Datasheet LTC1041 (Analog Devices)

LTC1041 BANG-BANG Controller
U FEATURES DESCRIPTIO
■ Micropower 1.5µW (1 Sample/Second) The LTC®1041 is a monolithic CMOS BANG-BANG ■ Wide Supply Range 2.8V to 16V controller manufactured using Linear Technology’s ■ High Accuracy enhanced LTCMOS™ silicon gate process. BANG-BANG Guaranteed SET POINT Error ±0.5mV Max loops are characterized by turning the control element fully ON or fully OFF to regulate the average value of Guaranteed Deadband ±0.1% of Value Max the parameter to be controlled. The SET POINT input ■ Wide Input Voltage Range V+ to Ground determines the average control value and the DELTA input ■ TTL Outputs with 5V Supply sets the deadband. The deadband is always 2 x DELTA and ■ Two Independent Ground-Referred Control Inputs is centered around the SET POINT. Independent control ■ Small Size 8-Pin SO of the SET POINT and deadband, with no interaction, is made possible by the unique sampling input structure of
U
the LTC1041.
APPLICATIO S
An external RC connected to the OSC pin sets the sampling ■ rate. At the start of each sample, internal power to the Temperature Control (Thermostats) ■ analog section is switched on for ≈ 80µs. During this time, Motor Speed Control the analog inputs are sampled and compared. After the ■ Battery Charger comparison is complete, power is switched off. This ■ Any ON-OFF Control Loop achieves extremely low average power consumption , LTC and LT are registered trademarks of Linear Technology Corporation. at low sampling rates. CMOS logic holds the output LTCMOS is a trademark of Linear Technology Corporation. continuously while consuming virtually no power. To keep system power at an absolute minimum, a switched power output (VP-P) is provided. External loads, such as bridge networks and resistive dividers, can be driven by this switched output. The output logic sense (i.e., ON = V+) can be reversed (i.e., ON = GND) by interchanging the VIN and SET POINT inputs. This has no other effect on the operation of the LTC1041.
U TYPICAL APPLICATIO Supply Current vs Sampling Frequency Ultralow Power 50
°
F to 100
°
F (2.4
µ
W) Thermostat
10000 VS = 6V 26V AC 2-WIRE THERMOSTAT 1000 0.1µF 4.32k 4.99k µA) 56Ω 1 8 ( S 100 TOTAL SUPPLY 2 7 CURRENT 5k 10M IS 3 LTC1041 6 10 400nA 4 5 + 2N6660 † 6.81k 6V 1 1N4002 1µF LTC1041 SUPPLY SUPPLY CURRENT, I (4) DELTA = 0.5°F CURRENT 0.1 49.9Ω LTC1041 • TA01 0.01 ALL RESISTORS 1%. YELLOW SPRINGS INSTRUMENT CO., INC. P/N 44007. † 0.1 1 10 100 1000 10000 DRIVING THERMISTOR WITH VP-P ELIMINATES 3.8°F ERROR DUE TO SELF-HEATING SAMPLING FREQUENCY, fS (Hz) LTC1041 • TA02 1041fa 1