ACT4303

ACT4303
Active-Semi
Rev 0, 05-Dec-11
30V/3A Sensorless CC/CV Step-Down DC/DC Converter
FEATURES
APPLICATIONS
•
•
•
•
•
•
•
•
•
•
•
32V Input Voltage Surge
30V Steady State Input Voltage
Up to 3A Output Current
Output Voltage up to 12V
Patent Pending Active CC Sensorless Constant
Current Control
− Integrated Current Control Improves
Efficiency, Lowers Cost, and Reduces
Component Count
• Resistor Programmable Current Limit from 1.5A
to 3A
USB Chargers
LCD TV and Monitors
Digital Video Recorders
Set-Top Box
Battery Chargers
General-Purpose CC/CV Power Supplies
GENERAL DESCRIPTION
ACT4303 is a wide input voltage, high efficiency
Active CC step-down DC/DC converter that
operates in either CV (Constant Output Voltage)
mode or CC (Constant Output Current) mode.
ACT4303 provides up to 3A output current at
225kHz switching frequency.
• ±7.5% CC Accuracy
− Compensation of Input /Output Voltage Change
− Temperature Compensation
− Independent of inductance and Inductor DCR
• 2% Feedback Voltage Accuracy
• Up to 94% Efficiency
• 225kHz Switching Frequency Eases EMI Design
• Advanced Feature Set
− Integrated Soft Start
− Thermal Shutdown
− Secondary Cycle-by-Cycle Current Limit
− Protection Against Shorted ISET Pin
• SOP-8EP Package
Active CC is a patent-pending control scheme to
achieve highest accuracy sensorless constant
current control. Active CC eliminates the expensive,
high accuracy current sense resistor, making it ideal
for battery charging applications and adaptors with
accurate current limit. The ACT4303 achieves
higher efficiency than traditional constant current
switching regulators by eliminating its associated
power loss.
Protection features include cycle-by-cycle current
limit, thermal shutdown, and frequency foldback at
short circuit. The devices are available in a SOP8EP package and require very few external devices
for operation.
CC/CV Curve
SW
C1
47µF
FB
GND COMP
R1
11.5k
C2
2.2nF
R2 52k
R4
10k
D1
SK34
VIN = 24V
5.0
L1 30µH
ACT4303
EN
ISET
5V
Output Voltage (V)
IN
C4
100µF
R3
8.2k
4.0
ACT4303-001
HSB
Input 10V~30V
6.0
C3
22nF
VIN = 12V
3.0
2.0
1.0
0.0
0
0.4
0.8
1.2
1.6
2.4
2.0
2.8
3.2
Output Current (A)
Innovative PowerTM
-1-
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
ORDERING INFORMATION
PART NUMBER
OPERATION TEMPERATURE RANGE
ACT4303YH-T
-40°C to 85°C
PACKAGE
PINS
PACKING
SOP-8EP
8
TAPE & REEL
PIN CONFIGURATION
PIN DESCRIPTIONS
PIN
NAME
DESCRIPTION
1
HSB
High Side Bias Pin. This provides power to the internal high-side MOSFET gate driver.
Connect a 22nF capacitor from HSB pin to SW pin.
2
IN
Power Supply Input. Bypass this pin with a 10µF ceramic capacitor to GND, placed as
close to the IC as possible.
3
SW
4
GND
Ground. Connect this pin to a large PCB copper area for best heat dissipation. Return
FB, COMP, and ISET to this GND, and connect this GND to power GND at a single
point for best noise immunity.
5
FB
Feedback Input. The voltage at this pin is regulated to 0.808V. Connect to the resistor
divider between output and GND to set the output voltage.
6
COMP
7
EN
8
ISET
Output Current Setting Pin. Connect a resistor from ISET to GND to program the
output current.
Exposed Pad
Heat Dissipation Pad. Connect this exposed pad to large ground copper area with
copper and vias.
Innovative PowerTM
Power Switching Output to External Inductor.
Error Amplifier Output. This pin is used to compensate the converter.
Enable Input. EN is pulled up to 5V with a 4μA current, and contains a precise 1.6V
logic threshold. Drive this pin to a logic-high or leave unconnected to enable the IC.
Drive to a logic-low to disable the IC and enter shutdown mode.
