GENERAL DESCRIPTION
ALD114804A/ALD114804/ALD114904A/ALD114904 are high precision monolithic
quad/dual depletion mode N-Channel MOSFETs matched at the factory using
ALD’s proven EPAD® CMOS technology. These devices are intended for low
voltage, small signal applications. They are excellent functional replacements for
normally-closed relay applications, as they are normally on (conducting) without
any power applied, but could be turned off or modulated when system power
supply is turned on. These MOSFETS have the unique characteristics of, when
the gate is grounded, operating in the resistance mode for low drain voltage levels
and in the current source mode for higher voltage levels and providing a constant
drain current.
ALD114804A/ALD114804/ALD114904A/ALD114904 MOSFETs are designed for
exceptional device electrical characteristics matching. As these devices are on
the same monolithic chip, they also exhibit excellent temperature tracking characteristics.
They are versatile as design components for a broad range of analog
applications, such as basic building blocks for current sources, differential amplifier
input stages, transmission gates, and multiplexer applications. Besides
matched pair electrical characteristics, each individual MOSFET also exhibits well
controlled parameters, enabling the user to depend on tight design limits corresponding
to well matched characteristics.
These depletion mode devices are built for minimum offset voltage and differential
thermal response, and they are suitable for switching and amplifying applications
in single supply (0.4V to +5V) or dual supply (+/-0.4V to +/-5V) systems
where low input bias current, low input capacitance and fast switching speed are
desired. These devices exhibit well controlled turn-off and sub-threshold
charactersitics and therefore can be used in designs that depend on sub-threshold
characteristics.
The ALD114804A/ALD114804/ALD114904A/ALD114904 are suitable for use in
precision applications which require very high current gain, beta, such as current
mirrors and current sources. A sample calculation of the DC current gain at a drain
current of 3mA and input leakage current of 30pA at 25°C is 3mA/30pA =
100,000,000. For most applications, connect the V+ pin to the most positive voltage
and the V- and IC pins to the most negative voltage in the system. All other
pins must have voltages within these voltage limits at all times.

ORDERING INFORMATION (“L” suffix denotes lead-free (RoHS))
• Depletion mode (normally ON)
• Precision Gate Threshold Voltages: -0.40V +/-0.02V
• Nominal RDS(ON) @ VGS = 0.0V of 5.4KΩ
• Matched MOSFET-to-MOSFET characteristics
• Tight lot-to-lot parametric control
• Low input capacitance
• VGS(th) match (VOS) — 20mV
• High input impedance — 1012Ω typical
• Positive, zero, and negative VGS(th) temperature coefficient
• DC current gain >108
• Low input and output leakage currents
FEATURES

VAPPLICATIONS
• Functional replacement of Form B (NC) relays
• Ultra low power (nanowatt) analog and digital
circuits
• Ultra low operating voltage (<0.2V) analog and
digital circuits
• Sub-threshold biased and operated circuits
• Zero power fail safe circuits in alarm systems
• Backup battery circuits
• Power failure and fail safe detector
• Source followers and high impedance buffers
• Precision current mirrors and current sources
• Capacitives probes and sensor interfaces
• Charge detectors and charge integrators
• Differential amplifier input stage
• High side switches
• Peak detectors and level shifters
• Sample and Hold
• Current multipliers
• Discrete analog switches and multiplexers
• Discrete voltage comparators