Siemens TLE 4271 Technical data

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5-V Low-Drop Fixed Voltage Regulator

TLE 4271

	Features
	•	Output voltage tolerance ≤ ± 2%
	• Low-drop voltage
	•	Integrated overtemperature protection
	•	Reverse polarity protection
	• Input voltage up to 42 V					P-TO220-7-11
	• Overvoltage protection up to 65 V (≤ 400 ms)
	•	Short-circuit proof				(P-TO220-7-1)
	• Suitable for use in automotive electronics
	•	Wide temperature range
	• Adjustable reset and watchdog time
	Type			Ordering Code	Package
	TLE 4271			Q67000-A9210-A901	P-TO220-7-11
	TLE 4271		S	Q67000-A9244-A901	P-TO220-7-12	P-TO220-7-12
						(P-TO220-7-2)
	TLE 4271		G	Q67006-A9195-A901	P-TO263-7-1
	▼ TLE 4271			Q67000-A9210-C801	P-TO220-7-1
	▼ TLE 4271		S	Q67000-A9244-A801	P-TO220-7-2
	▼ TLE 4271		G	Q67006-A9195-A801	P-TO220-7-8
	▼ Not for new design
						P-TO263-7-1
						(P-TO220-7-8)

Functional Description

This device is a 5-V low-drop fixed-voltage regulator. The maximum input voltage is 42 V (65 V, ≤ 400 ms). Up to an input voltage of 26 V and for an output current up to 550 mA it regulates the output voltage within a 2 % accuracy. The short circuit protection limits the output current of more than 650 mA. The IC can be switched off via the inhibit input. An integrated watchdog monitors the connected controller. The device incorporates overvoltage protection and temperature protection that disables the circuit at unpermissibly high temperatures.

Semiconductor Group

1

1998-11-01

TLE 4271

Pin Configuration

(top view)

P-TO220-7-11	P-TO220-7-12	P-TO263-7-1
(P-TO220-7-1)	(P-TO220-7-2)	(P-TO220-7-8)

1

7

	1			7
	Ι	RO	D	Q
1	7	INH GND		W
			AEP01938

Ι

RO

D

Q

Ι

RO

D

Q

INH GND

W

INH GND

W

AEP01939

AEP02017

Figure 1

Pin Definitions and Functions

Pin

Symbol

Function

1

I

Input; block to ground directly on the IC with ceramic capacitor.

2

INH

Inhibit

3

RO

Reset Output; the open collector output is connected to the 5 V output

via an integrated resistor of 30 kΩ.

4

GND

Ground

5

D

Reset Delay; connect a capacitor to ground for delay time adjustment.

6

W

Watchdog Input

7

Q

5-V Output; block to ground with 22 µF capacitor, ESR < 3 Ω.

Semiconductor Group

2

1998-11-01

TLE 4271

Application Description

The IC regulates an input voltage in the range of 5.5 V < VI < 36 V to VQnom = 5.0 V. Up to 26 V it produces a regulated output current of more than 550 mA. Above 26 V the

save-operating-area protection allows operation up to 36 V with a regulated output current of more than 300 mA. Overvoltage protection limits operation at 42 V. The overvoltage protection hysteresis restores operation if the input voltage has dropped below 36 V. The IC can be switched off via the inhibit input, which causes the quiescent current to drop below 50 µA. A reset signal is generated for an output voltage of VQ < 4.5 V. The watchdog circuit monitors a connected controller. If there is no positivegoing edge at the watchdog input within a fixed time, the reset output is set to low. The delay for power-on reset and the maximum permitted watchdog-pulse period can be set externally with a capacitor.

Design Notes for External Components

An input capacitor CI is necessary for compensation of line influences. The resonant circuit consisting of lead inductance and input capacitance can be damped by a resistor of approx. 1 Ω in series with CI. An output capacitor CQ is necessary for the stability of the regulating circuit. Stability is guaranteed at values of CQ ≥ 22 µF and an ESR of < 3 Ω.

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 drives the base of a series 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 decreases below 4.5 V, an external capacitor CD on pin 4 (D) will be discharged by the reset generator. If the voltage on this capacitor VD drops below VDRL, a reset signal is generated on pin 2 (RO), i.e. reset output is set low. If the output voltage rises above 4.5 V, CD will be charged with constant current. After the power-on-reset time VD reaches VDU and the reset output will be set high again. The value of the power-on- reset time can be set within a wide range depending on the capacity of CD. The value of the pull-up resistor at reset output is typically 30 kΩ.

After VD has reached the voltage VDU and reset was set to high, the watchdog circuit is enabled and discharges CD with a constant current. If there is no positive-going edge observed at watchdog input, CD will be discharged down to VDWL. Then reset will be set low and the watchdog circuit will be disabled. CD will be charged with the current as at power-on reset until VD reaches VDU and reset will be set high again.

If a watchdog pulse will be observed before CD is discharged down to VDWL, the watchdog circuit will be enabled and CD will be charged too, but reset will not be set low. After VD has reached VDU, the periodical behavior starts again.

Semiconductor Group

3

1998-11-01

TLE 4271

The IC also incorporates a number of internal circuits for protection against:

•Overload

•Overvoltage

•Overtemperature

•Reverse polarity

		Temperature		Saturation
				Control and
		Sensor
				Protection
				Circuit
Ι	1				7	Q
			Control
			Amplifier	Buffer	3
	Adjustment	Bandgap				R
			+
		Reference
			-
				Reset
				Generator	5	D
				Watchdog	6	W
		2		4
		INH		GND	AEB01940

Figure 2

Block Diagram

Semiconductor Group

4

1998-11-01

TLE 4271

Absolute Maximum Ratings

Tj = – 40 to 150 °C

Parameter	Symbol		Limit Values		Unit	Notes
		min.		max.
Input
Voltage	VI	– 42		42	V	–
Voltage	VI	–		65	V	t ≤ 400 ms
Current	II	–		–	mA	internally limited
Inhibit
Voltage	VE	– 42		42	V	–
Voltage	VE	–		65	V	t ≤ 400 ms
Current	IE	–		–	mA	internally limited
Reset Output
Voltage	VR	– 0.3		42	V	–
Current	IR	–		–	mA	internally limited
Reset Delay
Voltage	VD	– 0.3		7	V	–
Current	ID	– 5		5	mA	–
Watchdog
Voltage	VW	– 0.3		7	V	–
Current	IW	– 5		5	mA	–
Output
Voltage	VQ	– 1.0		16	V	–
Current	IQ	– 5		–	mA	internally limited
Ground
Current	IGND	– 0.5		–	A	–
Temperatures
Junction temperature	Tj	–		150	°C	–
Storage temperature	Tstg	– 50		150	°C	–
Semiconductor Group			5			1998-11-01

TLE 4271

Optimum reliability and life time are guaranteed if the junction temperature does not exceed 125 °C in operating mode. Operation at up to the maximum junction temperature of 150 °C is possible in principle. Note, however, that operation at the maximum permitted ratings could affect the reliability of the device.

Operating Range

Parameter	Symbol	Limit Values		Unit	Notes
		min.	max.
Input voltage	VI	6	40	V	–
Junction temperature	Tj	– 40	150	°C	–
Thermal Resistance
Junction ambient	Rthja	–	65	K/W	–
			70	K/W	SMD version
Junction case	Rthjc	–	3	K/W	–
		–	6	K/W	P-TO220-7-8
	Zthjc	–	2	K/W	t < 1 ms

Semiconductor Group

6

1998-11-01