Datasheet LT1521, LT1521-3, LT1521-3.3, LT1521-5 (Analog Devices) - 8

LT1521/LT1521-3 LT1521-3.3/LT1521-5
W U TYPICAL PERFORMANCE CHARACTERISTICS Ripple Rejection Load Regulation
100 0 I 90 LOAD = 150mA ∆ILOAD = 1mA TO 300mA V –5 IN = 6V + 50mVRMS RIPPLE 80 –10 70 LT1521-5 –15 LT1521-3 60 LT1521* C LT1521-3.3 50 OUT = 33µF –20 SOLID TANTALUM 40 –25 30 RIPPLE REJECTION (dB) LOAD REGULATION (mV) –30 20 COUT = 3.3µF V –35 IN = VOUT (NOMINAL + 1V) 10 SOLID TANTALUM *VADJ = VOUT 0 –40 10 100 1k 10k 100k 1M –50 –25 0 25 50 75 100 125 FREQUENCY (Hz) TEMPERATURE (°C) LT1521 • TPC31 LT1521 • TPC32
LT1521-5 LT1521-5 Transient Response Transient Response
V 0.2 VIN = 6V 0.2 IN = 6V C C IN = 0.1µF IN = 0.1µF 0.1 C C OUT = 1.5µF 0.1 OUT = 33µF 0 0 DEVIATION (V) –0.1 DEVIATION (V) –0.1 OUTPUT VOLTAGE OUTPUT VOLTAGE –0.2 –0.2 150 300 100 200 (mA) (mA) 50 100 LOAD CURRENT LOAD CURRENT 0 50 100 150 200 250 300 350 400 450 500 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 TIME (µs) TIME (ms) LT1521 • TPC33 LT1521 • TPC34
U U U PIN FUNCTIONS OUT (Pin 1):
The output pin supplies power to the load. A the output pin of the regulator. In critical applications small minimum output capacitor of 1.5µF is required to prevent voltage drops caused by the resistance (RP) of PC traces oscillations, but larger values of output capacitor will be between the regulator and the load, which would normally necessary to deal with larger load transients. See the degrade regulation, may be eliminated by connecting the Applications Information section for more on output sense pin to the output at the load as shown in Figure 1 capacitance and reverse output characteristics. (Kelvin Sense Connection). Note that the voltage drop across the external PC traces will add to the dropout
SENSE (Pin 2):
For fixed voltage versions of the LT1521 voltage of the regulator. The sense pin bias current is 5µA (LT1521-3, LT1521-3.3, LT1521-5), the sense pin is the input to the error amplifier. Optimum regulation will be at the nominal regulated output voltage. This pin is inter- obtained at the point where the sense pin is connected to nally clamped to – 0.6V (one VBE). 1521335fb 8