ACTIVE-SEMI ACT8311

ACT8309/8310/8311
Active-Semi
Rev PrA, 24-Jan-08
Advanced Product Information – All Information Subject to Change
1.5A, PWM Step-Down DC/DCs in TDFN
FEATURES
GENERAL DESCRIPTION
•
•
•
•
•
The patent-pending ACT8309/ACT8310/ACT8311
are current-mode, fixed-frequency PWM, synchronous step-down DC/DC converters that are capable
of delivering 1.5A with efficiency of up to 95%.
These devices operate with a fixed frequency of
1.35MHz, minimizing noise in sensitive equipment
as well as optimizing both efficiency and component
size and cost.
•
•
•
•
•
•
Multiple Patents Pending
Up to 95% High Efficiency
Up to 1.5A Guaranteed Output Current (ACT8311)
1.35MHz Constant Frequency Operation
Internal Synchronous Rectifier Eliminates
Schottky Diode
ACT8309: Up to 900mA
ACT8310: Up to 1.2A
ACT8311: Up to 1.5A
100% Duty Cycle Low-Dropout Operation
0.1µA Shutdown Current
Small TDFN33-8 Package
− RoHS-Compliant
These devices feature very low-resistance power
MOSFET and 100% duty cycle operation, making
them ideal choices for portable applications requiring a 3.0V or 3.3V rail to be generated from a Li+
battery.
The ACT8311 is capable of supplying up to 1.5A of
output current, while the ACT8309 and ACT8310
are capable of supplying up to 900mA and 1.2A,
respectively. All three devices have adjustable output voltages that are programmable down to 1.2V.
Contact Active-Semi for custom fixed output voltage
availability.
• Independent Enable/Disable Control
• Minimal External Components
APPLICATIONS
• Wireless Handhelds
• Portable Devices
• GPS/PND equipment
SYSTEM BLOCK DIAGRAM
2.7V to 5.0V
ON
OFF
Power-OK
Output
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IN
Active-Semi
SW
VOUT
Up to 1.5A
ACT8311
EN
FB
Pb-free
POK
GP
G
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Copyright © 2008 Active-Semi, Inc.
ACT8309/8310/8311
Active-Semi
Rev PrA, 24-Jan-08
ORDERING INFORMATION
PART
NUMBER
OUTPUT
CURRENT
OUTPUT
VOLTAGE
PACKAGE
PINS
TEMPERATURE
RANGE
ACT8309NHADJ-T
0.9A
Adjustable
TDFN33-8
8
-40°C to +85°C
ACT8309NHxyz-T
0.9A
1.2V, 1.5V, 1.8V,
2.5V, 3.0V, 3.3Vc
TDFN33-8
8
-40°C to +85°C
ACT8310NHADJ-T
1.2A
Adjustable
TDFN33-8
8
-40°C to +85°C
ACT8310NHxyz-T
1.2A
1.2V, 1.5V, 1.8V,
2.5V, 3.0V, 3.3Vc
TDFN33-8
8
-40°C to +85°C
ACT8311NHADJ-T
1.5A
Adjustable
TDFN33-8
8
-40°C to +85°C
ACT8311NHxyz-T
1.5A
1.2V, 1.5V, 1.8V,
2.5V, 3.0V, 3.3Vc
TDFN33-8
8
-40°C to +85°C
c: Fixed output voltage options are available for production subject to minimum order quantities. Contact Active-Semi for more information regarding fixed output voltage options.
PIN CONFIGURATION
IN
1
GP
2
IN
3
G
4
ACT8309
ACT8310
ACT8311
8
SW
7
EN
6
POK
5
FB
TDFN33-8
PIN DESCRIPTIONS
PIN
NAME
DESCRIPTION
1, 3
IN
Power Input. Bypass to GP close to IC with a high quality ceramic capacitor.
2
GP
Power Ground. Connect to G with a short trace.
4
G
Analog Ground. Connect to GP with a short trace.
5
FB
Feedback Node. For fixed output voltage versions, connect this pin directly to the output. For
the adjustable output versions the voltage at this pin is regulated to 0.8V, connect to this pin
to the center of the output feedback resistor divider for voltage setting.
