ALD110900 - Advanced Linear Devices

EPAD

ADVANCED

LINEAR

DEVICES, INC.

N/C*

314

413

512

N/C*

V+

V-

V+

V-

M 4 M 3

M 1 M 2

V-

V- V-

V-

GN1

DN1

N/C*

S12

DN2

GN2

M 1 M 2

V-

N/C*

V-

*N/C pins are internally connected.

Connect to V- to reduce noise

PC, SC PACKAGES

PA, SA PACKAGES

www.aldinc.com

ALD110800/ALD110900/

ALD1108XX/ALD1109XX/ALD1148XX/ALD1149XX

PERFORMANCE CHARACTERISTICS OF

EPAD® MATCHED PAIR MOSFET ARRAYS

GENERAL DESCRIPTION

ALD1108xx/ALD1109xx/ALD1148xx/ALD1149xx are monolithic quad/dual

N-Channel MOSFETs matched at the factory using ALD’s proven EPAD®

CMOS technology. These devices are intended for low voltage, small sig-

nal applications.

This EPAD MOSFET Array product family (EPAD MOSFET) is available in

the three separate categories, each providing a distinctly different set of

device electrical specifications and characteristics. The first category is the

ALD110800/ALD110900 zero-threshold mode EPAD MOSFETs. The sec-

ond category is the ALD1108xx/ALD1109xx enhancement mode EPAD

MOSFETs. The third category is the ALD1 148xx/ALD1 149xx depletion mode

EPAD MOSFETs. (The suffix “xx” denotes threshold voltage in 0.0 V steps,

for example, xx=08 denotes 0.8V).

The ALD110800/ALD110900 (quad/dual) are EPAD MOSFETs in which the

individual threshold voltage of each MOSFET is fixed at zero. The thresh-

old voltage is defined as Ids =1uA @ Vds=0.1V when the gate voltage Vgs

= 0.0V. Zero threshold devices operate in the enhancement region when

operated above threshold voltage and current level (Vgs>0.0V and Ids>1

uA) and subthreshold region when operated at or below threshold voltage

and current level (Vgs<=0.0V and Ids<1 uA). This device, along with other

very low threshold voltage members of the product family , constitute a class

of EPAD MOSFETs that enable ultra low supply voltage operation and

nanopower type of circuit designs, applicable in either analog or digital cir-

cuits.

The ALD1108xx/ALD1109xx (quad/dual) product family features precision

matched enhancement mode EPAD MOSFET devices, which require a

positive bias voltage to turn on. Precision threshold values such as +1.40V,

+0.80V, +0.20V are offered. No conductive channel exists between the

source and drain at zero applied gate voltage for these devices, except that

the +0.20V version has a subthreshold current at about 20 nA.

The ALD1148xx/ALD1149xx (quad/dual) features depletion mode EPAD

MOSFETs, which are normally-on devices when the gate bias voltage is at

zero volt. The depletion mode threshold voltage is at a negative voltage

level at which the EPAD MOSFET turns off. Without a supply voltage and/

or with Vg=0.0V the EP AD MOSFET device is already turned on and exhib-

its a defined and controlled on-resistance between the source and drain

terminals.

The ALD1148xx/ALD1149xx depletion mode EPAD MOSFETs are different

from most other types of depletion mode MOSFETs and certain types of

JFETs in that they do not exhibit high gate leakage currents and channel/

junction leakage currents. When negative signal voltages are applied to

the gate terminal, the designer/user can depend on the EPAD MOSFET

device to be controlled, modulated and turned off precisely. The device can

be modulated and turned-off under the control of the gate voltage in the

same manner as the enhancement mode EPAD MOSFET and the same

device equations apply.

EPAD MOSFETs are designed for exceptional device electrical character-

istics matching. As these devices are on the same monolithic chip, they

also exhibit excellent tempco tracking characteristics. Besides matched pair

electrical characteristics, each individual EP AD MOSFET also exhibits tightly

controlled parameters, enabling the user to depend on design limits. Even

units from different batches have well matched characteristics.

