Part Number: LT8609AEMSE#TRPBF

Manufacturer: Analog Devices Inc


Shipped from: Shenzhen/HK Warehouse

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Technical Specifications of LT8609AEMSE#PBF

Datasheet  LT8609AEMSE#PBF datasheet
Category Integrated Circuits (ICs)
Family PMIC – Voltage Regulators – DC DC Switching Regulators
Manufacturer Linear Technology
Packaging Tube
Part Status Active
Function Step-Down
Output Configuration Positive
Topology Buck
Output Type Adjustable
Number of Outputs 1
Voltage – Input (Min) 3V
Voltage – Input (Max) 42V
Voltage – Output (Min/Fixed) 0.782V
Voltage – Output (Max) 42V
Current – Output 2A
Frequency – Switching 200kHz ~ 2.2MHz
Synchronous Rectifier Yes
Operating Temperature -40°C ~ 125°C (TJ)
Mounting Type Surface Mount
Package / Case 10-TFSOP, 10-MSOP (0.118″, 3.00mm Width) Exposed Pad
Supplier Device Package 10-MSOP-EP

LT8609AEMSE#TRPBF Descriptions

The LT®8609/LT8609A/LT8609B is a compact, high efficiency, high speed synchronous monolithic step-down switching regulator that uses just 1.7A of non-switching quiescent current. It is available in three different versions: LT8609, LT8609A, and LT8609B. Continuous delivery of 3 A is possible with the LT8609/LT8609A/LT8609B. Operating in Burst Mode helps maintain high efficiency even at low output currents, while also keeping the output ripple to less than 10mVP-P. The spread spectrum modulation or synchronization to an external clock can be accomplished using a SYNC pin. Using peak current mode architecture, internal compensation enables the employment of small inductors, resulting in a quick reaction to transients and high loop stability.

The EN/UV pin, which has an exact threshold of 1V, can be utilized either to configure VIN UVLO or to turn off the component entirely. During start-up, a capacitor connected to the TR/SS pin programs the ramp rate at which the output voltage increases, VOUT is within 8.5% on the variable output sections or 7.5% on the fixed output sections of the intended output voltage, and the PG flag is set, in addition to fault conditions. To reduce EMI emissions, the LT8609A has more gradual switch edges. The LT8609B is only capable of operating in the pulse-skipping mode.

LT8609AEMSE#TRPBF Features

  • Wide Input Voltage Range: 3.0V to 42V.
  • Burst Mode® Operation with Ultralow Quiescent Current: 2.5 microamperes IQ Regulating 12VIN to 3.3VOUT.
  • Output Ripple <10mVP-P.
  • Excellent productivity 2MHz Synchronous operation has an efficiency of over 93% while operating at 1A and 5VOUT from 12VIN.
  • 3A Maximum Continuous Output.
  • Quick Minimum Turn-On Time of 45 nanoseconds
  • LT8609A Both a fixed 3.3V and a fixed 5V output are available.
  • 200 kHz to 2.2 MHz, variable and synchronizable frequency range.
  • Spread Spectrum Frequency Modulation for Reduced Interference from the Environment
  • Makes It Possible to Use Small Inductors
  • Low rate of dropout
  • The operation is in peak current mode.
  • The precise setting for the threshold of the 1V enables the pin.
  • Compensation within the Organization
  • Soft-Start and Tracking are to be output.
  • Small 10-Lead MSOP Package, 16-Lead MSOP Package, or 10-Lead 3mm DFN Package with Side Wettable Flanks are all options for the package type.
  • Automotive applications that meet the requirements of the AEC-Q100 standard.


The LT8609/LT8609A/LT8609B converters are a single-chip solution for DC-to-DC power conversion in the current mode. The initiation of each clock cycle is marked by the activation of an internal top power switch by an oscillator whose frequency is set by a resistor on the RT pin. When the inductor’s current reaches a certain threshold, the current comparator in the top switch will trip, cutting power to the top circuit. Depending on the voltage at the VC node, the peak inductor current at which the top switch closes can be adjusted. The error amplifier controls the VC node by comparing the signal at the VFB pin to an internal reference of 0.782V.

The VOUT pin and an integrated resistor divider are used by the LT8609A-5 and LT8609A-3.3 Fixed output components to create an on-board FB node. As the average inductor current rises to meet the new load current, the error amplifier raises the VC voltage to compensate for the drop in feedback voltage relative to the reference. Once the main power switch is turned off, the synchronous power switch will remain on until the next clock cycle begins or the inductor current reaches zero. If the bottom switch carries too much current because of an overload condition, the following clock cycle will not begin until the current has returned to a safe level. The LT8609/LT8609A/LT8609B is disabled and consumes 1A from the input when the EN/UV pin is low. The switching regulator switches at voltages greater than 1V on the EN/UV pin.

The LT8609/LT8609A switches to Burst Mode operation while processing light loads to maximize efficiency. Between pulses, the input supply current is reduced to 1.7A by turning off all circuitry involved in regulating the output switch. Typically, 2.5A will be drawn from the input supply during loadless regulation. When operating in Burst Mode, the SYNC pin is grounded, whereas when using the pulse-skipping mode, it is left floating. If an external clock signal is provided to the SYNC pin, the component will function in pulse-skipping mode at the external clock’s frequency. The oscillator constantly runs during the pulse-skipping mode, and the timing of the SW transitions in the positive direction follows the clock.

The quiescent current will be a few milliamperes (mA) when the load is low because switch pulses are skipped to control the output. Spread spectrum modulation mode is enabled by setting the SYNC pin to high; in this mode, the LT8609/ LT8609A functions similarly to the pulse-skipping way but adjusts the clock frequency to mitigate electromagnetic interference (EMI). If the output voltage deviates more than 8.5% (typical) from the set point or if a fault condition is present, comparators on the LT8609/LT8609A/LT8609B adjustable output parts will pull the PG pin low. The LT8609A-3.3 and LT8609A-5 are fixed output parts with built-in comparators that check the VOUT pin voltage and pull the PG pin low if the output voltage deviates by more than 7.5% (typical) from the set point or if a fault situation is present.

When the voltage on the FB pin is low, or when the voltage on the VOUT pin is low for the LT8609A-3.3 or LT8609A-5 fixed voltage choices, the oscillator lowers the working frequency of the LT8609/LT8609A. When the output voltage is below the set value, as can happen during startup, the inductor current is controlled by a frequency foldback. In the presence of a clock signal at the SYNC pin, frequency foldback is not activated. The LT8609B can only function in pulse-skipping mode and lacks a SYNC pin.

Applications Information

Obtaining Extremely Low Standby Current the LT8609/low LT8609A’s ripple Burst Mode operation improves efficiency at light loads by keeping the output capacitor charged to the correct output voltage with a bare minimum of input idle current and output voltage ripple. The output capacitor supplies the output power of the LT8609/LT8609A during the sleep intervals of its Burst Mode operation, which consists of single tiny bursts of current delivered to the output capacitor. Power consumption in sleep mode for the LT8609/LT8609A is 1.7A.


The top switch won’t be flipped until the current in the inductor has dropped below a certain safe threshold. This allows the LT8609/LT8609A/LT8609B to be optimized for specific uses and reduce heat generation in short-circuit situations.

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