CBM2596 [COREBAI]
OPERATION INSTRUCTION;
| 型号： | CBM2596 |
| 厂家： | 
Corebai |
| 描述： | OPERATION INSTRUCTION |
| 文件： | 总15页 (文件大小：1231K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
CBM2596-XX
OPERATION INSTRUCTION
FEATURES
3.3V, 5V, 12V, and adjustable output
GENERAL DESCRIPTION
versions
Adjustable version output voltage range,
1.2V to 37V± 4% max over line and load
conditions
The CBM2596 series of regulators are
monolithic integrated circuits that provide all
the active functions for a step-down switching
regulator, capable of driving a 3A load with
excellent line and load regulation. These
devices are available in fixed output voltages
of 3.3V, 5V, 12V and an adjustable output
version.
Guaranteed 3A output load current
Input voltage range up to 40V
Requires only 4 external components
Excellent line and load regulation
specifications
Requiring a minimum number of external
components, these regulators are simple to
use.
150kHz fixed frequency internal oscillator
TTL shutdown capability
The CBM2596 series operates at
a
Low power standby mode,
IQ typically 100μA
switching frequency of 150kHz. Available in
standard 5-lead TO-220 package.
Thermal shutdown and current limit
protection
Other features include a guaranteed ± 4%
tolerance on output voltage under specified
input voltage and output load conditions, and
± 15% on the oscillator frequency. External
shutdown is included, featuring typically
100μA standby current. Self protection
APPLICATIONS
Simple high-efficiency step-down
regulator
features include
a two stage frequency
reducing current limit for output switch and
an over temperature shutdown for complete
protection under fault conditions. The over
temperature shutdown level is about 145℃
with 5℃ hysteresis.
On-card switching regulators
Positive to negative converter
ABSOLUTE MAXIMUM RATINGS
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CBM2596-XX
OPERATION INSTRUCTION
(Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.)
Rating
Maximum Input Supply Voltage
Symbol
VI
Value
Unit
V
45V
ON/OFF Pin Input Voltage
Feedback Pin Voltage
VIN
-
-0.3V≤V≤+25V
-0.3V≤V≤+25V
-1V
V
V
Output Voltage to Ground
Power Dissipation
VO
PD
Tstg
TJ
V
Internally limited
-65℃ to +150℃
40℃≤TJ≤+125℃
4.5V to 40V
W
℃
℃
V
Storage Temperature Range
Operating Temperature Range
Operating Supply Voltage
VIN
* 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.
Typical Aplication (Fixed Output Voltage Versions)
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, TJ = 25℃，VIN = 12V for the 3.3V, 5V, and Adjustable version and
VIN = 24V for the 12V version. ILOAD = 500mA.
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CBM2596-XX
OPERATION INSTRUCTION
Characteristic
Symbol
Test Condition
4.75V≤VIN≤40V,
Min
Typ
Max
Unit
CBM2596–3
CBM2596–5
CBM2596–12
3.168
3.3
3.432
0.2A≤ILOAD≤3A
7V≤VIN≤40V,
Output Voltage
VOUT
4.8
5.0
5.2
V
0.2A≤ILOAD≤3A
15V≤VIN≤40V,
0.2A≤ILOAD≤3A
ILOAD = 3A
11.52
12.0
12.48
CBM2596–3
CBM2596–5
CBM2596–12
CBM2596–A
73
80
90
73
ILOAD = 3A
Efficiency
η
%
VIN = 25V, ILOAD = 3A
VOUT = 3V, ILOAD = 3A
4.5V≤VIN≤40V,
Feedback Voltage
VFB
CBM2596–A
CBM2596-A
0.2A≤ILOAD≤3A
VOUT
1.193
110
1.230
1.267
50
V
programmed for 3V
Feedback Bias
Current
ID
VFB = 1.3V
15
nA
Oscillator Frequency
Saturation Voltage
Max Duty Cycle
(ON)
fO
150
173
1.4
kHz
V
VSAT
IOUT = 3A(Note 1,2)
(Note 2)
1.16
100
DC
%
Max Duty Cycle
(OFF)
(Note 3)
0
Current Limit
Output Leakage
Current
ICL
IL
Peak Current(Note 1,2)
Output = 0V(Note 1,3)
Output = -1V, VIN = 40V
(Note 3)
3.4
4.5
6.0
50
30
10
A
μA
mA
mA
2
5
Quiescent Current
Standby Quiescent
Current
IQ
ISTBY
ON/OFF pin = 5V (OFF), VIN = 40V
100
1.3
200
0.6
μA
ON/OFF Pin Logic
Input
VIH
VIL
Low (Regulator ON)
High (Regulator OFF)
2.0
V
Threshold Voltage
ON/OFF Pin Input
Current
IH
IL
VLOGIC = 2.5V (regulator OFF)
VLOGIC = 0.5V (regulator ON)
5
15
5
μA
0.02
Note 1: No elements connected to output pin.
