Preliminary Data
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to
change without noti ce.
October 2006 Rev 6 1/17
1
STLM20
Ultra-low Current 2.4V precision analog temperature sensor
Feature summary
■Precision analog voltage output temperature
sensor
■±1.5°C temperature accuracy at 25°C
■Ultra-low quiescent supply current: 8.0µA
(max)
■Operating voltage range: 2.4V to 5.5V
■Operating temperature range:
–55°C to 130°C (grade - 7)
–40°C to 85°C (grade - 9)
■SOT323-5 (SC7 0-5) 5-lead package
■UDFN 4-lead packag e
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
2/17
Contents
1 Summary description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Transfer function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4 DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5 Capacitive load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6 Typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7 Package mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8 Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
STLM20 List of tables
3/17
List of tables
Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Table 2. First order equations optimized for different temperature ranges. . . . . . . . . . . . . . . . . . . . . 7
Table 3. Quadratic output equation (VCC = 2.7V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 4. Quadratic output equation for operations over the whole voltage range
(VCC = 2.4V to 5.5V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 5. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 6. DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 7. Resistor/capacitor combinations for the filter network . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 8. SOT323-5 – 5-lead small outlin e tra n sist or pac kag e mec ha n ical da ta. . . . . . . . . . . . . . . . 13
Table 9. UDFN - 4 lead mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 10. Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 11. Marking description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 12. Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
List of figures STLM20
4/17
List of figures
Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 2. Connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 3. Filter network for noisy environments or capacitive loads > 300pF . . . . . . . . . . . . . . . . . . 11
Figure 4. VOUT vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 5. SOT323-5 – 5-lead small outline transistor package outline . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 6. UDFN – 4-lead package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 4
STLM20 Summary description
5/17
1 Summary description
The STLM20 is a precision analog output temperature sensor for low current application s
where maximizing battery life is important. It operates over a –55°C to 130°C (gr ade 7) or
–40°C to 85°C (grade 9) temperatur e range. The power supply operating range is 2.4V to
5.5V. 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 2.7V to 5.5V, the temperature range
e xtreme s are +130°C and – 55°C . De creasing t he po wer su pply v olta ge to 2.4V ch anges the
negative extreme to –30°C, while the positive remains at +130°C.
The STLM20 has a maximum quiescent supply current of 8µA. 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.
Table 1. Signal names
VCC Supply voltage
GND Ground
VOUT Output voltage
NC No connect
AI12252
VCC
STLM20
GND(1)
VOUT
Summary description STLM20
6/17
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.
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
STLM20 Transfe r function
7/17
2 Transfer function
The STLM20’s transfer function can be described in different wa ys, with varying levels of
precision. A simple linear transfer function, with good accuracy near 25°C is expressed as:
Equation 1
Ov er the specifi ed operating t emperature r ange, t he best accuracy can be obtained b y using
the parabolic transfer function:
Equation 2
and solving f or T:
Equation 3
The best fit linear transfer function for many popular temperature ranges was calculated in
Table 2, where the error introduced by the linear transfer function increases with wider
temperature ran ges.
Table 2. First order equations optimized for different temperature ranges
Temperature range Linear equation
VO =
Maximum deviation of linear
equation fr om parabolic equ ation
(°C)
Tmin (°C) Tmax (°C)
–55 130 –11.79mV/°C * T + 1.8528V ±1.41
–40 110 –11.77mV/°C * T + 1.8577V ±0.93
–30 100 –11.77mV/°C * T + 1.8605V ±0.70
–40 85 –11.67mV/°C * T + 1.8583V ±0.65
–10 65 –11.71mV/°C * T + 1.8641V ±0.23
35 45 –11.81mV/°C * T + 1.8701V ±0.004
20 30 –11.69mV/°C * T + 1.8663V ±0.004
VO11 69mV∴–()°CT1 8663V∴+×⁄=
VO388∴10 6–T2
××–()115∴–10 2–T××()1 8639∴++=
T1481 96∴–21962∴1061 8639∴VO
–()
388∴10 6–
×
-----------------------------------+×+=
Transfer function STLM20
8/17
Table 3. Quad ratic output equation (VCC = 2.7V)
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 0.3 35
Table 4. Quadratic output equation for operations over the whole voltage range
(VCC = 2.4V to 5.5V)
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 = 2.7V.
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
STLM20 Maximum rating
9/17
3 Maximum rating
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 255°C to 260°C for < 30 seconds (total thermal budget not to exceed 180°C
for between 90 to 150 seconds).
Lead solder temperature for 10 seconds 260 °C
VOOutput voltage –0.6 to VCC + 0.6 V
VCC Supply voltage –0.2 to 6.5 V
IOOutput current 10 mA
TJ(max) Maximum junction temperature 150 °C
PDPower dissipation 377 mW
TA(2)
2. Grade 7: STLM20DD7F and STLM20W87F
Grade 9: STLM20DD9F and STLM20W89F.