EPAD MOSFETs are ideal for minimum offset voltage and

differential thermal response, and they are used for switch-

ing and amplifying applications in low voltage (1V to 10V

or +/-0.5V to +/-5V) or ultra low voltage (less than 1V or +/

- 0.5V) systems. They feature low input bias current (less

than 30 pA max.), ultra low power (microWatt) or Nanopower

(power measured in nanoWatt) operation, low input capaci-

tance and fast switching speed. These devices can be used

where a combination of these characteristics are desired.

KEY APPLICATION ENVIRONMENT

EP AD( MOSFET Array products are for circuit applications

in one or more of the following operating environments:

* Low voltage: 1V to 10V or +/- 0.5V to +/- 5V

* Ultra low voltage: less than 1V or +/- 0.5V

* Low power: voltage x current = power measured in mi-

crowatt

* Nanopower: voltage x current = power measured in

nanowatt

* Precision matching and tracking of two or more of the

MOSFETs

QUAD

DUAL

ALD110800/ALD110900/ Advanced Linear Devices 2

ALD1108xx/ALD1109xx/ALD1148xx/ALD1149xx

ELECTRICAL CHARACTERISTICS

The turn-on and turn-off electrical characteristics of the EPAD

MOSFET products are shown in the Drain-Source On Current vs

Drain-Source On Voltage and Drain-Source On Current vs Gate-

Source Voltage graphs. Each graph show the Drain-Source On

Current versus Drain-Source On V oltage characteristics as a func-

tion of Gate-Source voltage in a different operating region under

different bias conditions. As the threshold voltage is tightly speci-

fied, the Drain-Source On Current at a given gate input voltage is

better controlled and more predictable when compared to many

other types of MOSFETs.

EPAD MOSFETs behave similarly to a standard MOSFET, there-

fore classic equations for a n-channel MOSFET applies to EPAD

MOSFET as well. The Drain current in the linear region (Vds < Vgs

- Vth ) is given by:

Id = u .Cox . W/L . [Vgs - Vgs(th) - Vds/2] . Vds

where u is the mobility

Cox is capacitance per unit area of Gate electrode

Vgs is the Gate to Source voltage

Vgs(th) is the turn-on threshold voltage

Vds is the Drain to Source voltage

W is the channel width and L is the channel length

In this region of operation the Ids value is proportional to Vds value

and the device can be used as gate-voltage controlled resistor.

For higher values of Vds where Vds >= Vgs-Vgs(th), the saturation

current Ids is now given by (approx.):

Ids = u.Cox.W/L . [Vgs-Vgs(th) ]2

SUB-THRESHOLD REGION OF OPERATION

Low voltage systems, namely those operating at 5V, 3.3V or less,

typically require MOSFETs that have threshold voltage of 1V or

less. The threshold, or turn-on, voltage of the MOSFET is a voltage

below which the MOSFET conduction channel rapidly turns of f. For

analog designs, this threshold voltage directly affects the operating

signal voltage range and the operating bias current levels.

At or below threshold voltage, an EPAD MOSFET exhibits a turn-

off characteristic in an operating region called the subthreshold re-

gion. This is when the EPAD MOSFET conduction channel rapidly

turns off as a function of decreasing applied gate voltage. The con-

duction channel induced by the gate voltage on the gate electrode

decreases exponentially and causes the drain current to decrease

exponentially. However, the conduction channel does not shut off

abruptly with decreasing gate voltage, but decreases at a fixed rate

of approximately 116 mV per decade of drain current decrease.

Thus if the threshold voltage is +0.20V, for example, the drain cur-

rent is at 1 uA at Vgs = +0.20V. At Vgs = +0.09V, the drain current

would decrease to 0.1 uA. Extrapolating from this, the drain current

is at 0.01 uA (10 nA) at Vgs = -0.03V, 1 nA at Vgs -0.14V, and so

forth. This subthreshold characteristics extends all the way down

to current levels below 1 nA and is limited by other currents such as

junction leakage currents.

At a drain current to be declared “zero current” by the user , the Vgs

voltage at that zero current can now be estimated. Note that using

the above example the drain current still hovers around 20 nA when

the gate is at zero volt, or ground.

