MAX6656MEE Maxim Integrated Products, MAX6656MEE Datasheet - Page 5

• Manufacturer Part Number: MAX6656MEE
• Description: Board Mount Temperature Sensors Dual Remote/Local Temperature Sensor
• Manufacturer: Maxim Integrated Products

Specifications of MAX6656MEE

• Full Temp Accuracy: +/- 3 C
• Package / Case: QSOP-16
• Digital Output - Bus Interface: Serial (2-Wire)
• Digital Output - Number Of Bits: 11 bit
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Output Type: Digital

The MAX6655/MAX6656 are voltage and temperature
monitors that communicate through an SMBus-compat-
ible interface with a microprocessor or microcontroller
in thermal management applications.
Essentially an 11-bit serial ADC with a sophisticated front
end, the MAX6655/MAX6656 contain a switched-current
source, a multiplexer, an ADC, an SMBus interface, and
the associated control logic. Temperature data from the
ADC is loaded into a data register, where it is automati-
cally compared with data previously stored in over/under-
temperature alarm threshold registers. Temperature data
can be read at any time with 11 bits of resolution.
The MAX6655/MAX6656 can monitor external supply volt-
ages of typically 12V, 2.5V, and 3.3V for the MAX6655
and 5.0V for the MAX6656, as well as their own supply
voltage. All voltage inputs are converted to an 8-bit code
using an ADC. Each input voltage is scaled down by an
PIN
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
Dual Remote/Local Temperature Sensors and
SMBDATA
SMBCLK
OVERT
ALERT
NAME
DXN1
ADD0
ADD1
DXN2
DXP1
DXP2
STBY
GND
V
V
V
V
CC
IN3
IN1
IN2
_______________________________________________________________________________________
Detailed Description
Supply Voltage. +5V for MAX6655; +3.3V for MAX6656. Bypass V
External Diode 1 Positive Connection. DXP1 is the combined current source and ADC positive input
for remote-diode 1. If a remote-sensing junction is not used, connect DXP1 to DXN1.
External Diode 1 Negative Connection. DXN1 is the combined current sink and ADC negative input
for remote-diode 1. DXN1 is normally biased to a diode voltage above ground.
SMBus Slave Address Select Input. ADD0 and ADD1 are sampled upon power-up. Table 5 is the
truth table.
SMBus Slave Address Select Input. ADD0 and ADD1 are sampled upon power-up.
External Diode 2 Positive Connection. DXP2 is the combined current source and ADC positive input
for remote-diode 2. If a remote-sensing junction is not used, connect DXP2 to DXN2.
External Diode 2 Negative Connection. DXN2 is the combined current sink and ADC negative input
for remote-diode 2. DXN2 is normally biased to a diode voltage above ground.
Ground
External Voltage Monitor 3. V
External Voltage Monitor 1. V
External Voltage Monitor 2. V
and +5.0V for MAX6656.
SMBus Alert (Interrupt) Output, Open-Drain
SMBus Serial-Data Input/Output, Open-Drain
Overtemperature Alarm Output, Open-Drain. OVERT is an unlatched alarm output that responds to
the programmed maximum temperature limit for all temperature channels.
SMBus Serial-Clock Input
Hardware Standby Input. Drive STBY low for low-power standby mode. Drive STBY high for normal
operating mode. Temperature and comparison threshold data are retained in standby mode.
Four-Channel Voltage Monitors
IN3
IN1
IN2
is typically used to monitor +2.5V supplies.
is typically used to monitor +12V supplies.
is typically used to monitor voltage supplies of +3.3V for MAX6655
on-chip resistive-divider so that its output, at the nominal
input voltage, is approximately 3/4 of the ADC’s full-scale
range, or a decimal count of 198.
The averaging ADC integrates over a 40ms period (typ)
with excellent noise rejection. The ADC converts a tem-
perature measurement in 125ms (typ) and a voltage
measurement in 62.5ms (typ). For temperature mea-
surements, the multiplexer automatically steers bias
currents through the remote diode, then the forward
voltage is measured and the temperature is computed.
The DXN input is biased at one diode drop above
ground by an internal diode to set up the ADC inputs for
a differential measurement. The worst-case DXP-DXN
differential input voltage range is +0.25V to +0.95V.
Excess resistance in series with the remote diode caus-
es about +1/2°C error/Ω. A 200µV offset voltage at
DXP-DXN causes about -1°C error.
FUNCTION
CC
to GND with a 0.1µF capacitor.
Pin Description
ADC
5