ACTIVE-SEMI ACT4501

ACT4501
Rev 2, 14-Nov-12
1.25A CC/CV Step-Down DC/DC Converter
FEATURES
APPLICATIONS
•
•
•
•
•
•
• Car Charger
• Rechargeable Portable Devices
• General-Purpose CC/CV Power Supply
10V-30V Input Voltage
40V Transparent Input Voltage Surge
Up to 1.25A Constant Output Current
Output Voltage up to 12V
Good EMC Performance on Single Layer PCB
Patent Pending ActiveCC Constant Current
Control
− Integrated Current Control Improves
Efficiency, Lowers Cost, and Reduces
Component Count
• Resistor Programmable Outputs
GENERAL DESCRIPTION
ACT4501 is a dedicated cost-effective DC-DC
converter for 5V/1A car charger applications with a
wide input voltage and high efficiency. The
converter operates in either CV (Constant Output
Voltage) mode or CC (Constant Output Current)
mode. ACT4501 provides up to 1.25A output
current at 125kHz switching frequency.
− Current Limit from 500mA to 1250mA
•
•
•
•
•
ActiveCC is a patent-pending control scheme to
achieve high accuracy sensorless constant current
control. ActiveCC eliminates the expensive, high
accuracy current sense resistor, making it ideal for
battery charging applications and high-brightness
LED drive for architectural lighting. The ACT4501
achieves higher efficiency than traditional constant
current switching regulators by eliminating the
sense resistor and its associated power loss.
Patented cable compensation from DC Cable
Compensation from 0Ω to 0.5Ω
2% Feedback Voltage Accuracy
Up to 90% Efficiency
125kHz 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-8 Package
Protection features include cycle-by-cycle current
limit, thermal shutdown, and frequency foldback at
short circuit. The devices are available in a SOP-8
package and require very few external devices for
operation.
Efficiency vs. Load Current
ACT4501-001
100
90
Efficiency (%)
VIN = 12V
80
VIN = 16V
70
VIN = 24V
60
50
VOUT = 5V
40
1
10
100
1000
10000
Load Current (mA)
Innovative PowerTM
-1-
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
ORDERING INFORMATION
PART NUMBER
TEMPERATURE RANGE
PACKAGE
PINS
PACKING
ACT4501SH-T
-40°C to 85°C
SOP-8
8
TAPE & REEL
PIN CONFIGURATION
SOP-8
PIN DESCRIPTIONS
PIN
NAME
1
HSB
2
IN
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
Innovative PowerTM
DESCRIPTION
High Voltage Bias Pin. This provides power to the internal high-side MOSFET gate
driver. Connect a 10nF capacitor from HSB pin to SW pin.
Power Supply Input. Bypass this pin with a 10µF ceramic capacitor to GND, placed as
close to the IC as possible.
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 0.8V
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.
Output Current Setting Pin. Connect a resistor from ISET to GND to program the
output current.
-2-
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
ABSOLUTE MAXIMUM RATINGSc
PARAMETER
VALUE
UNIT
-0.3 to 40
V
SW to GND
-1 to VIN + 1
V
HSB to GND
VSW - 0.3 to VSW + 7
V
-0.3 to + 6
V
105
°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.
Innovative PowerTM
-3-
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
ELECTRICAL CHARACTERISTICS
(VIN = 14V, TA = 25°C, unless otherwise specified.)
