and dual supply monitor. It converts the temperature of
an external diode sensor and/or its own die temperature
to an analog output voltage while rejecting errors due to
noise and series resistance. Two supply voltages and the
measured temperature are compared against upper and
lower limits set with resistive dividers. If a threshold is
exceeded, the device communicates an alert by pulling
low the correspondent open drain logic output.
The LTC2995 gives ±1°C accurate temperature results
using commonly available NPN or PNP transistors or
temperature diodes built into modern digital devices. Volt-
ages are monitored with 1.5% accuracy. A 1.8V reference
output simplifies threshold programming and can be used
as an ADC reference input.
The LTC2995 provides an accurate, low power solution for
temperature and voltage monitoring in a compact 3mm ×
3mm QFN package.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Monitors Temperature and Two Voltages
Voltage Output Proportional to Temperature
Adjustable Thresholds for Temperature and Voltage
±1°C Remote Temperature Accuracy
±2°C Internal Temperature Accuracy
±1.5% Voltage Threshold Accuracy
3.5ms Update Time
2.25V to 5.5V Supply Voltage
Input Glitch Rejection
Adjustable Reset Timeout
220μA Quiescent Current
Open Drain Alert Outputs
Available in 3mm × 3mm QFN Package
APPLICATIONS
n
n
n
n
Network Servers
Core, I/O Voltage Monitors
Desktop and Notebook Computers
Environmental Monitoring
TYPICAL APPLICATION
Dual OV/UV Supply and Single OT/UT Remote Temperature Monitor
2.5V
1.2V
V
CC
0.1μF
194k
10.2k
VL1
45.3k
64.4k
VH2
10.2k
VL2
45.3k
V
REF
20k
VT2
20k
VT1
V
PTAT
TO2
TO1
OV
UV
GND TMR
5nF
4mV/K
OT
T > 125°C
UT
T < 75°C
+10%
–10%
SYSTEM
MONITOR
0.8
25 50 75 100 125 150
–50 –25 0
REMOTE DIODE TEMPERATURE (°C)
2995 TA01b
V
PTAT
vs Remote
Diode Temperature
1.8
ASIC
1.6
D
+
TEMPERATURE
SENSOR
V
PTAT
(V)
470pF
D
LTC2995
–
PS
DS
VH1
1.4
1.2
1.0
140k
2995 TA01a
2995f
1
LTC2995
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
PIN CONFIGURATION
TOP VIEW
TMR
15
UV
14
OV
21
13
TO2
12
T01
11 V
REF
6
D
+
7
D
–
8
V
PTAT
9 10
GND
V
CC
GND
VH1
VL1 1
VH2 2
VL2 3
VT2 4
VT1 5
DS
PS
V
CC
.............................................................. –0.3V to 6V
TMR, D
+
, D
–
, DS, PS, V
PTAT
, V
REF
........ –0.3V to V
CC
+ 0.3V
UV, OV, TO1, T02
.......................................... –0.3V to 6V
VH1, VL1, VH2, VL2, VT1, VT2 ..................... –0.3V to 6V
Operating Ambient Temperature Range
LTC2995C ................................................ 0°C to 70°C
LTC2995I .............................................–40°C to 85°C
LTC 2995H ......................................... –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
20 19 18 17 16
UD PACKAGE
20-LEAD (3mm
×
3mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 59°C/W
EXPOSED PAD PCB GROUND CONNECTED OPTIONAL
ORDER INFORMATION
LEAD FREE FINISH
LTC2995CUD#PBF
LTC2995IUD#PBF
LTC2995HUD#PBF
TAPE AND REEL
LTC2995CUD#TRPBF
LTC2995IUD#TRPBF
LTC2995HUD#TRPBF
PART MARKING*
LFQV
LFQV
LFQV
PACKAGE DESCRIPTION
20-Lead (3mm
×
3mm) Plastic QFN
20-Lead (3mm
×
3mm) Plastic QFN
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
–40°C to 125°C
20-Lead (3mm
×
3mm) Plastic QFN
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
ELECTRICAL CHARACTERISTICS
SYMBOL
V
CC
UVLO
I
CC
V
REF
PARAMETER
Supply Voltage
Supply Undervoltage Lockout Threshold
Average Supply Current
Reference Voltage
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 3.3V, unless otherwise noted.
CONDITIONS
l
MIN
2.25
1.7
l
l
TYP
1.9
220
MAX
5.5
2.1
300
1.803
1.804
1.807
1.808
±1.5
–192
UNITS
V
V
μA
V
V
V
V
mV
μA
V
CC
Falling
Temperature Measurement
LTC2995
LTC2995C
LTC2995I
LTC2995H
I
LOAD
= ±200μA
l
l
l
l
1.797
1.793
1.790
1.787
–8
1.8
1.8
1.8
1.8
V
REF
Load Regulation
Remote Diode Sense Current
2995f
2
LTC2995
ELECTRICAL CHARACTERISTICS
SYMBOL
T
conv
K
T
T
int
T
RMT
PARAMETER
Temperature Update Interval
V
PTAT
Slope
V
PTAT
Load Regulation
Internal Temperature Accuracy
T
AMB
= –40°C to 125°C
Remote Temperature Error,
η
= 1.004
0°C to 85°C (Notes 3, 4)
–40°C to 0°C (Notes 3, 4)
85°C to 125°C (Notes 3, 4)
Ideality Factor
η
= 1.004
I
LOAD
= ±200μA
±0.5
±2
±0.25
±0.25
±0.25
0.15
0.01
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 3.3V, unless otherwise noted.
CONDITIONS
l
MIN
TYP
3.5
4
MAX
5
±1.5
±1
±1
±1.5
±1.5
UNITS
ms
mV/K
mV
°C
°C
°C
°C
°C
°C
RMS
°C
RMS
/√Hz
Temperature Noise
T
VCC
T
RS
V
UOT
T
OFF
ΔT
HYST
t
UOD
I
IN
t
UOTO
I
TMR
Temperature Error vs Supply
Series Resistance Cancellation Error
Undervoltage/Overvoltage Threshold
VT1, VT2 Offset
VT1, VT2 Temperature Hysteresis
UV, OV
VH1, VL1, VH2, VL2, VT1, VT2, Input Current
UV/OV
Time-Out-Period
TMR Current
C
TMR
= TMR Open
C
TMR
= 1nF
Input 5mV Above/Below Threshold
R
SERIES
= 100Ω
±0.5
±0.25
492
–3
2
500
–1
5
0.5
0.5
10
±1
508
1
10
2
±20
5
20
±2.5
V
CC
– 0.4
0.1
V
CC
– 0.1
0.4
±4
±1
V
CC
– 1.2
0.4
°C/V
°C
mV
°C
°C
ms
nA
ms
ms
μA
V
V
μA
μA
V
V
l
Temperature and Voltage Monitoring
l
l
l
l
l
l
l
Three State Pins DS, PS
V
DS,PS(H,TH)
PS, DS Input High Threshold
V
DS,PS(H,TL)
PS, DS Input Low Threshold
I
DS,PS(IN,HL)
PS, DS High, Low Input Current
I
DS,PS(IN,Z)
V
OH
V
OL
Allowable Leakage Current
High Level Output Voltage,
TO1, TO2, UV, OV
Low Level Output Voltage,
TO1, TO2, UV, OV
I = –0.5μA
I = 3mA
Digital Outputs
l
l
l
l
l
l
DS, PS at 0V or V
CC
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
All currents into pins are positive; all voltages are referenced to
GND unless otherwise noted.
Note 3:
Remote diode temperature, not LTC2995 temperature.
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