LT1766EFE/LT1956EFE

Linear Technology announces the LT1766EFE and LT1956EFE, two constant frequency step-down switching regulators that include a 1.5A internal switch. Both switching regulators operate within a VIN range of 5.5V to 60V, and can deliver up to 1.25A of continuous output current at voltages as low as 1.25V. The LT1766EFE utilizes a 200kHz switching frequency, while the LT1956EFE switches at a frequency of 500kHz. Both devices are packaged in a thermally enhanced TSSOP package to keep the overall solution footprint very small while providing optimum thermal resistance.

The LT1766EFE and the LT1956EFE are respectively identical to the LT1766EGN and LT1956EGN except for their “exposed pad” package which provides a 50% reduction in thermal resistance within a very compact footprint, allowing them to operate over a wider ambient temperature range without exceeding the maximum junction temperature of 125°C. The “exposed pad” package integrates a copper pad as the bottom of the TSSOP package providing a direct thermal path from the die to the PC board. This is particularly beneficial in applications that require high VIN/VOUT ratios and moderate output current levels, yet are confined to small solution footprints.

Both the LT1766 and LT1956 “family” utilize a high efficiency 1.5A, 0.2 Ohm switch, with the necessary oscillator, control and logic circuitry integrated into a single die. Special design techniques and a new high voltage process enable high efficiency over a wide input voltage range while the current mode topology enables fast transient response and excellent loop stability. Proprietary circuitry maintains peak switch current over the entire duty cycle range. Supply current is only 2.5mA, while shutdown current is reduced to 25µA.

The LT1766 is available in both E and I temperature grades, each can be purchased with a fixed 5V or an adjustable output. Both of the LT1766EFE versions are available from stock, pricing starts at $3.75 each in 1,000-piece quantities. Similarly, both “I” grade versions, LT1766IFE, LT1766IFE–5 are available from stock, pricing starts at $4.45 in 1,000-piece quantities.

The LT1956 is also available in both E and I temperature grades. Each can be purchased with a fixed 5V or an adjustable output. Both of the LT1956EFE versions are available from stock and pricing starts at $3.75 each in 1,000-piece quantities. Similarly, both I-grade versions, the LT1956IFE and LT1956IFE-5, are available from stock. Pricing starts at $4.45 each in 1,000-piece quantities.

Summary of Features: LT1766EFE & LT1956EFE
Wide Input Voltage Range: 5.5V to 60V
1.5A Peak Switch Current
Constant 200kHz (500kHz for LT1956) Switching Frequency
Peak Switch Current Maintained Over Full Duty Cycle
Saturating Switch Design: 0.2 Ohm
1.2V Feedback Reference Voltage
Effective Supply Current: 2.5mA
Low Shutdown Current: 25µA
Easily Synchronizable
TSSOP-16E Thermally Enhanced Package
Cycle-by-Cycle Current Limiting