MIC23099 Datasheet, PDF (1/26 Pages) Micrel Semiconductor – Single AA/AAA Cell Step-Up/Step-Down Regulators

MIC23099
Single AA/AAA Cell Step-Up/Step-Down
Regulators with Battery Monitoring
General Description
The MIC23099 is a high-efficiency, low-noise, dual-output,
integrated power-management solution for single-cell
alkaline or NiMH battery applications. The synchronous
boost output voltage (V_OUT1) is enabled first and is
powered from the battery. Next the synchronous buck
output (V_OUT2), which is powered from the boost output
voltage, is enabled. This configuration allows V_OUT2 to be
independent of battery voltage, thereby allowing the buck
output voltage to be higher or lower than the battery
voltage.
To minimize switching artifacts in the audio band, both the
converters are design to operate with a minimum switching
frequency of 80kHz for the buck and 100kHz for the boost.
The high current boost has a maximum switching
frequency of 1MHz, minimizing the solution footprint.
The MIC23099 incorporates both battery-management
functions and fault protection. The low-battery level is
indicated by an external LED connected to the LED pin. In
addition, a supervisory circuit monitors each output and
asserts a power-good (PG) signal when the sequencing is
done or de-asserted when a fault condition occurs.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
Features
• V_IN range from 0.85V to 1.6V
• V_OUT1 (step-up) adjustable from 1.8V to 3.3V
• V_OUT2 (step-down) adjustable from 1.0V to V_OUT2
• V_OUT1/400mW and V_OUT2/30mA from a single cell
• Minimizes switching noise in the audio band
• Step-up regulator with output disconnect in shutdown
• V_OUT1, above 90% efficiency for 5mA to 200mA
• Anti-ringing control circuit to minimize EMI
• Turn-on inrush current limiting and soft-start
• Automatic output discharge
• Low-battery indicator
• Power Good (PG) output
• Low output ripple < 10mV
• Short-circuit and thermal protection
• 14-pin 2.5mm × 2.5mm × 0.55mm thin QFN (TQFN)
package
• −40°C to +125°C junction temperature range
Applications
• Audio headsets
• Portable applications
Typical Application
Efficiency (V_IN = 1.2V)
vs. Output Current
100
BOOST
V_OUT1 = 1.8V
90
BUCK
80
V_OUT2 = 1.0V
70
60
50
40
0.001
LED Pin = OPEN
L1 = IFSC1515AHER6R8M01M
L2 = SPM4012T-4R7M
0.01
0.1 0.2
OUTPUT CURRENT (A)
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
May 27, 2014
Revision 1.2