DS1780E Maxim Integrated Products, DS1780E Datasheet - Page 2

• Manufacturer Part Number: DS1780E
• Description: IC CPU PERIPHERAL MON 24-TSSOP
• Manufacturer: Maxim Integrated Products

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
• Full Temp Accuracy: +/- 12 %
• Digital Output - Bus Interface: Serial (2-Wire)
• Digital Output - Number Of Bits: 8 bit
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

DESCRIPTION
The DS1780 is a highly integrated system instrumentation monitor ideal for use in personal computers, or
any microprocessor-based system. It monitors ambient temperature, six power supply voltages, and the
speed of two fans. Fan speed can also be controlled with the use of an internal 8-bit DAC. All
measurements are internally converted to a digital format for easy processing by the CPU.
The DS1780 can be reset to its default power-up state via a remote reset function with internal debounce
and delay. It features an interrupt that can be programmed to become active should any of the functions
the DS1780 is monitoring fall out of spec.
For board-level testability, an internal NAND TREE function simplifies the system design. A chassis
intrusion input is featured to enhance system security.
Programming and data readout are accessed via a simple 2-wire interface with 2-bit addressability. The
DS1780 power supply range of 2.8V to 5.75V allows for monitoring of parameters for 3V or 5V systems.
The DS1780 is assembled in a compact 173-mil TSSOP package.
Detailed Pin Description Table 1
15-19
20-24
PIN
10
11
12
13
14
1
2
3
4
5
6
7
8
9
+2.5V
V
A0/NT
SIGNAL
+xxV
GNDD
OUT
GNDA
FAN1
FAN2
VIDx
SDA
CHS
RST
SCL
INT
V
A1
S
DD
/NT
/+V
OUT
IN
CCP2
IN
Analog Output
DIRECTION
Digital Output
Analog Inputs
Digital Inputs
Digital Input/
Analog Input
Digital Input
Digital Input
Digital Input
Digital Input
Digital I/O
Digital I/O
Digital I/O
Digital I/O
GROUND
GROUND
POWER
DESCRIPTION
The lowest order programmable bit of the 2-wire bus address. This pin
functions as an output when doing a NAND TREE test.
The highest order programmable bit of the 2-wire bus address.
2-wire bus bi-directional data. Open-drain output.
2-wire bus synchronous clock.
0 to V
0 to V
An active high input from an external circuit, which latches a Chassis
Intrusion event. This line can go high without any clamping action regardless
of the powered state of the DS1780. The DS1780 provides an internal open
drain on this line, controlled by Bit 6 of Configuration Register, to provide a
minimum 20 ms reset of this signal.
+3.3V or +5V V
(Electrolytic or Tantalum) and 0.1 µF (ceramic) bypass capacitors.
Active-low Programmable interrupt output. The output is enabled when Bit 1
of the Configuration Register is set to 1. The default state is disabled.
An active-high input that enables NAND Tree board-level connectivity
testing. Refer to “NAND Tree Testing” Section. Used as DAC output when
NAND Tree is not selected.
Master Reset, 5 mA open drain driver, active low output with at least a 20 ms
minimum pulse width. Available when enabled via Bit 4 in Configuration
Register. This is a bi-directional I/O pin. It acts as power on RESET input.
Internally connected to all analog circuitry. The ground reference for all
analog inputs.
Analog input for monitoring -12V or +V
on this pin from 0V to 3.6V. An external resistor ladder is required for
monitoring a -12V supply (see Figure 1).
A/D inputs for 5 positive voltages.
Voltage supply readouts from the processor. These values are read in the VID
and VID4 Status Registers.
Internally connected to all digital circuitry.
DD
DD
amplitude fan tachometer input.
amplitude fan tachometer input.
2 of 28
DD
power. Bypass with the parallel combination of 10 µF
CCP2
. DS1780 will measure voltages