September 2009 Doc ID 12495 Rev 12 1/18
1
STLM20
Ultra-low current 2.4 V precision analog temperature sensor
Features
■Precision analog voltage output temperature
sensor
■±1.5 °C temperature accuracy at 25 °C
■Ultra-low quiescent supply current:
8.0 µA (max)
■Operating voltage range: 2.4 V to 5.5 V
■Operating temperature range:
–55 °C to 130 °C (grade - 7)
–40 °C to 85 °C (grade - 9)
■SOT323-5 (SC70-5) 5-lead package
■UDFN 4-lead package
Applications
■Third generation (3G) cell phones
■Multimedia PDA devices
■GPS devices
■Portable medical instruments
■Voltage-controlled crystal oscillator
temperature monitors
■RF power transistor monitor
SOT323-5, SC70-5 (W8)
UDFN 4-lead (DD)
www.st.com
Contents STLM20
2/18 Doc ID 12495 Rev 12
Contents
1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Transfer function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4 DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5 Capacitive load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6 Typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8 Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
STLM20 List of tables
Doc ID 12495 Rev 12 3/18
List of tables
Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Table 2. First order equations optimized for different temperature ranges. . . . . . . . . . . . . . . . . . . . . 6
Table 3. Quadratic output equation (VCC = 2.7 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 4. Quadratic output equation for operations over the full voltage range
(VCC = 2.4 V to 5.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 5. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 6. DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 7. Resistor/capacitor combinations for the filter network . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 8. SOT323-5 – 5-lead small outline transistor package mechanical data. . . . . . . . . . . . . . . . 13
Table 9. UDFN – 4-lead package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 10. Carrier tape dimensions for SOT323-5L and UDFN-4L packages . . . . . . . . . . . . . . . . . . . 15
Table 11. Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 12. Marking description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 13. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
List of figures STLM20
4/18 Doc ID 12495 Rev 12
List of figures
Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 2. Connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 3. Filter network for noisy environments or capacitive loads > 300 pF . . . . . . . . . . . . . . . . . . 10
Figure 4. VOUT vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 5. SOT323-5 – 5-lead small outline transistor package outline . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 6. UDFN – 4-lead package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 7. Carrier tape for SOT323-5L and UDFN-4Lpackages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
STLM20 Description
Doc ID 12495 Rev 12 5/18
1 Description
The STLM20 is a precision analog output temperature sensor for low current applications
where maximizing battery life is important. It operates over a –55 °C to 130 °C (grade 7) or
–40 °C to 85 °C (grade 9) temperature range. The power supply operating range is 2.4 V to
5.5 V. The accuracy of the STLM20 is ± 1.5 °C, at an ambient temperature of 25 °C. The
temperature error increases linearly and reaches a maximum of ±2.5 °C at the temperature
range extremes. The temperature range is affected by the power supply voltage. For the
temperature grade 7 device, a power supply voltage of 2.7 V to 5.5 V, the temperature range
extremes are +130 °C and –55 °C. Decreasing the power supply voltage to 2.4 V changes
the negative extreme to –30 °C, while the positive remains at +130 °C.
The STLM20 has a maximum quiescent supply current of 8 µA. Therefore, self-heating is
negligible.
Figure 1. Logic diagram
1. Pin 2 GND may be grounded or left floating (SC70-5 only). For optimum thermal conductivity to the PC
board ground plane, it should be grounded.
Figure 2. Connections (top view)
1. Pin 1 NC should be left floating or grounded.
2. Pin 2 GND may be grounded or left floating. For optimum thermal conductivity to the PC board ground
plane, it should be grounded.
Table 1. Signal names
VCC Supply voltage
GND Ground
VOUT Output voltage
NC No connect
AI12252
VCC
STLM20
GND(1)
VOUT
1
VCC
GND(2)
NC(1) GND
VOUT
AI12253
2
3
5
4
SOT323-5(SC70-5)
1VCC
NC(1) GND
VOUT
AI12253_a
2
4
3
UDFN-4Lead
Transfer function STLM20
6/18 Doc ID 12495 Rev 12
2 Transfer function
The STLM20’s transfer function can be described in different ways, with varying levels of
precision. A simple linear transfer function, with good accuracy near 25 °C is expressed as:
Equation 1
Over the specified operating temperature range, the best accuracy can be obtained by using
the parabolic transfer function:
Equation 2
and solving for T:
Equation 3
The best fit linear transfer function for many popular temperature ranges was calculated in
Ta bl e 2 , where the error introduced by the linear transfer function increases with wider
temperature ranges.
