The LT1074 is a 5A (LT1076CT#PBF is rated at 2A) monolithic bipolar switching regulator which requires only a few external parts for normal operation. The power switch, all oscillator and control circuitry, and all current limit components,are included on the chip. The topology is a classic positive “buck” configuration but several design innovations allow this device to be used as a positive-to-negative converter, a negative boost converter, and as a flyback converter. The switch output is specified to swing 40V below ground, allowing the LT1074 to drive a tapped-inductor in the buck mode with output currents up to 10A.
The LT1074 uses a true analog multiplier in the feedback loop. This makes the device respond nearly instantaneously to input voltage fluctuations and makes loop gain independent of input voltage. As a result, dynamic behavior of the regulator is significantly improved over previous designs.
On-chip pulse by pulse current limiting makes the LT1074 nearly bust-proof for output overloads or shorts. The input voltage range as a buck converter is 8V to 60V, but a self-boot feature allows input voltages as low as 5V in the inverting and boost configurations.
The LT1074 is available in lowcost TO-220 or DD packages with frequency pre-set at 100kHz and current limit at 6.5A (LT1076CT#PBF =2.6A). A 7-pin TO-220 package is also available which allows current limit to be adjusted down to zero. In addition, full micropower shutdown can be programmed. See Application Note 44 for design details.
A fixed 5V output, 2A version is also available. See LT1076-5.
5A Onboard Switch (LT1074)
Operates Up to 60V Input
100kHz Switching Frequency
Greatly Improved Dynamic Behavior
Available in Low Cost 5 and 7-Lead Packages
Only 8.5mA Quiescent Current
Programmable Current Limit
Micropower Shutdown Mode
Buck Converter with Output Voltage Range of 2.5V to 50V
Tapped-Inductor Buck Converter with 10A Output at 5V
Positive-to-Negative Converter
Negative Boost Converter
Multiple Output Buck Converter

(Picture: Pinout)

(Picture: Diagram)
| Function | Step-Up, Step-Down, Step-Up/Step-Down | Voltage Output (Max) | 35V |
|---|---|---|---|
| Output Configuration | Positive or Negative | Current Output | 2A (Switch) |
| Topology | Buck, Boost, Flyback | Frequency Switching | 100kHz |
| Output Type | Adjustable | Synchronous Rectifier | No |
| Number of Outputs | 1 | Operating Temperature | 0??C ~ 70??C (TA) |
| Voltage Input (Min) | 8V | Mounting Type | Through Hole |
| Voltage Input (Max) | 45V | Package / Case | TO-220-5 Formed Leads |
| Voltage Output (Min/Fixed) | 2.5V | Supplier Device Package | TO-220-5 |
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LT1072LINEAR, SOP8Compare
LT1070CKJTI,Compare