PARAMETER
TEST CONDITIONS
Input Voltage
MIN
TYP
10
MAX
UNIT
30
V
9.65
V
VIN UVLO Turn-On Voltage
Input Voltage Rising
VIN UVLO Hysteresis
Input Voltage Falling
1.1
V
VEN = 3V, VFB = 1V
1.0
mA
VEN = 3V, VO = 5V, No load
2.5
mA
VEN = 0V
75
100
µA
808
824
mV
Standby Supply Current
Shutdown Supply Current
Feedback Voltage
9.05
792
Internal Soft-Start Time
Error Amplifier Transconductance
VFB = VCOMP = 0.8V, ∆ICOMP = ± 10µA
Error Amplifier DC Gain
9.35
800
µs
650
µA/V
4000
V/V
Switching Frequency
VFB = 0.808V
115
125
130
kHz
Foldback Switching Frequency
VFB = 0V
10
16
38
kHz
85
88
93
%
Maximum Duty Cycle
Minimum On-Time
800
ns
COMP to Current Limit Transconductance VCOMP = 1.2V
1.75
A/V
Switch Current Limit
Duty = 50%
1.8
A
Slope Compensation
Duty = DMAX
0.75
A
1
V
25000
A/A
ISET Voltage
ISET to IOUT DC Room Temp Current
Gain
IOUT / ISET
CC Controller DC Accuracy
RISET = 19.6kΩ, VIN = 10V - 30V
1020
1200
1380
mA
EN Threshold Voltage
EN Pin Rising
0.75
0.8
0.85
V
EN Hysteresis
EN Pin Falling
EN Internal Pull-up Current
High-Side Switch ON-Resistance
SW Off Leakage Current
VEN = VSW = 0V
Thermal Shutdown Temperature
Temperature Rising
Innovative PowerTM
-4-
80
mV
4
µA
0.3
Ω
1
155
10
µA
°C
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
FUNCTIONAL BLOCK DIAGRAM
IN
AVIN
BANDGAP,
REGULATOR,
&
SHUTDOWN
CONTROL
EN
PVIN
OSCILLATOR
VREF = 0.808V
EMI
CONTROL
HSB
PWM
CONTROLLER
VREF = 0.808V
FB
SW
+
CC
CONTROL
COMP
ISET
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 ACT4501
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 125kHz.
However, if FB voltage is less than 0.6V, then the
switching frequency decreases until it reaches a
typical value of 20kHz 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 ACT4501 has an enable input EN for turning
the IC on or off. The EN pin contains a precision
0.8V comparator with 75mV 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
0.8V, or driven with open-drain logic to provide
digital on/off control.
Thermal Shutdown
The ACT4501 disables switching when its junction
temperature exceeds 155°C and resumes when the
temperature has dropped by 20°C.
-5-
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
APPLICATIONS INFORMATION
Inductor Selection
Output Voltage Setting
The inductor maintains a continuous current to the
output load. This inductor current has a ripple that is
dependent on the inductance value:
Figure 1:
Output Voltage Setting
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 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
⎞
RFB1 = RFB2 ⎜ OUT −1⎟
⎝ 0.808V ⎠
the
two
the
and
(2)
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.
(1)
With a selected inductor value the peak-to-peak
inductor current is estimated as:
CC Current Setting
ACT4501 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.
ILPK _ PK =
VOUT × (VIN _VOUT )
L × VIN × fSW
1
ILPK = ILOADMAX + ILPK _ PK
2
IOUTMAX = ILIM _
Output Current vs. RISET
ACT4501-002
1600
1400
(4)
The selected inductor should not saturate at ILPK.
The maximum output current is calculated as:
Curve for Programming Output CC Current
1800
(3)
The peak inductor current is estimated as:
Figure 2:
Output Current (mA)
VOUT × (VIN _VOUT )
VIN fSW ILOADMAX K RIPPLE
1
I _
2 LPK PK
(5)
LLIM is the internal current limit, which is typically
2.5A, as shown in Electrical Characteristics Table.
1200
1000
800
600
External High Voltage Bias Diode
400
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.
200
0
0
10
20
30
40
50
60
70
80
90
RISET (kΩ)
Innovative PowerTM
-6-
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
APPLICATIONS INFORMATION CONT’D
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.
Figure 3:
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.
