LT3045 datasheet(14/62 Pages) AD

14 / 62 page

Data Sheet

LT3074

analog.com

Rev 0.

14 of 62

connect the pin to AGND to set the address to 110_0000b or to BIASAF to set the

address to 110_1111b. DO NOT FLOAT THIS PIN. See the Applications Information

section for more information.

BIASAF

Bias Filter Pin for analog circuity. The LT3074 requires a minimum 2.2µF bypass

capacitor on this pin.

BIAS

Bias Supply. This pin supplies current to the internal control circuitry and the output

stage driving the pass transistor. This pin does not require any bypass capacitor. To

ensure proper operation, the BIAS voltage must satisfy the following conditions:

2.375V ≤ VBIAS ≤ 5.5V and VBIAS ≥1.2 + VOUT.

BIASDF

Bias Filter Pin for digital circuity. The LT3074 requires a minimum 0.47µF bypass

capacitor on this pin.

DGND

Digital Ground. To ensure proper electrical and thermal performance, tie all ground

pins of the package to PCB ground.

20, 21,

Exposed

Pad 23

Input Supply. Pins 20, 21, and exposed pad 23 of the LQFN package are the electrical

connection to IN. These pins supply power to the high current pass transistor. Connect

all IN pins together for proper performance and solder pin 23 to the PCB for better

thermal performance. The LT3074 requires a bypass capacitor at IN to maintain

stability and low input impedance over frequency. A 10µF input bypass capacitor

suffices for most battery and power plane impedances. Minimizing input trace

inductance optimizes performance. Applications that operate with low VIN− VOUT

differential voltage and that have large, fast load transients may require a much higher

input capacitor to prevent the input supply from drooping and allowing the regulator

to enter dropout.

Device Enable. This pin enables/disables the output. Pulling the EN pin low pulls down

the reference, disables the output transistor, and disables auxiliary functions. Drive the

EN pin with either a digital logic port, or an open-collector NPN, or an open-drain

NMOS terminated with a pull-up resistor to VBIAS. The pull-up resistor must be less than

200kΩ to meet the VIH condition of the EN pin. If unused, connect the EN pin to BIAS.

LT3045 Datasheet(PDF) 14 Page - Analog Devices