LT1616 Linear Technology Corporation, LT1616 Datasheet
LT1616
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LT1616 Summary of contents
Page 1
... PWM step-down DC/DC converter with internal 0.6A power switch, packaged in a tiny 6-lead SOT-23. The wide input range of 3.6V to 25V makes the LT1616 suitable for regulating a wide variety of power sources, from 4-cell batteries and 5V logic rails to unregulated wall transformers and lead-acid batteries. Its high operating frequency allows the use of tiny, low cost inductors and ceramic capacitors ...
Page 2
... SHDN Bias Current Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. Note 2: The LT1616E is guaranteed to meet performance specifications from Specifications over the – operating temperature range are assured by design, characterization and correlation with statistical process controls ...
Page 3
... INPUT VOLTAGE (V) 1616 G05 Feedback Pin Voltage 1.27 1.26 1.25 1.24 1.23 1.22 – 100 –25 TEMPERATURE ( C) 1616 G08 LT1616 Switch Voltage Drop 500 400 300 200 100 0 0 200 400 600 SWITCH CURRENT (mA) 1616 G03 BOOST Pin Current ...
Page 4
... G09 SHDN (Pin 4): The SHDN pin is used to put the LT1616 in shutdown mode. Tie to ground to shut down the LT1616. Tie more for normal operation. If the shutdown feature is not used, tie this pin to the V V (Pin 5): The V IN internal regulator and to the internal power switch ...
Page 5
... GND FB SHDN pin is used to place the LT1616 in shutdown, disconnecting the output and reducing the input current to less than 1 A. The switch driver operates from either the input or from the BOOST pin. An external capacitor and diode are used . An error ...
Page 6
... If the output is shorted to ground, the output voltage will collapse and there will be very little voltage to reset the current in the inductor. The LT1616 can sense this condi- tion at its FB pin. In order to control the current, the LT1616 reduces its operating frequency, allowing more time for 1616 F01a the catch diode to reset the inductor current ...
Page 7
... DC)( )/(L • OUT D where f is the switching frequency of the LT1616 and L is the value of the inductor. The average inductor current is equal to the output current, so the peak inductor current will be the output current plus one half of the ripple current: I ...
Page 8
... F ceramic capacitor. However, input voltage ripple will be higher, and you may want to include an additional 0.1 F ceramic a short distance away from the LT1616 circuit in order to filter the high frequency ripple. The input capacitor should be rated for the maxi- mum input voltage. ...
Page 9
... V OUT 20mV/DIV I LOAD 100mA/DIV 100 F TANTALUM AND 2.2 F CERAMIC OUT Figure 3. Transient Load Response of the LT1616 10V 4 Figure 4. Circuit Used for Transient Load Test Shown in Figure 3 Regardless of which capacitor or combination of capaci- tors you choose, you should do transient load tests to evaluate the circuit’ ...
Page 10
... For proper start- up, the minimum input voltage is also limited by the boost circuit. If the input voltage is ramped slowly, or the LT1616 is turned on with its SHDN pin when the output is already in regulation, then the boost capacitor may not be fully ...
Page 11
... SW pin. This is fine if your system can tolerate a few mA in this state. If you ground V IN Figure 7. Diode D4 Prevents a Shorted Input from Discharging a Backup Battery Tied to the Output; It Also Protects the Circuit from a Reversed Input. The LT1616 Runs Only When the Input is Present GND I C1 Figure 8 ...
Page 12
... FB node as small as possible so that the ground pin and ground traces will shield it from the SW and BOOST nodes. Figure 9 shows component placement with trace, ground plane and via locations. Include two vias near the GND pin of the LT1616 to help remove heat from the LT1616 to the ground plane. SHUTDOWN V IN Figure 9 ...
Page 13
... IN C3 LT1616 0. SHDN SW GND 8.87k 20k 16V C1: TAIYO-YUDEN EMK212BJ105MG C2: TAIYO-YUDEN JMK316BJ106ML D1: ON SEMICONDUCTOR MBR0520L D2: 1N4148 OR EQUIVALENT L1: MURATA LQH3C4R7M24 LT1616 OUT 12V 300mA C2 2.2 F 16V GND 1616 TA03 L1 4 OUT 400mA 6.3V GND 1616 TA04 13 ...
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... 10k 16V C1: TAIYO-YUDEN EMK212BJ105MG C2: TAIYO-YUDEN JMK212BJ475MG D1: ON SEMICONDUCTOR MBR0520 D2: 1N4148 L1: MURATA LQH3C4R7M24 5V Output BOOST IN C3 LT1616 0. SHDN SW GND 30. 10k 25V C1: TAIYO-YUDEN TMK316BJ105ML C2: TAIYO-YUDEN JMK316BJ106MG D1: ON SEMICONDUCTOR MBR0530 D2: 1N4148 L1: TOKO A914BYW-150M L1 4 ...
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... REF (0.110 – 0.118) 1.50 – 1.75 0.00 – 0.15 (0.059 – 0.069) (0.00 – 0.006) 0.35 – 0.50 0.09 – 0.20 (0.014 – 0.020) (0.004 – 0.008) SIX PLACES (NOTE 2) (NOTE 2) LT1616 0.95 (0.037) REF 0.90 – 1.45 (0.035 – 0.057) 0.90 – 1.30 (0.035 – 0.051) S6 SOT-23 0898 15 ...
Page 16
... Micropower Step-Down in SOT-23 LTC1877 0.6A Synchronous Step-Down Regulator LT1962 300mA, Low Noise, LDO Micropower Regulator Linear Technology Corporation 16 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear-tech.com Bipolar Output DC/DC Converter BOOST IN C3 LT1616 0. SHDN SW GND 30. ...