LT1121CST-3.3#PBF Linear Technology, LT1121CST-3.3#PBF Datasheet - Page 12

• Manufacturer Part Number: LT1121CST-3.3#PBF
• Description: IC REG LDO 3.3V 150MA SOT223-3
• Manufacturer: Linear Technology

Specifications of LT1121CST-3.3#PBF

• Regulator Topology: Positive Fixed
• Voltage - Output: 3.3V
• Voltage - Input: 4.17 ~ 30 V
• Voltage - Dropout (typical): 0.42V @ 150mA
• Number Of Regulators: 1
• Current - Output: 150mA
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-223 (3 leads + Tab), SC-73, TO-261
• Primary Input Voltage: 20V
• Output Voltage Fixed: 3.3V
• Dropout Voltage Vdo: 420mV
• No. Of Pins: 3
• Output Current: 150mA
• Operating Temperature Range: 0°C To +125°C
• Msl: MSL 1 - Unlimited
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS Compliant
• Current - Limit (min): -

APPLICATIONS INFORMATION
LT1121/LT1121-3.3/LT1121-5
When the input of the LT1121 is forced to a voltage below
its nominal output voltage and its output is held high, the
reverse output current will still follow the curve in Figure
2. This condition can occur if the input of the LT1121 is
connected to a discharged (low voltage) battery and the
output is held up by either a backup battery or by a second
regulator circuit. When the input pin is forced below the
output pin or the output pin is pulled above the input pin,
the input current will typically drop to less than 2μA (see
Figure 3). The state of the shutdown pin will have no effect
on the reverse output current when the output is pulled
above the input.
Table 7. Fault Conditions
12
INPUT PIN
<V
<V
Open
Open
≤0.8V
≤0.8V
>1.5V
–30V < V
OUT
OUT
(Nominal)
(Nominal)
IN
< 30V
SHDN PIN
Open (Hi)
Grounded
Open (Hi)
Grounded
Open (Hi)
Grounded
Open (Hi)
Grounded
OUTPUT PIN
Forced to V
Forced to V
Forced to V
Forced to V
≤0V
≤0V
≤0V
≤0V
OUT
OUT
OUT
OUT
(Nominal)
(Nominal)
(Nominal)
(Nominal)
Reverse Output Current ≈ 15μA (See Figure 2)
Input Current ≈ 1μA (See Figure 3)
Reverse Output Current ≈ 15μA (See Figure 2)
Input Current ≈ 1μA (See Figure 3)
Reverse Output Current ≈ 15μA (See Figure 2)
Reverse Output Current ≈ 15μA (See Figure 2)
Output Current = 0
Output Current = 0
Output Current = Short-Circuit Current
Output Current = 0
5
4
3
2
1
0
0
V
V
OUT
OUT
= 3.3V (LT1121-3.3)
= 5V (LT1121-5)
Figure 3. Input Current
1
INPUT VOLTAGE (V)
2
3
4
1121 F03
5
1121ff