AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
1
Features
• 0.8V Low Start-Up Input Voltage
• Up to 90%Efficiency
• Adjustable 100mA Output with 1 Alkaline Cell
or 200mA Output with 2 Alkaline Cell
Battery input.
• 1.8V/3.0V/3.3V/300mA Output with USB
Power input.
• Small Number of External Components needed
• Load Disconnects from Input in Shutdown
• Power good output
• 32µA Quiescent(Switch OFF) Supply current
• 1µA Shutdown Mode Supply current
• 8-Pin TSSOP package
Applications
• MP3
• Power source for battery-powered equipment
• Power source for cameras, camcorders, VCRs,
PDAs, electronic data banks, and hand-held
Communication equipment
General Description
The AT1305 is a PFM step-up DC/DC converter
with LDO for applications using 1 Cell or 2 Cell
Alkaline battery and USB applications. Besides,
the 32µA low quiescent current together with high
efficiency maintains long battery life time. It
p
rovides a constant output voltage for inputs that
vary above and below the output voltage.
Block Dia
g
ram
Aimtron reserves the right without notice to change this circuitry and specifications.
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
2
Pin Configuration
Ordering Information
Part number Package Remarks
AT1305 8-pin Plastic TSSOP Date Code
AT1305_GRE 8-pin Plastic TSSOP, Green ,Date Code with one bottom line
AT1305 A 8-pin Plastic TSSOP Date Code
AT1305 A_GRE 8-pin Plastic TSSOP, Green ,Date Code with one bottom line
AT1305 B 8-pin Plastic TSSOP Date Code
AT1305 B_GRE 8-pin Plastic TSSOP, Green ,Date Code with one bottom line
AT1305:LDO set to 3.3V AT1305AP:LDO set to 3.0V AT1305BP:LDO set to 1.8V
*For more marking information, contact our sales representative directly
Pin Description
Pin No. Symbol I/O Description
1 LX O Switching Output
2 EN I Enable Control Input, active high
3 /ENPB I Enable Control Input, active low
4 GND - Ground
5 PG O Power Good Detected
6 FB I Step-Up Converter feedback input
7 OUT O Output
8 VDD - Power input
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
3
Absolute Maximum Ratings*1
(Ta=+250C)
Rated Value Parameter
Symbol
Condition
Min. Max.
Unit
Power supply voltage VDD — — 6.0 V
LX pin voltage VLX
— — 6.0 V
OUT output voltage VOUT — — 6.0 V
Other I/O pin voltage — — 6.0 V
LX pin output current ILX
— — 2 A
LDO output Peak Current ILDO — — 400 mA
Allowable dissipation PD TSSOP8 — 500 mW
Operating temperature TOP — -30 +85
0C
Storage temperature Tstg — -55 +165
0C
1. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. These are stress ratings only, and functional operation of the device at these or any other
conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure
to absolute maximum rating conditions for extended periods may affect device reliability.
Electrical Characteristics
(VIN=1.0V, VOUT =2.8V, IOUT=0mA ,Ta=+250C)
Values
Parameter Symbol Condition
Min. Typ. Max.
Unit
Start-Up Voltage VST I
OUT=1mA 0.7 0.8 - V
Power On Reset
Threshold VDD - 2 - V
AT1305,AT1305A 2.0 - 5.5 V
Operating V DD
Range VDD
AT1305B 1.65 5.5 V
No-Load Input
Current IIN1 IOUT=0mA - 87 -
μA
Switch- Off Input
Current IIN2 VIN=5V - 32 50
μA
Shutdown Current IIN3 EN=0V, /ENPB=High - 1 10 μA
Feedback Reference VFB Close Loop VDD =2.85V 1.176 1.2 1.224 V
FB Input Current IFB V
FB =1.2V - - 50 nA
LX Switch On-time FS VOUT =2.85V - 1.75 - μS
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
4
Maximum Duty DMAX VOUT =2.85V - 85 - %
LX ON Resistance RLX N-Channel - 0.3 - Ω
LX Leakage Current IL VLX =1.5V,
EN=0V,/ENPB=VDD - 1
μA
Current Limit Setting ILX V
DD =2.85V - 1.5 2 A
LDO Current Limit ILDO V
DD =3.2V - 350 - mA
OUT ON Resistance ROUT V
DD =2.85V, IOUT=100mA - 0.5 -
Ω
LDO enable threshold VDD1 OUT regulated to
1.8/3.0/3.3V - 4.0 - V
LDO Line Regulation Vin=4.5V~5.5V,
IOUT=100mA - 1 - %
LDO Load Regulation Vout=3.3V, IOUT=10~100mA - 1 - %
AT1305,AT1305A, VDD
falling - 2.7 - V
PG Threshold VDD2
AT1305B, VDD falling - 1.65 - V
PG sink current IPG I
PG=1mA - 0.4 - V
PG Leakage current ILPG V
DD =3V - - 1 μA
VIH 0.8 - - V
EN,/ENPB Trip Level
VIL - - 0.5 V
Note 1 : Once the output is in regulation , the AT1305/A/B operate down to a 0.7V input voltage.
