L4938ED013TR Fast Delivery |IC PHOENIX CO.,LIMITED

L4938ED013TR ,ADVANCED VOLTAGE REGULATORELECTRICAL CHARACTERISTICS (V = 14V; T = -40 to 150°C unless otherwise specified.)S jSymbol Paramet ..
L4938EPD ,ADVANCED VOLTAGE REGULATORBLOCK DIAGRAMVS1 OUT11.23V REFERENCEREG1VS2 OUT2ADJEN1.23VREG21.23VCTRESPR1.4VRESETSOSI1.23VSENSE G ..
L4938EPD ,ADVANCED VOLTAGE REGULATORELECTRICAL CHARACTERISTICS (V = 14V; T = -40 to 150°C unless otherwise specified.)S jSymbol Paramet ..
L4938N ,DUAL MULTIFUNCTION VOLTAGE REGULATORELECTRICAL CHARACTERISTICSRESETSymbol Parameter Test Conditions Min. Typ. Max. UnitV Reset Low Thre ..
L4938N ,DUAL MULTIFUNCTION VOLTAGE REGULATORapplications.(top view)PIN CONNECTION POWERDIPSO20 PowerSO20N.C. 1 20 SI1 20 GNDGNDN.C. 1 16 SIC7 2 ..
L4938ND ,DUAL MULTIFUNCTION VOLTAGE REGULATORfeatures and auxiliary functions are pro-undervoltage region and to improve the transientvided to ..
LBA673 , Lead (Pb) Free Product - RoHS Compliant
LBA676 , Lead (Pb) Free Product - RoHS Compliant
LBA676 , Lead (Pb) Free Product - RoHS Compliant
LBAS16HT1G , Switching Diode
LBAS16LT1 , Switching Diode
LBAS16LT1G , Switching Diode

