DS2790 Maxim Integrated Products, DS2790 Datasheet - Page 37

• Manufacturer Part Number: DS2790
• Description: Programmable 1-Cell Li-Ion Fuel Gauge and Protector
• Manufacturer: Maxim Integrated Products

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ADDRESS
Unused
Slave
Address
Trim Key
ADDRESS
IG
SRTC
PASSWORD PROTECTED USER TRIM
System software has the ability to change Temperature and Voltage protection levels, 2-wire slave address, and
current measurement gain of the IC through the User Trim in Program EEPROM (Word Addresses 001Dh–001Fh).
The user trim values are enabled through the Trim Key in the lower byte of address 001Dh. If the Trim Key is set to
76h, the user trim values replace the default trim values, if the Trim Key is set to any other value, default trim is
selected. Note that either all user trim values are enabled or none are enabled. Figure 20. shows the format of all
values that can be adjusted and their default trim values.
Figure 20. User Trim Registers
4
Field
Field
·
·
Gate to Source voltage. The external FETs must be able to withstand a voltage between their gate and
source pins of at least the charge pump voltage
Gate leakage. The gate leakage of both external FETs must be smaller than 0.9µA to ensure CC and
DC meet the V
001Dh
001Eh
14:8
15:8
7:0
7:0
Bit
15
Bit
OCP
specification.
Format
Format
R/W
R/W
R/W
R/W
R/W
Undefined¾General purpose
2-Wire Slave Address
Valid only if Trim Key = 76h
Default = 0001011b
Trim Key
Enables or disables all other user trim values.
76h = All User Trim values valid.
Other = All User Trim values invalid. Default trim used.
Current Gain Trim
These bits adjust the current gain by +/-25%. The most
significant bit is the 2’s compliment sign bit, 1LSB = 0.195%.
Example: A4h (-92d) adjusts the trim by -17.94%.
Valid only if Trim Key = 76h
Default = Factory trim value
Sense Resistor Temperature Coefficient
These bits adjust the current gain based on temperature of the
sense resistor. 1LSB = 30.5ppm/ºC.
Example: 1Ah (26d) adjusts current measurements for a sense
resistor with a 793ppm/ºC temperature coefficient.
Valid only if Trim Key = 76h
Default = 00h
DS2790 Programmable 1-Cell Li-Ion Fuel Gauge and Protector
37 of 41
V
OCP
to prevent damage.
BIT DEFINITION
Allowable Values
BIT DEFINITION
Allowable Values