CBM2576DT-ADJ [COREBAI]
OPERATION INSTRUCTION;
| 型号： | CBM2576DT-ADJ |
| 厂家： | 
Corebai |
| 描述： | OPERATION INSTRUCTION |
| 文件： | 总16页 (文件大小：1228K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
CBM2576-XX
OPERATION INSTRUCTION
The CBM2576 series of regulators are
FEATURES
monolithic integrated circuits ideally suited
for easy and convenient design of
a
3.3 V, 5.0 V, 12 V, 15 V, and Adjustable
step–down switching regulator (buck
Output Versions
converter). All circuits of this series are
capable of driving a 3.0 A load with excellent
line and load regulation. These devices are
available in fixed output voltages of 3.3 V, 5.0
V, 12 V, 15 V, and an adjustable output
version.
Adjustable Version Output Voltage
Range,1.23 to 37 V ±4%
Maximum Over Line and Load Conditions
Guaranteed 3.0 A Output Current
Wide Input Voltage Range
These regulators were designed to
minimize the number of external components
to simplify the power supply design. Standard
series of inductors optimized for use with the
CBM2576 are offered by several different
inductor manufacturers. Since the CBM2576
converter is a switch–mode power supply, its
efficiency is significantly higher in comparison
with popular three–terminal linear regulators,
especially with higher input voltages. In many
cases, the power dissipated is so low that no
heatsink is required or its size could be
reduced dramatically.
Requires Only 4 External Components
52 kHz Fixed Frequency Internal Oscillator
TTL Shutdown Capability, Low Power
Standby Mode
High Efficiency
Uses Readily Available Standard Inductors
Thermal Shutdown and Current Limit
Protection
APPLICATIONS
A standard series of inductors optimized
for use with the CBM2576 are available from
several different manufacturers. This feature
greatly simplifies the design of switch–mode
power supplies. The CBM2576 features
include a guaranteed ±4% tolerance on
output voltage within specified input voltages
and output load conditions, and ±10% on the
oscillator frequency (±2% over 0℃ to 125℃).
External shutdown is included, featuring 80 ㎂
(typical) standby current. The output switch
includes cycle–by–cycle current limiting, as
well as thermal shutdown for full protection
under fault conditions.
Simple High–Efficiency Step–Down (Buck)
Regulator
Efficient
Pre–Regulator
for
Linear
Regulators
On–Card Switching Regulators
Positive to Negative
(Buck–Boost)
Negative Step–Up Converters
Power Supply for Battery Chargers
Converter
GENERAL DESCRIPTION
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CBM2576-XX
OPERATION INSTRUCTION
Typical Application (Fixed Output Voltage Versions)
Figure 1.
Representative Block Diagram and Typical Application
This device contains 162 active transistors.
Figure 2.
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CBM2576-XX
OPERATION INSTRUCTION
ABSOLUTE MAXIMUM RATINGS
(Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.)
Rating
Symbol
Vin
Value
Unit
V
Maximum Supply Voltage
ON/OFF Pin Input Voltage
45
-
-
-0.3V≤V≤+Vin
-1.0
V
Output Voltage to Ground (Steady–State)
Power Dissipation
V
TO–220, 5–Lead
PD
Internally Limited
W
℃/W
℃/W
W
Thermal Resistance, Junction–to–Ambient
Thermal Resistance, Junction–to–Case
TO–263, 5–Lead (D2PAK)
RθJA
RθJC
PD
65
5.0
Internally Limited
Thermal Resistance, Junction–to–Ambient
Thermal Resistance, Junction–to–Case
Storage Temperature Range
RθJA
RθJC
Tstg
-
70
℃/W
℃/W
℃
5.0
–65℃ to +150℃
Minimum ESD Rating (Human Body Model:C=100pF, R=1.5kΩ)
Lead Temperature (Soldering, 10 seconds)
Maximum Junction Temperature
2.0
kV
-
260
150
℃
TJ
℃
* Stresses beyond those listed under “absolute maximum ratings” 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 under “recommended operating
conditions” is not implied.
