Datasheet LTC3633 (Analog Devices) - 9
| Manufacturer | Analog Devices |
| Description | Dual Channel 3A, 15V Monolithic Synchronous Step-Down Regulator |
| Pages / Page | 28 / 9 — PIN FUNCTIONS (QFN/TSSOP). V2P5 (Pin 18/Pin 21):. ITH1 (Pin 26/Pin 1):. … |
| File Format / Size | PDF / 411 Kb |
| Document Language | English |
PIN FUNCTIONS (QFN/TSSOP). V2P5 (Pin 18/Pin 21):. ITH1 (Pin 26/Pin 1):. INTVCC (Pin 19/Pin 22):. TRACKSS1 (Pin 27/Pin 2):
Model Line for this Datasheet
Text Version of Document
LTC3633
PIN FUNCTIONS (QFN/TSSOP) V2P5 (Pin 18/Pin 21):
2.5V Regulator Output. Outputs a VOUT1 < 6V. When VOUT1 > 6V, switching frequency may regulated 2.5V supply voltage capable of supplying 10mA. become higher than the set frequency. The pin impedance Bypass this pin with a minimum of 1µF low ESR ceramic is nominally 140kΩ. capacitor. Tie this pin to INTVCC when this output is not
ITH1 (Pin 26/Pin 1):
Channel 1 Error Amplifier Output and being used in the application. Switching Regulator Compensation Pin. Connect this pin
INTVCC (Pin 19/Pin 22):
Internal 3.3V Regulator Output. to appropriate external components to compensate the The internal power drivers and control circuits are powered regulator loop frequency response. Connect this pin to from this voltage. The internal regulator is disabled when INTVCC to use the default internal compensation. both channel 1 and channel 2 are disabled with the RUN1/
TRACKSS1 (Pin 27/Pin 2):
Output Tracking and Soft-Start RUN2 inputs. Decouple this pin to power ground with a Input Pin for Channel 1. Forcing a voltage below 0.6V on minimum of 1µF low ESR ceramic capacitor. this pin bypasses the internal reference input to the error
BOOST1 (Pin 20/Pin 23):
Boosted Floating Driver Supply amplifier. The LTC3633 will servo the FB pin to the TRACK for Channel 1. The (+) terminal of the bootstrap capacitor voltage. Above 0.6V, the tracking function stops and the connects to this pin while the (–) terminal connects to internal reference resumes control of the error amplifier. the SW pin. The normal operation voltage swing of this An internal 1.4µA pull up current from INTVCC allows a pin ranges from a diode voltage drop below INTVCC up soft-start function to be implemented by connecting a to VIN + INTVCC. capacitor between this pin and SGND.
VIN1 (Pins 21,22/Pins 24, 25):
Power Supply Input for
VFB1 (Pin 28/Pin 3):
Channel 1 Output Feedback Voltage Channel 1. Input voltage to the on chip power MOSFETs Pin. Input to the error amplifier that compares the feedback on channel 1. The internal LDO for INTVCC is powered off voltage to the internal 0.6V reference voltage. Connect this of this pin. pin to a resistor divider network to program the desired
SW1 (Pins 23,24/Pins 26, 27):
Channel 1 Switch Node output voltage. Connection to External Inductor. Voltage swing of SW is
PGND (Exposed Pad Pin 29/Exposed Pad Pin 29):
Power from a diode voltage drop below ground to VIN. Ground Pin. The (–) terminal of the input bypass capacitor,
V
CIN, and the (–) terminal of the output capacitor, COUT,
ON1 (Pin 25/Pin 28):
On-Time Voltage Input for Chan- nel 1. This pin sets the voltage trip point for the on-time should be tied to this pin with a low impedance connec- comparator. Tying this pin to the regulated output volt- tion. This pin must be soldered to the PCB to provide low age makes the on-time proportional to V impedance electrical contact to power ground and good OUT1 when thermal contact to the PCB. 3633fd For more information www.linear.com/LTC3633 9 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
PIN FUNCTIONS (QFN/TSSOP) V2P5 (Pin 18/Pin 21):
2.5V Regulator Output. Outputs a VOUT1 < 6V. When VOUT1 > 6V, switching frequency may regulated 2.5V supply voltage capable of supplying 10mA. become higher than the set frequency. The pin impedance Bypass this pin with a minimum of 1µF low ESR ceramic is nominally 140kΩ. capacitor. Tie this pin to INTVCC when this output is not
ITH1 (Pin 26/Pin 1):
Channel 1 Error Amplifier Output and being used in the application. Switching Regulator Compensation Pin. Connect this pin
INTVCC (Pin 19/Pin 22):
Internal 3.3V Regulator Output. to appropriate external components to compensate the The internal power drivers and control circuits are powered regulator loop frequency response. Connect this pin to from this voltage. The internal regulator is disabled when INTVCC to use the default internal compensation. both channel 1 and channel 2 are disabled with the RUN1/
TRACKSS1 (Pin 27/Pin 2):
Output Tracking and Soft-Start RUN2 inputs. Decouple this pin to power ground with a Input Pin for Channel 1. Forcing a voltage below 0.6V on minimum of 1µF low ESR ceramic capacitor. this pin bypasses the internal reference input to the error
BOOST1 (Pin 20/Pin 23):
Boosted Floating Driver Supply amplifier. The LTC3633 will servo the FB pin to the TRACK for Channel 1. The (+) terminal of the bootstrap capacitor voltage. Above 0.6V, the tracking function stops and the connects to this pin while the (–) terminal connects to internal reference resumes control of the error amplifier. the SW pin. The normal operation voltage swing of this An internal 1.4µA pull up current from INTVCC allows a pin ranges from a diode voltage drop below INTVCC up soft-start function to be implemented by connecting a to VIN + INTVCC. capacitor between this pin and SGND.
VIN1 (Pins 21,22/Pins 24, 25):
Power Supply Input for
VFB1 (Pin 28/Pin 3):
Channel 1 Output Feedback Voltage Channel 1. Input voltage to the on chip power MOSFETs Pin. Input to the error amplifier that compares the feedback on channel 1. The internal LDO for INTVCC is powered off voltage to the internal 0.6V reference voltage. Connect this of this pin. pin to a resistor divider network to program the desired
SW1 (Pins 23,24/Pins 26, 27):
Channel 1 Switch Node output voltage. Connection to External Inductor. Voltage swing of SW is
PGND (Exposed Pad Pin 29/Exposed Pad Pin 29):
Power from a diode voltage drop below ground to VIN. Ground Pin. The (–) terminal of the input bypass capacitor,
V
CIN, and the (–) terminal of the output capacitor, COUT,
ON1 (Pin 25/Pin 28):
On-Time Voltage Input for Chan- nel 1. This pin sets the voltage trip point for the on-time should be tied to this pin with a low impedance connec- comparator. Tying this pin to the regulated output volt- tion. This pin must be soldered to the PCB to provide low age makes the on-time proportional to V impedance electrical contact to power ground and good OUT1 when thermal contact to the PCB. 3633fd For more information www.linear.com/LTC3633 9 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
