TABLE 1. SUPERCAP AUTO BALANCING (SAB™) MOSFET EQUIVALENT ON RESISTANCE AT
DIFFERENT DRAIN-GATE SOURCE VOLTAGES AND DRAIN-SOURCE ON CURRENTS
Drain-Gate
Gate-
Source
Voltage (V)2
SAB MOSFET DRAIN-SOURCE ON CURRENT
ALD Part Threshold
I
(µA)1
T = 25°C
A
DS(ON)
Number
Voltage
Equivalent ON
V (V)
t
Resistance (MΩ) 0.0001 0.001
0.01
0.1
1
10
100
300
1000
3000 10000
ALD910028
ALD910027
ALD910026
ALD910025
ALD910024
ALD910023
2.80
2.70
2.60
2.50
2.40
2.30
V
= V
(V)
2.4
2.5
2.6
2.7
27
2.8
2.8
2.9
3.02
3.1
3.24
3.3 3.8
GS
DS
R
(MΩ)
24000 2500
260
0.29
0.030
0.01
0.003 0.001 0.0004
DS(ON)
V
= V
(V)
2.3
2.4
2.5
2.6
26
2.7
2.7
2.8
2.92
3.0
3.14
3.2
3.7
GS
DS
R
(MΩ)
23000 2400
250
0.28
0.029
0.01
0.003 0.001 0.0004
DS(ON)
V
= V
(V)
2.2
2.3
2.4
2.5
25
2.6
2.6
2.7
2.82
2.9
3.04
3.1
3.6
GS
DS
R
(MΩ)
22000 2300
240
0.27
0.028
0.01
0.003 0.001 0.0004
DS(ON)
V
= V
(V)
2.1
2.2
2.3
2.4
24
2.5
2.5
2.6
2.72
2.8
2.94
3.0
3.5
GS
DS
R
(MΩ)
21000 2200
230
0.26
0.027
0.01
0.003 0.001 0.0004
DS(ON)
V
= V
(V)
2.0
2.1
2.2
2.3
23
2.4
2.4
2.5
2.62
2.7
2.84
2.9
3.4
GS
DS
R
(MΩ)
20000 2100
220
0.25
0.026
0.009
0.003 0.001 0.0003
DS(ON)
V
= V
(V)
1.9
2.0
2.1
2.2
22
2.3
2.3
2.4
2.52
2.6
2.74
2.8
3.3
GS
DS
R
(MΩ)
19000 2000
210
0.24
0.025
0.009
0.003 0.001 0.0003
DS(ON)
Drain-Gate
Source
Voltage (V)2
Gate-
SAB MOSFET DRAIN-SOURCE ON CURRENT
ALD Part Threshold
I
(µA)1
T = 25°C
A
DS(ON)
Number
Voltage
Equivalent ON
Resistance (MΩ) 0.0001 0.001
V (V)
t
0.01
0.1
1
10
100
300
1000
3000 10000
ALD810028
ALD810027
ALD810026
ALD810025
ALD810024
ALD810023
2.80
2.70
2.60
2.50
2.40
2.30
V
= V
(V)
2.4
2.5
2.6
2.7
27
2.8
2.8
2.9
3.04
3.14
0.01
3.32
3.62 4.22
GS
DS
R
(MΩ)
24000 2500
260
0.29
0.030
0.003 0.001 0.0004
DS(ON)
V
= V
(V)
2.3
2.4
2.5
2.6
26
2.7
2.7
2.8
2.94
3.04
0.01
3.22
3.52
4.12
GS
DS
R
(MΩ)
23000 2400
250
0.28
0.029
0.003 0.001 0.0004
DS(ON)
V
= V
(V)
2.2
2.3
2.4
2.5
25
2.6
2.6
2.7
2.84
2.94
0.01
3.12
3.42
4.02
GS
DS
R
(MΩ)
22000 2300
240
0.27
0.028
0.003 0.001 0.0004
DS(ON)
V
= V
(V)
2.1
2.2
2.3
2.4
24
2.5
2.5
2.6
2.74
2.84
0.01
3.02
3.32
3.92
GS
DS
R
(MΩ)
21000 2200
230
0.26
0.027
0.003 0.001 0.0004
DS(ON)
V
= V
(V)
2.0
2.1
2.2
2.3
23
2.4
2.4
2.5
2.64
2.74
2.92
3.22
3.82
GS
DS
R
(MΩ)
20000 2100
220
0.25
0.026
0.009
0.003 0.001 0.0004
DS(ON)
V
= V
(V)
1.9
2.0
2.1
2.2
22
2.3
2.3
2.4
2.54
2.64
2.82
3.12
3.72
GS
DS
R
(MΩ)
19000 2000
210
0.24
0.025
0.009
0.003 0.001 0.0004
DS(ON)
Selection of a SAB MOSFET device depends on a set of desired voltage vs. current characteristics that closely match the selected nominal bias voltage and
bias currents that provide the best leakage and regulation profile of a supercap load. The V table, where Drain-Gate Source Voltage (V = V ) gives
t
GS DS
a range of V
= V
bias voltages as different V
load voltages. At each V
= V
bias voltage, a corresponding Drain-Source ON Current
GS
DS
supercap
GS
DS
(I
) is produced by a specific SAB MOSFET, which can be viewed as the amount of current available to compensate for supercap leakage current
DS(ON)
imbalances and results in an Equivalent ON Resistance (R
)across a supercap cell. Selection of a supercap bias voltage with a SAB MOSFET
that corresponds to the maximum supercap leakage current would result in the best possible tradeoff between leakage current balancing and
DS(ON)
I
DS(ON)
voltage regulation.
Notes: 1) The SAB MOSFET Drain Source ON Current (I ) is the maximum current available to offset the supercapacitor leakage current.
DS(ON)
2) The Drain-Gate Source Voltage (V =V ) is normally the same as the voltage across the supercapacitor.
GS DS
ALD810023, ALD810024, ALD810025,
ALD810026, ALD810027, ALD810028
Advanced Linear Devices, Inc.
5 of 17
ALD [ ADVANCED LINEAR DEVICES ]