-2-
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
ABSOLUTE MAXIMUM RATINGSc
PARAMETER
VALUE
UNIT
-0.3 to 34
V
SW to GND
-1 to VIN + 1
V
HSB to GND
VSW - 0.3 to VSW + 7
V
-0.3 to + 6
V
46
°C/W
Operating Junction Temperature
-40 to 150
°C
Storage Junction Temperature
-55 to 150
°C
300
°C
IN to GND
FB, EN, ISET, COMP to GND
Junction to Ambient Thermal Resistance
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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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
ELECTRICAL CHARACTERISTICS
(VIN = 20V, TA = 25°C, unless otherwise specified.)
PARAMETER
TEST CONDITIONS
Input Voltage
MIN
TYP
10
MAX
UNIT
30
V
9.7
V
VIN UVLO Turn-On Voltage
Input Voltage Rising
VIN UVLO Hysteresis
Input Voltage Falling
1.1
VEN = 3V, VFB = 1V
0.9
VEN = 3V, VOUT = 5V, No load
3.0
VEN = 0V
75
115
µA
808
824
mV
Standby Supply Current
Shutdown Supply Current
Feedback Voltage
9.0
792
Internal Soft-Start Time
Error Amplifier Transconductance
VFB = VCOMP = 0.8V,
∆ICOMP = ± 10µA
Error Amplifier DC Gain
Switching Frequency
VFB = 0.808V
Foldback Switching Frequency
VFB = 0V
200
9.4
V
1.4
mA
400
µs
650
µA/V
4000
V/V
225
250
30
Maximum Duty Cycle
85
Minimum On-Time
mA
kHz
kHz
88
91
%
200
ns
COMP to Current Limit Transconductance
VCOMP = 1.2V
5.25
A/V
Secondary Cycle-by-Cycle Current Limit
Duty = DMAX
4.5
A
Slope Compensation
Duty = DMAX
1.2
A
1
V
25000
A/A
ISET Voltage
ISET to IOUT DC Room Temp Current Gain
IOUT / ISET, RISET = 19.6kΩ
CC Controller DC Accuracy
RISET = 19.6kΩ, VOUT = 3.5V
Open-Loop DC Test
1175
1190
1205
mA
EN Threshold Voltage
EN Pin Rising
1.47
1.6
1.73
V
EN Hysteresis
EN Pin Falling
EN Internal Pull-up Current
High-Side Switch ON-Resistance
125
mV
4
µA
0.18
Ω
SW Off Leakage Current
VEN = VSW = 0V
Thermal Shutdown Temperature
Temperature Rising
150
°C
Thermal Shutdown Temperature Hysteresis
Temperature Falling
20
°C
Innovative PowerTM
-4-
1
10
µA
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
FUNCTIONAL BLOCK DIAGRAM
FUNCTIONAL DESCRIPTION
regulating output voltage to regulating output
current, and the output voltage will drop with
increasing load.
CV/CC Loop Regulation
As seen in Functional Block Diagram, the ACT4303
is a peak current mode pulse width modulation
(PWM) converter with CC and CV control. The
converter operates as follows:
The Oscillator normally switches at 225kHz.
However, if FB voltage is less than 0.6V, then the
switching frequency decreases until it reaches a
typical value of 30kHz at VFB = 0.15V.
A switching cycle starts when the rising edge of the
Oscillator clock output causes the High-Side Power
Switch to turn on and the Low-Side Power Switch to
turn off. With the SW side of the inductor now
connected to IN, the inductor current ramps up to
store energy in the magnetic field. The inductor
current level is measured by the Current Sense
Amplifier and added to the Oscillator ramp signal. If
the resulting summation is higher than the COMP
voltage, the output of the PWM Comparator goes
high. When this happens or when Oscillator clock
output goes low, the High-Side Power Switch turns
off.
Enable Pin
The ACT4303 has an enable input EN for turning
the IC on or off. The EN pin contains a precision
1.6V comparator with 125mV hysteresis and a 4µA
pull-up current source. The comparator can be used
with a resistor divider from VIN to program a startup
voltage higher than the normal UVLO value. It can
be used with a resistor divider from VOUT to disable
charging of a deeply discharged battery, or it can be
used with a resistor divider containing a thermistor
to provide a temperature-dependent shutoff
protection for over temperature battery. The
thermistor should be thermally coupled to the
battery pack for this usage.
