ADDtek AMC2576-ADJDDF 3a step down voltage regulator Datasheet

AMC2576
3A STEP DOWN VOLTAGE REGULATOR
www.addmtek.com
DESCRIPTION
The AMC2576 series is a step-down switching regulator with
all the required active functions. It is capable of driving 3A load
with excellent line and load regulations. These devices are
available in fixed output voltages of 3.3V, 5V, and an adjustable
output version.
The AMC2576 series offers a high-efficiency replacement for
popular three-terminal linear regulators. It requires only a
minimum number of external components. Substantially, it reduces
not only the area of board size but also the size of the heat sink. In
some cases, no heat sink is required.
The ± 4% tolerance on output voltage within specified input
voltages and output load conditions is guaranteed. The oscillator
frequency accuracy is within ±10%. External shutdown is included,
featuring 70µA(typical) standby current. The output switch
includes cycle-by-cycle current limitation, as well as thermal
shutdown for full protection under fault conditions.
FEATURES
„
„
„
„
„
„
„
„
„
Guaranteed 3A output current
3.3V, 5V and adjustable output versions
Wide input voltage range, up to 40V
Internal oscillator of 52 KHz fixed
frequency
Wide adjustable version output voltage
range, from 1.23V to 37V ±4% max over
line and load conditions
Low standby current, typ. 70µA, at
shutdown mode
Requires only 4 external components
Thermal shut down and current limit
protection
P+ Product enhancement tested
APPLICATIONS
„
„
„
„
PACKAGE PIN OUT
5. Enable
4. FB
3. GND
2. VOUT
1. VIN
LCD Monitors
ADD-ON Cards Switching Regulators
High Efficiency Step-Down Regulators
Efficient Pre-regulator for Linear
Regulators
5. Enable
4. FB
3. GND
2. VOUT
1. VIN
5-Pin Plastic TO-263
Surface Mount
(Top View)
5-Pin Plastic TO-220
(Top View)
5. Enable
4. FB
3. GND
2. V OUT
1. VIN
VOLTAGE OPTIONS
AMC2576-3.3 – 3.3V Fixed
AMC2576-5.0 – 5.0V Fixed
AMC2576-ADJ – Adjustable Output
5-Pin Plastic TO-220B
(Top View)
(Side View)
VIN 1
8 GND
VOUT 2
7 GND
FB 3
6 GND
Enable 4
5 GND
SO-8
(Top View)
ORDER INFORMATION
Plastic
TO-220
P
5-pin
AMC2576-ADJP
AMC2576-ADJPF
-40°C≤ TJ ≤ 125°C
AMC2576-X.XP
AMC2576-X.XPF
Temperature
Range
Note:
Plastic
TO-220B
PB
5-pin
AMC2576-ADJPB
AMC2576-ADJPBF
AMC2576-X.XPB
AMC2576-X.XPBF
1.All surface-mount packages are available in Tape & Reel.
AMC2576-X.XDDT).
2.The letter “F” is marked for Lead Free process.
Copyright © 2006 ADDtek Corp.
Plastic
DD TO-263
5-pin
AMC2576-ADJDD
AMC2576-ADJDDF
AMC2576-X.XDD
AMC2576-X.XDDF
DM
Plastic SO
8pin
AMC2576-ADJDMF
AMC2576-X.XDMF
Append the letter “T” to part number (i.e.AMC2576-X.XDMFT,
1
DD007_E
--
DECEMBER 2006
AMC2576
TYPICAL APPLICATION
AMC2576-X.X
4
FB
7V – 40V
DC INPUT
1 VIN
GND
CIN
100µF
3
VOUT
ENABLE
2
OUTPUT
L1
100µH
5
COUT
1000µF
Figure 1. Fixed Output Voltage Versions
AMC2576-ADJ
FB 4
7V – 40V
DC INPUT
1 V
IN
OUTPUT
VOUT 2
GND
CIN
100µF
3
ENABLE
5
L1
100µH
R2
COUT
1000µF
R1
Figure 2. Adjustable Output Voltage Versions
VOUT = VREF
R2 = R1
(1+
( VV
OUT
)
R2
R1
−1
REF
)
Where VREF = 1.23V, R1 between 1K and 5K
Copyright © 2006 ADDtek Corp.
