AP1605
PWM/PFM Dual-mode Step-Down Switching Regulator
Features
- Low current consumption:
In operation: 100µA max.
Power off: 2µA max.
- Input voltage: 2.5V to 7V.
Adjustable version (+2.5%)
- PWM/PFM dual Mode
- Oscillation frequency: 300KHz (Typ.)
- With a power-off function.
- Built-in internal SW P-channel MOS
- SOP-8L/TSSOP-8L Package.
General Description
AP1605 consists of CMOS step-down switching
regulator with PWM/PFM dual mode control. These
devices include a reference voltage source, oscillation
circuit, error amplifier, internal PMOS and etc.
AP1605 provides low-ripple power, high efficiency,
and
excellent
transient
characteristics.
The
PWM/PFM control circuit is able to very the duty ratio
linearly 0%~0.25% (PFM) and 25%~100% (PWM).
With the addition of an internal P-channel Power MOS,
a coil, capacitors, and a diode connected externally,
these ICs can function as step-down switching
regulators. They serve as ideal power supply units for
portable devices when coupled with the SOP–8L
mini-package, providing such outstanding features as
low current consumption. Since this converter can
accommodate an input voltage of up to 7V, it is also
ideal when operating via an AC adapter.
Applications
- On-board power supplies of battery devices for
portable telephones, electronic notebooks, PDA,
and other hand-held sets.
- Power supplies for audio equipment, including
portable CD players and headphone stereo
equipment.
- Fixed voltage power supply for cameras, video
equipment and communications equipment.
- Power supplies for microcomputers.
- Conversion from four Ni-H or Ni-Cd cells or two
lithium-ion cells to 3.3V/3V.
- Conversion of AC adapter input to 5V/3V.
Pin Assignments
FB
CE
1
2
AP1605
6 SW
5 SW
8 Vss
7 Vss
Pin Descriptions
Pin
Pin No.
Name SOP TSSOP
FB
CE
1
2
4
2、3
Description
Feedback pin
Chip Enable:
H: Enable
L: Disable
IC signal power supply pin,
add a 10Ω resistor to PVcc
and a 0.1µF capacitor to
GND.
IC power supply pin
Switch Pin. Connect external
inductor/diode here.
Minimize trace area at this
pin to reduce EMI.
GND Pin
Vcc 3
PVcc 4
Vcc
PVcc
3
4
5、6
7、8
5
6、7
8
1
SOP-8L
Vss
CE
CE
FB
1
2
3
4
AP1605
8
7
6
5
SW
PVcc
PVcc
Vcc
SW
Vss
TSSOP-8L
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 Jan 18, 2005
1/6
AP1605
PWM/PFM Dual-mode Step-Down Switching Regulator
Electrical Characteristics
(V
IN
= 5V, T
a
=25
°C
, unless otherwise specified)
Symbol
Parameter
Conditions
V
IN
Input Voltage
AP1605 Series
V
REF
Internal Reference Voltage
Voltage required to maintain
V
UVLO
UVLO Voltage
V
OUT
MAXDTY Maximum Duty Ratio
PFMDTY PFM Duty Ratio
SOP-8L
I
SW
Switch Current
Duty = 50%
TSSOP-8L
Current Consumption
I
SS
V
OUT
=2.5V
POWER
ON
Current Consumption
V
ON/OFF
=0V
I
SSS
During Power Off
∆V
OUT1
Line Regulation
2.5V~7V @ I
OUT
=0.1A
0.1A~3A(SOP-8L),
∆V
OUT2
Load Regulation
0.1A~1.5A(TSSOP-8L)
F
OSC
Oscillation Frequency
V
CEH
CE Pin “High” Voltage
Evaluate oscillation at SW pin
Evaluate oscillation stop at SW
V
CEL
CE Pin “Low” Voltage
pin
I
SH
--
Power-Off Pin Input
Leakage Current
I
SL
--
EFFI Efficiency
V
IN
= 5V, V
OUT
= 2.5V I
OUT
= 1A
Min.
2.5
1.1625
--
100
15
3
1.5
--
--
--
--
220
0.65
--
-0.1
-0.1
--
Typ.
--
1.2
--
--
25
--
--
35
--
0.2
1
300
--
--
--
--
93
Max. Unit
7
V
1.2375
V
2.2
--
35
--
--
100
2
0.5
1.5
380
--
0.2
0.1
0.1
--
V
%
%
A
µA
µA
%
%
KHz
*Vcc
µA
µA
%
Typical Application Circuit
（1）
Normal Application
OUT
PV
CC
SW
C
C
R
VCC
FB
V
CC
C
VCC
R
CE
100K
CE
V
SS
R
A
AP1605
D1
+
R
B
=~200K
-
C
CE
0.1uF
Vo
=
Vref
×
(1
+
R
A
R
B
)
Anachip Corp.
www.anachip.com.tw
3/6
Rev. 1.1 Jan 18, 2005
AP1605
PWM/PFM Dual-mode Step-Down Switching Regulator
Typical Application Circuit (Continued)
（2）
Application with Short Circuit Protection
V
OUT :
1.8V
PV
CC
D
VCC
1N4148 for above 5V Vin and
Schottky for below 5V Vin
V
IN :
2.5V~7V
SW
C
C
FB
R
A
AP 1605
V
CC
C
ON /OFF
0.2uF
R
ON /OFF
3.5M
R
Bias
10M
C
PVCC
C
VCC
100 uF 0.1uF
+
CE
V
SS
R
B
D1
=~10K
-
C
OUTPUT
100 uF
R
SENCE
1M
Vo
=
Vref
×
(1
+
R
A
R
B
)
Test Circuit
Vcc
PVcc
A
SW
FB
open
Oscillation
open
A
+
Vcc
PVcc
CE
SW
FB
CE
Vss
-
Vss
Vcc
+
-
SW
FB
+
V
PVcc
CE
Vss
-
Function Description
PWM/PFM Control (AP1605 Series)
The AP1605 consists of DC/DC converters that employ a PWM/PFM auto-switch system.
In converters of the AP1605, the PFM mode varies in a range of duty cycle from 0% to 25%, and the PWM
mode varies in a range of duty cycle from 25% to 100% according to the load current, and yet ripple voltage
produced by the switching can easily be removed through a filter because the switching frequency remains
constant. Therefore, these converters provide a low-ripple power over broad ranges of input voltage and load
current.
Anachip Corp.
www.anachip.com.tw
4/6
Rev. 1.1 Jan 18, 2005
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