Exposure to absolute-maximum-rated conditions for extended periods may affect device
reliability.
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CBM2576-XX
OPERATION INSTRUCTION
OPERATING RATINGS
(Operating Ratings indicate conditions for which the device is intended to be functional, but
do not guarantee specific performance limits. For guaranteed specifications and test conditions,
see the Electrical Characteristics.)
Rating
Operating Junction Temperature Range
Supply Voltage
Symbol
TJ
Value
–40℃ to +125℃
40
Unit
℃
Vin
V
SYSTEM PARAMETERS [Note 1]
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, Vin = 12 V for the 3.3 V, 5.0 V, and Adjustable version, Vin=25V
for the 12V version, and Vin=30V for the 15V version. ILoad=500mA, TJ=25℃, for min/max values
TJ is the operating junction temperature range that applies [Note 2], unless otherwise noted.)
Characteristics
CBM2576–3.3 ([Note 1] Test Circuit Figure 3)
Output Voltage
Symbol
Min
Max
Unit
Vout
Vout
3.234
3.366
V
V
Output Voltage (6.0V≤Vin≤40V, 0.5A≤ILoad≤3.0A)
TJ = 25℃
3.168
3.135
65
3.432
3.465
-
TJ = –40 to +125℃
η
Efficiency (Vin=12V, ILoad = 3.0A)
CBM2576–5 [Note 1]
%
Output Voltage
Vout
Vout
4.9
5.1
V
V
Output Voltage (8.0V≤Vin≤40V, 0.5A≤ILoad≤3.0A)
TJ = 25℃
4.8
4.75
67
5.2
5.25
-
TJ = –40℃ to +125℃
η
Efficiency (Vin = 12V, ILoad = 3.0A)
CBM2576–12 [Note 1]
%
Output Voltage
Vout
Vout
11.76
12.24
V
V
Output Voltage (15.0V≤Vin≤40V, 0.5A≤ILoad≤3.0 A)
TJ = 25℃
11.52
11.4
12.48
12.6
TJ = –40℃ to +125℃
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CBM2576-XX
OPERATION INSTRUCTION
η
Efficiency (Vin = 12V, ILoad = 3.0A)
CBM2576–15 [Note 1]
78
-
%
Output Voltage
Vout
Vout
14.7
15.3
V
V
Output Voltage (18V≤Vin≤40V, 0.5A≤ILoad≤3.0A)
TJ = 25℃
14.4
14.25
75
15.6
15.75
-
TJ = –40℃ to +125℃
η
Efficiency (Vin = 12V, ILoad = 3.0A)
CBM2576 ADJUSTABLE VERSION [Note 1]
Feedback Voltage (Vin=12V, ILoad=0.5A, VOUT=5.0V, TJ=25℃)
%
Vout
1.217
1.243
V
V
Feedback Voltage (8.0V≤Vin≤40V, 0.5A≤ILoad≤3.0A,VOUT=5.0 V) Vout
TJ= 25℃
1.193
1.18
67
1.267
1.28
-
TJ = –40℃ to +125℃
η
Efficiency (Vin = 12V, ILoad=3.0A, VOUT=5.0V)
%
1. External components such as the catch diode, inductor, input and output capacitors can affect
switching regulator system performance.
When the CBM2576 is used as shown in the test circuit, system performance will be as shown in
system parameters section .
2. Tested junction temperature range for the CBM2576: Tlow = –40℃ Thigh = +125℃
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CBM2576-XX
OPERATION INSTRUCTION
DEVICE PARAMETERS
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, Vin = 12V for the 3.3V, 5.0V, and Adjustable version, Vin = 25V
for the 12V version, and Vin = 30V for the 15V version. ILoad = 500mA, TJ = 25℃, for min/max
values TJ is the operating junction temperature range that applies [Note 2], unless otherwise
noted.)
