TS1935B_13 TSC | Alldatasheet

Document overview

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Technical content

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
  • ≤ 1µA Shutdown Current Application
  • White LED Current Source
  • Digital Still Cameras
  • Portable Electronics
  • PDA’s and Palm-Top Computers
  • Local Boost Regulator

Ordering Information

Part No. Package Packing TS1935BCX5 RFG SOT-25 3Kpcs / 7” Reel Note: “G” denotes for Halogen Free Absolute Maximum Rating Parameter Symbol Limit Unit Input Voltage VIN GND - 0.3 to GND + 6.5 V EN, V FB Voltage VEN , VFB GND - 0.3 to V CC + 0.3 V SW Voltage VSW 30 V Ambient Temperature Range T A -40 to +85 oC Junction Temperature Range T J -40 to +125 oC Storage Temperature Range T STG -40 to +150 oC Note: Stress above the listed absolute maximum rating may cause permanent damage to the device Thermal Information Parameter Symbol Maximum Unit Thermal Resistance* (Junction to Case) ӨJC 110 oC/W Thermal Resistance* (Junction to Ambient) ӨJA 250 oC/W Internal Power Dissipation PD (T J-TA)/ ӨJA mW Maximum Junction Temperature Tj 150 oC Lead Solder Temperature (260 oC) 5 S Note: ӨJA is measured with the PCB copper area of approximately 1 in2(Multi-layer). Pin Definition : 1. SW 2. Ground 3. FB 4. EN 5. Input

1.9A / 1.2MHz Boost DC to Dc Converter 2/8 Version: A12 Electrical Specifications (Ta = 25 oC, VIN =5V, EN=VIN , I L=0A unless otherwise noted) Characteristics Symbol Conditions Min Typ Max Units Input Voltage range V CC 2.6 -- 5.5 V Under Voltage Lockout UVLO Rising -- 2.35 2.60 V UVLO Hysteresis -- -130 -- mV Step-Up Voltage Adjust Range V OUT 3 -- 27 V Operating quiescent current I CCQ I OUT = 0mA, V FB =1.5V -- 150 250 µA Shutdown current I SD V EN =0V -- 0.1 1 µA Feedback Voltage V FB 1.213 1.238 1.263 V FB Input Leakage Current I FB-LKG V FB = 1.3V -100 0.01 +100 nA Line Regulation VIN = 2.5 to 5.5V IOUT = 20mA -- 0.2 -- % Load Regulation VIN = 5V IOUT = 1mA to 400mA - 0.2 -- % Switching frequency F OSC 900 1200 1500 KHz Maximum Duty D MAX 82 87 - % N-channel MOSFET current limit I LIM Duty=50% -- 1.9 -- A MOSFET on-resistance (Note 1) R DS(on) VCC=3V, I SW =1A -- 650 - m Ω VCC=5V, I SW =1A -- 500 -- SW Leakage Current I SWL V LX = 27V, VFB =1.5V -- -- 1 µA EN high-level input voltage V IH 1.0 -- -- V EN low-level input voltage V IL -- -- 0.4 V EN Hysteresis hys -- 200 - mV EN input leakage current I EN-LKG V EN =GND or VCC -- 0.01 0.1 µA Thermal Shutdown T DS -- 150 -- ° C Thermal Shutdown Hysteresis T SH -- 35 -- Note 1: Guaranteed by design Pin Description Pin Number Pin Name Description 1 SW Power Switch Output. SW is the drain of the internal MOSFET switch. Connect the power inductor and output rectifier to SW. SW can swing between GND and 27V. 2 GND Ground. Tie directly to ground plan. 3 FB Feedback Input. FB voltage is 1.238V. Connect a resistor divider to FB. 4 EN Regulator On/Off Control Input. A high input at EN turns on the converter, and a low input turns it off. When not used, connect EN to the input source for automatic startup. The EN pin cannot be left floating. 5 VCC Input Supply Pin. Must be locally bypassed.

1.9A / 1.2MHz Boost DC to Dc Converter 3/8 Version: A12 Block Diagram VCC SW Control and Driver Logic EN Soft Start Current Sense Slope Compensation Oscillator 1.2MHz FB Error Amplifier Summing Comparator Thermal Shutdown Enable/ Disable GND N-MOS UVLO Vref 1.238V Application Circuit 54K VIN=5V 10uF 4.7uH 470K VOUT=12V U1 AX5511 1VCC EN FB GND SW 1nF 4.7uF B240A R2 Suggest 390K~820K ON OFF VIN VOUT R3 2.6~3.6V 5V 120K Ω 2.6~5.3V 7V 82K Ω 2.6~5.5V 7.5~27V 0 Ω TS1935B

1.9A / 1.2MHz Boost DC to Dc Converter 4/8 Version: A12

Application Information

Setting the Output Voltage resistor sets the output voltage according to the following equation: )R1 R2 + (1 ×1.238V = VOUT For most applications, R2 is a suggested a value by 390K~820K Ω. 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 the device, if the input voltage falls below (2.35V-130mV). Input Capacitor Selection The input capacitor reduces the surge current drawn from the input and switching noise from the device. The input capacitor impedance at the switching frequency shall be less than input source impedance to prevent high frequency switching current passing to the input. A low ESR input capacitor sized for maximum RMS current must be used. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. A 10µF ceramic capacitor for most applications is sufficient. For a lower output power requirement application, this value can be decreased. Output Capacitor Selection The output capacitor is required to keep the output voltage ripple small and to ensure regulation loop stability. The output capacitor must have low impedance at the switching frequency. Ceramic capacitors with X5R or X7R dielectrics are recommended due to their low ESR and high ripple current. A 4.7uF ceramic capacitors works for most of the applications. Higher capacitor values can be used to improve the load transient response. Layout Guide

1.9A / 1.2MHz Boost DC to Dc Converter 7/8 Version: A12 SOT-25 Mechanical Drawing Unit: Millimeters

1.9A / 1.2MHz Boost DC to Dc Converter 8/8 Version: A12 Notice Specifications of the products displayed herein are subject to change without notice. TSC or anyone on its behalf, assumes no responsibility or liability for any errors or inaccuracies. Information contained herein is intended to provide a product description only. No license, express or implied, to any intellectual property rights is granted by this document. Except as provided in TSC’s terms and conditions of sale for such products, TSC assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of TSC products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications. Customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify TSC for any damages resulting from such improper use or sale.