LP2950 / LP2951
CORPORATION
BLOCK DIAGRAM
ERROR DETECTION
COMPARATOR
1D-21
1µF
REFERENCE
1.23V
UNREGULATED DC
ERROR
AMPLIFIER
60mV
+
+
TO CMOS OR
TTL
330kΩ
FROM
CMOS
OR TTL
+
+
5V @ 100mA
MAX
60kΩ
LP2950 AND LP2951 BLOCK DIAGRAM
180kΩ
817
SENSE
6
2
4
5
5V TAP
ERROR
GROUND
INPUT OUTPUTFEEDBACK
SHUTDOWN
3
–
+
–
+
CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-651-3025
ELECTRICAL CHARACTERISTIC S (continued)
PARAMETER
LP2951 LP2950AC / LP2951AC LP2950C / LP2951C
UNITS
CONDITIONS
(Note 2)
MIN TYP MAX MIN TYP MAX MIN TYP MAX
ERROR COMPARATOR
Output Leakage Current 0.01 1 0.01 1 0.01 1 µAV
OH
= 30V
Output Low Voltage 150 250 150 250 150 250 mV V
IN
= 4.5V, IOL = 400µA
Upper Threshold Voltage 40 60 40 60 40 60 mV (Note 7)
Lower Threshold Voltage 75 95 75 95 75 95 mV (Note 7)
Hysteresis 15 15 15 mV (Note 7)
SHUTDOWN INPUT
Inp ut Logic Voltage
2
1.3 0.6
2
1.3 0.7
2
1.3 0.7 V
V
Low (Regulato r ON)
High (Regulator OFF)
Shutdown Pin
Input Current
30
67550800
30
67550800
30
67550800
µAµAV
S
= 2.4V
V
S
= 30V
Regulator Output Current
in Shutdown
310 310 310µA (Note 9)
Note 1: Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range.
Note 2: Unless otherwise specified all limits guaranteed for T
J
= 25oC, VIN = 6V, IL=100µA and CL = 1µF. Additional conditions for the 8-pin
versions are feedback tied to 5V tap and output tied to output Sense (V
OUT
= 5V) and V
SHUTDOWN
≤ 0.8V.
Note 3: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to
heating effects are covered under the specification for thermal regulation.
Note 4: Line regulation for the LP2951 is tested at 150
o
C for IL = 1mA. For IL = 100µA and TJ = 125oC, line regulatio n is guara nte ed by desig n to
0.2%. See typical performance characteristics for line regulation versus temperature and load current.
Note 5: Dropout voltage is defined as the input to output differential at which the output voltage drops 100mV below its nominal value measured
at 1V differential at very low values of programmed output voltage, the minimum input supply voltage of 2V (2.3V over temperature) must be
taken input account.
Note 6: V
REF
≤ V
OUT
≤ (VIN - 1V), 2.3 ≤ VIN ≤ 30V, 100µA ≤ IL ≤ 100mA, TJ ≤ T
JMAX
.
Note 7: Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nominal reference voltage
measured at 6V input. To express these thre sh old s in terms of output vo lta ge chan ge , mu ltip l y by the erro r amp lifi er g ai n = V
OUT/VREF
=
(R1+R2)/R2. For example, at a programmed output voltage of 5V, the error output is guaranteed to go low when the output drops by 95 mV x
5V/1.235 = 384mV. Thresho lds remain constant as a percent of V
OUT
as V
OUT
is varied, with the dropout warning occurring at typically 5% below
nominal, 7.5% guaranteed.
Note 8: V
SHUTDOWN
≥ 2V, VIN ≤ 30V, V
OUT
= 0, Feedback pin tied to 5V Tap.
Note 9: All typical values are not guaranteed.