Fairchild Semiconductor MC78T05, MC78T12, MC78T15 Datasheet

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MC78TXX

3-Terminal 3A Positiv e Voltage Regulator

Features

• Output Current in Excess of 3.0A

• Output Transistor Safe Operating Area Compensation

• Power Diss ipation :25W

• Internal Short Circuit Current Limiting

• Internal Thermal Overload Protection

• Output Voltage Offered in 4% Tolerance

• No External Components Required

• Output Voltage of 5,12 and 15V

Internal Block Diagram

Description

This family of fixed voltage regulators are monolithic
integrated circuit capable of driving loads in excess of 3.0 A.

TO-220

1

1.Input 2. GND 3. Output

GND

INPUT

1

CURRENT
GENERATOR

STARTING
CIRCUIT

©2002 Fairchild Semiconductor Corporation

REFERENCE
VOLTAGE

ERROR
AMPLIFIER

SOA
PROTECTION

THERMAL
PROTECTION

SERIES
PASS
ELEMENT

OUTPUT

3

GND

2

Rev. 1.0.1

MC78TXX

Absolute Maximum Ratings

Parameter Symbol Value Unit

Input Voltage (for V
(for V

= 15V)

O

= 5V to 12V)

O

V

I

35
40

V

V
Power Dissipation PD Internally limited
Thermal Resistance, Junction to Air (Note1, 2)

Ta = +25°C
Thermal Resistance, Junction to Case (Note1)

Tc = +25°C
Operating Junction Temperature Range T
Storage Temperature Range T

Note:

1. Thermal resistance test board
Size: 76.2mm * 114.3mm * 1.6mm(1S0P)
JEDEC standard: JESD51 -3, JESD51-7

2. Assume no ambient airflow.

RθJA 65 °C/W

RθJC 2.5 °C/W

J

STG

0 ~ +125 °C

-65 ~ +150 °C

Electrical Characteristics(MC78T05)

(VI = 10V, IO = 3.0 A, 0°C ≤ T

Parameter Symbol Conditions Min. Typ. Max. Unit

Output Voltage Vo

Line Regulation (Note4) ∆V

Load Regulation (Note4) ∆V
Thermal Regulation

Quiescent Current I

Quiescent Current Change ∆I

Ripple Rejection RR
Dropout Voltage V

Output Noise Voltage V
Peak Output Current I
Output Resistance Ro f = 1.0kHz - 2.0 - mΩ
Short Circuit Current Limit Isc VI = 35V, T
Average Temperature

Coefficient of Output Voltage

Note:

3. Although power dissipation is internally limited, specifications apply only for P

4. Load and line regulation are specified at constant junction temperature. Change in Vo due heating effects must be taken into
account separately. Pulse testing with low duty is used.

≤ +125°C, Po ≤ P

J

5mA ≤≤≤≤ Io ≤≤≤≤ 3.0A , T

7.3V ≤≤≤≤ VI ≤≤≤≤ 20V, 5mA ≤≤≤≤ Io ≤≤≤≤ 2.0A

(Note3), unless otherwise specified. )

MAX

= +25°C

J

4.8

4.75

5.0

5.0

7.2V ≤≤≤≤ VI ≤≤≤≤ 35V , Io=5mA, TJ =+25°C

REG

Q

7.2V ≤≤≤≤ VI ≤≤≤≤ 35V , Io=1.0A, T

O

7.5V ≤≤≤≤ VI ≤≤≤≤ 20V, Io =2.0A, T

8.0V ≤≤≤≤ VI ≤≤≤≤ 12V, Io =3.0A, T
5mA ≤ Io ≤ 3.0A , TJ = +25°C

O

5mA ≤ Io ≤ 3.0A
Pulse =10ms, P = 20W

T

T

= +25°C

A

5mA ≤ Io ≤ 3.0A , TJ = +25°C
5mA ≤ Io ≤ 3.0A

= +25°C

J

= +25°C

J

= +25°C

J

-3.025mV

10

­15

- 0.002 0.03 %Vo/W

3.5

-

4.0

7.2V ≤ VI ≤ 35V, Io = 5mA
T

= +25°C ;

