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
•
•
•
•
•
•
•
•
•
•
•
•
•
•
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Applications
•
Audio headsets
•
Portable applications
Typical Application
Efficiency (V
IN
= 1.2V)
vs. Output Current
100
BOOST
V
OUT1
= 1.8V
90
EFFICIENCY (%)
80
BUCK
V
OUT2
= 1.0V
70
60
LED Pin = OPEN
L1 = IFSC1515AHER6R8M01M
L2 = SPM4012T-4R7M
50
40
0.001
0.01
0.1
0.2
OUTPUT CURRENT (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
May 27, 2014
Revision 1.2
Micrel, Inc.
MIC23099
Ordering Information
Part Number
MIC23099YFT
Notes:
1. Pin 1 identifier = “▲”.
2. Thin QFN is a Green RoHs-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Output
Voltages
Adjustable
Marking
23099
(1)
Junction
Temperature Range
–40°C to +125°C
Package
(2)
Lead
Finish
Pb-Free
14-Pin 2.5mm × 2.5mm × 0.55mm Thin QFN
Pin Configuration
14-Pin 2.5mm × 2.5mm QFN (YFT)
(Top View)
Pin Description
Pin
Number
1
Pin Name
PGND1
Pin Function
Power Ground 1: The power ground for the synchronous boost DC/DC converter power stage.
Battery Voltage Supply (Input): The internal circuitry operates from the battery voltage during start up.
Once V
OUT1
exceeds V
IN
, the bias current comes from V
OUT1
. The start-up sequence is initiated once the
battery voltage is above 0.9V. The boost output (V
OUT1
) is power-up first, then the buck output (V
OUT2
)
follows. If the battery voltage falls below 0.85V for more than 15 cool-off cycles, both outputs are
simultaneously turned off and an internal resistor discharges the output capacitors to 0V.
Feedback 1 (Input): Connect a resistor divider network to this pin to set the output voltage for the
synchronous boost regulator. Resistors should be selected based on a nominal V
FB1
= 0.6V.
No Connect Pin (NC): Leave open, do not connect to ground.
Power Good (Output): This is an open drain, active high output. When V
IN
, V
FB1
or V
FB2
are below their
nominal voltages the Power Good output gets pulled low after a de-glitch period. The PG pin will be
pulled low without delay when the enable is set low.
Enable (input): A logic level control of both outputs. The EN pin is CMOS-compatible. Logic high =
enable, logic low = shutdown. In the off state, supply current of the device is greatly reduced (typically
1µA). When the EN pin goes high, the start-up sequence is initiated. The boost output (V
OUT1
) is
powered up first then the buck output (V
OUT2
) follows. When EN goes low, both outputs are immediately
turned off and the boost output (V
OUT1
) is completely disconnected from the input voltage. Then both
converters output capacitors are discharged to ground through an internal pull down circuit. The EN pin
has a 4MΩ resistance to AGND.
2
VIN
3
4
5
FB1
NC
PG
6
EN
May 27, 2014
2
Revision 1.2
Micrel, Inc.
MIC23099
Pin Description (Continued)
Pin
Number
7
8
9
10
11
Pin Name
Pin Function
LED (Output): This is an open drain output that is used for a low battery indicator. Under normal
conditions, the LED is always ON. If the battery voltage is between 1.2V to 0.85V, the external LED will
blink with a duty cycle of 25% at 0.25Hz. The LED will be OFF if the battery voltage falls below 0.85V for
more than 15 cool-off cycles or the EN pin is low.
Analog Ground: The analog ground for both regulator control loops.
Feedback 2 (Input): Connect a resistor divider network to this pin to set the output voltage for the
synchronous buck regulator. Resistors should be selected based on a nominal V
FB2
= 0.6V.
Output Voltage 2 (Input): If the EN is low or the power good output is pulled low, an internal resistor
discharges V
OUT2
output capacitance to 0V. Also, if the inductor current falls to zero an internal anti-
ringing switch is connected between the SW2 and OUT2 pins to minimize the switch node ringing.
Power Ground 2: The power ground for the synchronous buck DC/DC converter power stage.