2
DD007_E --
DECEMBER 2006
AMC2576
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Voltage, VIN
ENABLE Pin Input Voltage
Operating Junction Temperature, TJ
Storage Temperature Range
Lead Temperature (soldiering, 10 seconds)
Note 1:
45V
-0.3V ≤ V ≤ VIN
150°C
-65°C to 150°C
260°C
Exceeding these ratings could cause damage to the device.
negative out of the specified terminal.
All voltages are with respect to Ground. Currents are positive into,
RECOMMENDED OPERATING RATINGS
-40°C ≤ TJ ≤ 125°C
40V(Max.)
Temperature Range
Input Voltage, VIN
THERMAL DATA
P,PB, DD PACKAGE:
Thermal Resistance-Junction to Tab, θJT
Thermal Resistance-Junction to Ambient, θJA
3.0°C /W
45°C /W
Junction Temperature Calculation: TJ = TA + (PD × θ JA).
The θJA numbers are guidelines for the thermal performance of the device/pc-board system.
All of the above assume no ambient airflow.
BLOCK DIAGRAM
VIN
FB
1
4
R2*
3
5
ENABLE
2
VOUT
Driver
Error
Amplifier
1.23V
Reference
VOUT = 3.3V
VOUT = 5.0V
VOUT = Adjustable
Copyright © 2006 ADDtek Corp.
Regulator
With
Enable
Comparator
R1*
GND
Thermal Shutdown
&
Current Limit
52KHz
Oscillator
Reset
: R2/R1 = 1.7
: R2/R1 = 3.1
: R2 = 0
R1 = Open
3
DD007_E --
DECEMBER 2006
AMC2576
DC ELECTRICAL CHARACTERISTICS
Unless otherwise specified, these specifications apply VIN = 12V, ILOAD = 0.5A and the operating ambient
temperatures TJ = 25°C.
Parameter
Output Voltage
(Note 1)
AMC2576-3.3
AMC2576-5.0
Output Voltage
(Note 1)
AMC2576-3.3
Output Voltage
(Note 1)
AMC2576-3.3
Feedback Voltage
(Note 1)
Feedback Voltage
(Note 1)
Feedback Voltage
(Note 1)
AMC2576-5.0
AMC2576-5.0
Symbol
Test Conditions
VOUT Test circuit of Figure 1
VOUT
3.432
8V ≤VIN ≤ 40V
4.800
5.000
5.200
0.5A ≤ ILOAD ≤ 3A,
6V ≤VIN ≤ 40V
3.135
3.300
3.482
8V ≤VIN ≤ 40V
4.750
5.000
5.250
1.217
1.230
1.243
V
0.5A ≤ ILOAD ≤ 3A
1.193
1.230
1.267
V
0.5A ≤ ILOAD ≤ 3A,
-40°C ≤ TJ ≤ 125°C
1.180
1.230
1.286
V
8V ≤VIN ≤ 40V, VOUT = 5V,
Test circuit of Figure 2
8V ≤VIN ≤ 40V, VOUT = 5V,
Test circuit of Figure 2
(Note 3)
58
63
10
Standby Current
ISTBY ENABLE = 5V
70
200
Saturation Voltage
VSAT ILOAD = 3A (Note 4)
1.4
1.8
Oscillator Frequency
Quiescent Current
ILOAD = 3A
fOSC
IQ
ILOAD = 3A, VOUT = 5V
TJ = 25°C
(Note 2)
O
-40 C ≤ TJ ≤ 125°C
Feedback Bias Current
IFB
VOUT = 5V
(ADJ version only)
Duty Cycle (ON)
DC
(Note 5)
Current Limit
ILIMIT (Note 2, 4)
Output Leakage Current
ILEAK (Note 3)
VIH
VOUT = 0V
VIL
VOUT = Normal
Output Voltage
IIH
IIL
Copyright © 2006 ADDtek Corp.
