DS1780E+ Maxim Integrated Products, DS1780E+ Datasheet - Page 6
![IC CPU PERIPHERAL MON 24-TSSOP](/photos/6/56/65600/175-24-tssop_sml.jpg)
DS1780E+
Manufacturer Part Number
DS1780E+
Description
IC CPU PERIPHERAL MON 24-TSSOP
Manufacturer
Maxim Integrated Products
Datasheet
1.DS1780E.pdf
(28 pages)
Specifications of DS1780E+
Function
Thermal Monitor, CPU Peripherals
Topology
ADC (Sigma Delta), Comparator, Fan Speed Control, Register Bank
Sensor Type
Internal
Sensing Temperature
-40°C ~ 125°C
Output Type
I²C™/SMBus™
Output Alarm
No
Output Fan
Yes
Voltage - Supply
2.8 V ~ 5.75 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
24-TSSOP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
DS1780
2-WIRE SERIAL COMMUNICATION WITH THE DS1780 Figure 2
OPERATION - Power-on
Applying power to the DS1780 causes a reset of several of the registers. Power-on conditions of the
registers are shown in Table 2 above. Some registers have indeterminate power-on values, such as the
Limit and RAM registers of the Value RAM page, and these are not shown in the table. Upon power-up
the ADC is inactive. Writing Limits into the Value RAM should usually be the first action performed
after power up. The
pin is bi-directional. It forces RESET at power-on, but can also be pulled low to
RST
force RESET internally.
OPERATION - Resets
The DS1780 features four distinct resetting functions. Each one has a different effect on register contents
and the state of the
output following the event. Each one is explained below:
RST
Power-on Reset - On POR, all internal logic is reset, and registers are cleared to their default state (see
tables 10.x). Because Value RAM is typically the first area programmed upon power-up, it does not have
a defined state upon POR. Also, on POR, the
output will be pulled to an active low state for 20 ms
RST
(minimum).
A POR occurs every time V
crosses the voltage level approximately equivalent to the sum of one n-
DD
channel threshold (V
) and one p-channel threshold (V
), on a power-up or power-down condition.
TN
TP
DS1780 SRAM contents get “scrambled” when V
falls below the greater of one n-channel V
or one p-
DD
T
channel V
. Therefore, SRAM contents will always be in a defined state as supply voltage reaches the
T
minimum spec level of 2.8V, even in a power supply brownout condition.
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