6
POK
Open-Drain Power-OK Status Output. POK is an open-drain output which sinks current when
the output voltage is less than 95% of the normal value. When the IC is disabled, POK is high
impedance.
7
EN
Enable Input. When higher than 1.4V, this pin turns the IC on. When lower than 0.4V, this pin
turn the IC off.
8
SW
Switch Output. Connect this pin to the switching end of the inductor.
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ACT8309/8310/8311
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Rev PrA, 24-Jan-08
ABSOLUTE MAXIMUM RATINGSc
PARAMETER
VALUE
UNIT
IN, SW to GP
-0.3 to +5.5
V
FB, EN, POK to G
-0.3 to +5.5
V
-0.3 to VIN + 0.3
V
-0.3 to +0.3
V
Internally limited
A
61
°C/W
1.63
W
Operating Junction Temperature
-40 to 150
°C
Storage Temperature
-55 to 150
°C
300
°C
FB, EN, SW Voltage
GP to G
Continuous SW Current
Junction to Ambient Thermal Resistance (θJA)
Maximum Power Dissipation (derate 5.3mW/°C above TA = 50°C)
Lead Temperature (Soldering, 10 sec)
c: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may
affect device reliability.
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ACT8309/8310/8311
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Rev PrA, 24-Jan-08
ELECTRICAL CHARACTERISTICS
(VIN = VEN = 3.6V, TA = 25˚C, unless otherwise specified.)
PARAMETER
Input Voltage Range
Under Voltage Lockout Threshold
SYMBOL
TEST CONDITIONS
VIN
VUVLO
MIN
TYP
MAX
UNIT
5.0
V
2.5
2.6
V
2.7
VIN rising, hysteresis = 80mV
2.35
Standby Supply Current
VFB = 103%VFB,TYP, IOUT = 0
150
310
µA
Shutdown Supply Current
EN = G, VIN = 4.2V
0.1
1
µA
TA = 25°C
0.786
0.80
0.814
-40°C < TA < 85°C
0.776
0.80
0.824
TA = 25°C
-2%
VNOM
+2%
-40°C < TA < 85°C
-3%
VNOM
+3%
Output Voltage Line Regulation
0.06
0.4
Output Voltage Load Regulation
0.6
FB Voltage
VFB
Output Voltage Accuracy
Current Limit
Max Output Current
Oscillator Frequency
PMOS On-Resistance
NMOS On-Resistance
fSW
RONP
RONN
1.1
1.3
1.8
ACT8310NH
1.4
1.7
2.2
ACT8311NH
1.75
2.1
2.8
ACT8309NH
0.9
ACT8310NH
1.2
ACT8311NH
1.5
1.35
1.6
VFB = 0.1V
450
ACT8309, ISW = -100mA
0.15
0.234
ACT8310, ISW = -100mA
0.12
0.192
ACT8311, ISW = -100mA
0.10
0.165
ISW = 100mA
0.15
0.26
EN Logic High Threshold
VIH
VIN = 2.7V to 5.0V
EN Logic Low Threshold
VIL
VIN = 2.7V to 5.0V
EN Input Bias Current
IEN
VIN = 5.0V, EN = G or IN
POK Threshold
1.05
V
%/V
%
ACT8309NH
VOUT = 80% of VOUT,NOM
V
A
A
MHz
kHz
1.4
Ω
Ω
V
0.01
% of VOUT,NOM
95
0.4
V
0.1
µA
%
POK Output Low Voltage
VOL
IPOK = 100µA
0.008
0.012
V
POK Leakage Current
IPOK
VPOK = 5.0V
0.01
0.1
µA
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ACT8309/8310/8311
Active-Semi
Rev PrA, 24-Jan-08
Figure1:
Functional Block Diagram
Active-Semi
ACT8309
ACT8310
ACT8311
IN
EN
IN
SW
GATE
DRIVER
PWM
CONTROL
OUT
OUT
GP
POK
FB
G
Figure 2:
Typical Application Circuit
2.7V to 5.0V
IN
10µF
IN
Active-Semi
3.3µH
SW
OUT
EN
ACT8311
549k?
549kΩ
OUT
3.0V
Up to 1.5A
22µF
FB
100k?
100kΩ
200k?