47
42
TJ = 25°C
-40°C ≤ TJ ≤ 125°C
50
93
4.2
3.5
2.2
2.4
98
7
7.2
0.3
9
1.4
100
500
8.8
9
2
20
1.0
0.8
ENABLE = 5V
12
30
ENABLE = 0V
0
10
DD007_E --
V
kHz
mA
µA
V
nA
%
1.2
4
V
%
2.0
TJ = 25°C
-40°C ≤ TJ ≤ 125°C
TJ = 25°C
-40°C ≤ TJ ≤ 125°C
VOUT = 0V
VOUT = -1V
TJ = 25°C
-40°C ≤TJ ≤125°C
TJ = 25°C
-40°C ≤ TJ ≤ 125°C
ENABLE Threshold Voltage
ENABLE Input Current
V
3.300
75
77
77
52
52
5
Efficiency
Units
3.168
AMC2576-ADJ VOUTFB Test circuit of Figure 2 VOUT = 5V
AMC2576-3.3
AMC2576-5.0
AMC2576-ADJ
Max
3.366
5.100
6V ≤VIN ≤ 40V
Test circuit of Figure 1
AMC2576-ADJ VOUTFB
Typ
3.300
5.000
0.5A ≤ ILOAD ≤ 3A
Test circuit of Figure 1
VOUT -40°C ≤ TJ ≤ 125°C
AMC2576-ADJ VOUTFB
AMC2576
Min
3.234
4.900
A
mA
V
µA
DECEMBER 2006
AMC2576
Note 1:
External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance.
Refer to Application Information for details.
Note 2:
The oscillator frequency reduces to approximately 11kHz in the event of fault conditions, such as output short or overload. And the
regulated output voltage will drop approximately 40% from the nominal output voltage. This self-protection feature lowers the average
power dissipation by lowering the minimum duty cycle from 5% down to approximately 2%.
Note 3:
For these parameters, FB is removed from VOUT and connected to +12V to force the output transistor OFF.
Note 4:
VOUT pin sourcing current. No diode, inductor or capacitor connect to VOUT.
Note 5:
FB is removed from VOUT and connected to 0V.
Copyright © 2006 ADDtek Corp.
5
DD007_E --
DECEMBER 2006
AMC2576
CHARACTERIZATION CURVES
Test circuits of Figure 1 and 2, TJ =25°C, unless otherwise specified.
Output voltage vs. temperature
5.00
5.10
5.08
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92
4.90
4.88
4.86
4.84
4.82
4.80
VOUT=5V
VIN = 12V, VOUT = 5V
ILOAD = 0.5A
4.98
VOUT(V)
VOUT(V)
Line regulation
ILOAD=0.5A
ILOAD=3A
4.96
4.94
4.92
4.90
0
5
10
15
20
25
30
35
-40
40
-20
0
20
VIN(V)
100 120
VOUT = 5V
VIN = 25V
Quiescent Current (mA)
Current Limit (A)
80
30.0
8.60
8.20
8.00
7.80
7.60
7.40
7.20
7.00
25.0
20.0
15.0
ILOAD=3A
10.0
5.0
ILOAD=200mA
0.0
-40 -20
0
20
40
60
80
0
100 120
10
20
30
40
Input Voltage(V)
TJ (°C)
Dropout voltage vs. temperature
Standby current vs. temperature
2.10
180
160
ILOAD=3A
1.80
140
1.50
Standby current (µA)
Dropout Voltage (V)
60
Quiescent current vs. input voltage
Current limit vs. temperature
8.40
40
TJ (°C)
1.20
0.90
ILOAD=0. 5A
0.60
0.30
VIN =40V
120
100
80
60
VIN =12V
40
20
0.00
0
-40 -20
0
20
40
60
80
-40
100 120
TJ (°C)
Copyright © 2006 ADDtek Corp.
-20
0
20
40
60
80
100 120
TJ (°C)
6
DD007_E --
DECEMBER 2006
AMC2576
CHARACTERIZATION CURVES (continued)
Test circuits of Figure 1 and 2, TJ =25°C, unless otherwise specified.
