AP1601
Step-Up DC/DC Converter
Features
-A Guaranteed Start-Up from less than 0.9 V.
-High Efficiency.
-Low Quiescent Current.
-Less Number of External Components needed.
-Low Ripple and Low Noise.
-Space Saving Packages: MSOP-8L and
MSOP-10L.
General Description
The AP1601 is a high efficiency step-up DC/DC
converter for applications using 1 to 4 NiMH battery
cells. Only three external components are required
to deliver a fixed output voltage of 3.3V or 5V. The
AP1601 starts up from less than 0.9V input with
1mA load. Pulse Frequency Modulation scheme
brings optimized performance for applications with
light output loading and low input voltages. The
output ripple and noise are lower compared with the
circuits operating in PSM mode.
The PFM control circuit operating in 100KHz (max.)
switching rate results in smaller passive
components. The space saving MSOP packages
make the AP1601 an ideal choice of DC/DC
converter for space conscious applications, like
pagers, electronic cameras, and wireless
microphones.
Applications
-Pagers.
-Cameras.
-Wireless Microphones.
-Pocket Organizers.
-Battery Backup Suppliers.
-Portable Instruments.
Pin Assignments
Pin Descriptions
Name
Description
Use a resistor network to set the output
voltage from +2.0V to +5.5V.
If FB=Vout, Vout=3.3V fix voltage
FB=GND, Vout=5V fix voltage
Low-Battery Comparator Input. Internally set
to trip at +1.30V.
Open-Drain Low-Battery Comparator Output.
Connect
LBO
to OUT through a 100kΩ
resistor. Output is low when V
LBI
is <1.2V.
LBO
is high impedance during shutdown.
1.2V Reference Voltage. Bypass with a 0.1µF
capacitor.
Power Output. OUT provides bootstrap power
to the IC.
N-Channel and P-Channel Power MOSFET
Drain
Ground
Shutdown Input. Drive high (>80% of V
OUT
) for
operating mode. Drive low (<20% of V
OUT
) for
shutdown mode. Connect to OUT for normal
operation.
Current-Limit Select Input. CLSEL = OUT sets
the current limit to 0.8A. CLSEL = GND sets
the current limit to 0.4A.
Battery
Input
and
Damping
Switch
Connection. If damping switch is unused,
leave BATT unconnected.
FB
LBI
LBO
REF
1
2
3
4
MSOP-8L
8
7
6
5
OUT
LX
GND
SHDN
FB
LBI
LBO
FB
LBI
LBO
CLSEL
REF
1
2
3
4
5
10
9
8
7
6
OUT
LX
GND
BATT
SHDN
REF
OUT
LX
GND
SHDN
MSOP-10L
CLSEL
BATT
This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of
this product. No rights under any patent accompany the sale of the product.
Rev. 1.1 Apr. 14, 2005
1/9
ANACHIP [ ANACHIP CORP ]