Table 2. First order equations optimized for different temperature ranges
Temperature range Linear equation
VO =
Maximum deviation of linear
equation from parabolic equation
(°C)
Tmin (°C) Tmax (°C)
–55 130 –11.79 mV/°C * T + 1.8528 V ±1.41
–40 110 –11.77 mV/°C * T + 1.8577 V ±0.93
–30 100 –11.77 mV/°C * T + 1.8605 V ±0.70
–40 85 –11.67 mV/°C * T + 1.8583 V ±0.65
–10 65 –11.71 mV/°C * T + 1.8641 V ±0.23
35 45 –11.81 mV/°C * T + 1.8701 V ±0.004
20 30 –11.69 mV/°C * T + 1.8663 V ±0.004
VO11.69mV–()°CT1.8663+×⁄ V=
VO3.88 10 6–T2
××–()1.15–10 2–T××()1.8639++=
T1481.96–2.1962 1061.8639 VO
–()
3.88 10 6–
×
-----------------------------------+×+=
STLM20 Transfer function
Doc ID 12495 Rev 12 7/18
Table 3. Quadratic output equation (VCC = 2.7 V)
Parameter Conditions Min Typ Max Unit
Temperature error based on:
VOUT = (–3.88e–6 × T2) + (–1.15e–2 × T) + 1.8639
where T is the temperature
TA = –55 °C 2.457 2.485 2.512
V
TA = –40 °C 2.292 2.318 2.343
TA = –30 °C 2.181 2.205 2.230
TA = –20 °C 2.069 2.092 2.116
TA = 0 °C 1.842 1.864 1.886
TA = 25 °C 1.556 1.574 1.592
TA = 50 °C 1.255 1.279 1.303
TA = 85 °C 0.833 0.859 0.884
TA = 130 °C 0.272 0.303 0.335
Table 4. Quadratic output equation for operations over the full voltage range
(VCC = 2.4 V to 5.5 V)
Parameter(1)
1. VOUT tolerance is ±4% (temperature grade 9 only).
Conditions Min Max Unit
Temperature error based on:
VOUT = (–3.88e–6 × T2) + (–1.15e–2 × T) + 1.8639,
where T is the temperature
TA = –55 °C(2)(3)
2. Valid for VCC min = 2.7 V.
3. Valid for temperature grade 7 only.
2.457 2.531
V
TA = –40 °C(2) 2.292 2.362
TA = –30 °C 2.180 2.249
TA = –20 °C 2.068 2.135
TA = 0 °C 1.841 1.904
TA = 25 °C 1.555 1.610
TA = 50 °C 1.254 1.322
TA = 85 °C 0.832 0.903
TA = 130 °C(3) 0.271 0.353
Maximum ratings STLM20
8/18 Doc ID 12495 Rev 12
3 Maximum ratings
Stressing the device above the rating listed in the absolute maximum ratings table may
cause permanent damage to the device. These are stress ratings only and operation of the
device at these or any other conditions above those indicated in the operating sections of
this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability. Refer also to the STMicroelectronics SURE
Program and other relevant quality documents.
Table 5. Absolute maximum ratings
Symbol Parameter Value Unit
TSTG Storage temperature –65 to +150 °C
TSLD(1)
1. Reflow at peak temperature of 260 °C. The time above 255 °C must not exceed 30 seconds.
Lead solder temperature for 10 seconds 260 °C
VOOutput voltage –0.3 to VCC + 0.3 V
VCC Supply voltage –0.2 to 6.5 V
IOOutput current 10 mA
TJ(max) Maximum junction temperature 150 °C
θJA Thermal resistance
SOT323-5
(SC70-5) 331.4 °C/W
UDFN 160.2 °C/W
TA(2)
2. Grade 7: STLM20W87F, STLM20DD7F
Grade 9: STLM20DD9F
Ambient operating temperature Grade 7 –55 to 130 °C
Grade 9 –40 to 85 °C
STLM20 DC and AC characteristics
Doc ID 12495 Rev 12 9/18
4 DC and AC characteristics
This section summarizes the DC and AC characteristics of the device. The parameters in
the DC and AC characteristics table that follows are derived from tests performed under the
test conditions. Designers should check that the operating conditions in their circuit match
the operating conditions when relying on the quoted parameters.
