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5-V Low-Drop Fixed Voltage Regulator
TLE 4278 G
Features * * * * * * * * * * * * Output voltage tolerance 2% Very low current consumption Separated reset and watchdog output Low-drop voltage Watchdog Adjustable watchdog activating threshold Settable reset threshold Overtemperature protection Reverse polarity protection Short-circuit proof Suitable for use in automotive electronics Wide temperature range Ordering Code Q67006-A9291
P-DSO-14-4
Type TLE 4278 G Functional Description
Package P-DSO-14-4 (SMD)
The TLE 4278 is a monolithic integrated low-drop fixed-voltage regulator which can supply loads up to 200 mA. The device is available in the P-DSO-14-4 package. It is designed to supply microprocessor systems under the severe conditions of automotive applications and therefore is equipped with additional protection functions against over load, short circuit and over temperature. Of course the TLE 4278 can also be used in other applications where a stabilized voltage is required. An input voltage VI in the range of 5.5 V VI 45 V is regulated to VQrated = 5 V within an accuracy of 2%. The device operates in the wide temperature range of Tj = - 40 to 150 C.
Semiconductor Group
1
1998-11-01
TLE 4278 G
Two additional features of the TLE 4278 are a load dependent watchdog function as well as a power on reset and under voltage reset function with an adjustable reset delay time and adjustable reset switching threshold. The watchdog function monitors whether the microcontroller is functioning appropriately, including time base failures. In the case that there is no positive-going edge within a certain pulse repetition-time the watchdog output is set to LOW. Programming of the max. repetition time is done by the reset delay capacitor so that no additional external components are necessary. To prevent the microcontroller from a automatic reset in case of missing pulses, the watchdog output WO is separated from the reset output RO for the TLE 4278. The watchdog output can be used as an interrupt signal for the microcontroller. Pin WO can be externally connected to pin RO. When the controller is set to sleep mode or low power mode its current consumption drops and no watchdog pulses are created. In order to prevent the microcontroller from unnecessary wake ups due to missing pulses at pin WI the watchdog feature can be disabled as a function of the load. The switch off threshold is set by an external resistor to pin WADJ. This function can also be used as a timer, which periodically wakes up the controller. Therefore the pin WADJ has to be connected to the output Q. The power on reset feature is necessary for a defined start of the microprocessor when switching on the application. For a certain delay time after the output voltage of the regulator has surpassed the reset threshold, a reset signal is generated. The delay time is set by an external delay capacitor. The under voltage reset circuit supervises the output voltage. In case VQ falls below the reset threshold the reset output is set LOW after a short reaction time. The reset LOW signal is generated down to an output voltage VQ of 1 V. In addition the reset switching threshold can be adjusted by an external voltage divider. This feature is useful with microprocessors which guarantee a safe operation down to voltages below the internally set reset threshold of 4.65 V typical.
Semiconductor Group
2
1998-11-01
TLE 4278 G
Pin Configuration (top view) P-DSO-14-4
WO WADJ GND GND GND D RADJ 1 2 3 4 5 6 7 14 13 12 11 10 9 8
AEP02113
RO V GND GND GND VQ W
Figure 1 Pin Definitions and Functions Pin 1 2 Symbol Function WO WADJ Watchdog Output; the open collector output is connected to the 5-V output via an integrated resistor of 30 k. Watchdog Adjust; an external resistor to GND determine the watchdog activating threshold. Ground Reset Delay; connect a capacitor to ground for delay time adjustment. Reset Switching Threshold Adjust; for setting the switching threshold, connect a voltage divider from output to ground. If this input is connected to ground, the reset is triggered at the internal threshold. Watchdog input; positive-edge-triggered input for monitoring a microcontroller. 5-V output voltage; block to ground with min. 10 F capacitor, ESR < 10 at 10 kHz. Input voltage; block to ground directly on the IC with ceramic capacitor. Reset output; the open collector output is connected to the 5-V output via an integrated resistor of 30 k.
