MIC2185_05 Datasheet, PDF (1/15 Pages) Micrel Semiconductor – Low Voltage Synchronous Boost PWM Control IC

MIC2185
MIC2185
Micrel, Inc.
Low Voltage Synchronous Boost PWM Control IC
General Description
Micrel’s MIC2185 is a high efficiency synchronous boost
PWM control IC. With its wide input voltage range of 2.9V to
14V, the MIC2185 can be used to efficiently boost voltages
in 1- or 2-cell Li Ion battery powered applications, as well as
fixed 3.3V and 5V systems. Its powerful 5Ω output drivers
allow the MIC2185 to supply large output currents with the
selection of the proper external MOSFETs.
With it’s fixed frequency PWM architecture, and easily
synchronized drive, the MIC2185 is ideal for noise-sensi-
tive telecommunications applications. The nominal 400kHz
operating frequency of the MIC2185 can be divided by two,
allowing the device to be externally synchronized to frequen-
cies below 400kHz.
The MIC2185 also features a low current shutdown mode
and a programmable undervoltage lockout. A skipped pulse
mode of operation can be manually set to achieve higher
efficiencies at light load conditions.
The MIC2185 is available in a 16 pin SOIC package and 16
pin QSOP package with an ambient temperature operating
range from –40°C to 85°C.
Features
• Input voltage range: 2.9V to 14V
• 95% efficiency
• Oscillator frequency of 200kHz/400kHz
• Frequency sync to 600kHz
• 0.5µA shutdown current
• Two 5Ω output drivers
• Front edge blanking
• PWM current mode control
• Cycle-by-cycle current limiting
• Frequency foldback protection
• Adjustable under-voltage lockout
• Precision 1.245V reference output
• 16 pin SOIC narrow body package
Applications
• 3.3V to 5V conversion in telecom systems
• Satellite phones
• Cable modems
• 1-and 2-cell Li Ion battery operated equipment
Ordering Information
Part Number
Standard
Pb-Free
MIC2185BM MIC2185YM
MIC2185BQS MIC2185YQS
Frequency
200/400kHz
200/400kHz
Voltage
Adj
Adj
Junction
Temp. Range
–40ºC to +125ºC
–40ºC to +125ºC
Package
16-pin SOIC
16-pin QSOP
Typical Application
V_IN = 3.3V
2.4µH
C_IN
1 _VINA
OUTP ¹⁴
7 _EN/UVLO
VINP ¹⁶
15 _FREQ/2
FB ⁶
10 _VDD
4 _COMP
MIC2185
OUTN ¹³
8 _VREF
11 _SYNC
CSH ⁹
2 _SKIP
SS
3
PGND ¹²
SGND
5
Si9803DY (x2)
Si4884DY (x2)
8m
V_OUT = 5V
C_OUT
5V Output Efficiency
100
95
90
85
80
75
V_IN = 3.3V
200kHz P WM
700
1
2
3
4
5
OUTPUT CURRENT (A)
Adjustable Output Synchronous Boost Converter
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
October 2005
1
MIC2185