ltc1622 Linear Technology Corporation, ltc1622 Datasheet
ltc1622
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ltc1622 Summary of contents
Page 1
... The LTC1622 boasts a 1.9% output voltage accuracy and consumes only 350 A of quiescent current. For applica- tions where efficiency is a prime consideration and the load current varies from light to heavy, the LTC1622 can be configured for Burst Mode operation enhances low current efficiency and extends battery run time ...
Page 2
... RUN/ 0. Ramping Down SYNC/MODE V Ramping Down IN V Ramping Up IN ORDER PART NUMBER TOP VIEW LTC1622CS8 7 PDRV LTC1622IS8 GND 6 5 SYNC/MODE S8 PART MARKING S8 PACKAGE 1622 = 150 1622I MIN TYP MAX 10 70 0.785 0.8 0.815 0.780 0.8 0.820 0.04 ...
Page 3
... A IN CONDITIONS C = 3000pF LOAD C = 3000pF LOAD Note 3: The LTC1622 is tested in a feedback loop that servos V feedback point for the error amplifier (V and power Note 4: Dynamic supply current is higher due to the gate charge being A delivered at the switching frequency. RUN/SS Current vs Supply Voltage 3.50 3.00 2 ...
Page 4
... Burst Mode operation. An external clock between 625kHz and 750kHz applied to this pin forces the LTC1622 to operate at the external clock frequency. Do not attempt to synchronize below 625kHz . Pin 5 has an internal 1 A pull-up current source. ...
Page 5
... Comparator OV guards against transient overshoots latch is > 16% by turning off the P-channel power MOSFET and S keeping it off until the fault is removed. Burst Mode Operation The LTC1622 can be enabled to go into Burst Mode relative to the operation at low load currents simply by leaving the SYNC/ FB voltage to TH MODE pin open or connecting voltage of at least 2V ...
Page 6
... Undervoltage Lockout To prevent operation of the P-channel MOSFET below safe input voltage levels, an undervoltage lockout is incorpo- rated into the LTC1622. When the input supply voltage drops below 2V, the P-channel MOSFET and all circuitry is turned off except the undervoltage block, which draws only several microamperes. ...
Page 7
... U U APPLICATIONS INFORMATION The basic LTC1622 application circuit is shown in Figure 1. External component selection is driven by the load requirement and begins with the selection of L and R Next, the Power MOSFET and the output diode D1 are selected followed by C and OUT R Selection for Output Current ...
Page 8
... V = 2.5V) is required for applications that GS work close to this voltage. When these MOSFETs are used, make sure that the input supply to the LTC1622 is less than the absolute maximum MOSFET V GS The gate drive voltage levels are from ground to V The required minimum R ...
Page 9
... Other capacitor types include Sanyo OS-CON, Sanyo POSCAP, Nichicon PL series and the Panasonic SP series. Low Supply Operation Although the LTC1622 can function down to 2V, the maximum allowable output current is reduced when V decreases below 3V. Figure 3 shows the amount of change as the supply is reduced down to 2V. Also shown in ...
Page 10
... Although all dissipative elements in the circuit produce losses, four main sources usually account for most of the losses in LTC1622 circuits: 1) LTC1622 DC bias current, 2) MOSFET gate charge current 2.8 3.0 drop of the output diode and 5) transition losses. ...
Page 11
... L MIN TH = 0V), the OUT In the application, a 3.9 H inductor is used to reduce inductor ripple current and thus, output voltage ripple. For the selection of the external MOSFET, the R must be guaranteed at 2.5V since the LTC1622 has to work LTC1622 LTC1622 ...
Page 12
... The resistive divider R1 and R2 must be connected between the (+) plate of C will require an ESR ground. Optional capacitor C1 should be located as close as possible to the LTC1622. R1 and R2 should be located as close as possible to the LTC1622. R2 should connect to the output as close to the load as practicable – SENSE ...
Page 13
... U TYPICAL APPLICATIONS LTC1622 1.8V/1.5A Regulator with Burst Mode Operation Disabled V IN 2.5V TO 8.5V 1 SENSE LTC1622 10K RUN/ 220pF SS C4 560pF C1: AVX TPSD476M016R0150 C2: AVX TPSD227M006R0100 L1: MURATA LQN6C3R3 LTC1622 2.5V/2A Regulator with Burst Mode Operation Enabled R1 10k C3 220pF C1: AVX TPSD476M016R0150 C2: SANYO POSCAP 6TPA47M ...
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... LTC1622 U TYPICAL APPLICATIONS LTC1622 2.5V/3A Regulator with External Frequency Synchronization R1 10k C3 220pF C1: AVX TPSD476M016R0150 C2: AVX TPSD107M010R0065 D1: MOTOROLA MBR320T3 D2 1N4818 R1 47k C3 470pF C4 0.1 F C1: AVX TPSD476M016R0150 C2: AVX TPSD107M010R0080 D1: MOTOROLA MBRS320T3 L1A, L1B: BH ELECTRONICS BH511-1012 R2: DALE WSL-1206 0. 0.01 – SENSE PDRV TH M1 ...
Page 15
... TYP 0.016 – 0.050 0.014 – 0.019 (0.406 – 1.270) (0.355 – 0.483) TYP LTC1622 0.118 0.004** (3.00 0.102 0.034 0.004 (0.86 0.102) 0.006 0.004 (0.15 0.102) ...
Page 16
... TA06a Efficiency vs Load Current 100 3.3V OUT R SENSE 100 LOAD CURRENT (mA) Efficiency vs Load Current With LTC1622 Configured as Boost Converter 100 OUT 0.015 SENSE 3.3V IN OUT 0.001 0.01 0.1 LOAD CURRENT (mA) COMMENTS 100% DC, 3.5V V ...