Document
AX5505
MICROPOWER VFM SYNCHRONOUS STEP-UP DC/DC Converter
GENERAL DESCRIPTION The AX5505 is a high efficiency VFM synchronous Step-up DC/DC converter for small, low input voltage or battery powered systems with ultra-low quiescent supply current. The AX5505 accept a positive input voltage from start-up voltage to VOUT and convert it to a higher output voltage in the 2.1V to 5.0V range. The AX5505 combine ultra-low quiescent supply current and high efficiency to give maximum battery life. The high switching frequency and the internally limited peak inductor current permits the use of small, low cost inductors. Only three external components are needed an inductor a diode and an output capacitor. The AX5505 is suitable to be used in battery powered equipment where low noise, low ripple and ultra-low supply current are required. Operating shutdown function is outside controlling. If EN connects to GND, the IC was been shut down and then the supply current is lower to 1uA.The AX5505 is available in very small packages: SOT23-3L, SOT23-5L and SOT89-3L. Typical applications are pagers, cameras and video camera, cellular telephones, wireless telephones, palmtop computer, battery backup supplies, battery powered equipment. FEATURES Very Low Supply Current is 13uA (typ.) Maximum shutdown current <1uA Output voltage is available form 2.1V to 5.0V by 0.1V steps Output Voltage Accuracy ±2% No Schottky Diode Required Output Current up to 100mA Low ripple and low noise Very low start-up voltage at 0.8V Few external components Low profile: SOT23-3L, SOT23-5L and SOT89-3L Pb-Free
1/11
Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Oct.09 2011
AX5505
BLOCK DIAGRAM
VOUT
P-MOS
-
Bandgap Reference
LIMITER AMP . N-MOS
VFM CONTROL
ERROR AMP .
ON/OFF Control
+
EN (SOT23-5L Only)
PIN ASSIGNMENT The packages type: SOT23-3L, SOT23-5L and SOT89-3L; the pin assignment is given by:
Top View NC EN
5 4
SOT23-5L
1
2
3
LX
GND VOUT
Top View VOUT 3
SOT23-3L 2 LX
Name EN VOUT NC GND LX
1 GND
Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Oct.09 2011
- +
+
Anti-Reverse Comparator
LX
GND
Top View Tab is VOUT
SOT89-3L 1 2 3
GND VOUT LX
Description Chip Enable Pin (SOT23-5L Only) Output Voltage Pin No Connect Pin Ground Pin Switch input pin which connected to inductor.
2/11
AX5505
ORDER/MARKING INFORMATION Order Information
AX5505 X XX X
Package Type R: SOT23-3L B: SOT23-5L F: SOT89-3L VOUT Packing 21 : 2.1V Blank : Bag 22 : 2.2V A : Taping : : 50 : 5.0V
Top Marking (SOT23-3L/SOT23-5L)
L LY WX
ID code:internal WW:01~26 (A~Z) 27~52 (a~z) Year: A=2010 1=2011
Identification code
Top Marking (SOT89-3L) Part number 55 05 Y WX ID code: internal WW: 01~26 (A~Z) 27~52 (a~z) Year: A=2010 1=2011 Part Number Identification Code AX5505-3.6V WU AX5505-3.7V WV AX5505-3.8V WW AX5505-3.9V WX AX5505-4.0V WY AX5505-4.1V WZ AX5505-4.2V Wa AX5505-4.3V Wb AX5505-4.4V Wc AX5505-4.5V Wd AX5505-4.6V We AX5505-4.7V Wf AX5505-4.8V Wg AX5505-4.9V Wh AX5505-5.0V Wi
Part Number Identification Code AX5505-2.1V WD AX5505-2.2V WE AX5505-2.3V WF AX5505-2.4V WG AX5505-2.5V WH AX5505-2.6V WJ AX5505-2.7V WK AX5505-2.8V WL AX5505-2.9V WM AX5505-3.0V WN AX5505-3.1V WP AX5505-3.2V WQ AX5505-3.3V WR AX5505-3.4V WS AX5505-3.5V WT
3/11
Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Oct.09 2011
AX5505
ABSOLUTE MAXIMUM RATINGS (at TA = 25°C) Characteristics Symbol Rating VIN Pin Voltage VIN 5.5 LX Voltage VLX 5.5 OUT Pin Voltage VOUT 5.5 EN Pin Voltage VEN -0.3 to VOUT+0.3 Storage Temperature Range TSTG -40 to +150 Operating Junction Temperature Range TJ -20 to +100 Power Dissipation PD ( TJ-TA ) / θJA SOT23-3L 180 Thermal Resistance from Junction to case SOT23-5L θJC SOT89-3L 100 SOT23-3L 250 Thermal Resistance from Junction to ambient SOT23-5L θJA SOT89-3L 160
Note: θJA is measured with the PCB copper area of approximately 1 in2 (Multi-layer).
Unit V V V V °C °C mW °C/W °C/W
ELECTRICAL CHARACTERISTICS (VIN = VOUT × 0.6, IOUT=10mA, TA = 25°C, unless otherwise specified) Characteristics Symbol Conditions △VOUT Output Voltage Accuracy I =1mA Start-up Voltage VSTART-UP OUT VIN =rising from 0 to 2V I =1mA Hold-on Voltage VHOLD OUT VIN =falling from 2 to 0V Supply Current ISUPPLY No Load Quiescent Current IQ IOUT =0mA, VIN=VOUT + 0.5V Shutdown Current ISD VEN=0V (SOT23-5L Only) PMOS Switch ON ILX=100mA Resistance P-RDS(ON) NMOS Switch ON ILX=100mA Resistance N-RDS(ON) Maximum Oscillator Frequency FOSC Oscillator Duty On DON To be measure on SW pin VENH Driver ON Enable Input Threshold (SOT23-5L Only) VENL Driver OFF IENH VEN=VIN Enable Input Current (SOT23-5L Only) IENL VEN=0V VIN=1.5V, VOUT=2.2V, IOUT=10mA η Efficiency VIN=1.5V, VOUT=3.0V, IOUT=10mA
Min Typ Max Units -2 - +2 % 0.6 0.8 0.95 13 6 1 V V uA uA uA mΩ mΩ
- 1000 600 -
- 125 - KHz - 77 % 0.75 V - 0.2 - 0.1 uA 1 89 87 % %
4/11
Axelite Confide.