LTM4622IV#PBF Detailed explanation of pin function specifications and circuit principle instructions
The part number "LTM4622IV#PBF" corresponds to a specific component manufactured by Analog Devices, specifically within their Linear Technology brand, which specializes in Power management solutions. The "LTM4622" is a dual-output DC/DC step-down regulator that provides efficient power conversion for various applications.
Key Specifications for LTM4622IV#PBF:
Package: QFN (Quad Flat No-lead) 20mm x 20mm, typically a 36-lead package for this component. Functionality: It is a dual-output buck converter designed to deliver two independent output voltages from a single input. This is ideal for applications requiring power for multiple subsystems from one power supply.Pin Function Specifications:
The following is a detailed breakdown of the pins, their functions, and a typical usage description for each:
Pin Configuration and Function Description Pin No. Pin Name Function Description 1 VIN Power Input Pin - Connects to the input voltage (typically 4.5V to 36V). 2 PGND Power Ground Pin - Connects to the ground reference for power return. 3 VOUT1 Output 1 Pin - Supplies regulated voltage output (e.g., 5V, 3.3V). 4 VOUT2 Output 2 Pin - Supplies second regulated voltage output (e.g., 2.5V, 1.8V). 5 TRACK1 Tracking Pin for Output 1 - Used to set the ramp-up sequence or tracking with other supplies. 6 TRACK2 Tracking Pin for Output 2 - Used similarly as TRACK1, for output 2 tracking with other devices. 7 RUN1 Run Control Pin for Output 1 - Allows enabling/disabling the output 1. Low = off, High = on. 8 RUN2 Run Control Pin for Output 2 - Similar to RUN1, controls output 2. 9 PGOOD1 Power Good Pin for Output 1 - Open-drain output indicating that the output is within regulation limits. 10 PGOOD2 Power Good Pin for Output 2 - Same as PGOOD1 but for output 2. 11 FB1 Feedback Pin for Output 1 - Connected to a voltage divider that monitors output 1's voltage. 12 FB2 Feedback Pin for Output 2 - Connected to a voltage divider that monitors output 2's voltage. 13 EN1 Enable Pin for Output 1 - Controls enabling/disabling the output 1. 14 EN2 Enable Pin for Output 2 - Controls enabling/disabling the output 2. 15 SYNC Synchronization Pin - Used for syncing the internal switching frequency with an external clock signal. 16 VDD Supply Pin - Provides internal supply voltage, typically from the VIN pin, regulated. 17 BOOT1 Bootstrap Pin for Output 1 - Provides the voltage to drive the high-side switch of output 1. 18 BOOT2 Bootstrap Pin for Output 2 - Provides the voltage to drive the high-side switch of output 2. 19 PGND (Dual) Ground Pin for Power Return - Connects to the system ground for both outputs. 20 VOUT1 (Additional) Output Pin for VOUT1 - A secondary pin for connection to output 1.FAQ Section for LTM4622IV#PBF
Q: What is the input voltage range for LTM4622IV#PBF? A: The LTM4622IV#PBF supports an input voltage range from 4.5V to 36V. Q: How do I enable the LTM4622 outputs? A: The outputs can be enabled by applying a logic high signal to the RUN1 (Output 1) and RUN2 (Output 2) pins. Q: What should I do if the power good signal is not present? A: If PGOOD1 or PGOOD2 is not high, check the output voltages and ensure they are within regulation limits. It may indicate a fault or under-voltage condition. Q: Can I synchronize the LTM4622 with an external clock? A: Yes, the SYNC pin allows the LTM4622 to synchronize with an external clock. Q: What are the maximum output current capabilities? A: Each output can provide up to 4A of continuous current, for a total of 8A. Q: How do I monitor the output voltages? A: Use the feedback pins (FB1 and FB2) to monitor and adjust the output voltage using external resistive dividers. Q: How can I set the output voltage for each output? A: The output voltages are determined by the feedback resistors connected to the FB1 and FB2 pins. Q: What type of external components are needed? A: Typical external components include input/output capacitor s, inductors, and feedback resistors. Q: How does the LTM4622 handle thermal shutdown? A: The LTM4622 has an internal thermal shutdown that protects the device from overheating, automatically disabling outputs if the junction temperature exceeds safe limits.Q: Can I adjust the switching frequency of the LTM4622?
A: Yes, the switching frequency is adjustable using the SYNC pin or can be set internally to a fixed value.Q: What is the output voltage ripple for the LTM4622?
A: The output voltage ripple is typically low, depending on the external capacitors and inductors used, typically under 50mV for both outputs.Q: Does the LTM4622 have short-circuit protection?
A: Yes, the LTM4622 includes short-circuit protection on both outputs.Q: How should I connect the ground pins?
A: All ground pins (PGND, PGND (Dual)) must be connected to the system ground with proper PCB layout to minimize noise.Q: Is there any noise filtering required on the LTM4622?
A: While the LTM4622 is designed to be low-noise, using proper decoupling capacitors and a good PCB layout will ensure optimal performance.Q: Can I use the LTM4622 in automotive applications?
A: Yes, the LTM4622 can be used in automotive applications as long as the input voltage range is met.Q: What is the efficiency of the LTM4622?
A: The LTM4622 typically operates with efficiency up to 95%, depending on the input voltage, output voltage, and load current.Q: How do I deal with excessive voltage drop?
A: If you notice a voltage drop, ensure that the input voltage is within the specified range and the wiring/PCB traces are appropriately sized.Q: What is the typical response time for the LTM4622 to a load step?
A: The LTM4622 typically responds in less than 1µs to load steps, depending on the external components used.Q: How can I calculate the output voltage of LTM4622?
A: The output voltage is calculated using the feedback resistor network on FB1 and FB2 pins, based on the formula: Vout = Vref × (1 + R1/R2).Q: Can I use the LTM4622 to power a 12V system?
A: Yes, the LTM4622 can provide 12V output if the correct feedback resistors are used for the required output voltage.This is a high-level overview of the part. Let me know if you'd like more specific details or more focused explanations on any aspect!