Ambient operating temperature Grade 7 –55 to 130 °C
Grade 9 –40 to 85 °C
DC and AC characteristics STLM20
10/17
4 DC and AC characteristics
This section summarizes the DC and AC characteristics of the device. The parameters in
the DC and AC characteristics tab le th at follows are derived from tests pe rformed under the
test conditions (see Table6 on page10). Designers sho u l d che ck 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)
1. Valid for Ambient Operating Temperature: TA = –55 to 130°C or TA = –40 to 85°C; VCC = 2.7V (except
where noted).
Min Typ(2)
2. TJ = TA = 25°C.
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) + 1.8639V
3. Error accuracy is between the measured and calculated output voltage at specified conditions of voltage,
current, and temperature.
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 ≤ 5.5V 4.8 8 µA
Sensor gain (temperature
sensitivity or average slope),
VO = –11.77mV/°C * T + 1.860V –30°C ≤ TA ≤ 100°C –11.4 –11.77 –12.2 mV/°C
Non-linearity –20°C ≤ TA ≤ 80°C ±0.4 %
∆IQChange of quiescent current 2.4V ≤ VCC ≤ 5.5V 0.7 µA
TCVOTemperature coefficient of
quiescent cu rre nt –11 nA/°C
ISD Shutdown current VCC ≤ 0.8V 0.02 µA
ZOOutput impedance 0µA ≤ IL ≤ 16µA(4)(5)
4. With negative current flowing into STLM20 and positive current flowing out, can typically sink less than 1µA
and source is 16µA.
5. Over the supply range of 2.4 to 5.5V.
160 Ω
RegL Load regulation(6)
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.
–2.5 mV
RegI1 Line regulati on 2.4V ≤ VCC ≤ 5.0V 3.3 mV/V
RegI2 5.0V ≤ VCC ≤ 5.5V 11 mV
STLM20 Capacitive load
11/17
5 Capacitive load
The STLM20 will handle capacitive loads of up to 300pF. Over the specified temperature
range, the STLM20 has a maximum output impedance of 160Ω.
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 1µF capacitor, in addition to the output impedance of the device,
and a 200Ω 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 enviro nments or capacitive loads > 300pF
Table 7. Resistor/capacitor combinations for the filter network
RFILTER CFILTER
200Ω1µF
470Ω0.1µF
680Ω0.01µF
1000Ω1000pF
10kΩ100pF
100kΩ10pF
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
STLM20 Package mechanical
13/17
7 Package mechanical
In order to meet environmental requirements , ST offers these devices in ECOPACK®
pac kages. These packages have a Lead-free second level interconnect. The category of
second Level Interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
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 dat a
Symbol mm inches
Typ Min Max Typ Min Max
A – 0.80 1.10 – 0.031 0.043
A1 – 0 0.10 – 0 0.004
A2 0.90 – – 0.035 – –
b – 0.15 0.30 – 0.006 0.012
C – 0.10 0.20 – 0.004 0.008
D 2.00 1.90 2.10 0.079 0.075 0.083
E – 1.80 2.40 – 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 – –
L0.52– –0.020– –
L1 0.40 0.35 0.45 0.016 0.014 0.018
s–0°5°–0°5°
SOT323-5
0.10 C
A
A2
A1
5X
C
e1
D
e
5X b
E
BE1
A
M
0.10 C A B
s s
1
C
L1
s
LC
Package mechanical STLM20
14/17
Figure 6. UDFN – 4-lead package outline
1. Drawing is not to scale.
Table 9. UDFN - 4 lead 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 Part numbering
15/17
8 Part numbering
Table 10. Ordering information scheme
For other options, or for more information on any aspect of th is device, please contact the
ST Sales Office nearest you.
Example: STLM20 DD 9 F
Device type
STLM20
Package
W8 = SOT323-5 (SC70-5)
DD= UDFN - ultra thin DFN4 lead
Temperature range
7 = –55 to 130°C(1)
1. Contact local sales office for availability
9 = –40 to 85°C
Shipping method
F = ECOPACK package, tape & reel
Table 11. Marking description
Part number Package Marking
STLM20W8 SOT323-5(SC70) M20
STLM20DD UDFN 20
Revision history STLM20
16/17
9 Revision history
Table 12. Revision history
Date Revision Changes
28-Jun-2006 1 Initial release.
19-Jul-2006 2 Added Table 11: Marking description
28-Aug-2006 3 Added a footnote concerning package availability in Feature
summary on page 1 and to Table 10 and Table 11; updated package
mechanica l data in Table 9
05-Sep-2006 4
Amended text in the Feature summary on page 1, Section 1:
Summary descr iption, Section 2: Transfer function, Table 6, and
Table 10 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 = 2.7V) and Table 4:
Quadratic output equation for oper a tions over the whole voltage
range (VCC = 2.4V to 5.5V) added. Section 6: Typical operating
characteristics added.
TA added to Table 5: Absolute maximum ratings.
STLM20
17/17
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