Output Capacitor
The output capacitor also needs to have low ESR to
keep low output voltage ripple. The output ripple
voltage is:
VRIPPLE = IOUTMAX K RIPPLE RESR +
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
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
STABILITY COMPENSATION
If RCOMP is limited to 15kΩ, then the actual cross
over frequency is 3.4 / (VOUTCOUT). Therefore:
Figure 4:
Stability Compensation
CCOMP = 1.2 ×10 −5 VOUTCOUT
(14)
(F)
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:
⎞
⎛ 1.1 × 10 −6
,0.012 × VOUT ⎟⎟
RESRCOUT ≥ Min⎜⎜
⎠
⎝ COUT
c: CCOMP2 is needed only for high ESR output capacitor
AVDC
The dominant pole P1 is due to CCOMP:
G EA
fP1 =
2 π AVEA C COMP
The second pole P2 is the output pole:
I OUT
fP 2 =
2 π V OUT C OUT
The first zero Z1 is due to RCOMP and CCOMP:
1
f Z1 =
2π RCOMP CCOMP2
CCOMP 2 =
1
(7)
(16)
Table 2 shows some calculated results based on
the compensation method above.
(8)
Table 1:
Typical Compensation for Different Output
Voltages and Output Capacitors
(9)
(10)
(11)
2πR COMP C COMP2
COUT RESRCOUT
RCOMP
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.
And finally, the third pole is due to RCOMP and
CCOMP2 (if CCOMP2 is used):
fP 3 =
VOUT
COUT
RCOMP
CCOMP CCOMP2c
2.5V
47μF SP CAP
25kΩ
1.5nF
3.3V
47μF SP CAP
25kΩ
1.8nF
None
5V
47μF SP CAP
25kΩ
2.2nF
None
2.5V
220μF/6.3V/30mΩ
25kΩ
1.5nF
100pF
220μF/6.3V/30mΩ
25kΩ
1.8nF
100pF
5V
220μF/6.3V/30mΩ
25kΩ
2.2nF
100pF
c: CCOMP2 is needed for high ESR output capacitor.
CCOMP2 ≤ 47pF is recommended.
STEP 1. Set the cross over frequency at 1/10 of the
switching frequency via RCOMP:
CC Loop Stability
2 πVOUT C OUT fSW
10 G EA GCOMP × 0 .808 V
= 2 . 75 × 10 8 VOUT C OUT
(Ω)
The constant-current control loop is internally
compensated over the 400mA-1500mA output
range. No additional external compensation is
required to stabilize the CC current.
(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 =
1 .8 × 10 −5
R COMP
Innovative PowerTM
(F)
None
3.3V
The following steps should be used to compensate
the IC:
R COMP =
(15)
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
3. The DC loop gain of the system is determined by
the following equation:
0 . 808 V
=
AVEA G COMP
I OUT
(Ω)
Output Cable Resistance Compensation
To compensate for resistive voltage drop across the
charger's output cable, the ACT4501 integrates a
simple, user-programmable cable voltage drop
compensation using the impedance at the FB pin.
Use the curve in Figure 4 to choose the proper
(13)
-8-
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
STABILITY COMPENSATION CONT’D
feedback resistance values for cable compensation.
RFB1 is the high side resistor of voltage divider.
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.
In the case of high RFB1 used, the frequency
compensation
needs
to
be
adjusted
correspondingly. As show in Figure 6, adding a
capacitor in paralled with RFB1 or increasing the
compensation capacitance at COMP pin helps the
system stability.
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.
4) Use copper plane for power GND for best heat
dissipation and noise immunity.
Figure 5:
5) Place feedback resistor close to FB pin.
Cable Compensation at Various Resistor Divider
Values
6) Use short trace connecting HSB-CHSB-SW loop
Figure 7 shows an example of PCB layout.
Delta Output Voltage vs. Output Current
Delta Output Voltage (V)
VIN = 12V
V0UT = 5V
0.25
R
0.2
1
FB
=3
R FB
1
R FB
0.15
R FB
0.1
1
R FB1
0.05
1
00
=2
=2
=2
k
70
40
k
00k
= 15
RFB1 =
k
ACT4501-003
0.3
0k
100k
k
RFB1 = 51
0
0
200
400
600
800
1000
Output Current (mA)
Figure 6:
Figure 7: PCB Layout
Frequency Compensation for High RFB1
Figure 8 gives one typical car charger application
schematics 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.
