ltc1960 Linear Technology Corporation, ltc1960 Datasheet
ltc1960
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ltc1960 Summary of contents
Page 1
... A proprietary PowerPath architecture supports simulta- neous charging or discharging of both batteries. Typical battery run times are extended by 10%, while charging times are reduced 50%. The LTC1960 automati- cally switches between power sources in less than 10µs to prevent power interruption upon battery or wall adapter removal ...
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... CSN SET 16 21 GND MOSI DCDIV 17 20 MISO SSB 18 19 SCK G PACKAGE 36-LEAD PLASTIC SSOP = 125°C, θ 95°C/ W JMAX JA ORDER PART NUMBER LTC1960CG = 12V 12V unless otherwise noted. BAT1 BAT2 MIN TYP MAX 1.5 1.3 2 UNITS 1960fa ...
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... DCDIV LOPWR ≥ – SCP SCN CC V Rising from V DCDIV CC V Rising from 0.8V until TGATE and BGATE SET Stop Switching Guaranteed Monotonic Above I /16 MAX LTC1960 = 12V unless otherwise noted. BAT2 MIN TYP MAX UNITS µA 175 0.8 V 0.7 V 0.7 V 0.7 V ● ...
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... LTC1960 ELECTRICAL CHARACTERISTICS temperature range (Note 7), otherwise specifications are at T SYMBOL PARAMETER DACs V VDAC Resolution RES V VDAC Granularity STEP V VDAC Offset OFF t VDAC Pulse Period VP Charge Mux Switches t GCH1/GCH2 Tur-On Time ONC t GCH1/GCH2 Turn-Off Time OFFC V CH Gate Clamp Voltage CON ...
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... V (16mV • VDAC OUT REF (VALUE) Note 7. The LTC1960C is guaranteed to meet specified performance from 0°C to 70°C and is designed, characterized and expected to meet specified performance at –40°C and 85°C, but is not tested at these extended temperature limits. LTC1960 = 12V unless otherwise noted. ...
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... LTC1960 W U TYPICAL PERFOR A CE CHARACTERISTICS Battery Drain Current (BAT1 Selected) 250 T = 25°C A 240 230 220 210 200 190 180 170 160 150 BAT1 VOLTAGE (V) 1960 G01 Charger Efficiency 100 0.025 2.5 4.0 0.10 0.50 I (A) OUT ...
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... REQUESTED VOLTAGE = 12.3V MAX CHARGER CURRENT = 4.1A 1960 G10 15 14 DUAL SEQUENTIAL MINUTES 10 140 160 120 180 1960 G12 LTC1960 Dual Charging Batteries with Different Charge State 17.0 BAT2 VOLTAGE 16.5 BAT1 VOLTAGE 16.0 15.5 15.0 BAT1 CURRENT 14.5 BAT2 14.0 CURRENT 13.5 300 ...
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... Input. This pin should be connected directly to the “bot- tom” (output side) of the low valued resistor in series with the three PowerPath switch pairs, for detecting short- circuit current events. Also powers LTC1960 internal circuitry when all other sources are absent. SCP (Pin 5/Pin 31): PowerPath Current Sensing Positive Input. This pin should be connected directly to the “ ...
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... SSB is low, on the falling edge of SCK. TTL levels. A 4.7k pullup resistor is recommended. MOSI (Pin 21/Pin 9): SPI Master-Out-Slave-In Input. Serial data is transmitted to the LTC1960, when SSB is low, on the rising edge of SCK. TTL levels. Exposed Pad (Pin 39, UHF Package Only): Ground. Must be soldered to the PCB ground for rated thermal performance ...
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... LTC1960 W BLOCK DIAGRA (LTC1960CG Pin Numbers Shown) CHARGE DCIN PUMP ON – GCH1 34 + SCH1 33 ON GCH2 – SCH2 36 BAT1 3 2 BAT2 V 1 PLUS REGULATOR GND 16 DCIN SET OSCILLATOR LOW DROP BGATE T DETECT ON BOOST 31 TGATE BGATE 27 PGND 26 g DCIN ...
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... U OPERATIO (Refer to Block Diagram and Typical Application) OVERVIEW The LTC1960 is composed of a battery charger controller, charge MUX controller, PowerPath controller, SPI inter- face, a 10-bit current DAC (IDAC) and 11-bit voltage DAC (VDAC). When coupled with a low cost microprocessor, it forms a complete battery charger/selector system for two batteries ...
