ADVANCED LINEAR DEVICES, INC. e TM EPAD EN (R) AB LE D ALD110800/ALD110900/ ALD1108XX/ALD1109XX/ALD1148XX/ALD1149XX PERFORMANCE CHARACTERISTICS OF EPAD(R) 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(R) CMOS technology. These devices are intended for low voltage, small signal 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 second category is the ALD1108xx/ALD1109xx enhancement mode EPAD MOSFETs. The third category is the ALD1148xx/ALD1149xx 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 threshold 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 circuits. 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 EPAD MOSFET device is already turned on and exhibits 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 characteristics matching. As these devices are on the same monolithic chip, they also exhibit excellent tempco tracking characteristics. Besides matched pair electrical characteristics, each individual EPAD 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 switching 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 capacitance and fast switching speed. These devices can be used where a combination of these characteristics are desired. KEY APPLICATION ENVIRONMENT EPAD( 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 microwatt * Nanopower: voltage x current = power measured in nanowatt * Precision matching and tracking of two or more of the MOSFETs QUAD N/C* 1 GN1 2 DN1 V- V- M1 3 S12 4 V- 5 DN4 6 GN4 7 N/C* 8 M2 V+ VM4 M3 16 N/C* 15 GN2 14 DN2 13 V+ 12 S34 11 DN3 10 GN3 9 N/C* V- VPC, SC PACKAGES DUAL N/C* 1 GN1 2 DN1 3 S12 4 V- V- M1 M2 V- 8 N/C* 7 GN2 6 DN2 5 V- PA, SA PACKAGES *N/C pins are internally connected. Connect to V- to reduce noise (c)2005 Advanced Linear Devices, Inc. 415 Tasman Drive, Sunnyvale, California 94089-1706 Tel: (408) 747-1155 Fax: (4080 747-1286 www.aldinc.com ELECTRICAL CHARACTERISTICS LOW POWER AND NANOPOWER 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 GateSource Voltage graphs. Each graph show the Drain-Source On Current versus Drain-Source On Voltage characteristics as a function of Gate-Source voltage in a different operating region under different bias conditions. As the threshold voltage is tightly specified, 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. 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. EPAD MOSFETs behave similarly to a standard MOSFET, therefore 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: 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. Id = u .Cox . W/L . [Vgs - Vgs(th) - Vds/2] . Vds ZERO TEMPERATURE COEFFICIENT (ZTC) OPERATION where 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 current 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. 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. PERFORMANCE CHARACTERISTICS 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 off. 