LT3464 WUTYPICAL PERFOR A CE CHARACTERISTICSFB Pin Voltage vsFB and CTRL PinCTRL Pin VoltageBias CurrentsFB Pin Hysteresis 1.50 8 12 7 1.25 CTRL PIN 10 6 1.00 8 5 0.75 4 6 FEEDBACK PIN 3 0.50 HYSTERESIS (mV) 4 FB PIN VOLTAGE (V) BIAS CURRENT (nA) 2 0.25 2 1 0 0 0 0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 CONTROL PIN VOLTAGE (V) TEMPERATURE (°C) TEMPERATURE (°C) 3464 G17 3464 G18 3464 G19 UUUPI FU CTIO SCTRL (Pin 1): Internal Reference Override Pin. This allows GND (Pin 4): Ground. Tie this pin directly to the ground the FB voltage to be externally set between 0V and 1.25V. plane. Tie this pin to above 1.5V (V IN for example) to use the internal 1.25V reference. CAP (Pin 5): PNP Emitter and Schottky Cathode. This pin connects to the output capacitor, and optionally to the external phase-lead capacitor. R2 VOUT = VCTRL + 1 R1 SW (Pin 6): Switch Pin and Schottky Anode. This is the collector of the internal NPN power switch. Minimize the when V metal trace area connected to the pin to minimize EMI. CTRL is less than 1.25V (see Figure 4) FB (Pin 2): Feedback Pin. The LT3464 regulates its feed- VIN (Pin 7): Input Supply Pin: Bypass this pin with a back pin to 1.25V if the internal reference is used or to capacitor located as close to the device as possible. VCTRL if the CTRL pin is between 0V and 1.25V. Connect SHDN (Pin 8): Shutdown Pin. This pin is used to put the the feedback resistor divider tap to this pin. Set the output device in shutdown mode. Tie the pin low to shut down the voltage by selecting R1 and R2 (see Figure 4). LT3464. Tie high for normal operation See the electrical specifications for the required voltages. V R2 = R OUT 1 – 1 VREF OUT (Pin 3): PNP Collector. This is the output of the Output Disconnect circuit. Bypass this pin with at least a 0.1µF capacitor connected to the CAP pin or to ground. 3464f 5