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Mingjiada Supply ADI LT3990 And LT3991 Series Monolithic Buck Switching Regulator

Against the backdrop of increasingly stringent requirements for power supply reliability, wide input ranges and low standby power consumption in automotive electronics, industrial control and battery-powered systems, the ADI/Linear LT3990/LT3991 buck regulators have become commonly used power supply components in high-voltage input and low-power standby applications, thanks to their ultra-low quiescent current and wide input voltage capability. Mingjiada Electronics has long supplied the LT3990/LT3991 series of buck regulators, providing component supply and selection support for related power supply designs.

I. LT3990 – A 62V, 350mA buck regulator with 2.5μA quiescent current and an integrated diode
The LT3990 is a variable-frequency, monolithic step-down switching regulator capable of handling a wide input voltage range up to 62V, whilst consuming only 2.5μA of quiescent current. The chip integrates a high-efficiency switch, along with a clamping diode, a boost diode and the necessary oscillator, controller and logic circuits.
Key features of the LT3990:
Low-ripple Burst Mode®
2.5 μA IQ (12 VIN to 3.3 VOUT)
Output ripple < 5 mV p-p
Wide input voltage range: 4.2 V to 62 V
Adjustable switching frequency: 200 kHz to 2.2 MHz
Integrated boost and freewheeling diodes
Output current: 350 mA
Fixed output voltages: 3.3V, 5V
2μA IQ (at 12VIN)
Accurate, programmable under-voltage protection
FMEA fault tolerance (MSOP package)
If adjacent pins are short-circuited or when a pin is left floating,
the output voltage remains at or below the regulated voltage
Low shutdown current: IQ = 0.7μA
Internal detection limits the current through the freewheeling diode
Power-good indicator
Compact, thermally enhanced 16-pin MSOP and (3mm × 3mm) DFN packages

II. LT3991 – 55V, 1.2A Buck Regulator with 2.8μA Quiescent Current
The LT3991 is a variable-frequency, monolithic buck switching regulator capable of accepting a wide input voltage range up to 55V. Its low quiescent current design consumes only 2.8 μA of supply current when regulating at no load. The chip incorporates a high-efficiency 0.44 Ω switch and a boost Schottky diode, as well as the necessary oscillator, control and logic circuits. An enable pin with a 1 V accurate threshold can be used to shut down the LT3991, thereby reducing the input supply current to 700 nA.
LT3991 Product Features:
Ultra-low quiescent current: 2.8 μA IQ regulating 12 VIN to 3.3 VOUT
Fixed output voltages: 3.3 V, 5 V
2.1 μA IQ regulating 12 VIN
Low-ripple Burst Mode® operation: output ripple <15 mV p-p
Wide input voltage range: 4.3 V to 55 V
1.2 A maximum output current
Adjustable switching frequency: 200 kHz to 2 MHz
Synchronisation frequency range: 250 kHz to 2 MHz
Fast transient response
Accurate 1 V enable pin threshold
Low shutdown current: IQ = 700 nA
Good Power Supply Indicator
Soft-start capability
Internal compensation
Saturated-switch design: 0.44 Ω on-resistance
Output voltage: 1.19 V to 30 V
Compact, thermally enhanced 10-pin MSOP and (3 mm × 3 mm) DFN packages

Availability Information
Mingjiada Electronics – a long-standing distributor of the ADI/LINEAR product range, with LT3990/LT3991 series step-down regulators regularly in stock, including but not limited to the following:
LT3990EDD
LT3990EMSE
LT3990EMSE-3.3
LT3990EMSE-5
LT3990HMSE
LT3990HMSE-3.3
LT3990HMSE-5
LT3990IDD
LT3990IMSE
LT3990IMSE-3.3
LT3990IMSE-5
LT3991EDD
LT3991EMSE
LT3991EMSE-3.3
LT3991EMSE-5
LT3991IDD
LT3991IMSE
LT3991IMSE-3.3
LT3991IMSE-5
Mingjiada Electronics supports sample orders, small-batch purchases and full-reel supply. To confirm specific part numbers, stock levels and real-time prices, please visit the Mingjiada Electronics website (https://www.integrated-ic.com/) for further supply details.