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Motorola Semiconductors |
Three-Terminal Negative
Voltage Regulators
The MC7900 series of fixed output negative voltage regulators are
intended as complements to the popular MC7800 series devices. These
negative regulators are available in the same seven–voltage options as the
MC7800 devices. In addition, one extra voltage option commonly employed
in MECL systems is also available in the negative MC7900 series.
Available in fixed output voltage options from – 5.0 V to – 24 V, these
regulators employ current limiting, thermal shutdown, and safe–area
compensation – making them remarkably rugged under most operating
conditions. With adequate heatsinking they can deliver output currents in
excess of 1.0 A.
• No External Components Required
• Internal Thermal Overload Protection
• Internal Short Circuit Current Limiting
• Output Transistor Safe–Area Compensation
• Available in 2% Voltage Tolerance (See Ordering Information)
Representative Schematic Diagram
2.0 k 8.0 k
Gnd
3.6 k 1.0 k 4.0 k R1
1.2 k 1.6 k
R2
Order this document by MC7900/D
MC7900
Series
THREE–TERMINAL
NEGATIVE FIXED
VOLTAGE REGULATORS
T SUFFIX
PLASTIC PACKAGE
CASE 221A
Heatsink surface
connected to Pin 2.
1
2
3
Pin 1. Ground
2. Input
3. Output
D2T SUFFIX
PLASTIC PACKAGE
CASE 936
(D2PAK)
12
3
Heatsink surface (shown as terminal 4 in
case outline drawing) is connected to Pin 2.
10 k
20 pF
10 pF 10 k
2.0 k 20 k 20 k
1.1 k
240
750
This device contains 26 active transistors.
VO
0.3
VI
ORDERING INFORMATION
Device
Output Voltage
Operating
Tolerance
Temperature Range
MC79XXACD2T
2%
MC79XXCD2T
MC79XXACT
4%
2%
TJ = 0° to +125°C
MC79XXCT
4%
MC79XXBD2T
MC79XXBT
4% TJ = – 40° to +125°C
XX indicates nominal voltage.
Package
Surface Mount
Insertion Mount
Surface Mount
Insertion Mount
STANDARD APPLICATION
Input
Cin*
0.33 µF
MC79XX
Output
CO**
1.0 µF
A common ground is required between the input
and the output voltages. The input voltage must
remain typically 2.0 V above more negative even
during the high point of the input ripple voltage.
XX, These two digits of the type number
indicate nominal voltage.
** Cin is required if regulator is located an
appreciable distance from power supply filter.
** CO improve stability and transient response.
DEVICE TYPE/NOMINAL OUTPUT VOLTAGE
MC7905
MC7905.2
MC7906
MC7908
5.0 V
5.2 V
6.0 V
8.0 V
MC7912
MC7915
MC7918
MC7924
12 V
15 V
28 V
24 V
MOTOROLA ANALOG IC DEVICE DATA
© Motorola, Inc. 1996
Rev 6
1
MC7900
MAXIMUM RATINGS (TA = +25°C, unless otherwise noted.)
Rating
Symbol
Value
Input Voltage (– 5.0 V ≥ VO ≥ –18 V) VI – 35
Input Voltage (24 V)
– 40
Power Dissipation
Case 221A
TA = +25°C
Thermal Resistance, Junction–to–Ambient
Thermal Resistance, Junction–to–Case
Case 936 (D2PAK)
TA = +25°C
Thermal Resistance, Junction–to–Ambient
Thermal Resistance, Junction–to–Case
Storage Junction Temperature Range
Junction Temperature
PD
θJA
θJC
PD
θJA
θJC
Tstg
TJ
Internally Limited
65
5.0
Internally Limited
70
5.0
– 65 to +150
+150
THERMAL CHARACTERISTICS
Characteristics
Thermal Resistance, Junction–to–Ambient
Thermal Resistance, Junction–to–Case
Symbol
RθJA
RθJC
Max
65
5.0
Unit
Vdc
W
°C/W
°C/W
W
°C/W
°C/W
°C
°C
Unit
°C/W
°C/W
MC7905C
ELECTRICAL CHARACTERISTICS (VI = –10 V, IO = 500 mA, 0°C < TJ < +125°C, unless otherwise noted.)
Characteristics
Symbol Min Typ Max Unit
Output Voltage (TJ = +25°C)
Line Regulation (Note 1)
(TJ = +25°C, IO = 100 mA)
–7.0 Vdc ≥ VI ≥ – 25 Vdc
– 8.0 Vdc ≥ VI ≥ –12 Vdc
(TJ = +25°C, IO = 500 mA)
–7.0 Vdc ≥ VI ≥ – 25 Vdc
– 8.0 Vdc ≥ VI ≥ –12 Vdc
Load Regulation, TJ = +25°C (Note 1)
5.0 mA ≤ IO ≤ 1.5 A
250 mA ≤ IO ≤ 750 mA
VO
Regline
Regload
– 4.8
–
–
–
–
–
–
– 5.0 – 5.2
7.0 50
2.0 25
35 100
8.0 50
11 100
4.0 50
Vdc
mV
mV
Output Voltage
–7.0 Vdc ≥ VI ≥ – 20 Vdc, 5.0 mA ≤ IO ≤ 1.0 A, P ≤ 15 W
VO Vdc
– 4.75 – – 5.25
Input Bias Current (TJ = +25°C)
Input Bias Current Change
–7.0 Vdc ≥ VI ≥ – 25 Vdc
5.0 mA ≤ IO ≤ 1.5 A
IIB – 4.3 8.0 mA
∆IIB mA
– – 1.3
– – 0.5
Output Noise Voltage (TA = +25°C, 10 Hz ≤ f ≤ 100 kHz)
Vn – 40 – µV
Ripple Rejection (IO = 20 mA, f = 120 Hz)
RR – 70 – dB
Dropout Voltage
IO = 1.0 A, TJ = +25°C
VI–VO
Vdc
– 2.0 –
Average Temperature Coefficient of Output Voltage
IO = 5.0 mA, 0°C ≤ TJ ≤ +125°C
∆VO/∆T
mV/°C
– –1.0 –
NOTE: 1. Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be taken into account separately.
NOTE: 1. Pulse testing with low duty cycle is used.
2 MOTOROLA ANALOG IC DEVICE DATA
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