200kΩ
POK
GP
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ACT8309/8310/8311
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Rev PrA, 24-Jan-08
FUNCTIONAL DESCRIPTION
For most applications, a 22µF ceramic output capacitor is recommended. Although the these regulators were designed to take advantage of the benefits of ceramic capacitors, namely small size and
very-low ESR, low-ESR tantalum capacitors can
provide acceptable results as well.
The patent-pending ACT8309/ACT8310/ACT8311
are current-mode, fixed-frequency PWM, synchronous step-down DC/DC converters that are capable
of delivering up to 1.5A (ACT8311) with efficiency of
up to 95%. These devices feature very lowresistance power MOSFETs and 100% duty cycle
operation, making them ideal choices for portable
applications requiring a 3.0V or 3.3V rail to be generated form a Li+ battery. These device operate
with a fixed frequency of 1.35MHz, minimizing noise
in sensitive equipment as well as optimizing both
efficiency and component size and cost.
Inductor Selection
These devices were optimized for operation with
3.3µH inductors, although inductors in the 1.5µH to
4.7µH range may be used. Choose an inductors
with a low DC-resistance, and avoid inductor saturation by choosing inductors with DC ratings that
exceed the maximum output current of the application by at least 30%.
100% Duty Cycle Operation
These devices are capable of operating at up to
100% duty cycle operation. During 100% duty cycle
operation, the high-side power MOSFET is held on
continuously, providing a direct connection from the
input to the output (through the inductor), ensuring
the lowest possible dropout voltage in batterypowered applications.
Output Voltage Setting
Figure 3 shows the feedback network necessary to
set the output voltage when using adjustable output
voltage options. output voltage options. Select components as follows: Set RFB2 = 200kΩ, calculate
RFB1 using the following equation:
Synchronous Rectification
⎛V
⎞
RFB1 = RFB2 ⎜⎜ OUT − 1⎟⎟
⎝ VFB
⎠
The ACT8309/ACT8310/ACT8311 each feature
integrated n-channel synchronous rectifiers, maximizing efficiency and minimizing the total solution
size and cost by eliminating the need for external
rectifiers.
Where VFB is 0.8V.
Figure 3:
Soft-Start
Output Voltage Setting
The ACT8309/ACT8310/ACT8311 each include
integrated soft-start circuitry. When enabled, the
output voltage track an internal 200µs soft-start
ramp so that the output power up in a controlled,
monotonic manner that is independent of loading.
VOUT
ACT8309/
ACT8310/
ACT8311
RFB1
FB
RFB2
Compensation
The ACT8309/ACT8310/ACT8311 each utilize current-mode control and a proprietary internal compensation scheme to simultaneously simplify external
component selection and optimize transient performance over their full operating range. No compensation
design is required, simply follow a few simple guidelines described below when choosing external components.
Enable/Disable Control
These devices may be enabled and disabled using
the EN input. Drive EN to a logic-high to enable the
regulator, drive EN to a logic-low to disable the
regulator. When disabled, each regulator’s quiescent supply current drops to less than 1µA.
Power-OK Output (POK)
Capacitor Selection
These devices feature an open-drain “Power-OK”
indicator output. This output sinks current whenever
the output voltage is (typically) 5% below the regulation voltage, and goes high-impedance when the
output voltage is above this threshold. To generate
The input capacitor reduces peak currents and
noise induced upon the voltage source. A 10µF
ceramic capacitor is recommended for most applications.
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ACT8309/8310/8311
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a logic-level “Power-OK” signal, simply connect a pullup resistor from POK to an appropriate output voltage.
PCB Layout Considerations
High switching frequencies and large peak current
make PC board layout an important part of stepdown DC/DC converter design. A good design minimizes excessive EMI on the feedback paths and voltage gradients in the ground plane, both of which can
result in instability or regulation errors. Step-down
DC/DCs exhibit discontinuous input current, so the
input capacitors should be placed as close as possible to the IC, and avoiding the use of vias if possible.
