)
220
200
180
160
140
120
2
1
Top MOSFET = Si4800
R
CS
= 1kΩ
0
0
2
4
6
I
LOAD
(A)
8
10
100
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
March 2009
5
M9999-032409
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