BQ2018SN-E1 Integrated Circuit for Battery Monitor, SOIC-8 in ANALYZER III.
- $ 699.00
- Brand: SYSCOM
- Availability: 5 In stock
- SKU: 296-2221-5-ND
Key Features Battery monitor with 128 bytes of NVRAM Compact SOIC-8 package Single-line digital interface Operating consumption <80µA Standby mode <10µA Signal resolution <12.5µV Internal calibration for greater precision Internal...
Key Features
- Battery monitor with 128 bytes of NVRAM
- Compact SOIC-8 package
- Single-line digital interface
- Operating consumption <80µA
- Standby mode <10µA
- Signal resolution <12.5µV
- Internal calibration for greater precision
- Internal temperature sensor
Technical Specifications
- Operating voltage: 2.8V to 5.5V
- Sense resistance: Low value (0.015Ω typical)
- Measurement range: ±200mV
- Resolution: 12.5µV/hour
- NVRAM memory: 1024 bits (128x8)
- Operating temperature: -40°C to +85°C
- Temperature sensor accuracy: ±2°C at 25°C
- SCR count rate: 1 count/hour at 25°C
Applications
- Rechargeable battery monitoring
- Power management systems
- Portable devices
- Precision instrumentation
- Backup power systems
Functional Description
The BQ2018SN-E1 is a battery monitoring integrated circuit that measures the differential voltage across a sense resistor between the SR1 and SR2 terminals. This measurement allows for precise calculation of the battery state of charge (SOC) using charge and discharge counters (DCR and CCR) that record changes of 12.5µV per hour.
The device includes an internal temperature sensor that adjusts the self-discharge count rate (SCR) based on ambient temperature, doubling the speed every 10°C above 25°C and halving it below this value. The time registers (DTC and CTC) allow for calculating the duration of charge and discharge cycles.
The calibration mode allows storing the device offset in the OFR register, improving measurement accuracy by canceling component tolerance effects. Communication with the host controller is carried out through the single-line HDQ interface, with the ability to enter a low-power mode (<10µA) when active monitoring is not required.
Typical Application
The circuit connects directly to the battery via a low-value sense resistor (0.015Ω typical). Power can be derived from the battery itself or an external regulated source, with the option to use the REG pin to control an external pass FET. The RBI pin allows for maintaining memory registers during shutdown periods.
The WAKE signal indicates to the system when the charge or discharge current exceeds the programmed threshold. The host must perform periodic maintenance of the registers, resetting the counters when necessary to maintain the accuracy of the state of charge calculation.
Communication Interface
Communication is performed via the HDQ pin, which operates in open-drain mode and requires a pull-up resistor on the battery pack. The host can access the registers via specific commands, allowing for read/write access to the 128 bytes of NVRAM. The MODE/WOE register allows for configuring the activation thresholds and operation mode control.
The block diagram shows the internal architecture with the differential measurement system, time counters, RAM, and precision oscillator. The status registers allow the host to obtain information regarding the charge state, self-discharge, and operating conditions of the circuit.