Datasheet LTC1759 (Analog Devices) - 5

LTC1759
ELECTRICAL CHARACTERISTICS The
●
denotes specifications which apply over the full operating temperature range (TJ = 0
°
C to 100
°
C), otherwise specifications are TA = 25
°
C. VCC = DCIN = 18V, VBAT1, 2 = 12.6V, VDD = 3.3V unless otherwise specified. PARAMETER CONDITIONS MIN TYP MAX UNITS Charger Timing
VTGATE, VBGATE Rise/Fall Time 1nF Load 25 ns TGATE, BGATE Peak Drive Current 10nF Load 1 A Regulator Switching Frequency ● 170 200 230 kHz Synchronization Frequency ● 240 280 kHz Maximum Duty Cycle in Start-Up Mode (Note 9) ● 85 90 % tTIMEOUT for Wake-Up Charging a ● 140 175 210 sec Cold or Underrange Battery
SMBus Timing (refer to System Management Bus Specification, Revision 1.0, section 2.1 for timing diagrams) (Note 12)
SCL Serial Clock High Period (tHIGH) IPULLUP = 350µA, CLOAD = 150pF ● 4 µs SCL Serial Clock Low Period (tLOW) IPULLUP = 350µA, CLOAD = 150pF ● 4.7 µs SDA/SCL Rise Time (tr) CLOAD = 150pF ● 1000 ns SDA/SCL Fall Time (tf) ● 30 300 ns SMBus Accelerator Boosted Pull-Up Current VDD = 3V ● 1 2.5 mA Start Condition Setup Time (tSU:STA) ● 4.7 µs Start Condition Hold Time (tHD:STA) ● 4.0 µs SDA to SCL Rising-Edge Setup Time (tSU:DAT) ● 250 ns SDA to SCL Falling-Edge Hold Time, ● 300 ns Slave Clocking in Data (tHD:DAT) tTIMEOUT Between Receiving Valid ● 140 175 210 sec ChargingCurrent() and ChargingVoltage() Commands (Note 10)
Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 7:
Power failure bit is set when the battery voltage is above 89% of of a device may be impaired. the power adapter voltage (VDCIN).
Note 2:
This limit is greater than the absolute maximum for the charger.
Note 8:
The charger provides wake-up current when a battery is inserted Therefore, there is no effective limitation on voltage when this option is into the connector, prior to the battery requesting charging current and selected. If the charger is requested to charge with a higher voltage than voltage. See Smart Battery Charger Specification (Revision 1.0), section the nominal limit, the VOLTAGE_OR bit will be set. 6.1.3 and 6.1.8.
Note 3:
Total system accuracy from SMBus request to output voltage or
Note 9:
In system start-up, C6 (boost capacitor) has no charge stored in it. output current. The LTC1759 will keep TGATE off, and turn BGATE on for 0.2µs, thus
Note 4:
Test Circuit #1. charging C6. A comparator senses VBOOST and switches to the normal
Note 5:
Voltage accuracy is calculated using measured reference voltage, PWM mode when VBOOST is above its threshold. obtained from V
Note 10:
Refer to Smart Battery Charge Specification (Revision 1.0), SET pin using Test Circuit #2, and VDAC resistor divider ratio. section 6.1.2.
Note 6:
When supply and battery voltage differential is low, high oscillator
Note 11:
Maximum total external capacitance on RNR and THERM pins duty cycle is required. The LTC1759 has a unique design to achieve duty is 75pF. cycle greater than 99% by skipping cycles. Only when VBOOST drops below
Note 12:
SMBus operation guaranteed by design from –40°C to 85°C. the comparator threshold, will TGATE be turned off. See Applications Information section. 5