TS1935B1.9A / 1.2MHz Boost DC to Dc Converter Pin Defi nition: General Description The TS1935B is a current mode step up converter intended for small, low power applications. The converter input voltage ranging from 2.6V to 5.5V. The Output voltage can be set up to 27V. The frequency is 1.2MHz allows the use of small external inductors and capacitors and provides fast transient response. Internal soft start results in small inrush current and extends battery life. Internal power MOSFET with very low RDS (ON) provides high efficiency. The TS1935B automatically transits from PWM to PFM during light load condition further increasing efficiency. The converter also provides protection functions such as under-voltage lockout, current limit and thermal shutdown. Application • White LED Current Source • Digital Still Cameras • Portable Electronics • PDA’s and Palm-Top Computers • Local Boost Regulator Features • 2.6V to 5.5 V operating input voltage range • Adjustable output voltage range up to 27V • 1.2MHz Fixed Switching Frequency • Internal soft-start function • Current limit and Thermal shutdown protection • Under voltage Lockout • < 1^A Shutdown Current Note: Stress above the listed absolute maximum rating may cause permanent damage to the device Thermal Information

TS1935B1.9A / 1.2MHz Boost DC to Dc Converter Electrical Specifications (Ta = 25oC, VIN=5V, Note 1: Guaranteed by design Pin Description

TS1935B 1.9A / 1.2MHz Boost DC to Dc Converter Block Diagram EN Soft Start Thermal Shutdown Enable/ Disable Summing Comparator SW Control and Driver Logic Error Amplifier Current Sense Slope Compensation

TS1935B 1.9A / 1.2MHz Boost DC to Dc Converter Application Information Setting the Output Voltage Application circuit item shows the basic application circuit with AX5511 adjustable output version. The external resistor sets the output voltage according to the following equation: R2 VOUT = 1.238V × (1+ ) R1 For most applications, R2 is a suggested a value by 390K~820KΩ. Place the resistor-divider as close to the IC as possible to reduce the noise sensitivity. Under Voltage Lockout (UVLO) To avoid mis-operation of the device at low input voltages an under voltage lockout is included that disables...

TS1935B 1.9A / 1.2MHz Boost DC to Dc Converter Electrical Characteristics Curve Figure 1. Quiescent Current vs. Input Voltage Figure 2. Frequency vs. Input Voltage Figure 3. FB Voltage vs. Input Voltage Figure 4. FB Voltage vs. Output Current Figure 5. FB Voltage vs. Temperature Figure 6. Frequency vs. Temperature

TS1935B1.9A / 1.2MHz Boost DC to Dc Converter COMPLIANCE Electrical Characteristics Curve 1.4 > V1-2 Q) 03 r° T3 o 0.8 Figure 11. Efficiency vs. Output Current Figure 12. Efficiency vs. Output Current

TAIWAN SEMICONDUCTOR SOT-25 Mechanical Drawing Unit: Millimeters W = Week Code WW: 01~26 (A~Z) 27~52 (a~z) X = Internal ID Code

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