J

7.5V ≤ VI ≤ 20V, Io =2.0A ;
5mA ≤ Io ≤ 3.0A, T

f = 120Hz, 8V ≤ V

= +25°C

T

J

= +25°C

J

≤ 18V, Io = 2.0A

I

Io = 3A ,TJ = +25°C-2.22.5V
TA = +25°C, 10Hz ≤ f ≤ 100kHz - 10 - µV/Vo
TA = +25°C-5.0-A

=+25°C-1.52.5A

J

/∆T Io = 5.0mA - 0.2 - mV/°C

≤ Pmax, Pmax = 25W

O

∆V

Q

D
N

PK

O

-0.10.8mA

-75- dB

5.2

5.25

30
80

5.0

6.0

V

mV
mV

mA
mA

2

MC78TXX

Electrical Characteristics(MC78T12)

(VI = 19V, IO = 3.0 A, 0°C ≤ TJ ≤ +125°C, Po ≤ P

(Continued)

(Note1), unless otherwise specified. )

MAX

Parameter Symbol Conditions Min. Typ. Max. Unit

Output Voltage Vo

5mA ≤ Io ≤ 3.0A , T

14.5V ≤ VI ≤ 27V, 5mA ≤ Io ≤ 2.0A

=+25°C

J

11.5

11.41212

12.5

12.8

14.5V ≤ VI ≤ 35V, Io=5mA, TJ =+25°C

Line Regulation (Note2) ∆V

Load Regulation (Note2) ∆V
Thermal Regulation

REG

Quiescent Current I

14.5V ≤ VI ≤ 35V, Io=1.0A, T

O

14.9V ≤ VI ≤ 28V, Io =2.0A, T
16V ≤ VI ≤ 22V, Io =3.0A, T

5mA ≤ Io ≤ 3.0A, TJ =+25°C

O

5mA ≤ Io ≤ 3.0A
Pulse =10ms, P = 20W

T

TA = +25°C
5mA ≤ Io ≤ 3.0A, TJ =+25°C

Q

5mA ≤ Io ≤ 3.0A

=+25°C

J

=+25°C

J

=+25°C

J

-6.045mV

10

­15

30
80

- 0.002 0.03 %Vo/W

3.5

-

4.0

5.0

6.0

14.5V ≤ VI ≤ 35V, Io = 5mA
T

Quiescent Current Change

∆I

Ripple Rejection RR
Dropout Voltage V

Output Noise Voltage V
Peak Output Current I

PK

Q

D
N

=+25°C ;

J

14.9V ≤ VI ≤ 27V, Io =2.0A ;
5mA ≤ Io ≤ 3.0A, T

f = 120Hz, 15V ≤ V

=+25°C

T

J

=+25°C

J

≤ 25V, Io = 2.0A

I

-0.10.8mA

-67- dB

Io = 3A,TJ =+25°C-2.22.5V
TA =+25°C, 10Hz ≤ f ≤ 100kHz - 10 - µV/Vo

TA =+25°C-5.0-A
Output Resistance Ro f = 1.0kHz - 2.0 - mΩ
Short Circuit Current Limit Isc VI = 35V, T
Average Temperature

Coefficient of Output Voltage

∆V

/∆T Io = 5.0mA - 0.5 - mV/°C

O

=+25°C-1.52.5A

J

V

mV
mV

mA
mA

Note:

1. Although power dissipation is internally limited, specifications apply only for P

2. Load and line regulation are specified at constant junction temperature. Change in Vo due heating effects must be taken into
account separately. Pulse testing with low duty is used. ( P

MAX

= 25W)

≤ Pmax, Pmax = 25W

O

3