LP2950/51
PARAMETER
CONDITIONS
(Note 2)
8-Pin Versions only (Continued)
LP2951AC
Min. Typ.
Max.
Min.
LP2951C
Typ. Max.
UNITS
Reference Voltage
Temperature
Coefficient
Feedback Pin Bias
Current
Temperature
Coefficient
Error Comparator
Output Leakage
Current
Output Low Voltage
Upper Threshold
Voltage
Lower Threshold
Voltage
Hysteresis
Shutdown Input
Input logic Voltage
Shut down Pin Input
Current
Regulator Output
Current in Shutdown
Thermal
Resistance
θ
JA
Low (Regulator ON)
High (Regulator OFF)
V
S
= 2.4V
V
S
= 30V
(Note 8)
8 Pin SOIC
2.0
20
0.1
50
0.1
ppm/°C
nA/°C
V
OH
= 30V
V
IN
= 4.5V
I
OL
= 400
μA
(Note 7)
(Note 7)
(Note 7)
0.01
150
40
60
75
15
1.3
30
675
3
128. 4
131.9
1
250
40
95
0.01
150
60
75
15
1
250
μA
mV
mV
95
mV
mV
0.7
50
800
10
2.0
1.3
30
675
3
0.7
50
800
10
V
V
μA
μA
μA
°C/W
3 Pin TO-92
°C/W
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
= 25°C, V
IN
= 6V, I
L
= 100
μA
and C
L
= 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 i n output voltage due to heating effects are
covered under the specification for thermal regulation.
Note 4:
Line regulation for the LP2951 is tested at I
L
= 1mA. For I
L
= 100
μA
and T
J
= 125°C, line regulation is guaranteed by design 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 100 mV 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 into account.
Note 6:
V
REF
≤V
OUT
≤(V
IN
- 1V), 2.3
≤V
IN
≤30V,
100μA≤I
L
≤100mA,
T
J
≤T
JMAX
.
Note 7:
Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nomi nal reference voltage measured at 6V input. To
express these thresholds in terms of output voltage change, multiply by the error amplifier gain = V
OUT
/V
REF
= (R
1
+ R
2
)/R
2
. 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 = 384 mV. Thresholds 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,
V
IN
≤30V,
V
OUT
=0, Feedback pin tied to 5V Tap.
Note 9:
All typical values are not guaranteed. The value could vary from lot to lot.
Rev G
LP2950-5 Low Dropout Linear Regulators
© 2008 Exar Corporation
3
EXAR [ EXAR CORPORATION ]