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 turnoff characteristic in an operating region called the subthreshold region. This is when the EPAD MOSFET conduction channel rapidly turns off as a function of decreasing applied gate voltage. The conduction 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 current 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. ALD110800/ALD110900/ ALD1108xx/ALD1109xx/ALD1148xx/ALD1149xx 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 subthreshold I-V curves to shift linearly as well. Accordingly, the subthreshold operating current can be determined by calculating the gate voltage drop relative from its threshold voltage, Vgs(th). RDS(ON) AT 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 ALD110800, 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, ALD114813 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 coefficient as a function of bias voltage that cancel out similar effects of the other device, resulting in a temperature stable circuit. As mentioned 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 consumption design consideration. Advanced Linear Devices 2 TYPICAL PERFORMANCE CHARACTERISTICS DRAIN-SOURCE ON RESISTANCE vs. DRAIN-SOURCE ON CURRENT OUTPUT CHARACTERISTICS DRAIN SOURCE ON CURRENT (mA) TA = +25C VGS-VGS(TH)=+5V 4 VGS-VGS(TH)=+4V 3 VGS-VGS(TH)=+3V 2 VGS-VGS(TH)=+2V 1 VGS-VGS(TH)=+1V 0 0 2 4 6 8 DRAIN-SOURCE ON RESISTANCE () 2500 5 TA = 25C 2000 1500 VGS = VGS(TH) +4V 1000 500 VGS = VGS(TH) +6V 0 100 10 10 DRAIN-SOURCE ON CURRENT (A) DRAIN-SOURCE ON VOLTAGE (V) TRANSCONDUCTANCE vs. AMBIENT TEMPERATURE 20 15 2.5 VGS(TH) = -3.5V TRANSCONDUCTANCE (mA/V) DRAIN- SOURCE ON CURRENT (mA ) FORWARD TRANSFER CHARACTERISTICS TA = 25C VDS = +10V VGS(TH) = -1.3V VGS(TH) = -0.4V 10 VGS(TH) = 0.0V VGS(TH) = +0.2V 5 VGS(TH) = +1.4V VGS(TH) = +0.8V 0 -4 0 -2 2 4 6 2.0 1.5 1.0 0.5 0 10 8 -50 -25 GATE-SOURCE VOLTAGE (V) VGS(TH)=-1.3V 100 10 VGS(TH)=+1.4V 1000 1 0.1 VGS(TH)=-3.5V VGS(TH)=+0.8V VGS(TH)=+0.2V 0.01 -4 -3 -2 -1 0 25 50 75 100 125 1 GATE-SOURCE VOLTAGE (V) ALD110800/ALD110900/ ALD1108xx/ALD1109xx/ALD1148xx/ALD1149xx SUBTHRESHOLD FORWARD TRANSFER CHARACTERISTICS DRAIN-SOURCE ON CURRENT (nA) VGS(TH)=0.0V TA = +25C VDS=+0.1V VGS(TH)=-0.4V DRAIN-SOURCE ON CURRENT (nA) 10000 0 AMBIENT TEMPERATURE (C) SUBTHRESHOLD FORWARD TRANSFER CHARACTERISTICS 100000 10000 1000 2 VDS=0.1V Slope ~= 116mV/decode 1000 100 10 1 0.1 0.01 VGS(th) -0.5 VGS(th) -0.4 VGS(th) -0.3 VGS(th) -0.2 VGS(th) -0.1 VGS(th) GATE-SOURCE VOLTAGE (V) Advanced Linear Devices 3 TYPICAL PERFORMANCE CHARACTERISTICS DRAIN SOURCE ON CURRENT, BIAS CURRENT vs. AMBIENT TEMPERATURE 100 5 DRAIN SOURCE ON CURRENT ( A) DRAIN SOURCE ON CURRENT (mA) DRAIN SOURCE ON CURRENT, BIAS