At this point, the SW side of the inductor swings to
a diode voltage below ground, causing the inductor
current to decrease and magnetic energy to be
transferred to output. This state continues until the
cycle starts again. The High-Side Power Switch is
driven by logic using HSB as the positive rail. This
pin is charged to VSW + 5V when the Low-Side
Power Switch turns on. The COMP voltage is the
integration of the error between FB input and the
internal 0.808V reference. If FB is lower than the
reference voltage, COMP tends to go higher to
increase current to the output. Output current will
increase until it reaches the CC limit set by the ISET
resistor. At this point, the device will transition from
Innovative PowerTM
If left floating, the EN pin will be pulled up to roughly
5V by the internal 4µA current source. It can be
driven from standard logic signals greater than
1.6V, or driven with open-drain logic to provide
digital on/off control.
Thermal Shutdown
The ACT4303 disables switching when its junction
temperature exceeds 150°C and resumes when the
temperature has dropped by 20°C.
-5-
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
APPLICATIONS INFORMATION
CC Current Line Compensation
Output Voltage Setting
When operating at constant current mode, the
current limit increase slightly with input voltage. For
wide input voltage applications, a resistor RC is
added to compensate line change and keep output
high CC accuracy, as shown in Figure 3.
Figure 1:
Output Voltage Setting
Figure 3:
Iutput Line Compensation
Figure 1 shows the connections for setting
output voltage. Select the proper ratio of the
feedback resistors RFB1 and RFB2 based on
output voltage. Typically, use RFB2 ≈ 10kΩ
determine RFB1 from the following equation:
⎛ V
⎞
R FB1 = R FB 2 ⎜ OUT − 1 ⎟
0
.
808
V
⎝
⎠
the
two
the
and
Inductor Selection
(1)
The inductor maintains a continuous current to the
output load. This inductor current has a ripple that is
dependent on the inductance value:
CC Current Setting
ACT4303 constant current value is set by a resistor
connected between the ISET pin and GND. The CC
output current is linearly proportional to the current
flowing out of the ISET pin. The voltage at ISET is
roughly 1V and the current gain from ISET to output
is roughly 25000 (25mA/1µA). To determine the
proper resistor for a desired current, please refer to
Figure 2 below.
Higher inductance reduces the peak-to-peak ripple
current. The trade off for high inductance value is
the increase in inductor core size and series
resistance, and the reduction in current handling
capability. In general, select an inductance value L
based on ripple current requirement:
L=
Figure 2:
VOUT × (VIN _VOUT )
VIN fSW ILOADMAX K RIPPLE
(2)
Curve for Programming Output CC Current
where VIN is the input voltage, VOUT is the output
voltage, fSW is the switching frequency, ILOADMAX is
the maximum load current, and KRIPPLE is the ripple
factor. Typically, choose KRIPPLE = 30% to
correspond to the peak-to-peak ripple current being
30% of the maximum load current.
Output Current vs. RISET
ACT4303-002
3500
Output Current (mA)
3000
2500
With a selected inductor value the peak-to-peak
inductor current is estimated as:
2000
1500
ILPK _ PK =
1000
VOUT × (VIN _VOUT )
L × VIN × fSW
(3)
500
The peak inductor current is estimated as:
VIN = 24V, VOUT = 4V
0
8
11
14
17
20
23
26
29
32
1
ILPK = ILOADMAX + ILPK _ PK
2
RISET (kΩ)
Innovative PowerTM
-6-
(4)
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
APPLICATIONS INFORMATION CONT’D
The selected inductor should not saturate at ILPK.
The maximum output current is calculated as:
IOUTMAX = ILIM
_
1
I _
2 LPK PK
Output Capacitor
The output capacitor also needs to have low ESR to
keep low output voltage ripple. The output ripple
voltage is:
(5)
VRIPPLE = IOUTMAX K RIPPLE RESR +
LLIM is the internal current limit, which is typically
3.2A, as shown in Electrical Characteristics Table.
VIN
2
28 × fSW LC OUT
(6)
Where IOUTMAX is the maximum output current,
KRIPPLE is the ripple factor, RESR is the ESR of the
output capacitor, fSW is the switching frequency, L is
the inductor value, and COUT is the output
capacitance. In the case of ceramic output
capacitors, RESR is very small and does not
contribute to the ripple. Therefore, a lower
capacitance value can be used for ceramic type. In
the case of tantalum or electrolytic capacitors, the
ripple is dominated by RESR multiplied by the ripple
current. In that case, the output capacitor is chosen
to have sufficiently low ESR.
External High Voltage Bias Diode
It is recommended that an external High Voltage
Bias diode be added when the system has a 5V
fixed input or the power supply generates a 5V
output. This helps improve the efficiency of the
regulator. The High Voltage Bias diode can be a
low cost one such as IN4148 or BAT54.
