lt3651-4.2 Linear Technology Corporation, lt3651-4.2 Datasheet
lt3651-4.2
Related parts for lt3651-4.2
lt3651-4.2 Summary of contents
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... The LT3651 is available in a 5mm × 6mm 36-Pin QFN package. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TO SYSTEM LOAD 22µF 1µF 3.3µH 1N5819 24m + 100µF BATTERY 365142 TA01a LT3651-4.2 Li-Ion Battery Charger V and Efficiency vs I BAT BAT 100 4.25 V BAT 90 4. 10V ...
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... LT3651-4.2 absoluTe MaxiMuM raTings (Note 1) V .......................................................................... 40V IN CLN, CLP , SHDN, CHRG, FAULT, ACPR . .............................. V CLP – CLN .............................................................±0.5V SW ...........................................................................40V SW – .................................................................4.5V IN BOOST ......................................... SW + 10V Up to 50V SENSE, BAT ............................................................ 10V SENSE-BAT ............................................. –0.5V to 0.5V TIMER, RNG/SS NTC ............................. 2.5V LIM Operating Junction Temperature Range (Notes ............................................... –40 to 125°C Storage Temperature Range . ...................... –65 to 150°C ...
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... 250kΩ T characterization and correlation with statistical process controls. The LT3651I is guaranteed over the full –40°C to 125°C operating junction temperature range. The junction temperature (T the ambient temperature (T according to the formula: where θ (in °C/W) is the package thermal impedance. JA LT3651-4.2 = 20V, SHDN = 2V, SENSE = BAT = V IN BAT(FLT) MIN TYP MAX 8 480 140 ) < 4 115 ...
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... LT3651-4.2 elecTrical characTerisTics Note 3: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. The maximum rated junction temperature will be exceeded when this protection is active. Typical perForMance characTerisTics Battery Float Voltage vs Temperature 1.0 0.5 0 –0.5 –1.0 –50 – 100 0 TEMPERATURE (°C) 365142 G01 C/10 Threshold (V vs Temperature –50 – TEMPERATURE (°C) Continuous operation above the specified absolute maximum operating junction temperature may impair device reliability or permanently damage the device ...
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... CHG(MAX) 120 100 100 110 TEMPERATURE (° 100 125 365142 G06 120 130 140 365142 G08 LT3651-4.2 SENSE and BAT Pin Current vs BAT Voltage SENSE BAT 150 I 100 SENSE 50 I BAT 0 –50 –100 –150 –200 –250 –300 – ...
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... LT3651-4.2 pin FuncTions NTC (Pin 1): Battery Temperature Monitor Pin. This pin is used to monitor battery temperature. Typically a 10kΩ NTC (negative temperature coefficient) thermistor (B = 3380) is embedded with the battery and connected from the NTC pin to ground. The pin sources 50µA into the resistor and monitors the voltage across the thermistor, regulating charging based on the voltage. If this function is not desired, leave the NTC pin unconnected. ACPR (Pin 2): Open-Collector AC Present Status Pin. This pin sinks current to indicate that V charger is on. Typically a resistor pull-up is used on this pin ...
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... ILIM to ground. The soft-start capacitor and the programming resistor can be implemented in parallel. The RNG/SS pin is pulled low during fault conditions, allowing graceful to ground. The recovery from faults if C LIM RT (Pin 36): Switcher Oscillator Timer Set Pin. A resis- tor from this pin to ground sets the switcher oscillator frequency. Typically this is 54.9k for f LT3651-4.2 together less than 100µA after charge termina- VIN SENSE ) to ground. RNG/SS ) from RNG/SS RNG/SS is used. RNG/SS = 1MHz ...
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... LT3651-4.2 block DiagraM 50µA I LIM 28 + CLN + 30 CLP – 29 A12 RT 36 TIMER 24 TIMER OSC RIPPLE COUNTER COUNT RESET COUNT COUNT RESET MODE ENABLE (TIMER OR C/10) CHRG 26 CONTROL LOGIC TERMINATE FAULT 25 SS/RESET STATUS C/10 PRECONDITION NTC A1 + – 1.36V 50µA A2 – + 0.29V NTC 1 + – 1.3V 46µA STANDBY UVLO – ...
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... The amplifier output voltage (I to the desired average voltage across the inductor sense resistor connected between the SENSE and BAT SENSE pins. The I voltage is divided down by a factor of 10, TH and provides a voltage offset on the input of the current error amplifier (C-EA). The difference between this im- posed voltage and the current sense resistor voltage is integrated by C-EA. The resulting voltage (V voltage that is compared against an internally generated ramp and generates the switch duty cycle that controls the charger’s switches. LT3651-4.2 ) corresponds TH ) provides a C 365142f ...