LOW POWER AND NANOPOWER

When supply voltages decrease, the power consumption of a given

load resistor decreases as the square of the supply voltage. So

one of the benefits in reducing supply voltage is to reduce power

consumption. While decreasing power supply voltages and power

consumption go hand-in-hand with decreasing useful AC bandwidth

and at the same time increases noise effects in the circuit, a circuit

designer can make the necessary tradeoffs and adjustments in any

given circuit design and bias the circuit accordingly.

With EPAD MOSFETs, a circuit that performs a specific function

can be designed so that power consumption can be minimized. In

some cases, these circuits operate in low power mode where the

power consumed is measure in micro-watts. In other cases, power

dissipation can be reduced to nano-watt region and still provide a

useful and controlled circuit function operation.

ZERO TEMPERATURE COEFFICIENT (ZTC) OPERATION

For an EPAD MOSFET in this product family, there exist operating

points where the various factors that cause the current to increase

as a function of temperature balance out those that cause the cur-

rent to decrease, thereby canceling each other , and resulting in net

temperature coefficient of near zero. One of this temperature stable

operating point is obtained by a ZTC voltage bias condition, which

is 0.55V above a threshold voltage when Vgs = Vds, resulting in a

temperature stable current level of about 68 uA. For other ZTC

operating points, see ZTC characteristics.

PERFORMANCE CHARACTERISTICS

Performance characteristics of the EPAD MOSFET product family

are shown in the following graphs. In general, the threshold voltage

shift for each member of the product family causes other affected

electrical characteristics to shift with an equivalent linear shift in

Vgs(th) bias voltage. This linear shift in Vgs causes the subthresh-

old I-V curves to shift linearly as well. Accordingly , the subthreshold

operating current can be determined by calculating the gate volt-

age drop relative from its threshold voltage, Vgs(th).

RDS(ON) A T VGS=GROUND

Several of the EPAD MOSFETs produce a fixed resistance when

their gate is grounded. For ALD110800, the drain current at Vds =

0.1V is at 1uA at Vgs=0.0V. Thus just by grounding the gate of the

ALD1 10800, a resistor with Rds(on)=~100KOhm is produced. When

an ALD114804 gate is grounded, the drain current Ids=18.5 uA@

Vds=0.1V , producing Rds(on)=5.4KOhm. Similarly , ALD1 14813 and

ALD114835 produces 77 uA and 185 uA respectively at Vgs=0.0V,

producing Rds(on) values of 1.3 KOhm and 540 Ohm respectively .

MATCHING CHARACTERISTICS

A key benefit of using matched-pair EPAD MOSFET is to maintain

temperature tracking. In general, for EPAD MOSFET matched pair

devices, one device of the matched pair has gate leakage currents,

junction temperature effects, and drain current temperature coef fi-

cient as a function of bias voltage that cancel out similar effects of

the other device, resulting in a temperature stable circuit. As men-

tioned earlier , this temperature stability can be further enhanced by

biasing the matched-pairs at Zero Tempco (ZTC) point, even though

that could require special circuit configuration and power consump-

tion design consideration.

ALD110800/ALD110900/ Advanced Linear Devices 3

ALD1108xx/ALD1109xx/ALD1148xx/ALD1149xx

TYPICAL PERFORMANCE CHARACTERISTICS

1086420

DRAIN SOURCE ON CURRENT

(mA)

DRAIN-SOURCE ON VOLTAGE (V)

OUTPUT CHARACTERISTICS

TA = +25°C

VGS-VGS(TH)=+5V

VGS-VGS(TH)=+4V

VGS-VGS(TH)=+3V

VGS-VGS(TH)=+2V

VGS-VGS(TH)=+1V

DRAIN-SOURCE ON RESISTANCE 

vs. DRAIN-SOURCE ON CURRENT



DRAIN-SOURCE ON CURRENT (µA)

2500

2000

1000

1500

500

10 10000

100 1000

DRAIN-SOURCE ON RESISTANCE 

(Ω)

TA = 25°C

VGS = VGS(TH) +6V

VGS = VGS(TH) +4V

TRANSCONDUCTANCE vs.