L4938ED013TR
ADVANCED VOLTAGE REGULATOR
L4938E/ED
L4938EPD
ADVANCED VOLTAGE REGULATOR
ENABLE AND SENSE INPUTS (EN, SI) PRO-
TECTED AGAINST NEGATIVE TRANSIENTS
DOWN TO -5V
RESET THRESHOLD ADJUSTABLE FROM
3.8 TO 4.7V
EXTREMELY LOW QUIESCENT CURRENT,
65μA (LESS THAN 90μA) IN STANDBY
MODE
OPERATING DC SUPPLY VOLTAGE RANGE
5V - 28V
OPERATING TRANSIENT SUPPLY VOLT-
AGE UP TO 40V
HIGH PRECISION STANDBY OUTPUT VOLT-
AGE 5V ± 1% WITH 100mA CURRENT CA-
PABILITY
OUTPUT 2 VOLTAGE 5V ± 2% WITH 400mA
CURRENT CAPABILITY (ADJ WIRED TO
VOUT2)
OUTPUT 2 VOLTAGE ADJUSTABLE BY EX-
TERNAL VOLTAGE DIVIDER
OUTPUT 2 DISABLE FUNCTION FOR
STANDBY MODE
DESCRIPTION
The L4938E/ED/EPD is a monolithic integrated
dual voltage regulator with two very low dropout
outputs and additional functions as power-on re-
set and input voltage sense. It is designed for
supplying the microcomputer controlled systems
especially in automotive applications.
PIN CONNECTIONS
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS
Note 1: The circuit is ESD protected according to MIL-STD-883C
Note 2: Current forced means voltage unlimited but current limited to the specified value
Voltage forced means voltage limited to the specified valueswhile the current is not limited
Note 3: Typical value soldered on a PC board with 8cm2 copper ground plane (35mm thick).
L4938E - L4938ED - L4938EPD
2/12
ELECTRICAL CHARACTERISTICS (VS = 14V; Tj = -40 to 150°C unless otherwise specified.)
PIN FUNCTIONS
THERMAL DATA
Note 3: Typical value soldered on a PC board with 8cm2 copper ground plane (35mm thick).
L4938E - L4938ED - L4938EPD
3/12
ELECTRICAL CHARACTERISTICS (Continued)
Note :
4) The reset threshold can be programmed continuously from typ 3.8V to 4.7V by changing a value of an external resistor from pin PR to GN
5) This is a minimum reset time according to the hysteresis of the comparator. Delay time starts with VOUT1 exceeding VRT
6) This is the nominal reset time depending on the discharging limit of CT (saturation voltage) and theupper threshold of the timer comparator.
Delay time starts with VOUT1 exceeding VRT
7) The leakage of CT must be less than 0.5mA (2V). If an external resistor between CT and VOUT1 is applied, the leakage current may be
increased. The external resistor should have more than 30KΩ.
for stability: Cs ≥ 1μF, C01 ≥ 10μF, C02 ≥ 10μF, ESR ≤ 5Ω (designed target) For details see application note.
8) For transients exceeding 20V or -20V external protection is required at the Pins SI and EN as shown at Pin EN. The protection proposed will
provide proper function for transients in the range of ±200V. If the zener diode is omitted the external resistor should be raised to 200KΩ
to limit the current to 1mA. Without the zener diode, the function 20V or -20V can not be guaranteed.
L4938E - L4938ED - L4938EPD
4/12
FUNCTIONAL DESCRIPTION
The L4938E/ED/EPD is a monolithic integrated
dual voltage regulator, based on the STM modu-
lator voltage regulator approach. Several out-
standing features and auxiliary functions are im-
plemented to meet the requirements of supplying
microprocessor systems in automotive applica-
tions. Nevertheless, it is suitable also in other ap-
plications where two stabilized voltages are re-
quired. The modular approach of this device
allows to get easly also other features and func-
tions when required.
Standby Regulator
The standby regulator uses an Isolated collector
Vertical PNP transistor as a regulating element.
With this structure very low dropout volotage at
currents up to 100mA is obtained. The dropout
operation of the standby regulator is maintained
down to 3V input supply voltage. The output volt-
age is regulated up to the transient input supply
voltage of 40V. With this feature no functional in-
terruption due to overvoltage pulses is generated.
In the standby mode when the output 2 is dis-
abled, the current consumption of the device (qui-
escent current) is less than 90μA (14V supply
voltage).
To reduce the quiescent current peak in the un-
dervoltage region and to improve the transient re-
sponse in this region, the dropout voltage is con-
trolled. A second regulation path will keep the
output voltage without load below 5.5V even at
high temperatures.
Output 2 Voltage
The output 2 regulator uses the same output
structure as the standby regulator but rated for
the output current of 400mA. The output voltage
is internally fixed to 5V if ADJ is connected to
VOUT2.
The output 2 regulator can be switches OFF via
the enable input.
Figure 1. Application Diagram.
Figure 2.
L4938E - L4938ED - L4938EPD
5/12
Connecting a resistor divider R1E, R2E to the ADJ,
OUT2 pin the output voltage 2 can be pro-
grammed to the value of
VOUT2 = VOUT1 
1 + R1E(R2E + RADJ)
R2E ⋅ RADJ
with RADJ = 60K to 150K and VOUT1 = 4.95 to
5.05V.
For an exact calculation the temperature coeffi-
cient (Tc -2000pprm) of the internal resistor
(RADJ) must be taken into account. Pin ADJ in this
mode should not have a capacitive burden be-
cause this would reduce the phase margin of the
regulator loop.
Reset circuit
The reset circuit supervises the standby output
voltage. The reset output (RES) is defined from
VOUT ≥ 1V.
Even if VS is lacking, the reset generator is sup-
plied by the output voltage VOUT1.
The reset threshold of 4.7V is defined with the in-
ternal reference voltage (note 9) and standby out-
put divider, when pin PR is left open. The reset
threshold voltage can be programmed in the
range from 3.8V to 4.7V by connecting an exter-
nal resistor from pin PR to GND.
The value of the programming resistor RPR can
be calculated with:
RPR = 22K
4.7K
VRT −1
− 92.9K, 3.8V ≤ VRT ≤ 4.7V
The reset pulse delay time tRD, is defined with the
charge time of an external capacitor CT:
tRDmin = CT ⋅ 0.6V
1μA (note 5)
tRDnom = CT ⋅ 1.4V
1μA (note 6)
The reaction time of the reset circuit originates
from the noise immunity. Standby output voltage
drops below the reset threshold only a bit longer
than the reaction time results in a shorter reset
delay time. The nominal reset delay time will be
generated for standby output voltage drops longer
than approximately 50μs.
The minimum rset time is generated if reset con-
dition only occures for a short time triggering a re-
set pulse but not completely discharging CT. The
reset can be related to output2 on request. If
higher charge currents for the reset capacitor are
required a resistors from Pin CT to OUT1, may be
used to increase the current. We recommended
the use of 10KΩ to 5V as an output pull up.
Sense Comparator
The sense comparator compares an input signal
with an internal voltage reference of typical 1.23V.
The use of an external voltage divider makes this
comparator very flexible in the application. It can
be used to supervise the input voltage either be-
fore or after the protection diode and to give addi-
tional information to the microprocessor like low
voltage warnings. We recommended the use of
10KΩ to 5V as an output pull up.
Note 9:
The reference is alternatively supplied from VS or VOUT1. If one supply
is present, the reference is operating.
Thermal Protection
Both outputs are provided with an overtempera-
ture shut down regulation power dissipation down
to uncritical values.
Output 2 will shut down approximately 10K before
output 1.
Under normal conditions shut down of output 2
will allow the chip to cool down again. Thus out-
put 1 will be unaffected.
The thermal shut down reduces the output volt-
ages until power dissipation and the flow of ther-
mal energy out of the chip balance.
Transient Sensitivity
In proper operation (VOUT > 4.5V) the reference is
supplied by VOUT1 thus reducing sensitivity to in-
put transients.
Precise Data will be issued as soon as samples
are available.
L4938E - L4938ED - L4938EPD
6/12

Partno	Mfg	Dc	Qty	Available	Descript
L4938ED013TR	STM	N/a	1000	avai	ADVANCED VOLTAGE REGULATOR