Table 6. DC and AC characteristics
Sym Description Test condition(1) Min Typ(2) Max Unit
VCC Supply voltage
TA = –30 °C to 130 °C 2.4 5.5 V
TA = –55 °C to 130 °C or
–40 °C to 85 °C 2.7 5.5 V
VOOutput voltage TA = 0 °C 1.8639 V
Temperature to voltage error(3)
VO = (–3.88E–6 * T2) +
(–1.15E–2 * T) + 1.8639 V
TA = 25 °C to 30 °C ±1.5 °C
TA = 125 °C to 130 °C ±2.5 °C
TA = 80 °C to 85 °C ±2.1 °C
TA = 0 °C ±1.9 °C
TA = –40 °C ±2.3 °C
TA = –55 °C ±2.5 °C
IQQuiescent current 2.4V ≤ VCC ≤ 5.5 V 4.8 8 µA
Sensor gain (temperature sensitivity
or average slope),
VO = –11.77 mV/°C * T + 1.860 V
–30 °C ≤ TA ≤ 100 °C –11.4 –11.77 –12.2 mV/°C
Non-linearity –20 °C ≤ TA ≤ 80 °C ±0.4 %
ΔIQChange of quiescent current 2.4 V ≤ VCC ≤ 5.5 V 0.7 µA
TCVO
Temperature coefficient of quiescent
current –11 nA/°C
ISD Shutdown current VCC ≤ 0.8 V 0.02 µA
ZOOutput impedance 0 µA ≤ IL ≤ 16 µA(4)(5) 160 Ω
RegL Load regulation(6) –2.5 mV
RegI1 Line regulation 2.4 V ≤ VCC ≤ 5.0 V 3.3 mV/V
RegI2 5.0 V ≤ VCC ≤ 5.5 V 11 mV
1. Valid for ambient operating temperature: TA = –55 to 130 °C or TA = –40 to 85 °C; VCC = 2.7 V (except where noted).
2. TJ = TA = 25 °C.
3. Error accuracy is between the measured and calculated output voltage at specified conditions of voltage, current, and
temperature.
4. With negative current flowing into STLM20 and positive current flowing out, can typically sink less than
1 µA and source is 16 µA.
5. Over the supply range of 2.4 to 5.5 V.
6. Measured at constant junction temperature, with pulse testing and low duty cycle. Output changes due to heating may be
calculated by multiplying internal dissipation by thermal resistance.
Capacitive load STLM20
10/18 Doc ID 12495 Rev 12
5 Capacitive load
The STLM20 will handle capacitive loads of up to 300 pF. Over the specified temperature
range, the STLM20 has a maximum output impedance of 160 Ω.
In a noisy environment, it may be advisable to add some filtering to minimize noise in the
output voltage. A 0.1µF capacitor added between the supply voltage and ground is
recommended.
In an extremely noisy environment, it may be necessary to add a low-pass filter network to
the output of the device. A 1 µF capacitor, in addition to the output impedance of the device,
and a 200 Ω series resistor, will provide a low-pass filter that will pass the slow thermal time
constant of the STLM20, while filtering the higher frequency noise.
Figure 3. Filter network for noisy environments or capacitive loads > 300 pF
Table 7. Resistor/capacitor combinations for the filter network
RFILTER CFILTER
200 Ω1 µF
470 Ω0.1 µF
680 Ω0.01 µF
1000 Ω1000 pF
10 kΩ100 pF
100 kΩ10 pF
1
VCC
RFILTER
CFILTER GND
0.1µF
Bypass Capacitor
VOUT
CL
AI12259
2
3
5
4
1
VCC
RFILTER
CFILTER
GND
0.1µF
Bypass Capacitor
VOUT
CL
AI12260
2
3
5
4
Package mechanical data STLM20
12/18 Doc ID 12495 Rev 12
7 Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
STLM20 Package mechanical data
Doc ID 12495 Rev 12 13/18
Figure 5. SOT323-5 – 5-lead small outline transistor package outline
1. Drawing is not to scale.
Table 8. SOT323-5 – 5-lead small outline transistor package mechanical data
Symbol
mm inches
Typ Min Max Typ Min Max
A – 0.80 1.10 – 0.031 0.043
A1 – 0 0.10 – 0.000 0.004
A2 0.90 0.80 1.00 0.035 0.031 0.039
b – 0.15 0.30 – 0.006 0.012
c – 0.10 0.22 – 0.004 0.009
D 2.00 1.80 2.20 0.079 0.071 0.087
E 2.10 1.80 2.40 0.083 0.071 0.094
E1 1.25 1.15 1.35 0.049 0.045 0.053
e0.65– –0.026– –
e1 1.30 – – 0.051 – –
L 0.36 0.26 0.46 0.014 0.010 0.018
<– 0° 8° – 0° 8°
7091413_E
Package mechanical data STLM20
14/18 Doc ID 12495 Rev 12
Figure 6. UDFN – 4-lead package outline
Note: Drawing is not to scale.