Saturation voltage vs. load current
Load transient response
1.60
5V
1.20
1.00
0.80
VOUT
100mV/ Div
TJ = 25°C
TJ =125°C
0.60
0.40
3A
1A/ Div
Saturation voltage (V)
1.40
0.20
0.00
0
0.5
1
1.5
2
2.5
3
ILOAD
0.5A
ILOAD (A)
Time:100µs/ Div
Copyright © 2006 ADDtek Corp.
7
DD007_E --
DECEMBER 2006
AMC2576
APPLICATION INFORMATION
Input Capacitors (CIN)
It is required that VIN must be bypassed with at least a 100µF electrolytic capacitor for stability. Also, it is strongly
recommended the capacitor’s leads must be dept short, and located near the regulator as possible.
For low operating temperature range, for example, below -25°C, the input capacitor value may need to be larger. This
is due to the reason that the capacitance value of electrolytic capacitors decreases and the ESR increases with lower
temperatures and age. Paralleling a ceramic or solid tantalum capacitor will increase the regulator stability at cold
temperatures.
Output Capacitors (COUT)
An output capacitor is also required to filter the output voltage and is needed for loop stability. The capacitor should
be located near the AMC2576 using short PC board traces. Low ESR types capacitors are recommended for low
output ripple voltage and good stability. Generally, low value or low voltage (less than 12V) electrolytic capacitors
usually have higher ESR numbers. For example, the lower capacitor values (220µF–1000µF) will yield typically 50
mV to 150 mV of output ripple voltage, while larger-value capacitors will reduce the ripple to approximately 20 mV
to 50 mV.
The amount of output ripple voltage is primarily a function of the ESR (Equivalent Series Resistance) of the output
capacitor and the amplitude of the inductor ripple current (∆IIND).
Output Ripple Voltage = (∆IIND) ×
(ESR of COUT)
Some capacitors called “high-frequency,” “low-inductance,” or “low-ESR.” are recommended to use to further reduce
the output ripple voltage to 10 mV or 20 mV. However, very low ESR capacitors, such as Tantalum capacitors, should
be carefully evaluated.
Catch Diode
This diode is required to provide a return path for the inductor current when the switch is off. It should be located
close to the AMC2576 using short leads and short printed circuit traces as possible.
To satisfy the need of fast switching speed and low forward voltage drop, Schottky diodes are widely used to provide
the best efficiency, especially in low output voltage switching regulators (less than 5V). Besides, fast-Recovery,
high-efficiency, or ultra-fast recovery diodes are also suitable. But some types with an abrupt turn-off characteristic
may cause instability and EMI problems. A fast-recovery diode with soft recovery characteristics is a better choice.
Copyright © 2006 ADDtek Corp.
8
DD007_E --
DECEMBER 2006
AMC2576
APPLICATION INFORMATION (contd.)
Output Voltage Ripple and Transients
The output ripple voltage is due mainly to the inductor saw tooth ripple current multiplied by the ESR of the output
capacitor.
The output voltage of a switching power supply will contain a saw tooth ripple voltage at the switcher frequency,
typically about 1% of the output voltage, and may also contain short voltage spikes at the peaks of the saw tooth
waveform.
Due to the fast switching action, and the parasitic inductance of the output filter capacitor, there is voltage spikes
presenting at the peaks of the saw tooth waveform. Cautions must be taken for stray capacitance, wiring inductance,
and even the scope probes used for transients evaluation. To minimize these voltage spikes, shortening the lead length
and PCB traces is always the first thought. Further more, an additional small LC filter (20µH & 100µF) (as shown in
Figure 3) will possibly provide a 10X reduction in output ripple voltage and transients.
AMC2576-ADJ
FB 4
L2
20µH
1 V
IN
7V – 40V
DC INPUT
CIN
100µF
GND
3
VOUT 2
ENABLE
L1
100µH
5
OUTPUT
COUT
1000µF
R2
50K
R1
1.21K
C1
100µF
Figure 3. LC Filter for Low Output Ripple
Inductor Selection
The AMC2576 can be used for either continuous or discontinuous modes of operation. Each mode has distinctively
different operating characteristics, which can affect the regulator performance and requirements.