Innovative PowerTM
-9-
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
Figure 8:
Typical Application Circuit for 5V/1A Car Charger
Table 2:
BOM List for 5V/1A Car Charger
ITEM
REFERENCE
1
U1
IC, ACT4501SH, SOP-8
Active-Semi
1
2
C1
Capacitor, Electrolytic, 47µF/50V, 6.3х7mm
Murata, TDK
1
3
C2
Capacitor, Ceramic, 2.2µF/50V, 1206, SMD
Murata, TDK
1
4
C3
Capacitor, Ceramic, 2.2nF/6.3V, 0603, SMD
Murata, TDK
1
5
C4
Capacitor, Ceramic, 10nF/50V, 0603, SMD
Murata, TDK
1
6
C5
Capacitor, Electrolytic, 100µF/10V, 6.3х7mm
Murata, TDK
1
7
C6
Capacitor, Ceramic, 1µF/10V, 0603, SMD
Murata, TDK
1
8
C7 (Optional)
Capacitor, Ceramic, 100pF/6.3V, 0603
Murata, TDK
1
9
L1
82µH, 1.4A, 20%, SMD CDRH125-820M
Sumida
1
10
D1
Diode, Schottky, 40V/2A, B240A, SMA
Diodes
1
11
D2
Diode, 75V/150mA, LL4148
Good-ARK
1
12
R1
Chip Resistor, 20kΩ, 0603, 1%
Murata, TDK
1
13
R2
Chip Resistor, 52kΩ, 0603, 1%
Murata, TDK
1
14
R3
Chip Resistor, 25kΩ, 0603, 5%
Murata, TDK
1
15
R4
Chip Resistor, 10kΩ, 0603, 1%
Murata, TDK
1
Innovative PowerTM
DESCRIPTION
- 10 -
MANUFACTURER
QTY
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
TYPICAL PERFORMANCE CHARACTERISTICS
(Circuit of Figure 7, IISET = 1A, L = 82µH, CIN = 10µF, COUT = 22µF, TA = 25°C, unless otherwise specified.)
Efficiency vs. Load Current
Switching Frequency vs. Input Voltage
ACT4501-004
Efficiency (%)
VIN = 12V
80
Switching Frequency (kHz)
90
130
VIN = 16V
70
VIN = 24V
60
50
VOUT = 5V
40
1
10
100
1000
ACT4501-005
100
125
120
115
110
105
5
10000
10
Load Current (mA)
VIN = 12V
RISET = 33kΩ
900
CC Current (mA)
Switching Frequency (kHz)
35
CC Current vs. Temperature
80
60
40
800
700
600
500
20
0
0.2
0.4
0.6
0.8
400
-40
1
-25
0
25
50
75
80
Temperature (°C)
Feedback Voltage (V)
Peak Current Limit vs. Duty Cycle
CC Current vs. Input Voltage
900
800
Maximum CC Current (mA)
RISET = 33kΩ
700
600
500
400
ACT4501-009
2500
ACT4501-008
1000
CC Current (mA)
30
ACT4501-007
100
25
1000
ACT4501-006
120
20
Input Voltage (V)
Switching Frequency vs. Feedback Voltage
140
0
15
100
2250
2000
1750
1500
1250
1000
750
500
250
0
10
12
18
24
30
0
Input Voltage (V)
Innovative PowerTM
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Duty Cycle
- 11 -
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(Circuit of Figure 7, IISET = 1A, L = 82µH, CIN = 10µF, COUT = 22µF, TA = 25°C, unless otherwise specified.)