Figure 4:
External High Voltage Bias Diode
For ceramic output capacitor, typically choose a
capacitance of about 22µF. For tantalum or
electrolytic capacitors, choose a capacitor with less
than 50mΩ ESR.
Rectifier Diode
Use a Schottky diode as the rectifier to conduct
current when the High-Side Power Switch is off.
The Schottky diode must have current rating higher
than the maximum output current and a reverse
voltage rating higher than the maximum input
voltage.
This diode is also recommended for high duty cycle
operation and high output voltage applications.
Input Capacitor
The input capacitor needs to be carefully selected
to maintain sufficiently low ripple at the supply input
of the converter. A low ESR capacitor is highly
recommended. Since large current flows in and out
of this capacitor during switching, its ESR also
affects efficiency.
The input capacitance needs to be higher than
10µF. The best choice is the ceramic type,
however, low ESR tantalum or electrolytic types
may also be used provided that the RMS ripple
current rating is higher than 50% of the output
current. The input capacitor should be placed close
to the IN and G pins of the IC, with the shortest
traces possible. In the case of tantalum or
electrolytic types, they can be further away if a
small parallel 0.1µF ceramic capacitor is placed
right next to the IC.
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
STABILITY COMPENSATION
If RCOMP is limited to 15kΩ, then the actual cross
over frequency is 6.58 / (VOUTCOUT). Therefore:
Figure 5:
Stability Compensation
C COMP = 6 . 45 × 10
_
6
VOUT C OUT
(F)
(14)
STEP 3. If the output capacitor’s ESR is high
enough to cause a zero at lower than 4 times the
cross over frequency, an additional compensation
capacitor CCOMP2 is required. The condition for using
CCOMP2 is:
R ESRCOUT ≥ (Min
c: CCOMP2 is needed only for high ESR output capacitor
0 . 808 V
A VEA G COMP
I OUT
C COMP 2 =
G
EA
2 π A VEA C
The second pole P2 is the output pole:
I OUT
fP 2 =
2 π V OUT C OUT
fZ 1 =
And finally, the third pole is due to RCOMP and
CCOMP2 (if CCOMP2 is used):
fP 3 =
1
(11)
2πR COMP C COMP2
RCOMP CCOMP CCOMP2c
VOUT
COUT
2.5V
47μF Ceramic CAP
5.6kΩ
3.3nF
None
3.3V
47μF Ceramic CAP
6.2kΩ
3.3nF
None
5V
47μF Ceramic CAP
8.2kΩ
3.3nF
None
2.5V
470μF/6.3V/30mΩ
39kΩ
22nF
47pF
3.3V
470μF/6.3V/30mΩ
45kΩ
22nF
47pF
5V
470μF/6.3V/30mΩ
51kΩ
22nF
47pF
The constant-current control loop is internally
compensated over the 1500mA-3000mA output
range. No additional external compensation is
required to stabilize the CC current.
2 π V OUT C OUT f SW
10 G EA G COMP × 0 . 808 V
(Ω)
(16)
CC Loop Stability
STEP 1. Set the cross over frequency at 1/10 of the
switching frequency via RCOMP:
= 5 . 12 × 10 7 VOUT C OUT
C OUT R ESRCOUT
R COMP
c: CCOMP2 is needed for high ESR output capacitor.
CCOMP2 ≤ 47pF is recommended.
The following steps should be used to compensate
the IC:
R COMP =
(15)
Typical Compensation for Different Output
Voltages and Output Capacitors
(9)
(10)
2 π R COMP C COMP
(Ω)
Table 1:
The first zero Z1 is due to RCOMP and CCOMP:
1
)
Table 1 shows some calculated results based on
the compensation method above.
(8)
COMP
,0 . 006 × VOUT
Though CCOMP2 is unnecessary when the output
capacitor has sufficiently low ESR, a small value
CCOMP2 such as 100pF may improve stability against
PCB layout parasitic effects.
(7)
The dominant pole P1 is due to CCOMP:
fP 1 =
_6
And the proper value for CCOMP2 is:
The feedback loop of the IC is stabilized by the
components at the COMP pin, as shown in Figure
5. The DC loop gain of the system is determined by
the following equation:
A VDC =
1 . 77 × 10
C OUT
(12)
STEP 2. Set the zero fZ1 at 1/4 of the cross over
frequency. If RCOMP is less than 15kΩ, the equation
for CCOMP is:
C COMP =
2 . 83 × 10
R COMP
Innovative PowerTM
5
(F)
(13)
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
STABILITY COMPENSATION CONT’D
Figure 7 gives a typical application schematic and
associated BOM list.
