Datasheet LTC3636, LTC3636-1 (Analog Devices) - 8

LTC3636/LTC3636-1
PIN FUNCTIONS ITH1 (Pin 1):
Channel 1 Error Amplifier Output and
ITH2 (Pin 8):
Channel 2 Error Amplifier Output and Switching Regulator Compensation Pin. Connect this pin Switching Regulator Compensation Pin. Connect this pin to appropriate external components to compensate the to appropriate external components to compensate the regulator loop frequency response. Connect this pin to regulator loop frequency response. Connect this pin to INTVCC to use the default internal compensation. INTVCC to use the default internal compensation.
RUN1 (Pin 2):
Channel 1 Regulator Enable Pin. Enables
VFB2 (Pin 9):
Channel 2 Output Feedback Voltage Pin. channel 1 operation by tying RUN above 1.25V. Tying it Input to the error amplifier that compares the feedback below 1V places the part into shutdown. Do not float this pin. voltage to the internal 0.6V reference voltage. Connect this
MODE/SYNC (Pin 3):
Mode Select and External Synchro- pin to a resistor divider network to program the desired nization Input. Tie this pin to ground to force continuous output voltage. synchronous operation. Floating this pin or tying it to
PGOOD2 (Pin 10):
Channel 2 Open-Drain Power Good INTVCC enables high efficiency Burst Mode operation at Output Pin. PGOOD2 is pulled to ground when the voltage light loads. Drive this pin with a clock to synchronize the on the VFB2 pin is not within ±8% (typical) of the internal LTC3636/LTC3636-1 switching frequency. An internal 0.6V reference. PGOOD2 becomes high impedance once phase-locked loop will force the bottom power NMOS’s the VFB2 pin returns to within ±5% (typical) of the internal turn on signal to be synchronized with the rising edge of reference. the CLKIN signal. When this pin is driven with a clock,
TRACKSS2 (Pin 11):
Output Tracking and Soft-Start Input forced continuous mode is automatically selected. Pin for Channel 2. Forcing a voltage below 0.6V on this pin
RT (Pin 4):
Oscillator Frequency Program Pin. Connect an bypasses the internal reference input to the error amplifier. external resistor (between 80k to 640k) from this pin to The LTC3636/LTC3636-1 will servo the FB pin to the TRACK GND in order to program the frequency from 500kHz to voltage. Above 0.6V, the tracking function stops and the 4MHz. When RT is tied to INTVCC, the switching frequency internal reference resumes control of the error amplifier. will default to 2MHz. An internal 1.4μA pull up current from INTVCC allows a
INTV
soft-start function to be implemented by connecting a
CC (Pin 5):
Internal 3.3V Regulator Output. The inter- nal power drivers and control circuits are powered from capacitor between this pin and PGND. this voltage. Decouple this pin to power ground with a
GND (Pins 12, 18, 19, 25):
Power and Signal Ground. These minimum of 4.7µF low ESR ceramic capacitor. pins must be tied together and soldered to PCB ground.
TMON (Pin 6):
Temperature Monitor Output. A voltage
SW2 (Pins 13, 17):
Channel 2 Switch Node Connection proportional to the measured on-die temperature will ap- to External Inductor. Voltage swing of SW is from a diode pear at this pin. The voltage-to-temperature scaling factor voltage drop below ground to VIN. is 200°K/V. See the Applications Information section for
BOOST2 (Pin 14):
Boosted Floating Driver supply for detailed information on the TMON function. Tie this pin to Channel 2. The (+) terminal of the bootstrap capacitor INTVCC to disable the temperature monitor circuit. connects to this pin while the (–) terminal connects to
RUN2 (Pin 7):
Channel 2 Regulator Enable Pin. Enables the SW pin. The normal operational voltage swing of this channel 2 operation by tying RUN above 1.22V. Tying it pin ranges from a diode voltage drop below INTVCC up below 1V places the part into shutdown. Do not float this pin. to VIN+INTVCC. 3636fb 8 For more information www.linear.com/LTC3636 Document Outline Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Operation Applications Information Package Description Typical Application Related Parts