3, 4, 5, GND 10, 11, 12 6 7 D RADJ
8 9 13 14
WI
VQ VI
RO
Semiconductor Group
3
1998-11-01
TLE 4278 G
Block Diagram
V
13
12
VQ
Temperature Sensor
Protection Circuit Reset Generator Control Amplifier
14
RO
7 1
RADJ WO D
+
-
Bandgap Reference
Watchdog
6
3-5, 10-12 GND
2 WADJ
8 W
AEB02114
Figure 2
Semiconductor Group
4
1998-11-01
TLE 4278 G
Absolute Maximum Ratings
Tj = - 40 to 150 C
Parameter Symbol Limit Values min. Input Voltage VI Voltage Current Output Voltage VQ Voltage Current Reset Output RO Voltage Current Reset Delay D Voltage Current max. Unit Notes
VI II
- 42 -
45 -
V mA
- Internally limited
VQ IQ
-1 -
25 -
V mA
- Internally limited
VRO IRO
- 0.3 -5
25 5
V mA
- -
VD ID
- 0.3 -2
7 2
V mA
- -
Reset Switching Threshold Adjust RADJ Voltage Current Watchdog Input WI Voltage Current Watchdog Output WO Voltage Current
VRADJ IRADJ
- 0.3 -
7 -
V mA
- Internally limited
VWI IWI
- 0.3 -
7 -
V mA
- Internally limited
VWO IWO
- 0.3 -5
25 5
V mA
- -
Semiconductor Group
5
1998-11-01
TLE 4278 G
Absolute Maximum Ratings (cont'd)
Tj = - 40 to 150 C
Parameter Symbol Limit Values min. Watchdog Adjust WADJ Voltage Current Ground GND Current Temperatures Junction temperature Storage temperature max. Unit Notes
VWADJ IWADJ
- 0.3 -
7 -
V mA
- Internally limited
IGND
- 100
50
mA
-
Tj Tstg
- 50 - 50
150 150
C C
- -
Note: ESD protection according to MIL Std. 883: 2 kV. Maximum ratings are absolute ratings; exceeding any one of these values may cause irreversible damage to the integrated circuit.
Operating Range Parameter Input voltage Junction temperature Thermal Resistance Junction ambient Junction pin Symbol Limit Values min. max. 45 150 V C - - 5.5 - 40 Unit Notes
VI Tj
Rthj-a Rthj-pin
- -
70 25
K/W K/W
Measured to pin 4 Measured to pin 4
Note: In the operating range the functions given in the circuit description are fulfilled.
Semiconductor Group
6
1998-11-01
TLE 4278 G
Electrical Characteristics
VI = 13.5 V; - 40 C Tj 125 C (unless otherwise specified)
Parameter Output voltage Output voltage Output current limiting Current consumption Iq = II - IQ Current consumption Iq = II - IQ Current consumption Iq = II - IQ Drop voltage; VDR = VI - VQ Load regulation Supply voltage regulation Reset Generator Reset threshold Reset headroom Reset adjust threshold Reset low voltage Reset high voltage Reset pull-up Charging current Symbol Limit Values min. typ. max. 5.10 5.2 - 200 230 12 0.5 - 20 V V mA A A mA V mV mV 1 mA IQ 150 mA; 6 V VI 28 V 1 mA IQ 50 mA; 28 V VI 45 V 4.90 5.00 4.8 200 - - - - 5.0 350 180 180 5 0.25 Unit Test Condition
VQ VQ IQ Iq Iq Iq VDR
VQ VQ
VQ = 4 V Tj = 25 C; IQ = 0 mA IQ = 0 mA; Tj = 85 C IQ = 150 mA IQ = 150 mA1) IQ = 5 to 150 mA; VI = 6 V VI = 6 to 28 V IQ = 5 mA
- 30 - 5 - 5
VRT
VQ,RT
4.5 180 - 4.5 20 2
4.65 300 0.20 - 30 5
4.8 - 1.45 0.40 - 45 8
V mV V V V k A
RADJ connected to GND
VRADJTH VROL VROH RRO Id
1.28 1.35
IQ = 10 mA VQ 3.5 V Rext = 10 k to VQ VQ 1 V
- Internal connected to VQ
VD = 1.0 V
Semiconductor Group
7
1998-11-01
TLE 4278 G
Electrical Characteristics (cont'd)
VI = 13.5 V; - 40 C Tj 125 C (unless otherwise specified)
Parameter Upper timing threshold Lower reset timing threshold Delay time Reset reaction time Watchdog Symbol Limit Values min. typ. max. 2.3 0.4 28 2.0 V V ms s - - 1.5 0.2 12 0.4 1.9 0.3 20 1.0 Unit Test Condition
VDU VDRL td tRR
CD = 47 nF CD = 47 nF
VWADJ IQ/IWADJ Current ratio VWI Slew rate Watchdog low voltage VWOL Watchdog high voltage VWOH RWO Watchdog pull-up Charge current Id Idis Discharge current Upper timing threshold VDU Lower watchdog timing VDWL
Activating threshold threshold Watchdog output period TWP Watchdog output low time Watchdog trigger time
1)
1.28 1.35 650 5 - 4.5 20 2 0.6 1.5 0.5 42 7 35 720 - 0.2 - 30 5 1.3 1.9 0.7 60 13 47
1.45 800 - 0.4 - 45 8 2.0 2.3 0.9 80 19 61
V - V V k A A V V ms ms ms
Voltage at WADJ
IQ 10 mA Rext = 10 k to VQ
- Internal connected to VQ
V/s From 20% up to 80% VQ
VD = 1.0 V VD = 1.0 V
- -
tWR TWT
Cd = 47 nF VQ > VRT Cd = 47 nF
Measured when the output voltage VQ has dropped 100 mV from the nominal value.