Note 2: Feedback pin removed from output and connected to 0V to force the output transistor switch ON.
Note 3: Feedback pin removed from output and connected to 12V for the 3.3V, 5V, and the A version, and 15V
for the 12V version. To force the output transistor switch OFF.
Typical Perfomance Characteristics
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CBM2596-XX
OPERATION INSTRUCTION
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CBM2596-XX
OPERATION INSTRUCTION
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CBM2596-XX
OPERATION INSTRUCTION
Test Circuits
Figure1. Standard Test Circuit for Fixed Output Voltage Versions
CIN —470 µF, 50V, Aluminum Electrolytic Nichicon “PL Series”
COUT —220 µF, 25V Aluminum Electrolytic, Nichicon “PL Series”
D1 —5A, 40V Schottky Rectifier, 1N5825
L1 —68 µH, L38
Figure 2. Standard Test Circuit for Adjustable Output Voltage Versions
V
where VREF = 1.23V
VOUT = VREF 1 + RR
R2 = R1 OUT − 1
V
REF
2
1
Select R1 to be approximately 1 kW, use a 1% resistor for best stability.
CIN —470 µF, 50V, Aluminum Electrolytic Nichicon “PL Series”
COUT —220 µF, 35V Aluminum Electrolytic, Nichicon “PL Series”
D1 —5A, 40V Schottky Rectifier, 1N5825
L1 —68µH, L38
R1 —1kW, 1%
1
CFF
=
31 × 103 × R2
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CBM2596-XX
OPERATION INSTRUCTION
Application Information
Figure 3. Delayed Startup
Figure 4. Undervoltage Lockout for Buck Regulator
DELAYED STARTUP
The circuit in Figure 3 uses the the ON /OFF pin to provide a time delay between the time the
input voltage is applied and the time the output voltage comes up (only the circuitry pertaining
to the delayed start up is shown). As the input voltage rises, the charging of capacitor C1 pulls
the ON /OFF pin high, keeping the regulator off. Once the input voltage reaches its final value
and the capacitor stops charging, and resistor R2 pulls the ON /OFF pin low, thus allowing the
circuit to start switching. Resistor R1 is included to limit the maximum voltage applied to the ON
/OFF pin (maximum of 25V), reduces power supply noise sensitivity, and also limits the capacitor,
C1, discharge current. When high input ripple voltage exists, avoid long delay time, because this
ripple can be coupled into the ON /OFF pin and cause problems. This delayed startup feature is
useful in situations where the input power source is limited in the amount of current it can
deliver. It allows the input voltage to rise to a higher voltage before the regulator starts
operating. Buck regulators require less input current at higher input voltages.
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CBM2596-XX
OPERATION INSTRUCTION
UNDERVOLTAGE LOCKOUT
Some applications require the regulator to remain off until the input voltage reaches a
predetermined voltage. An undervoltage lockout feature applied to a buck regulator is shown in
Figure 4, while Figure 5 and 6 applies the same feature to an inverting circuit. The circuit in Figure
5 features a constant threshold voltage for turn on and turn off (zener voltage plus
approximately one volt). If hysteresis is needed, the circuit in Figure 6 has a turn ON voltage
which is different than the turn OFF voltage. The amount of hysteresis is approximately equal to
the value of the output voltage. If zener voltages greater than 25V are used, an additional 47 k
resistor is needed from the ON /OFF pin to the ground pin to stay within the 25V maximum
limit of the ON /OFF pin.
INVERTING REGULATOR
The circuit in Figure 7 converts a positive input voltage to a negative output voltage with a
common ground. The circuit operates by bootstrapping the regulator’s ground pin to the
negative output voltage, then grounding the feedback pin, the regulator senses the inverted
output voltage and regulates it.
This circuit has an ON/OFF threshold of approximately 13V.
Figure 5. Undervoltage Lockout for Inverting Regulator
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CBM2596-XX
OPERATION INSTRUCTION
This example uses the CBM2596-5.0 to generate a −5V output, but other output voltages are
possible by selecting other output voltage versions, including the adjustable version. Since this
regulator topology can produce an output voltage that is either greater than or less than the
input voltage, the maximum output current greatly depends on both the input and output
voltage. The curve shown in Figure 8 provides a guide as to the amount of output load current
possible for the different input and output voltage conditions.
The maximum voltage appearing across the regulator is the absolute sum of the input and
output voltage, and this must be limited to a maximum of 40V. For example, when converting
+20V to −12V, the regulator would see 32V between the input pin and ground pin. The
CBM2596 has a maximum input voltage spec of 40V.