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
5
Typical Operating Charateristics
Boost Converter Line Transient Response Boost Converter Line Transient Response
Boost Converter Load Transient Response Boost Converter Load Transient Response
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
6
LDO Line Transient Response LDO Load Transient Response
Boost Converter Start-up After Enable
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
7
Typical Application Circuit
1Cell And USB Power Input
1Cell or USB Power Input
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
8
Typical Operating Charateristics
1Cell and USB Power Input
Vin(V)
0
85
1.0 1.1 1.3 1.4
Efficiency (Load at LDO output)
80
75
70
90
L=33uH
VDD=2.91V
Iout=100mA
1.2
0.9 1.5
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
9
2Cell And USB Power Input
Vin(V)
0
90
2.2 2.6 2.8 3.0
Efficiency (Load at LDO output)
85
80
75
95
L=33uH
VDD=3.3V
Iout=100mA
2.4
2.0
1.8
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
10
Function Description
Boost Converter
The AT1305 integrates a step-up, switch-mode DC/DC converter with a linear
regulator to provide step up/down voltage conversion. A pulse frequency modulation
(PFM) with a constant on time 4.5us and minimum off-time 1.4µs controls the
N-channel MOSFET. The linear regulator contains a P-channel MOSFET. In 1-cell or
2-cell battery input (When VBAT <VOUT), only the step-up regulator is active, and
the linear regulator behaves as a pass gate. The output voltage can be adjusted with
two external resistors. The formula show as follow equation.
The maximum efficiency could be 89% over 50mA load range. The AT1305
guarantee starts up as low as 1.0V input.
LDO mode
The low-dropout linear regulator consists of a reference, an error amplifier and a
P-channel MOSFET. In USB mode, when VIN>4V, the linear regulator is active
automatically whether the EN and /ENPB is enabled or not. The output voltage is
default 3.3V, 3.0V and 1.8V version. Its driving capability is nearly 250mA.
)
2
1
1(2.1
2
1
1
R
R
R
R
VVDD FB
+×=
+=
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
11
Power good
The PG pin stays high impedance when the dc/dc converter or the LDO output
voltage high than 2.7 V, and falling down when the voltage low than 2.6V. It could be
used to enable the processor after the push-button start-up.
On/Off Control
A single pushbutton switch can be used to turn the AT1305 on and off. EN is pulled
low (internal) and /ENPB is pulled high when the AT1305 is off. When the switch is
pressed, /ENPB is pulled low and the IC turns on. The switch should be on long
enough for the processor to exit reset. The controller issues a logic high to EN, which
guarantees the IC will stay on regardless of the switch state.
EN /ENPB AT1305
0 0 ON
0 1 OFF
1 0 ON
1 1 ON
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
12
Package Outline : 8-pin TSSOP
INCHES MILLIMETERS
SYMBOL MIN MAX MIN MAX
NOTES
A 0.114 0.122 2.90 3.10 -
B 0.169 0.177 4.30 4.50 -
C 0.244 0.260 6.20 6.60 -
D 0.026 BSC 0.65 BSC -
E 0.010 0.012 0.25 0.30 -
F 0.002 0.006 0.05 0.15 -
H 0.041 0.047 1.05 1.20 -
K 0.005 BSC 0.127 BSC -
M 0.020 0.028 0.50 0.70
α 00 80 00 80 -
AT1305
Preliminary Product Information
PFM Step-Up DC/DC Converter with LDO
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw
2/8/2006 REV:1.1 Email: service@aimtron.com.tw
13
Reflow Profiles
Sn-Pb Eutectic Assembly Pb-Free Assembly Profile Feature
Large Body
Pkg. thickness
≥2.5mm or Pkg.
volume ≥350mm3
Small Body
Pkg. thickness
<2.5mm or Pkg.
volume <350mm3
Large Body
Pkg. thickness
≥2.5mm or Pkg.
volume ≥350mm3
Small Body
Pkg. thickness
≥2.5mm or Pkg.
volume ≥350mm3
Average ramp-up rate
(TL to TP)
3°C/second max. 3°C/second max.
Preheat
-Temperature Min(Tsmin)
-Temperature Max (Tsmax)
-Time (min to max)(ts)
100°C
150°C
60-120 seconds
150°C
200°C
60-180 seconds
Tsm ax t o TL
-Ramp-up Rate
3°C/second max.
Time maintained above:
-Temperature (TL)
-Time (tL)
183°C
60-150 seconds
217°C
60-150 seconds
Peak Temperature(TP) 225+0/-5°C 240+0/-5°C 245+0/-5°C 250+0/-5°C
Time within 5°C of actual Peak
Temperature (tP)
10-30 seconds 10-30 seconds 10-30 seconds 20-40 seconds
Ramp-down Rate 6°C/second max. 3°C/second max.
Time 25°C to Peak
Temperature
6 minutes max. 8 minutes max.
*All temperatures refer to topside of the package, measured on the package body surface.