With relatively heavy load currents, the circuit operates in the continuous mode (inductor current always flowing), but
under light load conditions, the circuit will be forced to the discontinuous mode (inductor current falls to zero for a
period of time). For light loads (less than approximately 300 mA) it may be desirable to operate the regulator in the
discontinuous mode, primarily because of the lower inductor values required for the discontinuous mode.
Inductors are available in different styles such as pot core, toroid, E-frame, bobbin core, et., as well as different core
materials, such as ferrites and powdered iron. The least expensive, the bobbin core type, consists of wire wrapped on a
ferrite rod core. This type of construction makes for an inexpensive inductor, but since the magnetic flux is not
completely contained within the core, it generates more electromagnetic interference (EMI). This EMI can cause
problems in sensitive circuits, or can give incorrect scope readings because of induced voltages in the scope probe.
An inductor should not be operated beyond its maximum rated current because it may saturate. When an inductor
begins to saturate, the inductance decreases rapidly and the inductor begins to look mainly resistive (the DC resistance
of the winding). This will cause the switch current to rise very rapidly. Different inductor types have different
saturation characteristics, and this should be well considered when selecting as inductor.
Copyright © 2006 ADDtek Corp.
9
DD007_E --
DECEMBER 2006
AMC2576
APPLICATION INFORMATION (contd.)
Feedback Connection
For fixed output voltage version, the FB (feedback) pin must be connected to VOUT. For the adjustable version, it is
important to place the output voltage ratio resistors near AMC2576 as possible in order to minimize the noise
introduction.
ENABLE
It is required that the ENABLE must not be left open. For normal operation, connect this pin to a “LOW” voltage
(typically, below 1.6V). On the other hand, for standby mode, connect this pin with a “HIGH” voltage. This pin can
be safely pulled up to +VIN without a resistor in series with it.
Grounding
To maintain output voltage stability, the power ground connections must be low-impedance. For the 5-lead TO-220
and TO-263 style package, both the tab and pin 3 are ground and either connection may be used.
Heat Sink and Thermal Consideration
Although the AMC2576 requires only a small heat sink for most cases, the following thermal consideration is
important for all operation. With the package thermal resistances θJA and θJC, total power dissipation can be estimated
as follows:
PD = (VIN × IQ)+(VOUT / VIN)(ILOAD × VSAT);
When no heat sink is used, the junction temperature rise can be determined by the following:
∆TJ = PD × θJA;
With the ambient temperature, the actual junction temperature will be:
TJ = ∆TJ +TA ;
If the actual operating junction temperature is out of the safe operating junction temperature (typically 125°C), then a
heat sink is required. When using a heat sink, the junction temperature rise will be reduced by the following:
∆TJ = PD × (θJC + θinterface + θHeat sink);
As one can see from the above, it is important to choose an heat sink with adequate size and thermal resistance, such
that to maintain the regulator’s junction temperature below the maximum operating temperature.
Copyright © 2006 ADDtek Corp.
10
DD007_E
--
DECEMBER 2006
AMC2576
PACKAGE
5-Pin Plastic TO-220 (P)
S
B
INCHES
C
T
MILLIMETERS
MIN
TYP
MAX
MIN
TYP
MAX
A
0.560
-
0.650
14.23
-
16.51
B
0.380
-
0.420
9.66
-
10.66
C
0.140
-
0.190
3.56
-
4.82
D
0.018
-
0.035
0.46
-
0.89
F
0.140
-
0.160
3.56
-
4.06
G
0.134
-
-
3.40
-
-
J
0.012
-
0.045
0.31
-
1.14
K
0.500
-
0.580
12.70
-
14.73
F
A
K
N
D
R
G
N
J
0.268 TYP
6.80 TYP
R
0.080
-
0.115
2.04
-
2.92
S
0.045
-
0.055
1.14
-
1.39
T
0.230
-
0.270
5.85
-
6.85
5-Pin Surface Mount TO-263 (DD)
C
A
INCHES
D
I
B
K
N
M
L
E
F
G
Copyright © 2006 ADDtek Corp.