Characteristics
Symbol
Min
Max
Unit
ALL OUTPUT VOLTAGE VERSIONS
Feedback Bias Current (Vout = 5.0V [Adjustable Version Only]) Ib
nA
TJ = 25℃
-
-
100
TJ = –40℃ to +125℃
500
Oscillator Frequency [Note 3]
TJ = 25℃
fosc
kHz
-
-
TJ = –40℃ to +125℃
42
63
Saturation Voltage (Iout = 3.0 A [Note 4])
TJ = 25℃
Vsat
V
-
1.8
2.0
-
TJ = –40℃ to +125℃
-
Max Duty Cycle (“on”) [Note 5]
Current Limit (Peak Current [Notes 3 and 4])
TJ = 25℃
DC
ICL
93
%
A
4.2
3.5
6.9
7.5
TJ = –40℃ to +125℃
Output Leakage Current [Notes 6 and 7], TJ = 25℃
Output = 0V
IL
mA
mA
-
-
2.0
30
Output = –1.0V
Quiescent Current [Note 6]
TJ = 25℃
IQ
-
-
10
11
TJ = –40℃ to +125℃
Standby Quiescent Current (ON/OFF Pin = 5.0 V (“off”))
TJ = 25℃
Istby
uA
V
-
200
ON/OFF Pin Logic Input Level
Vout = 0V
VIH
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CBM2576-XX
OPERATION INSTRUCTION
TJ = 25℃
2.2
2.4
-
-
TJ = –40℃ to +125℃
Vout = Nominal Output Voltage
TJ = 25℃
VIL
-
-
1.0
0.8
TJ = –40℃ to +125℃
ON/OFF Pin Input Current
ON/OFF Pin = 5.0 V (“off”), TJ = 25℃
ON/OFF Pin = 0 V (“on”), TJ = 25℃
uA
IIH
IIL
-
-
30
10
3. The oscillator frequency reduces to approximately 18 kHz in the event of an output short or
an overload which causes the regulated output voltage to drop approximately 40% from the
nominal output voltage. This self protection feature lowers the average dissipation of the IC
by lowering the minimum duty cycle from 5% down to approximately 2%.
4. Output (Pin 2) sourcing current. No diode, inductor or capacitor connected to output pin.
5. Feedback (Pin 4) removed from output and connected to 0 V.
6. Feedback (Pin 4) removed from output and connected to +12 V for the Adjustable, 3.3 V,
and 5.0 V versions, and +25 V for the 12 V and 15 V versions, to force the output transistor
“off”.
7. Vin = 40 V.
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CBM2576-XX
OPERATION INSTRUCTION
Fixed Output Voltage Versions
Figure 3.
Cin – 100 mF, 75 V, Aluminium Electrolytic
Cout – 1000 mF, 25 V, Aluminium Electrolytic
D1 – Schottky, MBR360
L1 – 100 mH, Pulse Eng. PE–92108
R1 – 2.0 k, 0.1%
R2 – 6.12 k, 0.1%
Adjustable Output Voltage Versions
Figure 4.
R2
VOUT
VOUT = VREF 1.0 +
,
R2 = R1
− 1.0
R1
VREF
Where Vref = 1.23 V, R1 between 1.0 k and 5.0 k
C1 = 10 nF
C2 = 1 nF
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CBM2576-XX
OPERATION INSTRUCTION
Application Information
INVERTING REGULATOR
Figure 5 shows a CBM2576-12 in a buck-boost configuration to generate a negative 12V
output from a positive input voltage. This circuit bootstraps the regulator’s ground pin to the
negative output voltage, then by grounding the feedback pin, the regulator senses the inverted
output voltage and regulates it to −12V.
For an input voltage of 12V or more, the maximum available output current in this
configuration is approximately 700 mA. At lighter loads, the minimum input voltage required
drops to approximately 4.7V.
The switch currents in this buck-boost configuration are higher than in the standard
buck-mode design, thus lowering the available output current. Also, the start-up input current of
the buck-boost converter is higher than the standard buck-mode regulator, and this may
overload an input power source with a current limit less than 5A. Using a delayed turn-on or an
undervoltage lockout circuit (described in the next section) would allow the input voltage to rise
to a high enough level before the switcher would be allowed to turn on.