7986858
Table 9. UDFN – 4-lead package mechanical data
Symbol
mm inches
Min Typ Max Min Typ Max
A 0.45 0.50 0.55 0.018 0.020 0.022
A1 0 0.025 0.05 0 0.001 0.002
A3 0.119 0.127 0.177 0.0046 0.0050 0.0069
b 0.20 0.25 0.30 0.008 0.010 0.012
D 0.95 1.00 1.05 0.037 0.039 0.041
E 1.25 1.30 1.35 0.049 0.051 0.053
e 0.45 0.50 0.55 0.018 0.020 0.022
L 0.35 0.40 0.45 0.014 0.016 0.018
L1 0.45 0.50 0.55 0.018 0.020 0.022
ddd 0 0.04 0.08 0 0.0016 0.0031
STLM20 Package mechanical data
Doc ID 12495 Rev 12 15/18
Figure 7. Carrier tape for SOT323-5L and UDFN-4Lpackages
T
K0
P1
A0
B0
P2
P0
CENTER LINES
OF CAVITY
W
E
F
D
TOP COVER
TAPE
USER DIRECTION OF FEED
AM03073v1
Table 10. Carrier tape dimensions for SOT323-5L and UDFN-4L packages
Package W D E P0P2FA
0B0K0P1TUnit
Bulk
Qty
SOT323-5L
8.00
+0.30
–0.10
1.50
+0.10/
–0.00
1.75
±0.10
4.00
±0.10
2.00
±0.10
3.50
±0.05
2.25
±0.10
2.40
±0.10
1.22
±0.10
4.00
±0.10
0.30
±0.05 mm 3000
UDFN-4L
8.00
+0.30
–0.10
1.50
+0.10/
–0.00
1.75
±0.10
4.00
±0.10
2.00
±0.10
3.50
±0.05
1.25
±0.10
1.55
±0.10
0.65
±0.05
4.00
±0.10
0.250
±0.05 mm 3000
Part numbering STLM20
16/18 Doc ID 12495 Rev 12
8 Part numbering
Table 11. Ordering information scheme
For other options, or for more information on any aspect of this device, please contact the
ST sales office nearest you.
Example: STLM20 DD 9 F
Device type
STLM20
Package
W8 = SOT323-5 (SC70-5)(1)
1. Available in temperature grade 7 (–55 to 130 °C) only
DD= UDFN - ultra thin DFN 4-lead(2)
2. Available in both temperature grade 7 (–55 to 130 °C) and grade 9 (–40 to 85 °C)
Temperature range
7 = –55 to 130°C
9 = –40 to 85°C
Shipping method
F = ECOPACK® package, tape & reel
Table 12. Marking description
Part number Package Marking
STLM20W8 SOT323-5 (SC70-5) M20
STLM20DD UDFN 20
STLM20 Revision history
Doc ID 12495 Rev 12 17/18
9 Revision history
Table 13. Document revision history
Date Revision Changes
28-Jun-2006 1 Initial release.
19-Jul-2006 2 Added Table 12: Marking description
28-Aug-2006 3
Added a footnote concerning package availability in Features on
page 1 and to Ta b l e 1 1 and Ta b l e 1 2 ; updated package mechanical
data in Ta ble 9
05-Sep-2006 4
Amended text in the Features on page 1, Section 1: Description,
Section 2: Transfer function, Ta bl e 6, and Ta b l e 1 1 to elucidate that
two packages exist each with specific temperature ranges: SOT323-
5 (SC70-5) 5-lead package (–55 to 130 °C) and UDFN 4-lead
package (–40 to 85 °C)
25-Sep-2006 5 Updated Operating Temperature Ranges (now 7 and 9); updated
Table 6: DC and AC characteristics
10-Oct-2006 6
Table 3: Quadratic output equation (VCC = 2.7 V) and Tabl e 4:
Quadratic output equation for operations over the full voltage range
(VCC = 2.4 V to 5.5 V) added. Section 6: Typical operating
characteristics added.
TA added to Table 5: Absolute maximum ratings.
04-Dec-2006 7
Document status updated to full datasheet; updated text in the title of
Table 4: Quadratic output equation for operations over the full voltage
range (VCC = 2.4 V to 5.5 V); added footnotes regarding
temperature ranges in Table 11: Ordering information scheme.
08-Feb-2007 8 Added thermal resistance in Table 5: Absolute maximum ratings.
09-May-2007 9 Modified Equation 1, 2, and 3.
26-Nov-2007 10 Updated footnote 2 in Ta b l e 5 ; minor text updates.
07-Nov-2008 11
Updated Figure 6: UDFN – 4-lead package outline to reflect location
of pin 1 with respect to the orientation of the topside marking;
updated Figure 5, Ta b l e 5 , 8, 11.
10-Sep-2009 12
Updated Ta bl e 5 , text in Section 7: Package mechanical data; added
tape and reel specifications (Figure 7 and Ta bl e 1 0 ); reformatted
document.
STLM20
18/18 Doc ID 12495 Rev 12
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