The inductor, input filter capacitor, and output filter
capacitor should be connected as close together as
possible, with short, direct, and wide traces. The
ground nodes for each regulator’s power loop should
be connected at a single point in a star-ground configuration, and this point should be connected to the
backside ground plane with multiple vias. For fixed
output voltage options the output node for each regulator should be connected to its corresponding FB pin
through the shortest possible route, while keeping
sufficient distance from switching nodes to prevent
noise injection. Adjustable output versions should
follow the same guidelines, but additionally connect
the feedback resistors to the FB pin as close to the
IC as possible to minimize noise injection.
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ACT8309/8310/8311
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TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = VEN = 3.6V, TA = 25°C, unless otherwise specified.)
ACT8309 Dropout Voltage vs. Load Current
ACT8309 Efficiency vs. Load Current
VOUT = 3.0V
60
VOUT = 1.2V
VOUT = 1.8V
VOUT = 3.3V
50
40
180
Dropout Voltage (mV)
Efficiency (%)
80
30
20
10
140
VOUT = 3.0V
120
100
80
60
40
0
10
1
VOUT = 3.3V
160
20
VIN = 3.6V
0
100
1000
0
10000
100
200
ACT8310 Efficiency vs. Load Current
40
180
Dropout Voltage (mV)
Efficiency (%)
VOUT = 1.2V
VOUT = 3.3V
50
30
20
10
700
800
900
VOUT = 3.3V
160
140
VOUT = 3.0V
120
100
80
60
40
20
VIN = 3.6V
0
0
1
10
100
1000
0
10000
40
200
Dropout Voltage (mV)
VOUT = 1.2V
VOUT = 3.3V
50
30
20
10
0
VOUT = 3.3V
180
160
VOUT = 3.0V
140
120
100
80
60
40
20
VIN = 3.6V
1
1200
ACT8309/8310/8311-006
80
VOUT = 1.8V
1000
220
ACT8309/8310/8311-005
90
VOUT = 3.0V
800
ACT8311 Dropout Voltage vs. Load Current
ACT8311 Efficiency vs. Load Current
60
600
Load Current (mA)
100
70
400
200
Load Current (mA)
Efficiency (%)
600
ACT8309/8310/8311-004
80
VOUT = 1.8V
500
200
ACT8309/8310/8311-003
90
VOUT = 3.0V
400
ACT8310 Dropout Voltage vs. Load Current
100
70
300
Load Current (mA)
Load Current (mA)
60
ACT8309/8310/8311-002
90
70
200
ACT8309/8310/8311-001
100
0
10
100
1000
0
10000
Load Current (mA)
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0.2
0.4
0.6
0.8
1.0
1.2
1.4 1.5
Load Current (mA)
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ACT8309/8310/8311
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Rev PrA, 24-Jan-08
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = VEN = 3.6V, TA = 25°C, unless otherwise specified.)
Startup Waveform
ACT8309/8310/8311-008
CH1
ACT8309/8310/8311-007
VIN = 4.2V
VOUT = 3.3V
IOUT = 1A
Load Transient Response
VVOUT
= 3.3V
IN = 4.2V
VOUT = 3.3V
CH1
CH2
CH2
CH1: VOUT, 100mV/div (AC COUPLED)
CH2: Load Current (100mA to 1000mA)
TIME: 100µs
CH1: VOUT, 1.0V/div
CH2: POK, 2.0V/div
TIME: 100µs
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PACKAGE OUTLINE
TDFN33-8 PACKAGE OUTLINE AND DIMENSIONS
SYMBOL
DIMENSION IN
MILLIMETERS
DIMENSION IN
INCHES
MIN
MAX
MIN
MAX
A
0.700
0.800
0.028
0.031
A1
0.000
0.050
0.000
0.002
A3
0.153
0.253
0.006
0.010
D
2.900
3.100
0.114
0.122
E
2.900
3.100
0.114
0.122
D2
2.200
2.400
0.087
0.094
E2
1.400
1.600
0.055
0.063
b
0.200
0.320
0.008
0.013
e
L
0.650 TYP
0.375
0.575
0.026 TYP
0.015
0.023
Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each product to make
sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical components in lifesupport devices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any product or circuit described in
this datasheet, nor does it convey any patent license.
Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact [email protected] or visit http://www.active-semi.com. For other inquiries, please send to:
1270 Oakmead Parkway, Suite 310, Sunnyvale, California 94085-4044, USA
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