Because of the structural differences between the buck and the buck-boost regulator
topologies, the buck regulator design procedure section can not be used to to select the
inductor or the output capacitor. The recommended range of inductor values for the buck-boost
design is between 68 µ H and 220 µ H, and the output capacitor values must be larger than what
is normally required for buck designs. Low input voltages or high output currents require a large
value output capacitor (in the thousands of micro Farads).
The peak inductor current, which is the same as the peak switch current, can be calculated
from the following formula:
IP ≈ I
+
×
V +|V | 2L f
O
(V +|V |)
V |V |
1
LOAD IN
O
IN
O
V
IN
IN
1 OSC
Where fosc = 52 kHz. Under normal continuous inductor current operating conditions, the
minimum VIN represents the worst case. Select an inductor that is rated for the peak current
anticipated.
FIGURE 5. Inverting Buck-Boost Develops −12V
Also, the maximum voltage appearing across the regulator is the absolute sum of the input and output
voltage. For a −12V output, the maximum input voltage for the CBM2576 is +28V.
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CBM2576-XX
OPERATION INSTRUCTION
NEGATIVE BOOST REGULATOR
Another variation on the buck-boost topology is the negative boost configuration. The
circuit in Figure 6 accepts an input voltage ranging from −5V to −12V and provides a regulated
−12V output. Input voltages greater than −12V will cause the output to rise above −12V, but will
not damage the regulator.
Typical Load Current
400 mA for VIN = −5.2V
750 mA for VIN = −7V
Note: Heat sink may be required.
FIGURE 6. Negative Boost
Because of the boosting function of this type of regulator, the switch current is relatively
high, especially at low input voltages.
Output load current limitations are a result of the maximum current rating of the switch. Also,
boost regulators can not provide current limiting load protection in the event of a shorted load,
so some other means (such as a fuse) may be necessary.
10
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CBM2576-XX
OPERATION INSTRUCTION
UNDERVOLTAGE LOCKOUT
In some applications it is desirable to keep the regulator off until the input voltage reaches a
certain threshold. An undervoltage lockout circuit which accomplishes this task is shown in
Figure 7 while Figure 8 shows the same circuit applied to a buck-boost configuration. These
circuits keep the regulator off until the input voltage reaches a predetermined level.
VTH =VZ1 + 2VBE(Q1)
Note: Complete circuit not shown.
FIGURE 7. Undervoltage Lockout for Buck Circuit
Note: Complete circuit not shown (see Figure 10).
FIGURE 8. Undervoltage Lockout for Buck-Boost Circuit
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CBM2576-XX
OPERATION INSTRUCTION
DELAYED STARTUP
The ON /OFF pin can be used to provide a delayed startup feature as shown in Figure 9. With
an input voltage of 20V and for the part values shown, the circuit provides approximately 10 ms
of delay time before the circuit begins switching.
Increasing the RC time constant can provide longer delay times. But excessively large RC
time constants can cause problems with input voltages that are high in 60 Hz or 120 Hz ripple, by
coupling the ripple into the ON /OFF pin.
Note: Complete circuit not shown.
FIGURE 9. Delayed Startup
ADJUSTABLE OUTPUT, LOW-RIPPLE POWER SUPPLY
A 3A power supply that features an adjustable output voltage is shown in Figure 10. An
additional L-C filter that reduces the output ripple by a factor of 10 or more is included in this
circuit.
FIGURE 10. Adjustable 3A Power Supply with Low Output Ripple
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CBM2576-XX
OPERATION INSTRUCTION
Definition of Terms
BUCK REGULATOR
A switching regulator topology in which a higher voltage is converted to a lower voltage.
Also known as a step-down switching regulator.
BUCK-BOOST REGULATOR
A switching regulator topology in which a positive voltage is converted to a negative voltage
without a transformer.