Additional diodes are required in this regulator configuration. Diode D1 is used to isolate
input voltage ripple or noise from coupling through the CIN capacitor to the output, under light
or no load conditions. Also, this diode isolation changes the topology to closley resemble a buck
configuration thus providing good closed loop stability. A Schottky diode is recommended for
low input voltages, (because of its lower voltage drop) but for higher input voltages, a fast
recovery diode could be used.
Without diode D3, when the input voltage is first applied, the charging current of CIN can
pull the output positive by several volts for a short period of time. Adding D3 prevents the
output from going positive by more than a diode voltage.
Figure 6. Undervoltage Lockout with Hysteresis for Inverting Regulator
This circuit has hysteresis
Regulator starts switching at VIN = 13V
Regulator stops switching at VIN = 8V
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CBM2596-XX
OPERATION INSTRUCTION
Figure 7. Inverting −5V Regulator with Delayed Startup
CIN —68 µF/25V Tant. Sprague 595D
470 µF/50V Elec. Panasonic HFQ
COUT —47 µF/20V Tant. Sprague 595D
220 µF/25V Elec. Panasonic HFQ
Figure 8. Inverting Regulator Typical Load Current
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CBM2596-XX
OPERATION INSTRUCTION
Because of differences in the operation of the inverting regulator, the standard design
procedure is not used to select the inductor value. In the majority of designs, a 33µH, 3.5A
inductor is the best choice. Capacitor selection can also be narrowed down to just a few values.
Using the values shown in Figure 7will provide good results in the majority of inverting designs.
This type of inverting regulator can require relatively large amounts of input current when
starting up, even with light loads. Input currents as high as the CBM2596 current limit (approx
4.5A) are needed for at least 2ms or more, until the output reaches its nominal output voltage.
The actual time depends on the output voltage and the size of the output capacitor. Input power
sources that are current limited or sources that can not deliver these currents without getting
loaded down, may not work correctly. Because of the relatively high startup currents required by
the inverting topology, the delayed startup feature (C1, R1 and R2) shown in Figure 7 is
recommended. By delaying the regulator startup, the input capacitor is allowed to charge up to a
higher voltage before the switcher begins operating. A portion of the high input current needed
for startup is now supplied by the input capacitor (CIN). For severe start up conditions, the input
capacitor can be made much larger than normal.
INVERTING REGULATOR SHUTDOWN METHODS
To use the ON /OFF pin in a standard buck configuration is simple, pull it below 1.3V (@25℃,
referenced to ground) to turn regulator ON, pull it above 1.3V to shut the regulator OFF. With
the inverting configuration, some level shifting is required, because the ground pin of the
regulator is no longer at ground, but is now setting at the negative output voltage level. Two
different shutdown methods for inverting regulators are shown in Figure 9 and Figure 10.
Figure 9. Inverting Regulator Ground Referenced
Shutdown
Figure 10. Inverting Regulator Ground Referenced
Shutdown using Opto Device
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CBM2596-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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CBM2596-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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CBM2596-XX
OPERATION INSTRUCTION
TO-220-5L (Bent Staggered)
Dimensions In Millimeters
Dimensions Inches
Symbol
Min
4.4
0.7
8.4
1.0
6.3
9.91
1.6
1.2
6.4
20.8
2.7
3.9
8.4
2.5
Nom
4.6
Max
4.7
Min
Nom
0.180
0.032
0.340
Max
0.185
0.037
0.350
A
b
0.175
0.027
0.330
0.039
0.248
0.390
0.062
0.048
0.250
0.820
0.105
0.147
0.331
0.100
0.8
0.9
D
8.7
8.9
d1
d2
E
10.16
1.7
10.41
1.8
0.400
0.067
0.050
0.410
0.072
0.052
e
F
1.25
1.3
H1
H2
J1
J2
J3
Q
21.6
4.5
22.4
5.3
0.850
0.177
0.110
0.880
0.207
0.120
2.8
3.0
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CBM2596-XX
OPERATION INSTRUCTION
PACKAGE/ORDERING INFORMATION
ORDERING
PAKEAGE
MARKING
TRANSPOT
PRODUCT
TEMPRANGE
PACKAGE
NUMBER
MEDIA,QUANTILY
CBM2596T-ADJ -40℃~125℃
CBM2596DT-ADJ -40℃~125℃
TO-220
TO-263-5
TO-220
2596T-ADJ
2596DT-ADJ
2596T-3.3
2596DT-3.3
2596T-5.0
2596DT-5.0
2596T-12
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
CBM2596
CBM2596T-3.3
-40℃~125℃
CBM2596DT-3.3 -40℃~125℃
CBM2596T-5.0 -40℃~125℃
CBM2596DT-5.0 -40℃~125℃
CBM2596T-12 -40℃~125℃
CBM2596DT-12 -40℃~125℃
CBM2596-3.3
CBM2596-5.0
CBM2596-12
TO-263-5
TO-220
TO-263-5
TO-220
TO-263-5
2596DT-12
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