Dual tracking LDO output provided

October 21, 2014 – Linear Technology Korea (CEO Hong Sa-kwak, www.linear.com ) announced the release of the LT3668, a 400mA, 40V step-down switching regulator featuring dual tracking LDO outputs, available in an MSOP-16E package. The LT3668 is a complete and robust power solution suitable for applications requiring power supplies for sensors that meticulously track the power supply's measurement ASIC. With transient protection up to 60V and operating within a VIN range of 4.3V to 40V, the LT3668 is ideal for automotive and industrial applications. Its internal 600mA switch can provide up to 400mA, which is distributed to both the mixed load on the primary output and the two tracking LDOs. The primary switching channel can provide a low output of 1.2V, while each LDO can provide a low output of 1.1V. The LT3668 has a standby current of only 50µA when all three channels are regulated, making it ideal for always-on automotive applications.

The switching frequency of the LT3668 is user-programmable within the range of 250 kHz to 2.2 MHz, allowing designers to maximize efficiency while avoiding noise-sensitive frequency bands. Each highly integrated tracking LDO features a precise, programmable current limit of up to 200 mA, ensuring an additionally high level of reliability. Due to the high precision characteristics of the tracking LDOs, this product is ideal for powering ADCs and sensors. Even though the LDOs are powered by independent inputs, powering them from the primary switching output provides high efficiency and low noise. This product combines the thermally enhanced MSOP-16E with a high switching frequency, allowing for smaller external capacitor and inductor sizes, thereby providing a compact and thermally efficient footprint.

The LT3668's primary switch utilizes a high-efficiency 600mA switch in which essential oscillator, control, and logic circuits are integrated on a single die. High efficiency over a wide input voltage range is achieved through special design techniques, and this current-mode topology enables fast transient response and excellent loop stability. Other features include a power good indicator, synchronization capabilities, reverse battery protection, current and thermal limiting functions, and programmable low-voltage lockout.
The LT3668EMSE is available in a thermally enhanced 16-pin MSOP package and is priced at $2.55 per unit. The LT3668IMSE has been tested and guaranteed to operate over an operating junction temperature range of –40°C to 125°C and is priced at $2.81 per unit. Available in quantities of 1,000, and all versions of the LT3668 are currently available. For more information, please refer to www.linear.com/product/LT3668 .

Photo Caption: 40V, 400mA (IOUT), Triple Output DC/DC Converter

Product Features: LT3668

• A triple-output power supply from a single input requires only one inductor.
• Dual Low Dropout Linear Tracking Regulator
o 200mA output with programmable current limiting function
o 1.6V ~ 45V input range
o Error protection with +45V
• Buck Regulator:
o Low Ripple (<15mVP-P) Burst Mode® Operation
o 400mA with internal power switch
o 4.3V ~ 40V input operating range (60V Max)
• IQ = 50μA at 12VIN ~ 6V, 5V and 5V under no-load
• Adjustable 250kHz ~ 2.2MHz switching frequency
• Synchronizable between 300kHz and 2.2MHz
• Programmable low-voltage lockout
• Power Good Indicator
• Available in a 16-pin MSOP package with improved thermal performance

The pricing information presented above is for general budget planning purposes applicable to the USA region. Country-specific pricing may vary depending on regional customs duties, taxes, fees, exchange rates, etc.