|
|
BUCK CONTROLLER. MIC2169 Datasheet |
|
|
|
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 RDS(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
• 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
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
VIN = 5V
100μF
SD103BWS
4.7μF
0.1μF
VDD
BST
CS
1kΩ
150pF
100nF
VIN HSD
MIC2169
VSW
COMP/EN
LSD
4kΩ GND FB
IRF7821
2.5μH
IRF7821
3.3V
10kΩ
3.24kΩ
150μF x 2
MIC2169 Adjustable Output 500kHz Converter
100
95
90
85
80
75
70
65
60
55
50 0
MIC2169 Efficiency
VIN = 5V
VOUT = 3.3V
2 4 6 8 10 12 14 16
ILOAD (A)
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
Ordering Information
Part Number
Pb-Free Part Number
MIC2169BMM
MIC2169YMM
Frequency
500kHz
Micrel
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
3
4
5
6
7
8
9
10
Pin Name
VIN
VDD
CS
COMP
FB
GND
LSD
VSW
HSD
BST
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 (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 VIN is between 3.0V to 5V, 2.5V threshold 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.
M9999-032409 2 March 2009
|
MIC2169
Absolute Maximum Ratings(1)
Supply Voltage (VIN)................................................... 15.5V
Booststrapped Voltage (VBST) .................................VIN +5V
Junction Temperature (TJ) ..................–40°C ≤ TJ ≤ +125°C
Storage Temperature (TS) ........................ –65°C to +150°C
Micrel
Operating Ratings(2)
Supply Voltage (VIN)..................................... +3V to +14.5V
Output Voltage Range .......................... 0.8V to VIN × DMAX
Package Thermal Resistance
θJA 10-lead MSOP ............................................. 180°C/W
Electrical Characteristics(3)
TJ = 25°C, VIN = 5V; bold values indicate –40°C < TJ < +125°C; unless otherwise specified.
Parameter
Condition
Min Typ Max Units
Feedback Voltage Reference
(± 1%)
0.792 0.8 0.808 V
Feedback Voltage Reference
(± 2% over temp)
0.784 0.8 0.816 V
Feedback Bias Current
30 100 nA
Output Voltage Line Regulation
0.03 % / V
Output Voltage Load Regulation
Output Voltage Total Regulation
Oscillator Section
3V ≤ VIN ≤ 14.5V; 1A ≤ IOUT ≤ 10A; (VOUT = 2.5V)(4)
0.5 %
0.6 %
Oscillator Frequency
450 500 550 kHz
Maximum Duty Cycle
Minimum On-Time(4)
92 %
30 60 ns
Input and VDD Supply
PWM Mode Supply Current
Digital Supply Voltage (VDD)
Error Amplifier
VCS = VIN –0.25V; VFB = 0.7V (output switching but excluding
external MOSFET gate current.)
1.5 3 mA
VIN ≥ 6V
4.7 5 5.3 V
DC Gain
70 dB
Transconductance
1 ms
Soft-Start
Soft-Start Current
After timeout of internal timer. See “Soft-Start” section.
8.5 μA
Current Sense
CS Over Current Trip Point
Temperature Coefficient
ppm/°C
VCS = VIN –0.25V
160 200 240
+1800
μA
Output Fault Correction Thresholds
Upper Threshold, VFB_OVT
Lower Threshold, VFB_UVT
(relative to VFB)
(relative to VFB)
+3 %
–3 %
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, TJ(max),
the junction-to-ambient thermal resistance, θJA, and the ambient temperature, TA. 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.
March 2009 3 M9999-032409
|
| @ 2014 :: Datasheetspdf.com :: Semiconductors datasheet search & download site (Privacy Policy & Contact) |