5-V Low-Drop Voltage Regulator
TLE 4261-2
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
High accuracy 5 V
±
2%
Very low-drop voltage
Very low quiescent current
Low starting-current consumption
Proof against reverse polarity
Input voltage up to 42 V
Overvoltage protection up to 65 V (
≤
400 ms)
Short-circuit-proof
External setting of reset delay
Integrated watchdog circuit
Wide temperature range
Overtemperature protection
Suitable for automotive use
EMC proofed (100 V/m)
Ordering Code
Q67000-A9110
Q67000-A9140
Q67006-A9193
Package
P-TO220-7-1
P-DSO-20-6
(SMD)
P-TO220-7-8
(SMD)
P-TO220-7-1
Type
w
TLE 4261-2
w
TLE 4261-2 G
w
TLE 4261-2 GL
P-DSO-20-6
w
Please also refer to the new pin compatible device
TLE 4271
P-TO220-7-8
Functional Description
TLE 4261-2 is a high accuracy 5-V low-drop voltage regulator in a P-TO220-7 or in a P-
DSO package. The maximum input voltage is 42 V (65 V/≤ 400 ms). The device can
produce an output current of more than 500 mA. It is short-circuit-proof and incorporates
temperature protection that disables the circuit at impermissibly high temperatures.
Semiconductor Group
1
1998-11-01
TLE 4261-2
Application Description
The IC regulates an input voltage
V
I
in the range 6 V <
V
I
< 40 V to
V
Qrated
= 5.0 V. A
reset signal is generated for an output voltage
V
O
of < 4.75 V. The reset delay can be
set with an external capacitor. A connected microprocessor is monitored by the
integrated watchdog circuit; if pulses are missing, the reset output is set low. The pulse
repetition rate can be set within wide limits with the capacitor for reset delay. If this input
is connected to a voltage of > 6 V, the watchdog function is deactivated. The device also
features an inhibit input, which is activated by a voltage of > 6 V and then works on this
input through internal hysteresis up to approx. 3 V. A voltage of < 2 V on the inhibit input
turns off the regulator, current drain then dropping to max. 50
µ
A.
Design Notes for External Components
The input capacitor
C
I
causes a low-resistant powerline and limits the rise times of the
input voltage. The IC is protected against rise times up to 100 V/
µ
s. It is possible to damp
the tuned circuit consisting of supply inductance and input capacitance with a resistor of
approx. 1
Ω
in series to
C
I
.
The output capacitor maintains the stability of the regulating loop. Stability is guaranteed
with a rating of 22
µ
F min. at an ESR of 3
Ω
max. in the operating temperature range.
Circuit Description
The control amplifier compares a reference voltage, which is kept highly accurate by
resistance adjustment, to a voltage that is proportional to the output voltage and controls
the base of the series PNP transistor via a buffer. Saturation control as a function of the
load current prevents any over-saturation of the power element. If the output voltage
drops below 95.5% of its typical value for more than 2
µ
s, a reset signal is triggered on
pin 3 and an external capacitor discharged on pin 5. The reset signal is not cancelled
until the voltage on the capacitor has exceeded the upper switching threshold
V
DT
. A
positive-edge-triggered watchdog circuit monitors the connected microprocessor and
will likewise trigger a reset if pulses are missing. The IC can be disabled by a low level
on the inhibit input and the current consumption drops to
<
50
µ
A.
The IC also incorporates a number of circuits for protection against:
•
•
•
•
Overload
Overvoltage
Overtemperature
Reverse polarity
Semiconductor Group
2
1998-11-01
TLE 4261-2
Pin Configuration
(top view)
TLE 4261-2
TLE 4261-2 GL
1
2
3 4 5
6
7
INH GND Watch
V
Ι
QRES DRES
V
Q
AEP00592
Pin Definitions and Functions
Pin No. Symbol Function
1
V
I
Input voltage;
block a capacitor directly to ground on the IC. The
capacitor rating will depend on the vihicle electric system.
Oscillation of the output voltage can be damped by a resistor of
approx. 1
Ω
in series with the input capacitor.
Inhibit;
switches off the IC when low.
Reset output;
open collector output controlled by the reset delay.
Ground
Reset delay;
wired to ground using a capacitor.
Watchdog;
monitors the microprocessor when active.
5-V output;
block to ground using a capacitor of
≥
22-µF. ESR is
≤
3
Ω
in the operating temperature range.
2
3
4
5
6
7
INH
QRES
GND
DRES
Watch
V
Q
Semiconductor Group
3
1998-11-01
TLE 4261-2
TLE 4261-2 G
N.C.
N.C.
QRES
GND
GND
GND
GND
N.C.
DRES
N.C.
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
AEP01182
INH
N.C.
V
Ι
GND
GND
GND
GND
N.C.
V
Q
Watch
Pin No. Symbol Function
18
V
I
Input voltage;
block a capacitor directly to ground on the IC. The
capacitor rating will depend on the vihicle electric system.
Oscillation of the output voltage can be damped by a resistor of
approx. 1
Ω
in series with the input capacitor.
Inhibit;
switches off the IC when low.
Reset output;
open collector output controlled by the reset delay.
Ground
Reset delay;
wired to ground using a capacitor.
Watchdog;
monitors the microprocessor when active.
5-V output;
block to ground using a capacitor of
≥
22-µF. ESR is
≤
3
Ω
in the operating temperature range.
Not connected
20
3
4 -7,
14 - 17
9
11
12
1, 2, 8,
10, 13,
19
INH
QRES
GND
DRES
Watch
V
Q
N.C.
Semiconductor Group
4
1998-11-01
TLE 4261-2
Overvoltage
Monitoring
Temperature
Sensor
Saturation
Control and
Protection
Input
1
(18)
BANDGAP
Reference
Control
Amplifier
Buffer
+
-
7
Output
(12)
RESET
Generator
5
(9)
3
(3)
RESET
Delay
RESET
Output
Adjustment
Inhibit
(4-7)
(14-17) 4
GND
Watchdog
(20) 2
Inhibit
(11) 6
Watchdog
AEB00002
Block Diagram
Semiconductor Group
5
1998-11-01
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