DUTY CYCLE (D)
Ratio of the output switch’s on-time to the oscillator period.
V
D = t
=
=
ON
OUT
for buck regulator
T
V
IN
|V |
D = t
ON
O
for buck-boost regulator
T
|V |+V
O IN
CATCH DIODE OR CURRENT STEERING DIODE
The diode which provides a return path for the load current when the CBM2576 switch is
OFF.
EFFICIENCY (η)
The proportion of input power actually delivered to the load.
POUT
PIN
POUT
η =
=
POUT + PLOSS
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CBM2576-XX
OPERATION INSTRUCTION
PACKAGE
TO-220-5L
Dimensions In Millimeters
Min Max
Dimensions Inches
Symbol
Nom
4.45
0.89
0.50
14.86
10.16
1.71
6.81
1.27
6.16
2.74
13.97
3.81
2.73
Min
Nom
0.175
0.035
0.020
0.585
0.400
0.067
0.268
0.050
0.243
0.108
0.550
0.150
0.107
Max
0.190
0.040
0.025
0.610
0.415
0.073
0.273
0.055
0.270
0.125
0.580
0.155
0.115
A
b
4.07
0.76
0.36
14.22
9.78
1.57
6.68
1.14
5.46
2.29
13.21
3.68
2.54
4.82
1.02
0.64
15.50
10.54
1.85
6.93
1.40
6.86
3.18
14.73
3.94
2.92
0.160
0.030
0.014
0.560
0.385
0.062
0.263
0.045
0.215
0.090
0.520
0.145
0.100
C
D
E
e
e1
F
H1
J1
L
Øp
Q
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CBM2576-XX
OPERATION INSTRUCTION
TO-263-5L
Dimensions In Millimeters
Min Max
Dimensions Inches
Symbol
Nom
4.46
0.84
0.50
1.27
9.15
10.16
1.71
6.86
15.24
2.54
-
Min
0.160
0.026
0.014
0.045
0.341
0.385
0.062
0.260
0.575
0.090
-
Nom
0.176
0.033
0.020
0.050
0.360
0.400
0.068
0.270
0.600
0.100
-
Max
0.191
0.040
0.025
0.055
0.380
0.415
0.073
0.280
0.625
0.110
0.115
A
B
4.07
0.66
0.36
1.14
8.65
9.78
1.57
6.60
14.61
2.29
-
4.85
1.02
0.64
1.40
9.65
10.54
1.85
7.11
15.88
2.79
2.92
C
C2
D
E
e
F
L
L1
L2
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CBM2576-XX
OPERATION INSTRUCTION
PACKAGE/ORDERING INFORMATION
ORDERING
PAKEAGE
MARKING
TRANSPOT
PRODUCT
TEMPRANGE
PACKAGE
NUMBER
MEDIA,QUANTILY
CBM2576T-ADJ -40℃~125℃
CBM2576DT-ADJ -40℃~125℃
CBM72576T-3.3 -40℃~125℃
CBM2576DT-3.3 -40℃~125℃
CBM2576T-5.0 -40℃~125℃
CBM2576DT-5.0 -40℃~125℃
TO-220
TO-263-5
TO-220
2576T-ADJ
2576DT-ADJ
2576T-3.3
2576DT-3.3
2576T-5.0
2576DT-5.0
2576T-12
Tape and Reel,46
Tape and Reel,800
Tape and Reel,46
Tape and Reel,500
Tape and Reel,46
Tape and Reel,500
Tape and Reel,46
Tape and Reel,500
Tape and Reel,46
Tape and Reel,500
CBM2576
CBM2576-3.3
CBM2576-5
CBM2576-12
CBM2576-15
TO-263-5
TO-220
TO-263-5
TO-220
CBM2576T-12
CBM2576DT-12 -40℃~125℃
CBM2576T-15 -40℃~125℃
CBM2576DT-15 -40℃~125℃
-40℃~125℃
TO-263-5
TO-220
2576DT-12
2576T-15
TO-263-5
2576DT-15
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