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Micropower Voltage Reference
Features Description
The AS1004 is a two-terminal precision band-gap voltage reference with a low turn-on current of 10 µA. Emulating a 1.235 V zener diode, the AS1004 operates more than three orders of magnitude of output current with minute output impedance and guaranteed stability. With an initial tolerance of ± 4 mV and guaranteed temperature performance, it is ideal for precision instrumentation, especially in low power applications. Being a low-voltage reference, the AS1004 is also well-suited as a reference for low-voltage power supply applications, especially in power supplies intended for low-voltage logic systems, laptop computers and other portable or battery operated equipment. The AS1004 is pin-for-pin compatible with the LT1004 and the LM385 and offers improved specifications over both the LM385 and the MP5010. It is also available as a 2.5 V reference with a guaranteed start-up current of 20 µA.
AS1004
• • • • • • • •
Low voltage reference 10 µA turn-on current for AS1004-1.2 20 µA turn-on current for AS1004-2.5 ± 4 mV (0.3 %) initial accuracy for AS1004-1.2 ± 20 mV (0.8 %) initial accuracy for AS1004-2.5 Guaranteed operation to 20 mA. Over three orders of magnitude of operating current! Temperature performance guaranteed Very low dynamic impedance
Pin Configuration —
TO-92 (LP)
Top view
SOIC (D)
SOT-89 (S)
N/C
1 2 3 4
8 7 6 5
CATHODE N/C
ANODE
N/C
N/C
CATHODE
N/C CATHODE ANODE
ANODE
N/C
ANODE
CATHODE
Ordering Information
Description Temperature Range Order Codes
TO-92 8-Pin Plastic SOIC SOT-89
© ASTEC Semiconductor
0 to 70° C 0 to 70° C 0 to 70° C
29
AS1004-1.2LP AS1004-1.2D AS1004-1.2S
AS1004-2.5LP AS1004-2.5D AS1004-2.5S
AS1004
Simplified Schematic
Micropower Voltage Reference
K
R2 Q13 Q12 Q4 Q3
C2 R10 Q7 R4 Q11 C3 R11 Q5 Q10 Q1 C1
R12 Q9 Q14 Q8 R6 R7
Q6
A
Absolute Maximum Ratings
Parameter Symbol Rating Units
Reverse Breakdown Current Forward Current Continuous Power Dissipation at 25° C TO-92 8LSOIC SOT-89 Maximum Junction Temp Storage Temperature Lead Temperature, Soldering 10 Seconds
IZ IF PD
30 30
mA mA
775 750 1000 TJ TSTG TL 150 – 65 to 150 300
mW mW mW °C °C °C
Recommended Conditions
Parameter Symbol Rating Unit
Typical Thermal Resistances
Package θJA θJC Typical Derating
Cathode Current
IZ
100
µA
TO-92 8L SOIC SOT-89
160° C/W 175° C/W 110° C/W
80° C/W 45° C/W 8° C/W
6.3 mW/°C 5.7 mW/°C 9.1 mW/°C
ASTEC Semiconductor
30
Micropower Voltage Reference
Electrical Characteristics
AS1004
Electrical Characteristics are guaranteed over full junction temperature range (0 to 70° C). Ambient temperature must be derated based on power dissipation and package thermal characteristics. Parameter Reverse Breakdown Voltage Symbol VZ Test Condition IZ = 100 µA, TJ = 25° C 0° C ≤ TA ≤ 70° C Average Temperature Coefficient Minimum Operating Current Reverse Breakdown Voltage Change With Current ∆ VZ / ∆ T IZ (min) ∆ VZ / ∆ I Z Imin ≤ IZ ≤ 1 mA Over Temperature 1 mA ≤ IZ ≤ 20 mA Over Temperature Reverse Dynamic Impedance ZZ IZ = 100 mA, f = 25 Hz Over Temperature Wide Band Noise Long Term Stability en ∆ VZ / ∆ T IZ = 100 µA 10 Hz ≤ f ≤ 10 KHz IZ = 100 µA TA = 25° C ± 0.1° C Imin ≤ IZ ≤ 20 mA Min AS1004-1.2 Typ Max 1.235 1.235 20 4 0.5 0.5 6.5 6.5 0.2 1 60 20 10 1 1.5 10 20 0.6 1.5 60 60 1.239 1.245 Min 2.480 2.470 AS1004-2.5 Typ Max 2.500 2.500 60 12 0.5 0.5 6.5 6.5 0.8 20 1 1.5 10 20 0.9 1.5 2.520 2.530 Unit V V ppm/°C µA mV mV mV mV Ω Ω µV ppm/kH
1.231 1.225
Typical Performance Curves
Calculating Average Temperature Coefficient for the AS1004-1.2 Reference
1.245
AS1004-1.2 Reference Voltage vs. Ambient Temperature
IZ = 100 µA
ppm
0
0
0 ∆VREF
V Z – Reference Voltage (V)
mV
%
∆T
1.240
-5 5000 0.5
1.235
-10 0 10 20 30 40 50 60 70 Temperature (°C) 0.025 mV/ °C 0.002 %/ °C 20 ppm/ °C Average Temperature Coefficient = ∆VREF ∆T
1.230
1.225
–55 –35
–15 5 25 45 65 85 TA – Ambient Temperature (°C)
105
125
Figure 1
ASTEC Semiconductor
Figure 2
31
AS1004
Typical Performance Curves
Micropower Voltage Reference
Calculating Average Temperature Coefficient for the AS1004-2.5 Reference
ppm mV
2.520
AS1004-2.5 Reference Voltage versus Ambient Temperature
IZ = 100 µA
0
0
% 0
∆VREF
V Z – Reference Voltage (V)
∆T -5 5000 0.5
2.510
2.500
-10 0 10 20 30 40 50 60 70 Temperature (°C) 0.046 mV/ °C 0.004 %/ °C 37 ppm/ °C Average Temperature Coefficient = ∆VREF ∆T
2.490
2.480
–55 –35
–15 5 25 45 65 85 TA – Ambient Temperature (°C)
105
125
Figure 3
Figure 4
AS1004-1.2 Reverse Operating Characteristics
100 TA = –55° C to 125° C
100
AS1004-2.5 Reverse Operating Characteristics
TA = –55° C to 125° C
IR – Reverse Current (µA)
10
IR – Reverse Current (µA)
0 0.2 0.4 0.8 0.6 1 VR – Reverse Voltage (V) 1.2 1.4
10
1
1
0.1
0.1
0
0.5
1.0 1.5 2.0 VR – Reverse Voltage (V)
2.5
3.0
Figure 5
Figure 6
ASTEC Semiconductor
32
Micropower Voltage Reference
Typical Performance Curves
AS1004.