AMBIENT TEMPERATURE



TRANSCONDUCTANCE 

(mA/V)

AMBIENT TEMPERATURE (°C)

-50 -25 025 50 12510075

2.5

2.0

1.5

1.0

0.5

SUBTHRESHOLD FORWARD TRANSFER

CHARACTERISTICS



GATE-SOURCE VOLTAGE (V)

-0.5 -0.4 -0.3 -0.2 -0.1

1000

100

0.1

0.01

DRAIN-SOURCE ON CURRENT

(nA)



GS(th)

=0.1V

Slope = 116mV/decode

FORWARD TRANSFER CHARACTERISTICS



DRAIN- SOURCE ON CURRENT

(mA )

GATE-SOURCE VOLTAGE (V)

-4 0

-2 246810

= 25°C

= +10V

VGS(TH) = -1.3V

VGS(TH) = -3.5V

VGS(TH) = +1.4V

VGS(TH) = -0.4V

VGS(TH) = 0.0V

VGS(TH) = +0.2V

VGS(TH) = +0.8V

SUBTHRESHOLD FORWARD TRANSFER 

CHARACTERISTICS



GATE-SOURCE VOLTAGE (V)

DRAIN-SOURCE ON CURRENT

(nA)



100000

10000

1000

100

0.1

0.01

-4 -3 -2 -1 0 1 2

VGS(TH)=-3.5V

VGS(TH)=-1.3V

TA = +25°C

VDS=+0.1V

VGS(TH)=0.0V

VGS(TH)=-0.4V

VGS(TH)=+1.4V

VGS(TH)=+0.2V VGS(TH)=+0.8V

ALD110800/ALD110900/ Advanced Linear Devices 4

ALD1108xx/ALD1109xx/ALD1148xx/ALD1149xx

TYPICAL PERFORMANCE CHARACTERISTICS

DRAIN SOURCE ON CURRENT vs.

OUTPUT VOLTAGE

DRAIN SOURCE ON CURRENT

(mA)

OUTPUT VOLTAGE (V)

VGS(TH) VGS(TH)+3

VGS(TH)+2 VGS(TH)+4

VGS(TH)+1 VGS(TH)+5

VDS = +5V

VDS = +1V

VDS = +10V

TA = 25°C

OFFSET VOLTAGE vs.

AMBIENT TEMPERATURE

AMBIENT TEMPERATURE (°C)

-50 -25 0 25 50 12510075

-1

-2

-3

-4

OFFSET VOLTAGE (mV)

REPRESENTATIVE UNITS

GATE LEAKAGE CURRENT 

vs. AMBIENT TEMPERATURE

GATE LEAKAGE CURRENT (pA)



-50 -25 025 50 12510075

500

400

300

200

600

100

AMBIENT TEMPERATURE (°C)

IGSS

DRAIN SOURCE ON CURRENT, BIAS 

CURRENT vs. AMBIENT TEMPERATURE

GATE AND DRAIN SOURCE VOLTAGE

(VGS = VDS) (V)





DRAIN SOURCE ON CURRENT

(mA)



70°C

125°C

-25°C

0°C

-55°C

VGS(TH) VGS(TH)+3VGS(TH)+2 VGS(TH)+4

VGS(TH)+1VGS(TH)-1

DRAIN-SOURCE ON CURRENT vs. ON RESISTANCE



ON RESISTANCE (KΩ)

DRAIN-SOURCE ON CURRENT

(µA)



100000

10000

1000

100

0.1

0.01 10000

0.1 101 100 1000

VDS=+0.1V

VDS=+1V

VDS=+5V

VDS=+10V

TA = 25°C

VGS=-4.0V to +5.4V

GATE SOURCE VOLTAGE 

vs. ON - RESISTANCE



0.1 110010 1000 10000

+25°C

GATE SOURCE VOLTAGE (V)

ON - RESISTANCE (KΩ)

+125°C

DS(ON)

0.0V ≤ V

≤ 5.0V

VGS(TH)

VGS(TH)+3

VGS(TH)+2

VGS(TH)+4

VGS(TH)+1

DRAIN SOURCE ON CURRENT, BIAS

CURRENT vs. AMBIENT TEMPERATURE

GATE AND DRAIN SOURCE VOLTAGE

(VGS = VDS) (V)

100

DRAIN SOURCE ON CURRENT

( µA)

Zero Temperature

Coefficient (ZTC)

