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STMicroelectronics
STMicroelectronics

L4812 Datasheet

VERY LOWDROP VOLTAGE REGULATORS


L4812 Datasheet Preview


L4805-L4885-L4892
L4808-L4810-L4812
VERY LOW DROP VOLTAGE REGULATORS
....... INPUT/OUTPUT DROP TYP. 0.4V
400mA OUTPUT CURRENT
LOW QUIESCENT CURRENT
REVERSE POLARITY PROTECTION
OVERVOLTAGE PROTECTION (± 60V)
FOLDBACK CURRENT LIMITING
THERMAL SHUTDOWN
DES CRI P TI O N
L4800 series devices are voltage regulators with a
very low voltage drop (typically 0.4V at full rated cur-
rent), output current up to 400mA, low quiescent
current and comprehensiveon-chip protection.The-
se devices are protected against load dump and
field decay transients of ± 60V, polarity reversal and
overheating. A foldback current limiter protects
against load short circuits. Available in 5V, 8.5V,
9.2V,10V and 12V versions (all± 4%, TI = 25°C) the-
se regulators are designed for automotive, industrial
and consumer applications where low consumption
is particularly important.
SO T-82
T O - 22 0
In automotive applications the L4805 is ideal for 5V
logic supplies becauseit can operateeven when the
batteryvoltage falls below 6V. In battery backup and
standby applications the low consumption of these
devices extends battery life.
BLOCK DIAGRAM
March 1992
1/7
Page 1

L4805-L4808-L4885-L4892-L4810-L4812
ABSOLUTE MAXIMUM RATINGS
Symbol
VI
Tj, Tstg
Parameter
DC Input Voltage
DC Input Reverse Voltage
Transient Input Overvoltages :
Load Dump :
5ms < Trise < 10ms,
τf Fall Time Constant = 100ms,
Rsource < 0.5
Field Decay :
5ms < tfall < 10ms, Rsource < 10
τr Rise Time Constant = 33ms
Junction and Storage Temperature Range
Value
+ 35
- 18
60
Unit
V
V
V
- 60
- 55 to + 150
V
°C
THERMAL DATA
Symbol
Rth j-case
Rth j-amb
Parameter
Thermal Resistance Junction-case
Thermal Resistance Junction-ambient
PIN CONNECTION (top view)
Max.
Max.
SOT82
8
100
TO220
4
75
Unit
°C/W
°C/W
Order Codes
TO-220
SOT-82
L4805CV
L4808CV
L4885CV
L4892CV
L4810CV
L4812CV
L4805CX
L4808CX
L4885CX
L4892CX
L4810CX
L4812CX
Output Voltage
5V
8V
8.5 V
9.2 V
10 V
12 V
TEST AND APPLICATION CIRCUIT
The output capacitor is required for stability. Though
the 100 µF shown is the minimum recommended
value, actual size and type may vary depending
upon the application load and temperature range.
Capacitor effectiveseries resistance (ESR) also fac-
tors in the IC stability. Since ESR varies from one
brand to the next,some bench work may be required
to determine the minimum capacitor value to use in
production. Worst-case is usually determined at the
minimum ambient temperature and maximum load
expected.
Output capacitors can be increased in size to any
desired value above the minimum. One possible
purpose of this would be to maintain the output vol-
tages during brief conditions of negative input tran-
sients that might be characteristics of a particular
system.
Capacitors must also be rated at all ambient tempe-
rature expected in the system. Many aluminum type
electrolytics will freeze at temperatures less than –
30 °C, reducing their effective capacitance to zero.
To maintain regulator stability down to – 40 °C, ca-
pacitors rated at that temperature (such as tan-
talums) must be used.
2/7
Page 2

L4805-L4808-L4885-L4892-L4810-L4812
ELECTRICAL CHARACTERISTICS (VI = 14.4V; CO = 100µF; Tj = 25°C unless otherwise specified.)
Symbol
VO
Parameter
Output Voltage
VI
VO/VO
VO/VO
VI - VO
Operating Input Voltage
Line Regulation
Load Regulation
Dropout Voltage
Iq Quiescent Current
VO
TVO
SVR
IO
ISC
Temperature Output Voltage
Drift
Supply Voltage Rejection
Max Output Current
Output Short Circuit Current
(fold back condition)
T est Con di tio n
IO = 5mA to 400mA (L4805)
IO = 5mA to 400mA (L4808)
IO = 5mA to 400mA (L4810)
IO = 5mA to 400mA (L4812)
IO = 5mA to 400mA (L4885)
IO = 300mA (L4892)
VI = 13 to 26V; IO = 5mA
IO = 5 to 400mA*
IO = 400mA*
IO = 150mA
IO = 0mA
IO = 150mA
IO = 400mA*
IO = 350mA; f = 320Hz;
CO = 100µF; VI = VO +3V+2Vpp
Min.
4.80
7.68
8.16
8.83
9.60
11.50
Typ.
5.00
8.00
8.50
9.20
10.00
12.00
1
3
0.4
0.2
0.8
25
65
0.1
60
800
350
Max.
5.20
8.32
8.84
9.57
10.40
12.50
26
10
15
0.7
0.4
2
45
90
500
Unit
V
V
V
V
V
V
V
mV/V
mV/V
V
V
mA
mA
mA
mV
°CV
dB
mA
mA
* only for L4892 the current test conditions is IO = 300mA
ELECTRICAL CHARACTERISTICS (VI = 14.4V; CO = 100µF; Tj = -40 to 125°C (note 1) unless
otherwise specified.)
Symbol
VO
Parameter
Output Voltage
VI
VO/VO
VO/VO
VI - VO
Operating Input Voltage
Line Regulation
Load Regulation
Dropout Voltage
Iq Quiescent Current
IO Max Output Current
ISC Output Short Circuit Current
(fold back condition)
T est Con di tio n
IO = 5mA to 400mA (L4805)
IO = 5mA to 400mA (L4808)
IO = 5mA to 400mA (L4810)
IO = 5mA to 400mA (L4812)
IO = 5mA to 400mA (L4885)
IO = 300mA (L4892)
see note 2
VI = 14 to 26V; IO = 5mA
IO = 5 to 400mA*
IO = 400mA*
IO = 150mA
IO = 0mA
IO = 150mA
IO = 400mA*
Min.
4.70
7.50
8.00
8.65
9.40
11.30
Typ.
5.00
8.00
8.50
9.20
10.00
12.00
2
5
0.5
0.25
1.2
40
80
870
230
Max.
5.30
8.50
9.00
9.75
10.60
12.70
26
15
25
0.9
0.5
3
70
140
Unit
V
V
V
V
V
V
V
mV/V
mV/V
V
V
mA
mA
mA
mA
mA
Notes : 1. This limits are guaranteed by design, correlation and statistical control on production samples over the indicated temperature and
supply voltage ranges..
2. For a DC voltage 26V < Vi < 35V the device is not operating.
3/7
Page 3

L4805-L4808-L4885-L4892-L4810-L4812
Figure 1: Dropout Voltage vs. Output Current
Figure 2: Quiescent Current vs. Output Current
Figure 3: Output Voltage vs. Temperature
Figure 4: Foldback Current Limiting(L4805)
Figure 5: Preregulator for Distributed Supplies
4/7
Page 4
Part Number L4812
Manufactur STMicroelectronics
Description VERY LOWDROP VOLTAGE REGULATORS
Total Page 7 Pages
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