TLE 4261
5-V Low-Drop Voltage Regulator
TLE 4261
Bipolar IC
Features
q
q
q
q
q
q
q
q
q
q
q
q
q
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)
P-TO220-7-1
P-TO220-7-2
Type
w
TLE 4261
w
TLE 4261 S
w
TLE 4261 G
Ordering Code
Q67000-A9003
Q67000-A9109
Q67000-A9059
Package
P-TO220-7-1
P-TO220-7-2
P-DSO-20-6 (SMD)
w
Please also refer to the new pin compatible
device TLE 4271
P-DSO-20-6
Functional Description
TLE 4261 is a 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
Application Description
The IC regulates an input voltage
V
I
in the range
V
I
= 6 V to 40 V to
V
Qrated
= 5.0 V. A
reset signal is generated for a maximum output voltage of
V
Q
less than 4.75 V. The reset
delay can be set externally with a capacitor. A connected microprocessor is monitored
by the integrated watchdog circuit. Connecting this input to the input voltage makes the
watchdog function inactive. The presence of a voltage less than 2 V on inhibit input
disables the regulator. The current consumption drops to max. 50
µA.
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/µs. 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
µF
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
µs,
a reset signal is triggered on
pin 3 and an external capacitor is 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
µA.
The IC also incorporates a number of circuits for protection against:
q
q
q
q
Overload
Overvoltage
Overtemperature
Reverse polarity
Semiconductor Group
2
1998-11-01
TLE 4261
Pin Configuration
(top view)
TLE 4261
TLE 4261 S
1
2
3 4 5
6
7
1
2
3 4 5
6
7
INH GND Watch
V
Ι
QRES DRES
V
Q
AEP00592
INH GND Watch
QRES DRES
V
Q
V
Ι
AEP01181
Pin Definitions and Functions (TLE 4261; S)
Pin
1
Symbol
Function
Input voltage;
block a capacitor directly to ground on the IC. The
capacitor rating will depend on the vehicle electrical system.
Oscillation of the input 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 rese delay.
Ground
Reset delay;
wired to ground using a capacitor.
Watchdog;
monitors the microprocessor when active.
5-V output voltage;
block to ground using a capacitor of
≥
22
µF.
ESR is
≤
3
Ω
in the operating temperature range.
3
1998-11-01
V
I
2
3
4
5
6
7
INH
QRES
GND
DRES
Watch
V
Q
Semiconductor Group
TLE 4261
Pin Configuration
(top view)
TLE 4261 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 Definitions and Functions (TLE 4261 G)
Pin
18
Symbol
Function
Input voltage;
block a capacitor directly to ground on the IC. The
capacitor rating will depend on the vehicle electrical system.
Oscillation of the input 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;
internally connected with pins 14 to 17.
Reset delay;
wired to ground using a capacitor.
Watchdog;
monitors the microprocessor when active.
5-V output voltage;
block to ground using a capacitor of
≥
22
µF.
ESR is
≤
3
Ω
in the operating temperature range.
Not connected
V
I
20
3
4-7
14 - 17
9
11
12
INH
QRES
GND
DRES
Watch
V
Q
1, 2, 8, 10, N.C.
13, 19
Semiconductor Group
4
1998-11-01
TLE 4261
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
Numbers in parentheses for TLE 4261 G
(11) 6
Watchdog
AEB00002
Block Diagram
Semiconductor Group
5
1998-11-01
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