- 25°C

125°C

+0.8

+0.4 +0.6+0.2

GS(TH)

+1.0

GS(TH)

+0.0 V

GS(TH)

GATE SOURCE VOLTAGE vs. DRAIN

SOURCE ON CURRENT

DRAIN SOURCE ON CURRENT (µA)

GATE SOURCE VOLTAGE (V)

0.1 110010 1000 10000

= 0.5V

= +125°C

= 0.5V

= +25°CV

= 5V

= +25°C

= 5V

= +125°C

= R

• I

DS(ON)

GS(TH)

-1

DS(ON)

ALD110800/ALD110900/ Advanced Linear Devices 5

ALD1108xx/ALD1109xx/ALD1148xx/ALD1149xx

TYPICAL PERFORMANCE CHARACTERISTICS

DRAIN - GATE DIODE CONNECTED VOLTAGE

TEMPCO vs. DRAIN SOURCE ON CURRENT



DRAIN- GATE DIODE CONNECTED 

VOLTAGE TEMPCO (mV/ °C )

DRAIN SOURCE ON CURRENT (µA)

1 10 100 1000

-55°C ≤ T

≤ +125°C

-5

-2.5

2.5

NORMALIZED SUBTHRESHOLD 

CHARACTERISTICS RELATIVE

GATE THRESHOLD VOLTAGE



DRAIN-SOURCE CURRENT (nA)

0.3

0.2

0.1

-0.1

-0.2

GATE-SOURCE VOLTAGE - THRESHOLD 

VOLTAGE (V)

VGS - VGS(th)



-0.3

-0.4

10000 1000 100 10 1 0.1

VD = 0.1V

55°C

25°C

TRANCONDUCTANCE vs. DRAIN-SOURCE



ON CURRENT

DRAIN -SOURCE ON CURRENT(mA)

TARNCONDUCTANCE

( mΩ-1)



246810



0.0



1.2

0.9

0.6

0.3

= 25°C

= +10V



0.5 1.0 2.0 5.0

0.2

0.1 DRAIN-SOURCE ON VOLTAGE (V)

ZERO TEMPERETURE COEFFICIENT CHARACTERISTIC

GATE-SOURCE VOLTAGE - THRESHOLD

VOLTAGE (V)



0.0

0.2

0.5

0.6

0.3

VGS(TH)=-3.5V

VGS(TH)=-1.3V, -0.4V, 0.0V, +0.2V, +0.8V, +1.4V

TRANSFER CHARACTERISTICS



GATE-SOURCE VOLTAGE (V)

-4 -2 0 2 4 8 106

1.6

1.2

0.8

0.4

TRANSCONDUCTANCE

( mΩ

-1

)



0.0

TA = 25°C

VDS = +10V

VGS(TH) = -3.5V

VGS(TH) = -0.4V

VGS(TH) = 0.0V

VGS(TH) = +0.2V

VGS(TH) = +0.8V

VGS(TH) = -1.3V

VGS(TH) = +1.4V

GATE-SOURCE VOLTAGE (V)



SUBTHRESHOLD CHARACTERISTICS 





DRAIN -SOURCE CURRENT (nA)

2.5

2.0

1.0

0.5

0.0

1.5

-0.5



100000 10000 1000 100 10 10.1

55°CV

GS(th)

= 0.2V



GS(th)

= 0.4V



25°C

THRESHOLD VOLTAGE

(V)

THRESHOLD VOLTAGES

vs. AMBIENT TEMPERATURES

AMBIENT TEMPERATURE (OC)

2.0

1.0

-1.0

-2.0

-3.0

0.0

-4.0

-25 25 75 125

IDS = +1µA

VDS = +0.1V

VGS(th) = -0.4V

VGS(th) = -1.3V

VGS(th) = -3.5V

VGS(th) = 0.0V

THRESHOLD VOLTAGE vs.

AMBIENT TEMPERATURE

4.0

3.0

2.0

THRESHOLD VOTAGE

(V)

AMBIENT TEMPERATURE (°C)

-50 -25 0 25 50 125

10075

1.0

= +0.1V

= 1.0

µA

= 0.8V

= 1.4V

= 0.4V

= 0.2V

= 0.0V