LTC6802IG-2 LINER [Linear Technology], LTC6802IG-2 Datasheet - Page 24

• Manufacturer Part Number: LTC6802IG-2
• Description: Multicell Addressable Battery Stack Monitor
• Manufacturer: LINER [Linear Technology]

applicaTions inForMaTion
LTC6802-2
SERIAL COMMAND
Example for LTC6802-2 (Addressable Configuration)
Examples below use a configuration of three stacked
devices: bottom (B), middle (M), and top (T)
Write Configuration Registers (Broadcast Command)
Read Cell Voltage Registers (Address Command)
Start Cell Voltage A/D Conversions and Poll Status (Broadcast Command with Toggle Polling)

1. Pull CSBI low
2. Send WRCFG command byte
3. Send CFGR0 byte, then CFGR1, CFGR2, … CFGR5 (All devices on bus receive same data)
4. Pull CSBI high; data latched into all devices on rising edge of CSBI
Calculation of serial interface time for sequence above:
1. Pull CSBI low
2. Send Address byte for bottom device
3. Send RDCV command byte
4. Read CVR00 byte of bottom device, then CVR01 (B), CVR02 (B), … CVR17 (B), and then PEC (B)
5. Pull CSBI high
6. Repeat steps 1-5 for middle device and top device
Calculation of serial interface time for sequence above:
1. Pull CSBI low
2. Send STCVAD command byte (all devices in stack start A/D conversions simultaneously)
3. SDO output of all devices in parallel pulled low for approximately 12ms
4. SDO output toggles at 1kHz rate, indicating conversions complete for all devices
5. Pull CSBI high to exit polling
Number of devices in stack= N
Number of bytes in sequence = B = 1 command byte and 6 data bytes
Serial port frequency per bit = F
Time = (1/F) * B * 8 bits/byte = (1/F) * (1+6) * 8
Time for 3 cell stacks example above, with 1MHz serial port = (1/1000000) * (1+6)*8 = 56us
Number of devices in stack= N
Number of bytes in sequence = B = 1 address, 1 command, 18 register, and 1 PEC byte per device = 21*N
Serial port frequency per bit = F
Time = (1/F) * B * 8 bits/byte = (1/F) * (21*N) * 8
Time for 3-cell stacks example above, with 1MHz serial port = (1/1000000) * (21*3)*8 = 504us
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