MAX6889 Datasheet, PDF (14/40 Pages) Maxim Integrated Products – EEPROM-Programmable, Octal/Hex/Quad, Power-Supply Sequencers/Supervisors

EEPROM-Programmable, Octal/Hex/Quad,
Power-Supply Sequencers/Supervisors
1) Apply a voltage between 2.7V and 5.5V to one of
V_CC or IN2–IN5.
2) Program the internal/external V_CC power EEPROM
at AEh, Bit[2] = 1 (see Table 22).
3) Power down the device.
Subsequent power-ups and software reboots require
an externally supplied V_CC to ensure the device is fully
operational.
The MAX6889/MAX6890/MAX6891 also generate a dig-
ital supply voltage (DBP) for the internal logic circuitry
and the EEPROM. Bypass DBP to GND with a 1µF
ceramic capacitor installed as close to the device as
possible. The nominal DBP output voltage is 2.55V. Do
not use DBP to provide power to external circuitry.
Inputs
The MAX6889/MAX6890/MAX6891 contain multiple
logic and voltage detector inputs. Each voltage detec-
tor input is monitored for undervoltage thresholds.
Table 1 summarizes these various inputs. Set the
threshold voltage for each voltage detector input with
registers 00h–07h. Each threshold voltage is an under-
voltage threshold. Set the threshold range for each volt-
age detector with register 08h.
High-Voltage Input (IN1)
IN1 offers threshold voltages of 2.5V to 13.2V in 50mV
increments, or 1.25V to 7.625V in 25mV increments.
Use the following equations to set the threshold volt-
ages for IN1:
x = ^{VTH − 2.5V} for 2.5V to 13.2V range
0.05V
x = ^{VTH −1.25V} for 1.25V to 7.625V range
0.025V
where V_TH is the desired threshold voltage and x is the
decimal code for the desired threshold (Table 2). For
the 2.5V to 13.2V range, x must equal 214 or less; oth-
erwise the threshold exceeds the maximum operating
voltage of IN1.
IN2–IN7
The IN2–IN7 positive voltage detectors monitor volt-
ages from 1V to 5.5V in 20mV increments, 0.5V to
3.05V in 10mV increments, or 0.1667V to 1.0167V in
3.3mV increments in high-Z mode. Use the following
equations to set the threshold voltages for IN_:
x = ^{VTH −1V} for 1V to 5.5V range
0.02V
x = ^{VTH − 0.5V} for 0.5V to 3.05V range
0.1V
x = ^{VTH − 0.1667V} for 0.1667V to 1.0167V high − Z range
0.0033V
where V_TH is the desired threshold voltage and x is the
decimal code for the desired threshold (Table 3). For
the 1V to 5.5V range, x must equal 225 or less; other-
wise the threshold exceeds the maximum operating
voltage of IN2–IN7.
High-Voltage Input (IN8)
Configure IN8 to detect positive thresholds from 2.5V to
15.25V in 50mV increments, 1.25V to 7.625V in 25mV
increments, or 0.1667V to 1.0167V in 3.3mV increments
in high-Z mode. Use the following equations to set the
threshold voltages for IN8:
x = ^{VTH − 2.5V} for 2.5V to 15.25V range
0.05V
x = ^{VTH −1.25V} for 1.25V to 7.625V range
0.025V
x = ^{VTH − 0.1667V} for 0.1667V to 1.0167V high − Z range
0.0033V
where V_TH is the desired threshold voltage and x is the
decimal code for the desired threshold (Table 4).
Table 2. IN1 Threshold Settings
REGISTER
ADDRESS
EEPROM
MEMORY
ADDRESS
00h
80h
08h
88h
09h
89h
BIT
RANGE
[7:0]
[0]
[0]
DESCRIPTION
IN1 undervoltage detector threshold (V1) (see equations in the Inputs section)
IN1 range selection. 0 = 2.5V to 13.2V range in 50mV increments. 1 = 1.25V to 7.625V
range in 25mV increments.
Must be set to “0” for normal operation
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