PC Board Layout Guidance
When laying out the printed circuit board, the
following checklist should be used to ensure proper
operation of the IC.
1) Arrange the power components to reduce the
AC loop size consisting of CIN, IN pin, SW pin
and the schottky diode.
2) Place input decoupling ceramic capacitor CIN as
close to IN pin as possible. CIN is connected
power GND with vias or short and wide path.
3) Return FB, COMP and ISET to signal GND pin,
and connect the signal GND to power GND at a
single point for best noise immunity. Connect
exposed pad to power ground copper area with
copper and vias.
4) Use copper plane for power GND for best heat
dissipation and noise immunity.
5) Place feedback resistor close to FB pin.
6) Use short trace connecting HSB-CHSB-SW loop
Figure 6 shows an example of PCB layout.
Figure 6: PCB Layout
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
Figure 7:
Typical Application Circuit for 5V/2.5A DC/DC Converter
Table 2:
BOM List for 5V/2.5A DC/DC Converter
ITEM REFERENCE
DESCRIPTION
MANUFACTURER
QTY
1
U1
IC, ACT4303YH, SOP-8EP
Active-Semi
1
2
C1
Capacitor, Electrolytic, 47µF/35V, 6.3х7mm
Murata, TDK
1
3
C2
Capacitor, Ceramic, 10µF/35V, 1206, SMD
Murata, TDK
1
4
C3
Capacitor, Ceramic, 2.2nF/6.3V, 0603, SMD
Murata, TDK
1
5
C4
Capacitor, Ceramic, 22nF/35V, 0603, SMD
Murata, TDK
1
6
C5
Capacitor, Electrolytic, 220µF/10V, 6.3х7mm
Murata, TDK
1
7
C6
Capacitor, Ceramic, 1µF/10V, 0603, SMD
Murata, TDK
1
8
L1
Inductor,30µH, 3A, 20%, SMD
Tyco Electronics
1
9
D1
Diode, Schottky, 40V/3A, SK34
Diodes
1
10
D2
Diode, 75V/150mA, LL4148
Good-ARK
1
11
R1
Chip Resistor, 11.5kΩ, 0603, 1%
Murata, TDK
1
12
R2
Chip Resistor, 52kΩ, 0603, 1%
Murata, TDK
1
13
R3
Chip Resistor, 8.2kΩ, 0603, 5%
Murata, TDK
1
14
R4
Chip Resistor, 10kΩ, 0603, 1%
Murata, TDK
1
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS
(L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC)
Efficiency vs. Load current
90
85
VIN = 24V
80
75
70
65
VOUT = 5V
ACT4303-005
ACT4303-004
VIN = 12V
95
Efficiency (%)
Switching Frequency vs. Input Voltage
250
Switching Frequency (kHz)
100
230
210
190
170
150
130
110
60
200
600
1000
1800
1400
10
2200
15
Load Current (mA)
30
2600
CC Current (mA)
210
ACT4303-007
2700
ACT4303-006
Switching Frequency (kHz)
25
CC Current vs. Temperature
Switching Frequency vs. Feedback Voltage
260
160
110
2500
2400
2300
2200
60
2100
10
0
100
200
300
400
500
600
700
800
2000
900
25
45
65
85
105
125
CC Current vs. Input Voltage
Maximum Peak Current vs. Duty Cycle
Maximum CC Current (A)
2400
2200
2000
1800
1600
ACT4303-009
4.2
ACT4303-008
2600
4.05
3.9
3.75
3.6
3.45
3.3
3.15
3
10
14
18
22
26
20
30
30
40
50
60
70
Duty Cycle
Input Voltage (V)
Innovative PowerTM
145
Temperature (°C)
Feedback Voltage (mV)
CC Current (mA)
20
Input Voltage (V)
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC)
Shutdown Current vs. Input Voltage
130
Standby Current vs. Input Voltage
3
Standby Supply Current (mA)
