MIC2184 Datasheet, PDF (1/12 Pages) Micrel Semiconductor – Low Voltage Buck PWM Control IC Final Information

MIC2184
Micrel
MIC2184
Low Voltage Buck PWM Control IC
Final Information
General Description
Micrel’s MIC2184 is a high efficiency PWM buck control IC.
With its wide input voltage range of 2.9V to 14V, the MIC2184
can be used to efficiently step voltages down in 1- or 2-cell Li
Ion battery powered applications, as well as in fixed 3.3V, 5V,
or 12V systems.
Efficiencies over 90% are achievable over a wide range of
load conditions with the MIC2184’s PWM control scheme.
The operating frequency can be divided by two by raising the
FREQ/2 pin to V_DD. This allows the user to optimize efficiency
versus board space. It also allows the MIC2184 to be exter-
nally synchronized to frequencies below its nominal 400KHz.
The MIC2184 features an oscillator output, FreqOut, which
can be used to implement a simple charge pump in low
voltage applications. The output of the charge pump can be
fed into the gate drive power circuitry via the V_INP pin,
allowing enhanced gate drive, hence higher efficiencies,
despite low input voltages.
MIC2184 features a 1µA shutdown mode, and a program-
mable undervoltage lockout, making it well suited for portable
applications.
The MIC2184 is available in 16 pin SOP and QSOP package
options with a junction temperture range range from –40°C
to +125°C.
Features
• Input voltage range: 2.9V to 14V
• >90% efficiency
• Oscillator frequency of 400kHz
• Frequency divide-by-two pin
• Frequency sync to 600kHz
• FrequOut oscillator output allows simple charge pump
implementation in low voltage systems
• 1.245V reference output
• Front edge blanking
• 5Ω output driver
• Soft start
• PWM current mode control
• 1µA shutdown current
• Cycle-by-cycle current limiting
• Frequency foldback short circuit protection
• Adjustable under-voltage lockout
• 16 pin narrow-body SOIC and QSOP package options
Applications
• 3.3V to 2.5V/1.8V/1.5V conversion
• DC power distribution systems
• Wireless Modems
• ADSL line cards
• 1-and 2-cell Li Ion battery operated equipment
• Satellite Phones
Typical Application
V_IN = 3.3V
120µF (x2)
6.3V
1
VINA
16
VINP
7 _EN/UVLO
2
FreqOut
16
FREQ/2
10
VDD
MIC2184
4
COMP
3
SS
13 _VREF
SYNC SGND
11
5
9
CSH
CSL ⁸
14
OUTP
12
PGND
6
FB
15mΩ
Q3
Si9803DY(x2)
4.7µH
V_OUT
2.5V @5A
220µF(x2)
6.3V
100
95
90
85
80
75
70
65
60
55
500
MIC2184 EFFICIENCY
V_IN = 3.3V
V_OUT = 2.5V
f_S = 200kHz
12345
OUTPUT CURRENT (A)
Adjustable Output Buck Converter
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
December 10, 2001
1
MIC2184