Switch Pin 2 (Input): Inductor connection for the synchronous step-down regulator. Connect the inductor
between V
OUT2
and the SW2 pin. Due to the high-speed switching on this pin, the SW2 pin should be
routed away from sensitive nodes and trace length should be kept as short and wide as possible to
reduce EMI. If the inductor current falls to zero or EN is low, then an internal anti-ringing switch is
connected between the SW2 and VOUT2 pins to minimize the switch node ringing.
Output 1 (Output): Output of the synchronous boost regulator and is the bias supply once V
OUT1
is
greater than V
IN
. The boost output also serves as the supply input for the buck converter (V
OUT2
). If the
EN is low or the power good output is pulled low, an internal resistor discharges V
OUT1
output
capacitance to 0V.
Switch Pin 1 (Input): Inductor connection for the synchronous boost regulator. Connect the inductor
between V
IN
and SW1. Due to the high-speed switching on this pin, the SW1 pin should be routed away
from sensitive nodes and trace length should be kept as short and wide as possible to reduce EMI. If the
inductor current falls to zero, an internal anti-ringing switch is connected between the SW1 and VIN pins
to minimize the switch node ringing.
Exposed Pad (Power): Must make a full connection to a GND plane.
LED
AGND
FB2
OUT2
PGND2
12
SW2
13
OUT1
14
SW1
EP
GND
May 27, 2014
3
Revision 1.2
Micrel, Inc.
MIC23099
Absolute Maximum Ratings
(3)
Supply Voltage (V
IN
) .....................................
−0.3V
to +6.0V
Switch Voltage (V
SW1
)...................................
−0.3V
to +6.0V
Switch Voltage (V
SW2
)...................................
−0.8V
to +6.0V
Enable Voltage (V
EN
) .........................................
−0.3V
to V
IN
Feedback Voltage (V
FB
) ...............................
−0.3V
to +6.0V
LED Output (V
LED
) ........................................
−0.3V
to +6.0V
Power Good (V
PG
) ........................................
−0.3V
to +6.0V
AGND to PGND1, PGND2 ...........................
−0.3V
to +0.3V
Ambient Storage Temperature (Ts) ..........
−65°C
to +150°C
(6)
ESD HBM Rating ......................................................... 2kV
ESD MM Rating............................................................ 200V
Operating Ratings
(4)
Input Voltage after Start-Up (V
IN
) ............. +0.875V to +1.6V
Enable Voltage (V
EN
) .............................................. 0V to V
IN
LED Output (V
LED
) .............................................. 0V to V
OUT1
Output Voltage Range (V
OUT1
) ..................... +1.8V to +3.3V
Output Voltage Range (V
OUT2
) ...................... +1.0V to V
OUT1
(5)
Junction Temperature (T
J
) ..................... –40°C to +125°C
Junction Thermal Resistance
2.5mm × 2.5mm Thin QFN-14 (θ
JA
) ................. +70°C/W
2.5mm × 2.5mm Thin QFN-14 (θ
JC
) ................ +25°C/W
Electrical Characteristics
(7)
V
IN
= V
EN
= +1.25V; V
OUT1
= +1.8V; V
OUT2
= 1.0V; L
OUT1
= 6.8µH; L
OUT2
= 4.7µH; C
OUT1
= 47µF; C
OUT2
= 10µF
T
A
= 25°C, unless otherwise noted.
Bold
values indicate –40°C ≤ T
J
≤ +125°C.
Parameter
Input Supply (VIN)
Minimum Start Up Voltage
Quiescent Current - PFM Mode
Quiescent Current - PFM Mode
Shutdown Current
Enable Input (EN)
EN Logic Level High to Start Up
EN Logic Level Low
EN Bias Current
EN Pull-Down Resistance
Solution Efficiency
System Efficiency
System Efficiency
Notes:
3. Absolute maximum ratings indicate limits beyond which damage to the component may occur.
4. The device is not guaranteed to function outside its operating ratings.
5. 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.
6. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF.
