Datasheet

LM77
SNIS103F –JUNE 1999–REVISED MARCH 2013 www.ti.com
D0: Shutdown - When set to 1 the LM77 goes to low power shutdown mode. Power up default of “0”.
D1: Interrupt mode - 0 is Comparator Interrupt mode, 1 is Event Interrupt mode. Power up default of “0”.
D2, D3: T_CRIT_A and INT Polarity - 0 is active low, 1 is active high. Outputs are open-drain. Power up default
of “0”
D4: Fault Queue - When set to 1 the Fault Queue is enabled, see FAULT QUEUE. Power up default of “0”.
D5–D7: These bits are used for production testing and must be kept zero for normal operation.
Table 4. T
HYST
, T
LOW
, T
HIGH
AND T_CRIT_A REGISTERS (Read/Write):
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Sign Sign Sign Sign MSB Bit7 Bit6 Bit5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 X X X
D0–D2: Undefined
D3–D15: T
HYST
, T
LOW
, T
HIGH
or T_CRIT Trip Temperature Data. Power up default is T
LOW
= 10°C, T
HIGH
= 64°C,
T_CRIT = 80°C, T
HYST
= 2°C.
T
HYST
is subtracted from T
HIGH
, and T_CRIT, and added to T
LOW
.
Avoid programming setpoints so close that their hysteresis values overlap. See TEMPERATURE COMPARISON.
TEST CIRCUIT DIAGRAMS
I
2
C Timing Diagrams
Figure 10. Typical 2-Byte Read From Preset Pointer Location Such as Temp or Comparison Registers
Figure 11. Typical Pointer Set Followed by Immediate Read for 2-Byte Register such as Temp or
Comparison Registers
Figure 12. Typical 1-Byte Read from Configuration Register with Preset Pointer
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