Semiconductor Group
8
1998-11-01
TLE 4278 G
Test Circiut
C 1 1000 F WO V VWO VWADJ VW
V C 2 470 nF
WO
13
9
VQ
Q
CQ 10 F
WADJ WADJ
W
1 2 8 6 D
TLE 4278 G
3-5, 10-12 GND RO 14 7 RADJ
RO
VRO
VO
VD
dis d
CD 47 nF
GND
VRE
AES02115
VDR = V -VO Outside the control range
Figure 3
Semiconductor Group
9
1998-11-01
TLE 4278 G
Application Information Input, Output The input capacitors CI1 and CI2 are necessary for compensating line influences. Using a resistor of approx. 1 in series with CI1, the LC circuit of input inductivity and input capacitance can be damped. To stabilize the regulation circuit the output capacitor CQ is necessary. Stability is guaranteed at values CQ 10 F with an ESR 5 within the operating temperature range.
+12 V
V
C 1 C2
13
9
VQ
R1 CQ 22 F
470 nF
1
WO
RO W RADJ
TLE 4278G
3-5, 10-12 GND Cooling Area
14 8
P
*)
6 D
7 2 WADJ
CD
47 nF
R WADJ
R2
*) or short to GND
for internal threshold
AES02116
Figure 4 Application Circuit
Semiconductor Group
10
1998-11-01
TLE 4278 G
Reset Timing The power-on reset delay time is defined by the charging time of an external capacitor Cd which can be calculated as follows:
Cd = (td x Id)/V
Definitions:
Cd = delay capacitor
td = delay time
Id = charge current, typical 5 mA V = VDU, typical 1.9 V VDU = upper delay switching threshold at Cd for reset delay time The reset reaction time trr is the time it takes the voltage regulator to set the reset out
LOW after the output voltage has dropped below the reset threshold. It is typically 1 s for delay capacitor of 47 nF. For other values for Cd the reaction time can be estimated using the following equation:
trr 20 s/F x Cd
V
< t RR
V RT VQ
dV d = dt C D
VDT VST
VD td t RR
V RO
Power-on-Reset Thermal Shutdown Voltage Dip at Input Undervoltage Secondary Spike Overload at Output
AED01542
Figure 5 Reset Timing (Watchdog Disabled)
Semiconductor Group
11
1998-11-01
TLE 4278 G
Reset Switching Threshold The present default value is 4.65 V. When using the TLE 4278 the reset threshold can be set to 3.5 V < VRTH < 4.6 V by connecting an external voltage divider to pin RADJ. The calculation can be easily done since the reset adjust input current can be neglected. If this feature is unused, the pin can be left open or even better connected to GND.
R1 = R2 x (VRTH - Vref)/Vref
Definitions:
VRT = Reset threshold Vref = comparator reference voltage, typical 1.35 V
(Reset adjust input current 50 nA)
TLE 4278 G
V
30 k
VQ
RO Band-GapReference 1.35 V >1 Band-GapReference 1.35 V
+ -
R1
RADJ
GND
R2
AES02553
Figure 6 The reset output pin is internally connected to the 5 V-output Q via a 30 k pull-up resistor. Down to an output voltage VQ of typical 1 V the reset LOW signal at pin RO in generated. For the timing of the reset feature please refer to the data sheet, figure 5.
