FEATURES & BENEFITS
Precision VGS(th) = +0.40V +0.020V
VOS (VGS(th) match) 10mV max.
Sub-threshold voltage (nano-power) operation
< 400mV min. operating voltage
< 1nA min. operating current
< 1nW min. operating power
> 100,000,000:1 operating current ranges
High transconductance and output conductance
Low RDS(ON) of 14Ω
Output current > 50mA
Matched and tracked tempco
Tight lot-to-lot parametric control
Positive, zero, and negative VGS(th) tempco
Low input capacitance and leakage currents

APPLICATIONS
• Low overhead current mirrors and current sources
• Zero Power Normally-On circuits
• Energy harvesting circuits
• Very low voltage analog and digital circuits
• Zero power fail-safe circuits
• Backup battery circuits & power failure detector
• Extremely low level voltage-clamps
• Extremely low level zero-crossing detector
• Matched source followers and buffers
• Precision current mirrors and current sources
• Matched capacitive probes and sensor interfaces
• Charge detectors and charge integrators
• High gain differential amplifier input stage
• Matched peak-detectors and level-shifters
• Multiple Channel Sample-and-Hold switches
• Precision Current multipliers
• Discrete matched analog switches/multiplexers
• Nanopower discrete voltage comparators

GENERAL DESCRIPTION
The ALD212904 precision enhancement mode N-Channel EPAD® MOSFET
array is precision matched at the factory using ALD’s proven EPAD® CMOS
technology. These dual monolithic devices are enhanced additions to the
ALD110904 EPAD® MOSFET Family, with increased forward transconductance
and output conductance, particularly at very low supply voltages.
Intended for low voltage, low power small signal applications, the ALD212904
features precision +0.40V threshold voltage, which enables circuit designs with
input/output signals referenced to very low operating voltage ranges. With these
devices, a circuit with multiple cascading stages can be built to operate at extremely
low supply/bias voltage levels. For example, a nanopower input amplifier
stage operating at less than 0.2V supply voltage has been successfully built
with these devices.
ALD212904 EPAD MOSFETs feature exceptional matched pair electrical characteristics
of Gate Threshold Voltage VGS(th) set precisely at +0.40V +0.020V,
IDS = +20μA @ VDS = 0.10V, with a typical offset voltage of only +0.002V (2mV).
Built on a single monolithic chip, they also exhibit excellent temperature tracking
characteristics. These precision devices are versatile as design components
for a broad range of analog small signal applications such as basic building
blocks for current mirrors, matching circuits, current sources, differential amplifier
input stages, transmission gates, and multiplexers. They also excel in limited
operating voltage applications, such as very low level voltage-clamps and
nano-power normally-on circuits.
In addition to precision matched-pair electrical characteristics, each individual
EPAD MOSFET also exhibits well controlled manufacturing characteristics, enabling
the user to depend on tight design limits from different production batches.
These devices are built for minimum offset voltage and differential thermal response,
and they can be used for switching and amplifying applications in +0.1V
to +10V (+0.05V to +5V) powered systems where low input bias current, low
input capacitance, and fast switching speed are desired. At VGS > +0.40V, the
device exhibits enhancement mode characteristics whereas at VGS < +0.40V
the device operates in the subthreshold voltage region and exhibits conventional
sub threshold characteristics, with well controlled turn-off and sub-threshold
levels that operate the same as standard enhancement mode MOSFETs.
The ALD212904 features high input impedance (2.5 x 1010Ω) and high DC current
gain (>108). A sample calculation of the DC current gain at a drain output
current of 30mA and input current of 300pA at 25°C is 30mA/300pA =
100,000,000, which translates into a dynamic operating current range of about
eight orders of magnitude. A series of four graphs titled “Forward Transfer Characteristics”,
with the 2nd and 3rd sub-titled “expanded (subthreshold)” and “further
expanded (subthreshold)”, and the 4th sub-titled “low voltage”, illustrates
the wide dynamic operating range of these devices.
Generally it is recommended that the V+ pin be connected to the most positive
voltage and the V- and IC (internally-connected) pins to the most negative voltage
in the system. All other pins must have voltages within these voltage limits
at all times. Standard ESD protection facilities and handling procedures for static
sensitive devices are highly recommended when using these devices.