The LT 1370 is a monolithic high frequency current mode switching regulator. It is available in all standard switching configurations including Boost, Buck, Flyback, Forward, Inverter and "Cuk". A 6A high efficiency switch is mounted on the die, along with all oscillator, control and protection circuits. The LT1370 typically consumes only 4.5mA of quiescent current and is more efficient than previous parts. High frequency switching allows the use of very small inductors. New design techniques increase flexibility while maintaining ease of use. Switching is easily synchronized to an external logic level source. A logic low current of 12µA turns off the pin to reduce supply. A unique error amplifier circuit regulates positive or negative output voltage while maintaining simple frequency compensation techniques. The nonlinear error amplifier transconductance reduces output overshoot during startup or overload recovery. The oscillator frequency shift protects external components from overload conditions. describe you

With improved efficiency ■ Faster switching using small inductance: 4.7μh ■ ■ All surface mount components Low supply voltage Minimum: 2.7 v ■ Quiescent current: 4.5 ma Typ current limited power switch: ■ ■ ■ Adjust positive or negative output 6 power off Current: 12μa Typ External Synchronization Simple Switch Resistance: 0.065?Typ

Typical application U

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VREF Reference Voltage Measured at Feedback Pin 1.230 1.245 1.260 V VC = 0.8V ● 1.225 1.245 1.265 V IFB Feedback Input Current VFB = VREF 250 550 nA ● 900 nA Reference Voltage Line Regulation 2.7V ≤ VIN ≤ 25V , VC = 0.8V ● 0.01 0.03 %/V VNFR Negative Feedback Reference Voltage Measured at Negative Feedback Pin –2.525 –2.48 –2.435 V Feedback Pin Open, VC = 0.8V ● –2.560 –2.48 –2.400 V INFB Negative Feedback Input Current VNFB = VNFR ● –45 –30 –15 μA Negative Feedback Reference Voltage 2.7V ≤ VIN ≤ 25V, VC = 0.8V ● 0.01 0.05 %/V Line Regulation gm Error Amplifier Transconductance ?IC = ±25μA 1100 1500 1900 μmho ● 700 2300 μmho Error Amplifier Source Current VFB = VREF – 150mV, VC = 1.5V 120 200 350 μA Error Amplifier Sink Current VFB = VREF + 150mV, VC = 1.5V 1400 2400 μA

VC: Compensation pin is used for frequency compensation, current limiting, soft start. It is the output of the error amplifier and the input of the current comparator. Loop frequency compensation can be achieved by connecting the RC network from the VC pin to ground. See application information. FB: Feedback pin for positive output voltage sensing and oscillator frequency shifting. It is the inverting input of the error amplifier. The non-inverting input of this amplifier is internally connected to the 1.245V reference. The negative feedback pin is used for negative output voltage sensing. It is connected to the inverting input of the negative feedback amplifier through a 100k source resistor.

S/S: Shutdown and sync pins. The S/S pins are logic level compatible. Shutdown is active low and the shutdown threshold is typically 1.3V. For normal operation, pull the S/S pin high, tie to VIN or let it float. To switch synchronously, drive the S/S pin between 600kHz and 800kHz. See application information. Text: Bypass input pins to provide low ESR capacitors, 10µF or more. When the VIN voltage falls below 2.5V, the regulator enters an undervoltage lockout state. Undervoltage lockout stops switching and pulls the VC pin low. The switch pin is the collector of the power switch, and a large current flows through it. Keep traces to switching elements as short as possible to minimize emissions and voltage spikes. Tie all feet to a high-quality ground. see application information