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... LT3651-4.2 operaTion The I error voltage corresponds linearly to average TH current sensed across the inductor current sense resistor. Maximum charge current is controlled by clamping the maximum voltage 1V. This limits the maximum TH current sense voltage (voltage across R setting the maximum charge current. Manipulation of maximum charge current is possible through the RNG/SS and I pins (see the RNG/SS: Dynamic Charge Current LIM Adjust, RNG/SS: Soft-Start and I LIM If the voltage on the BAT pin ( below V BAT initiates the precondition mode. During the precondition ...
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... V IN The LT3651 operates with a V charger begins a charging cycle when the detected battery is the maximum voltage is below the 4.1V auto-restart float voltage and the part is enabled. , When V IN(MIN) IN charged, the high side switch would normally not have sufficient head room to start switching. During normal operation the low side switch is deactivated when charge current is very low to prevent reverse current in the inductor. LT3651-4.2 is approximated by: CVIN(RMS) BAT ≈ I • • ) CHARGE MAX ...
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... MAX(AVG 24mΩ for a 4A charger. SENSE SW BOOST LT3651-4.2 CS BAT Figure 1. Programming Maximum Charge Current Using R Inductor Selection The primary criteria for inductor value selection in the LT3651 charger is the ripple current created during switch- ing. Ripple current, ∆I MAX 25% to 35% of the maximum charge current, I percentage typically gives a good compromise between losses due to ripple and inductor size. An approximate ...
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... If reduced voltage overhead or better efficiency is required then reduce the maximum voltage across R instance, a 10k R 43mV. This reduction comes at the expense of slightly increased limit variation. pin voltage LIM Figure 4. Input Current Limit for 4A Maximum Charger and 6A System Current Limit LT3651-4 µA R • ILIM ILIM = = ) • ...
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... Figure 7. Using the RNG/SS Pin for Soft-Start RNG/SS 10k LOGIC HIGH = HALF CURRENT 365142 F05 LT3651-4.2 RNG/SS + SERVO – REFERENCE 365142 F06 , connected from the RNG/SS RNG/SS is calculated RNG/ 50µA • LT3651-4.2 RNG/SS C RNG/SS 365142 F07 ) following 365142f ...
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... When V BAT voltage, whether by battery loading or replacement of the battery, the charger automatically re-engages and starts charging. Precondition and Bad Battery Fault A LT3651 charger has a precondition mode, in which charge current is limited to 15% of the programmed I as set 14mV across R Precondition mode is engaged while the voltage on the BAT pin is below the precondition threshold (V LT3651-4 connected from the TIMER TIMER EOC following the relation: TIMER t ( Hrs ) ( ) EOC = • ...
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... LT3651-4.2 applicaTions inForMaTion the BAT voltage rises above the precondition threshold, normal full-current charging can commence. The LT3651 incorporates 2.5% of threshold for hysteresis to prevent mode glitching. When the internal timer is used for termination, bad battery detection is engaged. This fault detection feature is designed to identify failed cells. A bad battery fault is triggered when the voltage on BAT remains below the precondition threshold for greater than one-eighth of a full timer cycle (one-eighth end-of-cycle). A bad battery fault is also triggered if a normally charging battery re-enters precondition mode after one-eighth end-of-cycle. ...
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... It is also possible to lower the sense resistance (with a reduction in R less accurate current accuracy. All high current board traces should have the lowest resistance possible. Addition of input current limit sense resistance reduces efficiency. Charger efficiency drops approximately linearly with in- creasing frequency all other things constant. At 15V V SENSE there improvement in efficiency for every 200kHz + reduction in frequency (100kHz to 1MHz); At 28V V C BATTERY BAT for every 100kHz. Of course all of these must be experimentally confirmed 365142 F08 in the actual charger. LT3651-4.2 as well), with a trade-off of slightly RNG/SS 365142f ...
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... RNG/SS GND LIM 68k 5.1k 1µF 7.5V to 32V 4A Charger with Approximately Constant Input Power R SENSE SBM540 50m V IN 8.2V CLP V CLN IN SHDN SW ACPR 180k FAULT BOOST CHRG LT3651-4.2 20k SENSE RT 6. 54.9k BAT 180k TIMER NTC I RNG/SS GND LIM 0.1µF 22k V IN 3.3µH R SENSE 24m ...
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... DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.20mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE LT3651-4.2 0.70 0.05 PACKAGE OUTLINE PIN 1 NOTCH R = 0.30 TYP OR 0 ...
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... LT3651-4.2 Typical applicaTion 7.5V to 32V 4A Charger with 3-Hour Charge Timeout, 6.3A Input Current Limit, 10ms Soft-Start and Battery Temperature Monitoring V LOGIC 50k TO CONTROLLER relaTeD parTs PART NUMBER DESCRIPTION LT1511 3A Constant Current/Constant Voltage Battery Charger LT1513 SEPIC Constant or Programmable Current/Constant Voltage Battery Charger LT3650 2A Monolithic Li-Ion Battery Charger LT3652 Power Tracking 2A Battery Charger LTC4002 Standalone Li-Ion Switch Mode Battery Charger ...