Shutdown Current (µA)
100
85
70
55
40
25
10
15
20
25
ACT4303-011
ACT4303-010
115
2.5
2
1.5
1
0.5
0
2
30
6
10
18
22
26
30
Input Voltage (V)
Input Voltage (V)
Start up into CC mode
Reverse Leakage Current (VIN Floating)
120
ACT4303-013
ACT4303-012
160
Reverse Leakage Current (µA)
14
VOUT = 5V
RLORD = 1.5Ω
IISET = 2A
VIN = 12V
CH1
80
40
CH2
0
0
1
2
3
4
5
CH1: VOUT, 2V/div
CH2: IOUT, 1A/div
TIME: 200µs/div
VOUT (V)
Start up into CC mode
ACT4303-015
ACT4303-014
VOUT = 5V
RLORD = 1.5Ω
IISET = 2A
VIN = 24V
SW vs. Output Voltage Ripples
VIN = 12V
VOUT = 5V
IOUT = 2.1A
CH1
CH1
CH2
CH2
CH1: VOUT, 2V/div
CH2: IOUT, 1A/div
TIME: 200µs/div
Innovative PowerTM
CH1: VOUT Ripple, 20mV/div
CH2: SW, 5V/div
TIME: 2µs/div
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC)
SW vs. Output Voltage Ripple
Start up with EN
CH1
ACT4303-017
ACT4303-016
VIN = 24V
VOUT = 5V
IOUT = 2.1A
VIN = 12V
VOUT = 5V
IOUT = 2.1A
CH1
CH2
CH2
CH1: EN, 2V/div
CH2: VOUT, 2V/div
TIME: 400µs//div
CH1: VRIPPLE, 20mV/div
CH2: SW, 10V/div
TIME: 2µs/div
Load Step Waveforms
Start up with EN
VIN = 12V
VOUT = 5V
IISET = 2.1A
ACT4303-019
VIN = 12V
VOUT = 5V
IISET = 2.1A
ACT4303-021
ACT4303-018
VIN = 24V
VOUT = 5V
IISET = 2.1A
CH1
CH1
CH2
CH2
CH1: EN, 2V/div
CH2: VOUT, 2V/div
TIME: 400µs//div
CH1: VOUT, 200mV/div
CH2: IOUT, 1A/div
TIME: 200µs//div
Short Circuit
Load Step Waveforms
ACT4303-020
VIN = 24V
VOUT = 5V
IISET = 2.1A
CH1
CH1
CH2
CH2
CH1: VOUT, 200mV/div
CH2: IOUT, 1A/div
TIME: 200µs//div
Innovative PowerTM
CH1: VOUT, 2V/div
CH2: IOUT, 1A/div
TIME: 100µs//div
- 13 -
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC)
Short Circuit
Short Circuit Recovery
VIN = 12V
VOUT = 5V
IISET = 2.1A
ACT4303-023
ACT4303-022
VIN = 24V
VOUT = 5V
IISET = 2.1A
CH1
CH1
CH2
CH2
CH1: VOUT, 2V/div
CH2: IOUT, 1A/div
TIME: 100µs//div
CH1: VOUT, 2V/div
CH2: IOUT, 2A/div
TIME: 1ms/div
Short Circuit Recovery
ACT4303-024
VIN = 24V
VOUT = 5V
IISET = 2.1A
CH1
CH2
CH1: VOUT, 2V/div
CH2: IOUT, 2A/div
TIME: 1ms/div
Innovative PowerTM
- 14 -
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Copyright © 2011 Active-Semi, Inc.
ACT4303
Active-Semi
Rev 0, 05-Dec-11
PACKAGE OUTLINE
SOP-8EP PACKAGE OUTLINE AND DIMENSIONS
SYMBOL
DIMENSION IN
MILLIMETERS
DIMENSION IN
INCHES
MIN
MAX
MIN
MAX
A
1.350
1.700
0.053
0.067
A1
0.000
0.100
0.000
0.004
A2
1.350
1.550
0.053
0.061
b
0.330
0.510
0.013
0.020
c
0.170
0.250
0.007
0.010
D
4.700
5.100
0.185
0.200
D1
3.202
3.402
0.126
0.134
E
3.800
4.000
0.150
0.157
E1
5.800
6.200
0.228
0.244
E2
2.313
2.513
0.091
0.099
e
1.270 TYP
0.050 TYP
L
0.400
1.270
0.016
0.050
θ
0°
8°
0°
8°
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 life-support 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
sales@active-semi.com or visit http://www.active-semi.com.
®
is a registered trademark of Active-Semi.
Innovative PowerTM
- 15 -
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Copyright © 2011 Active-Semi, Inc.