Standby Supply Current vs. Input Voltage
Shutdown Current vs. Input Voltage (EN pulled low)
100
5
4
Input Current (mA)
Shutdown Current (µA)
120
ACT4501-011
ACT4501-010
140
80
60
40
3
2
1
20
0
0
5
10
15
20
25
30
5
15
Input Voltage (V)
35
SW vs. Output Voltage Ripples
Reverse Leakage Current (VIN Floating)
80
ACT4501-013
ACT4501-012
100
Reverse Leakage Current (µA)
25
Input Voltage (V)
VIN = 12V
V0UT = 5V
I0UT = 1A
CH1
60
40
CH2
20
0
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
CH1: VOUT, 50mV/div
CH2: VSW, 5V/div
TIME: 4µs/div
5
VOUT (V)
SW vs. Output Voltage Ripples
ACT4501-015
CH1
ACT4501-014
VIN = 24V
V0UT = 5V
I0UT = 1A
Start up with EN
VIN = 12V
V0UT = 5V
I0UT = 1A
CH1
CH2
CH2
CH1: EN, 1V/div
CH2: VOUT, 1V/div
TIME: 2ms/div
CH1: VOUT, 50mV/div
CH2: VSW, 10V/div
TIME: 4µs/div
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(Circuit of Figure 7, IISET = 1A, L = 82µH, CIN = 10µF, COUT = 22µF, TA = 25°C, unless otherwise specified.)
Load Step Waveforms
Start up with EN
CH1
VIN = 12V
V0UT = 5V
IISET = 1A
CH1
ACT4501-017
ACT4501-016
VIN = 24V
V0UT = 5V
IISET = 1A
CH2
CH2
CH1: VOUT, 200mV/div
CH2: IOUT, 1A/div
TIME: 400μs/div
CH1: EN, 1V/div
CH2: VOUT, 1V/div
TIME: 2ms/div
Load Step Waveforms
CH1
ACT4501-018
VIN = 24V
V0UT = 5V
IISET = 1A
CH2
CH1: VOUT, 200mV/div
CH2: IOUT, 1A/div
TIME: 400μs/div
Innovative PowerTM
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(Circuit of Figure 7, IISET = 1A, L = 82µH, CIN = 10µF, COUT = 22µF, TA = 25°C, unless otherwise specified.)
Short Circuit
Short Circuit Recovery
ACT4501-020
VIN = 12V
V0UT = 5V
IISET = 1A
ACT4501-019
CH1
VIN = 12V
V0UT = 5V
IISET = 1A
CH1
CH2
CH2
CH3
CH3
CH1: VOUT, 2V/div
CH2: IOUT, 1A/div
CH3: VSW, 10V/div
TIME: 40µs/div
CH1: VOUT, 2V/div
CH2: IOUT, 1A/div
CH3: VSW, 10V/div
TIME: 40µs/div
Short Circuit Recovery
Short Circuit
VIN = 24V
V0UT = 5V
IISET = 1A
ACT4501-022
ACT4501-021
VIN = 24V
V0UT = 5V
IISET = 1A
CH1
CH1
CH2
CH2
CH3
CH3
CH1: VOUT, 2V/div
CH2: IOUT, 1A/div
CH3: VSW, 20V/div
TIME: 40µs/div
CH1: VOUT, 2V/div
CH2: IOUT, 1A/div
CH3: VSW, 20V/div
TIME: 40µs/div
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Copyright © 2012 Active-Semi, Inc.
ACT4501
Rev 2, 14-Nov-12
PACKAGE OUTLINE
SOP-8 PACKAGE OUTLINE AND DIMENSIONS
D
L
C
E1
E
SYMBOL
?
θ
A
A2
B
A1
e
DIMENSION IN
MILLIMETERS
DIMENSION IN
INCHES
MIN
MAX
MIN
MAX
A
1.350
1.750
0.053
0.069
A1
0.100
0.250
0.004
0.010
A2
1.350
1.550
0.053
0.061
B
0.330
0.510
0.013
0.020
C
0.190
0.250
0.007
0.010
D
4.700
5.100
0.185
0.201
E
3.800
4.000
0.150
0.157
E1
5.800
6.300
0.228
0.248
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.
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Copyright © 2012 Active-Semi, Inc.