LT3470AEDDB-PBF LINER [Linear Technology], LT3470AEDDB-PBF Datasheet
LT3470AEDDB-PBF
Related parts for LT3470AEDDB-PBF
LT3470AEDDB-PBF Summary of contents
Page 1
FEATURES n Low Quiescent Current: 35μA at 12V n Integrated Boost and Catch Diodes n Input Range 40V n 3.3V at 250mA from 4V to 40V Input 250mA from 5.7V to 40V Input n Low ...
Page 2
... ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL LT3470AEDDB#PBF LT3470AEDDB#TRPBF LT3470AIDDB#PBF LT3470AIDDB#TRPBF Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi label on the shipping container. Consult LTC Marketing for information on non-standard lead based fi nish parts. ...
Page 3
ELECTRICAL CHARACTERISTICS l The denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are 10V 10V 15V, V SHDN IN BOOST BIAS PARAMETER Minimum Input Voltage ...
Page 4
LT3470A TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency 3.3V OUT TOKO D52LC 47μ 25° 12V 36V V = 24V ...
Page 5
TYPICAL PERFORMANCE CHARACTERISTICS FB Bias Current (V vs Temperature –50 – TEMPERATURE (°C) Switch V (I CESAT vs Temperature 300 250 200 150 100 50 0 –50 – TEMPERATURE ...
Page 6
LT3470A TYPICAL PERFORMANCE CHARACTERISTICS Switch V CESAT 700 600 500 400 300 200 100 0 0 100 200 SWITCH CURRENT (mA) Catch Diode Forward Voltage 1.0 0.8 0.6 0.4 0 100 200 CATCH DIODE CURRENT (mA) Minimum Input ...
Page 7
PIN FUNCTIONS SHDN (Pin 8): The SHDN pin is used to put the LT3470A in shutdown mode. Tie to ground to shut down the LT3470A. Apply 2V or more for normal operation. If the shutdown feature is not used, tie ...
Page 8
LT3470A BLOCK DIAGRAM 500ns ONE SHOT NC SHDN V REF 1.25V – R Qʹ – ENABLE + BURST MODE DETECT BIAS BOOST ...
Page 9
OPERATION The LT3470A uses a hysteretic control scheme in conjunc- tion with Burst Mode operation to provide low output ripple and low quiescent current while using a tiny inductor and capacitors. Operation can best be understood by studying the Block ...
Page 10
LT3470A APPLICATIONS INFORMATION Input Voltage Range The minimum input voltage required to generate a par- ticular output voltage in an LT3470A application is limited by either its 4V undervoltage lockout or by its maximum duty cycle. The duty cycle is ...
Page 11
APPLICATIONS INFORMATION Table 2. Inductor Vendors VENDOR URL Coilcraft www.coilcraft.com Sumida www.sumida.com Toko www.tokoam.com Würth Elektronik www.we-online.com Coiltronics www.cooperet.com Murata www.murata.com be used important to note that inductor saturation current is reduced at high temperatures—see inductor vendors for ...
Page 12
LT3470A APPLICATIONS INFORMATION Ceramic Capacitors Ceramic capacitors are small, robust and have very low ESR. However, ceramic capacitors can cause problems when used with the LT3470A. Not all ceramic capacitors are suitable. X5R and X7R types are stable over temperature ...
Page 13
APPLICATIONS INFORMATION (Figure 2b). The circuit in Figure 2a is more effi cient because the BOOST pin current and BIAS pin quiescent current comes from a lower voltage source. You must also be sure that the maximum voltage ratings of ...
Page 14
LT3470A APPLICATIONS INFORMATION PCB Layout For proper operation and minimum EMI, care must be taken during printed circuit board layout. Note that large, switched currents fl the power switch, the internal catch diode and the input capacitor. The ...
Page 15
APPLICATIONS INFORMATION Hot-Plugging Safely The small size, robustness and low impedance of ceramic capacitors make them an attractive option for the input bypass capacitor of LT3470A. However, these capacitors can cause problems if the LT3470A is plugged into a live ...
Page 16
LT3470A APPLICATIONS INFORMATION CLOSING SWITCH SIMULATES HOT PLUG + LOW STRAY IMPEDANCE INDUCTANCE ENERGIZED DUE TO 6 FEET 24V SUPPLY (2 METERS) OF TWISTED PAIR 10μF 35V AI.EI. 0.1μF Figure 6: A Well Chosen Input Network Prevents Input Voltage Overshoot ...
Page 17
APPLICATIONS INFORMATION 40V 5.7V TO 40V 40V 3.3V Step-Down Converter IN C3 0.22μF , 6.3V V BOOST IN L1 LT3470A 33μH OFF ON SHDN SW BIAS 22pF C1 FB 1μF GND C1: TDK C3216JB1H105M ...
Page 18
LT3470A TYPICAL APPLICATIONS 23V V 15V TO 34V 18 1.8V Step-Down Converter IN C3 0.22μF , 25V V BOOST IN L1 LT3470A 22μH OFF ON SHDN SW BIAS 22pF C1 FB 1μF GND C1: TDK C3216JB1H105M C2: ...
Page 19
PACKAGE DESCRIPTION 0.61 ±0.05 (2 SIDES) 0.70 ±0.05 2.55 ±0.05 1.15 ±0.05 0.25 ± 0.05 0.50 BSC 2.20 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229 2. ...
Page 20
LT3470A RELATED PARTS PART NUMBER DESCRIPTION LT1616 25V, 500mA (I ), 1.4MHz, High Effi ciency OUT Step-Down DC/DC Converter LT1676 60V, 440mA (I ), 100kHz, High Effi ciency OUT Step-Down DC/DC Converter LT1765 25V, 2.75A (I ), 1.25MHz, High Effi ...