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... FA = FAULT. This bit is set for any of the following conditions: 1) The LTC1960 is still in power on reset. 2) The LTC1960 has detected a short circuit and has shut down power and charging. 3) The system has asserted a fast off using DCDIV. Note: All other values of A[2:0] are reserved and must not be used. ...
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... MISO Figure 2. SPI Read and Battery Charger Controller The LTC1960 charger controller uses a constant off-time, current mode step-down architecture. During normal op- eration, the top MOSFET is turned on each cycle when the oscillator sets the SR latch and turned off when the main current comparator I resets the SR latch ...
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... LTC1960 U OPERATIO reverse current from flowing in the switches. In essence, this system performs as a low forward voltage diode. Operation is identical for BAT2. DCIN + 10V (CHARGE PUMPED) BAT1 TO – BATTERY 1 EAC 35mV CSN FROM + CHARGER + CC 20mV – OFF Figure 3. Charge MUX Switch Driver Equivalent Circuit ...
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... PLUS and 2µ including tolerances) should keep the CC LTC1960 operating above the UVLO trip voltage long enough to perform the short-circuit function when the input voltages are greater than 8V. Increasing the capaci- tor across V to 4.7µF will allow operation down to the CC recommended 6V minimum ...
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... LTC1960 U OPERATIO Note that the reference voltage must be subtracted from the VDAC value in order to obtain the correct output voltage. This value is V /16mV = 50 (32 REF Capacitors C and C are used to average the voltage B1 B2 present at the V pin as well as provide a zero in the SET voltage loop to help stability and transient response time to voltage variations ...
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... Using MOSFETs in the charge MUX with lower R Adapter Limiting An important feature of the LTC1960 is the ability to automatically adjust charging current to a level which avoids overloading the wall adapter. This allows the prod- uct to operate at the same time that batteries are being charged without complex load management algorithms ...
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... Extending System to More than 2 Batteries The LTC1960 can be extended to manage systems with more than 3 sources of power. Contact Linear Technology Applications Engineering for more information. Charging Depleted Batteries ...
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... The constant k = 1.7 can be used to estimate the contribu- tions of the two terms in the main switch dissipation equation. If the LTC1960 charger is to operate in low dropout mode or with a high duty cycle greater than 85%, then the topside N-channel efficiency generally improves with a larger MOSFET. Using asymmetrical MOSFETs may achieve cost savings or efficiency gains ...
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... LTC1960 U U APPLICATIONS INFORMATION 10µs and the internal IDAC resistor, R ripple voltage can be approximated by: V • T ∆ ∑ REF ∆ ISET R • SET Then the equation to extract C7 is: V • T ∆ ∑ REF ∆ V • R ISET SET = 0.8/0.01/18.77k(10µs) ≅ 0.043µF ...
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... DS(ON) R value becomes unreasonably low for MOSFETs DS(ON) available at this time. The need for the LTC1960 voltage drop regulation only comes into play for parallel battery configurations that terminate charge or discharge using voltage. At first this seems problem, but there are several factors helping out: 1 ...
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... APPLICATIONS INFORMATION I is the fixed drive current into the gate from the DRIVE LTC1960 and “t” is the time it takes to move that charge to a new state and change the MOSFET conduction mode. Hence time is directly related to Q GATE up with MOSFETs of lower R ...
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... SIDES) 3.15 ± 0.05 (2 SIDES) 0.25 ± 0.05 0.50 BSC 5.15 ± 0.05 (2 SIDES) 6.10 ± 0.05 (2 SIDES) 7.50 ± 0.05 (2 SIDES) RECOMMENDED SOLDER PAD LAYOUT 0.75 ± 0.05 5.00 ± 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) 0.200 REF 0.00 – 0.05 LTC1960 12.67 – 12.93* (.499 – .509 ...
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... SMBus Controlled Smart Battery Charger LT1769 2A Battery Charger Linear Technology Corporation 24 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● (LTC1960CG Pin Numbers Shown) Dual Battery Selector & 4A Charger POWER PATH MUX C2 1µF 100Ω 0.1µF LTC1960 ...