7. Specification for packaged product only.
8. Guaranteed by design.
Test Conditions
V
IN
Rising; R
LOAD
≥ 500Ω, I
OUT2
= 0mA
I
OUT1
, I
OUT2
= 0mA (Switching, Closed Loop)
Measured at V
IN
with LED pin open
I
OUT1
, = 2mA; I
OUT2
= 10mA
(Switching, Closed Loop) Measured at V
IN
V
EN
= 0V; V
IN
= 1.6V
Measured at V
IN
Min.
Typ.
Max.
Units
0.75
200
12.6
0.02
0.9
270
V
μA
mA
2
μA
V
EN
Rising, Regulator Enabled
V
EN
Falling, Regulator Shutdown
V
EN
= 0V (Regulator Shutdown)
I
EN
= 0.5µA into Pin
0.8
0.58
0.5
0.3
0.2
1
5.0
V
V
µA
MΩ
3.0
4.0
V
IN
= 1.25V; V
OUT1
= 1.8V; V
OUT2
= 1.0V
P
OUT1
= 8mW; P
OUT2
= 20mW
V
IN
= 1.25V; V
OUT1
= 1.8V; V
OUT2
= 1.0V
P
OUT1
= 80mW; P
OUT2
= 20mW
88
92
%
%
May 27, 2014
4
Revision 1.2
Micrel, Inc.
MIC23099
Electrical Characteristics
(7)
(Continued)
V
IN
= V
EN
= +1.25V; V
OUT1
= +1.8V; V
OUT2
= 1.0V; L
OUT1
= 6.8µH; L
OUT2
= 4.7µH; C
OUT1
= 47µF; C
OUT2
= 10µF;
T
A
= 25°C, unless otherwise noted.
Bold
values indicate –40°C ≤ T
J
≤ +125°C.
Parameter
Test Conditions
Fault Conditions
V
IN
and V
OUT1, 2
Fault Conditions
V
IN
Turn Off Threshold Voltage
PG Deglitch Delay, V
IN
Fault
PG Deglitch Delay, V
OUT1, 2
Fault
Cool OFF Delay Time
Hiccup Cycles before Latch OFF
OUT1 Active Discharge Resistance
OUT2 Active Discharge Resistance
Power Good Output (PG)
PG Threshold Voltage
PG Threshold Voltage
PG Output Low Voltage
PG Leakage Current
PG Turn-On Delay
LED Low-Battery Indicator Output (LED)
Low-Battery Threshold
Low-Battery Hysteresis
LED Flash Frequency
LED Flash Duty Cycle
LED Output Leakage Current
LED Switch On-Resistance
Thermal Protection
Thermal Shutdown
Thermal Hysteresis
T
J
Rising
Temperature Decreasing
150
20
°C
°C
V
IN
Falling
V
IN
Rising
V
IN
= 1.15V; V
EN
= 1.15V
V
IN
= 1.15V; V
EN
= 1.15V
V
LED
= 4.0V; V
EN
= 0V
V
IN
= V
EN
= 1.25V; I
LED
= 1.0mA
0.125
22.5
0.25
25
0.01
1.15
1.2
1.25
31
0.5
27.5
1
25
V
mV
Hz
%
μA
Ω
V
REF1
Rising or Falling
V
REF2
Rising or Falling
I
PG
= 1mA (sinking), V
EN
= 0V
V
PG
= 1.8V; V
EN
= 1.8V
−1
10
90
90
92.5
92.5
0.1
0.01
95
95
0.5
1
50
%V
REF1
%V
REF2
V
μA
ms
V
IN
Falling; after Start Up
V
IN
Falling below 0.85V to V
PG
= LOW
V
OUT1
or V
OUT2
falling below 90% of target
value to V
PG
= LOW
V
PG
= Low to V
OUT1
Enabled
C
OUT1
= 47µF; C
OUT2
= 10µF
Counts Cool OFF cycles
V
EN
= 0V
V
EN
= 0V
0.825
120
60
750
1300
15
500
500
700
700
0.85
0.875
180
120
2250
V
ms
ms
ms
Cycles
Ω
Ω
Min.
Typ.
Max.
Units
May 27, 2014
5
Revision 1.2
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