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Datasheet
AS1334
650mA, Ultra low Ripple Step Down DC/DC Converter
1 General Description
The AS1334 is a step-down DC-DC converter designed to power
portable applications from a single Li-Ion battery. The device also
achieves high-performance in mobile phones and other applications
requiring low dropout voltage.
The AS1334 operates from an input voltage range of 2.7 to 5.5V
while providing output voltages of 1.2, 1.5, 1.8, 2.5, 3.0 and 3.3V.
Fixed-frequency PWM operation minimizes RF interference.
Shutdown function turns the device off and reduces battery
consumption to 0.01µA (typ).
2 Key Features
Output Voltage Ripple: 2mV
Single Lithium-Ion Cell Operation
The AS1334 is available in a TDFN(3x3) 8-pin package. A high
switching frequency (2 MHz) allows use of tiny surface-mount
components. Only three small external surface-mount components,
an inductor and two ceramic capacitors are required.
Figure 1. AS1334 - Typical Application Circuit
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Maximum Load Capability of 650mA
Current Overload Protection
Power-OK
Soft Start
97% High Efficiency, 94% Average Efficiency
Thermal Overload Protection
Low Dropout Voltage (140 mΩ Typ PFET)
TDFN(3x3) 8-pin
Output Voltage Range: 1.2V to 3.4V
(available in 100mV steps,
see Ordering Information on page 17)
Fixed Output Voltages:
- 1.2V, 1.5V, 1.8V, 2.5V, 3.0V, 3.3V
3 Applications
The AS1334 is an ideal solution to supply noise sensitive
applications as cellular phones, hand-held radios, RF PC cards,
battery powered RF devices, RFID chipsets, A/D Converter, Sensors
and OpAmps.
PVIN
SW
3.3 µH
V
OUT
10 µF
VDD
AS1334
FB
10 µF
EN
POK
ON
OFF
PGND
SGND
Revision 1.09
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PWM Switching Frequency: 2MHz
AS1334
Datasheet - P i n A s s i g n m e n t s
4 Pin Assignments
Figure 2. Pin Configuration
FB 1
POK 2
8 PGND
7 SW
4.1 Pin Descriptions
Table 1. Pin Descriptions
Pin Number
1
2
3
4
5, 9
6
7
Pin Name
FB
POK
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EN
VDD
SGND
PVIN
SW
8
PGND
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EN 3
6 PVIN
VDD 4
SGND 9
5 SGND
AS1334
Description
Feedback Pin.
Connect to the output at the output filter capacitor.
Power-OK.
0 = V
OUT
< 90% of V
OUTNOM
.
1 = V
OUT
> 90% of V
OUTNOM
.
Enable Input.
Set this digital input high for normal operation. For shutdown, set low.
+2.7V to +5.5V Power Supply Voltage.
Analog Supply Input.
Analog and Control Ground.
Connect these pins with low resistance to
PGND.
+2.7V to +5.5V Power Supply Voltage.
Input to the internal PFET switch.
Switch Pin.
Switch node connection to the internal PFET switch and NFET synchronous rectifier.
Connect to an inductor with a saturation current rating that exceeds the maximum switch peak
current limit specification of the AS1334.
Power Ground.
Connect this pin with low resistance to
SGND.
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AS1334
Datasheet - A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in
Table 2
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
Electrical Characteristics on page 4
is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
Table 2. Absolute Maximum Ratings
Parameter
Electrical Parameters
VDD, PVIN to SGND
PGND to SGND
POK, EN, FB
SW
PVIN to VDD
-0.3
-0.3
SGND - 0.3
PGND - 0.3
-0.3
2.7
+7.0
+0.3
VDD + 0.3
PVIN + 0.3
+0.3
5.5
650
V
V
V
V
V
7.0V max
Min
Max
Units
Notes
Input Voltage Range
Recommended Load Current
Ambient Temperature (T
A
) Range
Electrostatic Discharge
Human Body Model
Temperature Ranges and Storage Conditions
Junction Temperature (T
J-MAX
)
Storage Temperature Range
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Package Body Temperature
Humidity
Moisture Sensitive Level
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V
mA
-40
+85
ºC
2
kV
ºC
Norm: MIL 883 E method 3015
+150
-55
+150
ºC
+260
ºC
5
1
86
%
Non-condensing
Represents a max. floor life time of unlimited
Revision 1.09
In applications where high power dissipation and/
or poor package thermal resistance is present,
the maximum ambient temperature may have to
be derated.
Maximum ambient temperature (T
A-MAX
) is
dependent on the maximum operating junction
temperature (T
J-MAX-OP
= 125ºC), the maximum
power dissipation
of the device in the application (P
D-MAX
), and the
junction-to ambient thermal resistance of the
part/package in the application (θ
JA
), as given by
the following
equation: T
A-MAX
= T
J-MAX-OP
– (θ
JA
× P
D-MAX
).
The reflow peak soldering temperature (body
temperature) specified is in accordance with
IPC/
JEDEC J-STD-020“Moisture/Reflow Sensitivity
Classification for Non-Hermetic Solid State
Surface Mount Devices”.
The lead finish for Pb-free leaded packages is
matte tin (100% Sn).
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AS1334
Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
T
A
= T
J
= -40ºC to +85ºC; PV
IN
= VDD = EN = 3.6V, unless otherwise noted. Typical values are at T
A
=25°C.
Table 3. Electrical Characteristics
Symbol
T
A
Parameter
Operating Temperature Range
Conditions
Min
-40
1.176
1.47
V
OUT
Output Voltage
PV
IN
= 3.6V
1.764
2.45
2.94
3.234
1.2
1.5
1.8
2.5
3.0
3.3
Typ
Max
+85
1.224
1.53
2.55
3.06
1.836
Units
°C
V
V
V
V
V
I
SHDN
I
Q
R
DSON(P)
R
DSON(N)
I
LIM,PFET
POK Output
V
OL
Shutdown supply current
DC bias current into VDD
Pin-Pin Resistance for PFET
Pin-Pin Resistance for NFET
Switch peak current limit
POK Output Low Voltage
POK Threshold
POK Output High Leakage Current
Enable Input
V
IH,EN
V
IL,EN
I
PIN,ENABLE
Oscillator
F
OSC
Logic high input threshold
Logic low input threshold
Pin pull down current
1. Shutdown current includes leakage current of PFET.
2. I
Q
specified here is when the part is operating at 100% duty cycle.
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Internal oscillator frequency
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3.366
2
V
EN = SW = 0V
1
0.01
1
FB = 0V, No Switching
I
SW
= 200mA
2
I
SW
= 200mA; T
A
= +25°C
140
I
SW
= -200mA; T
A
= +25°C
I
SW
= -200mA
300
935
1100
0.05
90
POK sinking 0.1mA
POK = 3.6V
Falling edge, referenced to V
OUT(NOM)
87
1.2
5
1.8
2
Revision 1.09
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µA
1.4
mA
200
230
485
mΩ
mΩ
mA
V
415
1200
0.2
93
500
nA
%
V
0.5
10
V
µA
2.2
MHz
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