LT1521 Linear Technology, LT1521 Datasheet - Page 8

• Manufacturer Part Number: LT1521
• Description: 300mA Low Dropout Regulators with Micropower Quiescent Current and Shutdown
• Manufacturer: Linear Technology

LT1521/LT1521-3
LT1521-3.3/LT1521-5
8
PIN
OUT (Pin 1): The output pin supplies power to the load. A
minimum output capacitor of 1.5 F is required to prevent
oscillations, but larger values of output capacitor will be
necessary to deal with larger load transients. See the
Applications Information section for more on output
capacitance and reverse output characteristics.
SENSE (Pin 2): For fixed voltage versions of the LT1521
(LT1521-3, LT1521-3.3, LT1521-5), the sense pin is the
input to the error amplifier. Optimum regulation will be
obtained at the point where the sense pin is connected to
TYPICAL PERFORMANCE CHARACTERISTICS
U
FUNCTIONS
U
–0.1
–0.2
100
150
100
0.2
0.1
90
80
70
60
50
40
30
20
10
50
0
0
10
LT1521-5
Transient Response
0
Ripple Rejection
I
V
LOAD
V
C
C
50
IN
IN
IN
OUT
U
= 6V + 50mV
= 6V
= 0.1 F
100
100
= 150mA
= 1.5 F
150
FREQUENCY (Hz)
W
200
1k
RMS
TIME ( s)
250
RIPPLE
U
C
SOLID TANTALUM
C
SOLID TANTALUM
300
10k
OUT
OUT
350
= 33 F
= 3.3 F
100k
400
LT1521 • TPC31
LT1521 • TPC33
450
500
1M
the output pin of the regulator. In critical applications small
voltage drops caused by the resistance (R
between the regulator and the load, which would normally
degrade regulation, may be eliminated by connecting the
sense pin to the output at the load as shown in Figure 1
(Kelvin Sense Connection). Note that the voltage drop
across the external PC traces will add to the dropout
voltage of the regulator. The sense pin bias current is 5 A
at the nominal regulated output voltage. This pin is inter-
nally clamped to – 0.6V (one V
–0.1
–0.2
–10
–15
–20
–25
–30
–35
–40
300
200
100
0.2
0.1
–5
0
0
–50
LT1521-5
Transient Response
0
Load Regulation
LT1521*
V
*V
0.5
IN
–25
I
LOAD
ADJ
= V
1.0
= V
OUT
LT1521-5
= 1mA TO 300mA
1.5
OUT
0
TEMPERATURE ( C)
(NOMINAL + 1V)
2.0
TIME (ms)
25
2.5
50
BE
3.0
).
3.5
V
C
C
75
LT1521-3
IN
IN
OUT
LT1521-3.3
= 6V
= 0.1 F
4.0
LT1521 • TPC32
= 33 F
LT1521 • TPC34
100
4.5
P
125
5.0
) of PC traces