11
MILLIMETERS
MIN
TYP
MAX
MIN
TYP
MAX
A
0.395
-
0.420
10.03
-
10.67
B
0.325
-
0.361
8.25
-
9.17
C
0.171
-
0.181
4.34
-
4.59
D
0.045
-
0.055
1.14
-
1.40
E
0.013
-
0.017
0.330
-
0.432
F
0.029
-
0.035
0.737
-
0.889
G
0.062
-
0.072
1.57
-
1.83
I
-
-
0.065
-
-
1.65
K
0.575
0.635
14.60
16.13
L
0.090
0.110
2.29
2.79
M
7°
7°
N
3°
3°
DD007_E
--
DECEMBER 2006
AMC2576
5-Pin Plastic TO-220B (PB)
INCHES
G
A
MILLIMETERS
MIN TYP MAX MIN TYP MAX
A 0.380 0.401 0.420 9.65 10.20 10.65
I
B
0.248
6.30
c 0.348 0.358 0.368 8.85 9.10 9.35
B
f
z1
f1
M
c
c1
d1
z4
H
J
z2
c1
0.167
4.25
d1
0.138
3.50
d2
0.154
3.90
d3
0.213
5.40
e1
0.134
3.40
e2
0.268
6.80
e3
0.032
0.81
f
0.151
3.84
f1
0.039
1.00
G 0.048 0.05 0.052 1.22 1.27 1.32
z3
H
K
d3
0.996
25.30
I 0.175 0.180 0.185 4.44 4.57 4.70
d2
J
0.965
24.50
K
0.105
2.67
L 0.164 0.173 0.182 4.17 4.40 4.63
e1
N
L
e2
O
M
0.05
1.27
N 0.013 0.015 0.025 0.33 0.381 0.63
O 0.322 0.331 0.340 8.17 8.40 8.63
z5
z1
7°
7°
z2
7°
7°
z3
7°
7°
z4
5°
5°
Z5
5°
5°
e3
Copyright © 2006 ADDtek Corp.
12
DD007_E
--
DECEMBER 2006
AMC2576
8-Pin Plastic S.O.I.C.
SYMBOLS
A
A1
A2
D
E
H
L
θ°
MIN.
0.053
0.002
0.190
0.150
0.228
0.016
0
MAX.
0.069
0.006
0.059
0.197
0.155
0.244
0.050
8
UNIT: INCH
NOTES:
1. JEDEC OUTLINE. N/A
2. DIMENSIONS “D” DOES NOT INCLUDE MOLD
FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS AND GATE
BURRS SHALL NOT EXCEED 15mm (.005in) PER
SIDE.
3. DIMENSIONS “E” DOES NOT INCLUDE
INTER-LEAD FLASH, OR PROTRUSIONS.
INTER-LEAD FLASH AND PROTRUSIONS
SHALL NOT EXCEED .25mm (.010in) PER SIDE.
Copyright © 2006 ADDtek Corp.
13
DD007_E
--
DECEMBER 2006
AMC2576
IMPORTANT NOTICE
ADDtek reserves the right to make changes to its products or to discontinue any integrated circuit product or service
without notice, and advises its customers to obtain the latest version of relevant information to verify, before placing
orders, that the information being relied on is current.
A few applications using integrated circuit products may involve potential risks of death, personal injury, or severe
property or environmental damage. ADDtek integrated circuit products are not designed, intended, authorized, or
warranted to be suitable for use in life-support applications, devices or systems or other critical applications. Use of
ADDtek products in such applications is understood to be fully at the risk of the customer. In order to minimize risks
associated with the customer’s applications, the customer should provide adequate design and operating safeguards.
ADDtek assumes to no liability to customer product design or application support. ADDtek warrants the performance of
its products to the specifications applicable at the time of sale.
ADDtek Corp.
9F, No. 20, Sec. 3, Bade Rd., Taipei, Taiwan, 105
TEL: 2-25700299
FAX: 2-25700196
Copyright © 2006 ADDtek Corp.
14
DD007_E
--
DECEMBER 2006
Similar pages