MAX6505 Maxim, MAX6505 Datasheet - Page 5

• Manufacturer Part Number: MAX6505
• Description: Dual Trip SOT Temperature Switches
• Manufacturer: Maxim

The MAX6505–MAX6508 fully integrated temperature
switches incorporate two temperature-dependent refer-
ences and a comparator. One reference exhibits a pos-
itive temperature coefficient and the other a negative
temperature coefficient. The temperature at which the
two reference voltages are equal determines the tem-
perature trip point. There are two versions, each of
which has two logic outputs.
The MAX6505/MAX6506 have a main trip point (T
and a lower, “warning” trip point (T
temperature rises above these trip points, the ALARM
and WARN outputs are asserted (Figure 1). The differ-
ence between the two trip points (∆T
table to +5°C, +10°C, +20°C, or +30°C by connecting
the two control pins (S0 and S1) high or low (Table 1).
MAX6505 has open-drain active-low outputs; MAX6506
has push-pull active-high outputs.
The MAX6507/MAX6508 have two factory-programmed
threshold temperatures (T
outputs (OK and OVER). One output (OK) asserts
when the temperature is between T
The other output (OVER) asserts when the temperature
is above T
mine the part numbers associated with specific values
of T
lower trip point (T
higher trip point (T
DER
number MAX6508UTA04B (Table 4 and Figure 2).
MAX6507 has open-drain outputs; MAX6508 has push-
pull outputs.
The temperature threshold hysteresis for the ALARM
output of the MAX6505/MAX6506 is 2°C. The hysteresis
for the WARN output depends on the value of ∆T
∆T
teresis is 5°C. If ∆T
sis is 10°C. MAX6507 and MAX6508 have pin-selectable
hysteresis of 2°C or 10°C for both OVER and OK out-
puts (Table 2).
The MAX6505–MAX6508 supply current is typically
30µA. When used to drive high-impedance loads, the
devices dissipate negligible power. Therefore, the die
temperature is essentially the same as the package
temperature. The key to accurate temperature monitor-
ing is good thermal contact between the MAX6505–
MAX6508 package and the device being monitored. In
_______________Detailed Description
AW
OVER
= -10°C and T
is 5°C or 10°C (set by S0 and S1), WARN hys-
and T
OVER
. Table 4 shows the hex codes to deter-
UNDER
Applications Information
UNDER
_______________________________________________________________________________________
OVER
AW
OVER
. The first hex code indicates the
Hysteresis Selection
is 20°C or 30°C, WARN hystere-
). For example, a part with T
) and the second indicates the
Thermal Considerations
Dual Trip SOT Temperature Switches
OVER
= +75°C will have the part
and T
WARN
OVER
AW
UNDER
). When the die
) is pin selec-
and T
) and two
UNDER
ALARM
AW
UN-
. If
)
.
some applications, the SOT23-6 packages may be
small enough to fit underneath a socketed micro-
processor (µP), allowing the device to monitor the µP’s
temperature directly. Use the monitor’s output to reset
the µP, assert an interrupt, or trigger an external alarm.
Accurate temperature monitoring depends on the ther-
mal resistance between the device being monitored
and the MAX6505–MAX6508 die.
The rise in die temperature due to self-heating is given
by the following formula:
where P
MAX6505–MAX6508, and θ
resistance. The typical thermal resistance is +115°C/W
for the SOT23-6 package. To limit the effects of self-heat-
ing, minimize the output currents. For example, if the
MAX6505 sinks 5mA, the output voltage is guaranteed to
be less than 0.5V. Therefore, an additional 2.5mW of
Table 1. MAX6505/MAX6506 ∆T
Selection Table
Figure 1. Temperature Response—MAX6505UTP065 Outputs,
∆T
AW
GND
GND
= 10°C, and WARN Hysteresis ≈ 5°C
V
V
S0
CC
CC
ALARM
CONTROL PINS
WARN
65°C
55°C
DISSIPATION
∆T
J
= P
GND
GND
V
V
S1
CC
CC
is the power dissipated by the
DISSIPATION
JA
is the package’s thermal
∆T
AW
✕
DESCRIPTION
θ
=T
HYSTERESIS ≈ 2°C
HYSTERESIS ≈ 5°C
JA
ALARM
AW
(°C)
10
20
30
5
– T
WARN
5