MC79L00, A Series
4
MOTOROLA ANALOG IC DEVICE DATA
ELECTRICAL CHARACTERISTICS
(VI = –33 V, IO = 40 mA, CI = 0.33
μ
F, CO = 0.1
μ
F, 0
°
C < TJ < +125
°
C, unless otherwise noted).
MC79L24C
MC79L24AC
Characteristics
Symbol
Min
Typ
Max
Min
Typ
Max
Unit
Output Voltage (TJ = +25
°
C)
Input Regulation
(TJ = +25
°
C)
–27 Vdc
≥
VI
≥
–38 Vdc
–27.5 Vdc
≥
VI
≥
–38 Vdc
–28 Vdc
≥
VI
≥
–38 Vdc
Load Regulation
TJ = +25
°
C, 1.0 mA
≤
IO
≤
100 mA
1.0 mA
≤
IO
≤
40 mA
VO
–22.1
–24
–25.9
–23
–24
–25
Vdc
Regline
–
–
–
–
–
–
–
350
300
–
–
–
–
–
–
350
–
300
mV
Regload
–
–
–
–
200
100
–
–
–
–
200
100
mV
Output Voltage
–27 Vdc
≥
VI
≥
–38 V, 1.0 mA
≤
IO
≤
40 mA
–28 Vdc
≥
VI
≥
–38 Vdc, 1.0 mA
≤
IO
≤
40 mA
VI = –33 Vdc, 1.0 mA
≤
IO
≤
70 mA
VO
–
–21.4
–21.4
–
–
–
–
–26.4
–26.4
–22.8
–
–22.8
–
–
–
–25.2
–
–25.2
Vdc
Input Bias Current
(TJ = +25
°
C)
(TJ = +125
°
C)
IIB
–
–
–
–
6.5
6.0
–
–
–
–
6.5
6.0
mA
Input Bias Current Change
–28 Vdc
≥
VI
≥
–38 Vdc
1.0 mA
≤
IO
≤
40 mA
IIB
–
–
–
–
1.5
0.2
–
–
–
–
1.5
0.1
mA
Output Noise Voltage
(TA = +25
°
C, 10 Hz
≤
f
≤
100 kHz)
Vn
–
200
–
–
200
–
μ
V
Ripple Rejection
(–29
≤
VI
≤
–35 Vdc, f = 120 Hz, TJ = +25
°
C)
RR
30
43
–
31
47
–
dB
Dropout Voltage
IO = 40 mA, TJ = +25
°
C
|VI–VO|
–
1.7
–
–
1.7
–
Vdc
APPLICATIONS INFORMATION
Design Considerations
The MC79L00, A Series of fixed voltage regulators are
designed with Thermal Overload Protections that shuts down
the circuit when subjected to an excessive power overload
condition, Internal Short Circuit Protection that limits the
maximum current the circuit will pass.
In many low current applications, compensation
capacitors are not required. However, it is recommended that
the regulator input be bypassed with a capacitor if the
regulator is connected to the power supply filter with long wire
length, or if the output load capacitance is large. An input
bypass capacitor should be selected to provide good
high–frequency characteristics to insure stable operation
under all load conditions. A 0.33
μ
F or larger tantalum, mylar,
or other capacitor having low internal impedance at high
frequencies should be chosen. The bypass capacitor should
be mounted with the shortest possible leads directly across
the regulator’s input terminals. Normally good construction
techniques should be used to minimize ground loops and
lead resistance drops since the regulator has no external
sense lead. Bypassing the output is also recommended.
Figure 1. Positive and Negative Regulator
Figure 2. Standard Application
+Vin
+VO
0.1
μ
F
–Vin
–VO
0.33
μ
F
MC78LXX
MC79LXX
0.1
μ
F
0.33
μ
F
Input
Output
CO**
0.1
μ
F
CI*
0.33
μ
F
MC79LXX
A common ground is required between the input and the output
voltages. The input voltage must remain typically 2.0 V above
the output voltage even during the low point on the ripple voltage.
* CI is required if regulator is located an appreciable
*
distance from the power supply filter
** CO improves stability and transient response.