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MC33761SNT1-028

P1-P3P4-P6P7-P9P10-P12P13-P13
MC33761
http://onsemi.com
4
DEFINITIONS
Load Regulation
The change in output voltage for a change in output
current at a constant chip temperature.
Dropout Voltage
The input/output differential at which the regulator output
no longer maintains regulation against further reductions in
input voltage. Measured when the output drops 100 mV
below its nominal value (which is measured at 1.0 V
differential value). The dropout level is affected by the chip
temperature, load current and minimum input supply
requirements.
Output Noise Voltage
This is the integrated value of the output noise over a
specified frequency range. Input voltage and output current
are kept constant during the measurement. Results are
expressed in mVRMS.
Maximum Power Dissipation
The maximum total dissipation for which the regulator
will operate within its specs.
Quiescent Current
The quiescent current is the current which flows through
the ground when the LDO operates without a load on its
output: internal IC operation, bias etc. When the LDO
becomes loaded, this term is called the Ground current. It is
actually the difference between the input current (measured
through the LDO input pin) and the output current.
Line Regulation
The change in output voltage for a change in input voltage.
The measurement is made under conditions of low
dissipation or by using pulse technique such that the average
chip temperature is not significantly affected. One usually
distinguishes static line regulation or DC line regulation (a
DC step in the input voltage generates a corresponding step
in the output voltage) from ripple rejection or audio
susceptibility where the input is combined with a frequency
generator to sweep from a few hertz up to a defined
boundary while the output amplitude is monitored.
Thermal Protection
Internal thermal shutdown circuitry is provided to protect
the integrated circuit in the event that the maximum junction
temperature is exceeded. When activated at typically 125°C,
the regulator turns off. This feature is provided to prevent
catastrophic failures from accidental overheating.
Maximum Package Power Dissipation
The maximum power package power dissipation is the
power dissipation level at which the junction temperature
reaches its maximum operating value, i.e. 125°C.
Depending on the ambient temperature, it is possible to
calculate the maximum power dissipation and thus the
maximum available output current.
MC33761
http://onsemi.com
5
CHARACTERIZATION CURVES
All curves taken with V
in
= V
out
+ 1.0 V, V
out
= 2.8 V, C
out
= 1.0 mF
25°C
−40°C
25°C
85°C
Figure 2. Ground Current versus
Output Current
Figure 3. Quiescent Current versus
Temperature
Figure 4. Dropout versus Output Current Figure 5. Output Voltage versus
Output Current
OUTPUT CURRENT (mA)
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
10080600
GROUND CURRENT (mA)
AMBIENT TEMPERATURE (°C)
100806040200−20−40−60
180
175
170
mQUIESCENT CURRENT ( A)
165
0.5
0
185
40
20
OUTPUT CURRENT (mA)
200
150
100
50
10080600
DROPOUT (mV)
OUTPUT CURRENT (mA)
100806040200
2.800
2.795
2.790
OUTPUT VOLTAGE (V)
2.775
0
2.805
4020
2.785
2.780
Figure 6. Dropout versus Temperature
TEMPERATURE (°C)
180
160
120
100
60
40
1008060−60
DROPOUT VOLTAGE (mV)
20
0
0−20
80
140
−40 4020
−40°C
25°C
85°C
−40°C
85°C
40°C
−20°C
0°C
1.0 mA
30 mA
60 mA
80 mA
MC33761
http://onsemi.com
6
APPLICATION HINTS
Input Decoupling
As with any regulator, it is necessary to reduce the
dynamic impedance of the supply rail that feeds the
component. A 1.0 mF capacitor either ceramic or tantalum is
recommended and should be connected close to the
MC33761 package. Higher values will correspondingly
improve the overall line transient response.
Output Decoupling
Thanks to a novel concept, the MC33761 is a stable
component and does not require any specific Equivalent
Series Resistance (ESR) neither a minimum output current.
Capacitors exhibiting ESRs ranging from a few mW up to
3.0 W can thus safely be used. The minimum decoupling
value is 1.0 mF and can be augmented to fulfill stringent load
transient requirements. The regulator accepts ceramic chip
capacitors as well as tantalum devices.
Noise Decoupling
Unlike other LDOs, the MC33761 is a true low−noise
regulator. Without the need of an external bypass capacitor,
it typically reaches the incredible level of 40 mVRMS overall
noise between 100 Hz and 100 kHz. To give maximum
insight on noise specifications, ON Semiconductor includes
spectral density graphics. The classical bypass capacitor
impacts the start−up phase of standard LDOs. However,
thanks to its low−noise architecture, the MC33761 operates
without a bypass element and thus offers a typical 40 ms
start−up phase.
Protections
The MC33761 hosts several protections, giving natural
ruggedness and reliability to the products implementing the
component. The output current is internally limited to a
maximum value of 180 mA typical while temperature
shutdown occurs if the die heats up beyond 125°C. These
values let you assess the maximum differential voltage the
device can sustain at a given output current before its
protections come into play.
The maximum dissipation the package can handle is given
by:
P
max
+
T
Jmax
* T
A
R
qJA
If T
Jmax
is limited to 125°C, then the MC33761 can
dissipate up to 470 mW @ 25°C. The power dissipated by
the MC33761 can be calculated from the following formula:
Ptot +
ǒ
V
in
I
gnd
(I
out
)
Ǔ
)
ǒ
V
in
* V
out
Ǔ
I
out
or
Vin
max
+
Ptot ) V
out
I
out
I
gnd
) I
out
If a 80 mA output current is needed, the ground current is
extracted from the data−sheet curves: 4.0 mA @ 80 mA. For
a MC33761SNT1−28 (2.8 V) delivering 80 mA and
operating at 25°C, the maximum input voltage will then be
8.3 V.
Typical Applications
The following picture portrays the typical application of
the MC33761.
P1-P3P4-P6P7-P9P10-P12P13-P13

MC33761SNT1-028

Mfr. #:
Buy MC33761SNT1-028
Manufacturer:
ON Semiconductor
Description:
LDO Voltage Regulators 2.8V 80mA Output
Lifecycle:
New from this manufacturer.
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