Semiconductor Group
12
1998-11-01
TLE 4278 G
Watchdog Activating The calculation of the external resistor which adjusts the watchdog switch off threshold can be done by the following equation.
RWADJ = VWADJ x (IQ/IWADJ)/IQACT
Definitions:
VWADJ = switch off threshold, typical 1.35 V IQ/IWADJ = current ratio, typical 720 IQACT = switch off load current
TLE 4278 G
V
VQ
Band-GapReference
HIGH
Watchdog active
WADJ
+ -
LOW
Watchdog disabled
R WADJ
GND
AES02552
Figure 7
Semiconductor Group
13
1998-11-01
TLE 4278 G
Watchdog Timing The frequency of the watchdog pulses has to be higher than the minimum pulse sequence which is set by the external reset delay capacitor Cd. Calculation can be done according to the formulas given in figure 8. The watchdog output is internally connected to the output Q via a 30 k pull-up resistor. To generate a watchdog created reset signal for the microcontroller the pin WO can be connected to the reset input of the microcontroller. It is also allowed to parallel the watchdog out to the reset out.
VW
V T WP VQ VDU VD VDWL VWO T WP =
(VDU -VDWL ) ( d + dis )
T WT
t WR
d x dis
C D;
t WR =
(VDU - VDWL )
d
C D;
T WT =
(VDU - VDWL )
dis
CD
VDUL = VDRL
AED01543
Figure 8 Timing of the Watchdog Function
Semiconductor Group
14
1998-11-01
TLE 4278 G
Hints for Unused Pins Symbol RO D RADJ WI WO WADJ Function Reset output Reset delay Reset switching threshold adjust Watchdog input Watchdog output Watchdog adjust Connect to open open or to output Q GND GND open
1)
2)
to output Q via a 270 k resistor: Watchdog always active to GND: Watchdog disabled
Semiconductor Group
15
1998-11-01
TLE 4278 G
Drop Voltage VDR versus Output Current IQ
mV
AED01544
Current Consumption Iq versus Output Current IQ
mA 14 12 10 8
AED01545
V DR
700 600 500 400
q
V =13.5 V
Tj = 25 C
Tj = 125 C
300 6
Tj = 25 C
200 100 0 4 2 0
0
50
100
150
200
250
mA
0
50
100
150
200
250
mA
Q
Q
Current Consumption Iq versus Input Voltage VI
mA
AED01546
Output Voltage VQ versus Input Voltage VI
mA
AED01547
q
10
Tj = 25 C
VQ
10
8
8
R L= 33
6
6
R L= 33
4
4
R L= 50
2
R L= 100
0 10 20 30 40 V
2
0
0
0
2
4
6
8
V
V
V
Semiconductor Group
16
1998-11-01
TLE 4278 G
Charge Current Id and Discharge Current Idis versus Temperature Tj
A
AED01548
Switching Voltage VDU, VDWL and VDRL versus Temperature Tj
V
AED01549
7 6 5 4 3 2 1 0 -40
V = 13.5 V VD = 1.0 V
VD
2.8
V = 13.5 V
2.4
d
2.0 1.6 1.2 0.8 0.4 0 -40
V DU
dis
V DWL V DRL
0
40
80
120
C
0
40
80
120
C
Tj
Tj
Output Voltage VQ versus Temperature Tj
V
AED01550
Output Current Limit IQ versus Input Voltage VI
mA
AED01551
VQ
5.1
Q
250
Tj = 25 C
V = 13.5 V
5.0
200
4.9
150
4.8
100
4.7
50
4.6 -40
0
0 40 80 120 V
0
10
20
30
40
V
Tj
Vj
Semiconductor Group
17
1998-11-01
TLE 4278 G
Package Outlines P-DSO-14-4 (Plastic Dual Small Outline Package)
0.35 x 45
1.75 max 1.45 -0.2
0.19 +0.06
0.2 -0.1
4 -0.2 1)
1.27 0.35 +0.15 2) 14 0.1 0.2 14x 6 0.2 8 0.4 +0.8
1 7 8.75 -0.21) Index Marking 1) Does not include plastic or metal protrusion of 0.15 max. per side 2) Does not include dambar protrusion of 0.05 max. per side
GPS05093
Sorts of Packing Package outlines for tubes, trays etc. are contained in our Data Book "Package Information". SMD = Surface Mounted Device Semiconductor Group 18
8 max.
Dimensions in mm 1998-11-01

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