CURRENT vs. AMBIENT TEMPERATURE -55C 4 -25C 3 0C 2 1 70C 0 VGS(TH)-1 125C Zero Temperature Coefficient (ZTC) 125C 50 - 25C 0 VGS(TH)+1 VGS(TH)+2 VGS(TH)+3 VGS(TH)+4 VGS(TH) GATE AND DRAIN SOURCE VOLTAGE (VGS = VDS) (V) VGS(TH) VGS(TH) VGS(TH) VGS(TH) VGS(TH) +0.0 +0.4 +0.2 +0.6 +0.8 GATE AND DRAIN SOURCE VOLTAGE (VGS = VDS) (V) VGS(TH)+4 VDS=+10V GATE SOURCE VOLTAGE (V) DRAIN-SOURCE ON CURRENT (A) 10000 TA = 25C VGS=-4.0V to +5.4V 1000 100 10 1 VDS=+5V VDS=+0.1V VDS=+1V 0.1 VDS D VGS(TH)+3 IDS(ON) VGS 1 10 100 1000 S VDS = 0.5V TA = +25C VGS(TH)+1 VDS = 5V VDS = RON * IDS(ON) TA = +125C 1 0.1 10000 10 100 1000 10000 DRAIN SOURCE ON CURRENT (A) OFFSET VOLTAGE vs. AMBIENT TEMPERATURE DRAIN SOURCE ON CURRENT vs. OUTPUT VOLTAGE 4 5 TA = 25C 3 4 OFFSET VOLTAGE (mV) DRAIN SOURCE ON CURRENT (mA) VDS = 5V TA = +25C VGS(TH) ON RESISTANCE (K) VDS = +10V 3 VDS = +5V 2 1 VDS = +1V 0 REPRESENTATIVE UNITS 2 1 0 -1 -2 -3 -4 VGS(TH) -50 VGS(TH)+1 VGS(TH)+2 VGS(TH)+3 VGS(TH)+4 VGS(TH)+5 -25 0 25 50 75 100 125 AMBIENT TEMPERATURE (C) OUTPUT VOLTAGE (V) GATE SOURCE VOLTAGE vs. ON - RESISTANCE GATE LEAKAGE CURRENT vs. AMBIENT TEMPERATURE VGS(TH)+4 600 GATE SOURCE VOLTAGE (V) GATE LEAKAGE CURRENT (pA) VDS = 0.5V TA = +125C VGS(TH)+2 VGS(TH)-1 0.01 0.1 +1.0 GATE SOURCE VOLTAGE vs. DRAIN SOURCE ON CURRENT DRAIN-SOURCE ON CURRENT vs. ON RESISTANCE 100000 VGS(TH) 500 400 300 200 IGSS 100 0 -50 -25 0 25 50 75 100 125 D VGS(TH)+3 +125C VGS IDS(ON) S 0.0V VDS 5.0V VGS(TH)+2 +25C VGS(TH)+1 VGS(TH) 0.1 1 10 100 1000 10000 ON - RESISTANCE (K) AMBIENT TEMPERATURE (C) ALD110800/ALD110900/ ALD1108xx/ALD1109xx/ALD1148xx/ALD1149xx VDS Advanced Linear Devices 4 TYPICAL PERFORMANCE CHARACTERISTICS TRANSFER CHARACTERISTICS DRAIN - GATE DIODE CONNECTED VOLTAGE TEMPCO vs. DRAIN SOURCE ON CURRENT 1.6 DRAIN- GATE DIODE CONNECTED VOLTAGE TEMPCO (mV/ C ) 5 TRANSCONDUCTANCE ( m-1) -55C TA +125C 2.5 0 -2.5 TA = 25C VDS = +10V VGS(TH) = -3.5V 1.2 VGS(TH) = -1.3V VGS(TH) = -0.4V VGS(TH) = 0.0V 0.8 VGS(TH) = +0.2V 0.4 VGS(TH) = +1.4V VGS(TH) = +0.8V 0.0 -5 1 10 100 1000 -4 -2 0 6 8 10 2.5 0.6 VGS(TH)=-3.5V 0.5 VGS(TH)=-1.3V, -0.4V, 0.0V, +0.2V, +0.8V, +1.4V 0.3 0.2 0.0 0.1 0.2 2.0 0.5 1.0 DRAIN-SOURCE ON VOLTAGE (V) 2.0 1.5 1.0 25C 0.5 VGS(th) = 0.4V 0.0 55C -0.5 100000 10000 5.0 VGS(th) = 0.2V 1000 100 1 10 0.1 DRAIN -SOURCE CURRENT (nA) THRESHOLD VOLTAGE vs. AMBIENT TEMPERATURE TRANCONDUCTANCE vs. DRAIN-SOURCE ON CURRENT 1.2 4.0 TA = 25C VDS = +10V VDS = +0.1V ID = 1.0A THRESHOLD VOTAGE (V) TARNCONDUCTANCE ( m-1) 4 SUBTHRESHOLD CHARACTERISTICS GATE-SOURCE VOLTAGE (V) GATE-SOURCE VOLTAGE - THRESHOLD VOLTAGE (V) ZERO TEMPERETURE COEFFICIENT CHARACTERISTIC 0.9 0.6 0.3 0.0 3.0 2.0 Vt = 1.4V 1.0 Vt = 0.0V Vt = 0.8V Vt = 0.2V Vt = 0.4V 0 0 2 4 8 6 10 -50 -25 0 25 50 75 NORMALIZED SUBTHRESHOLD CHARACTERISTICS RELATIVE GATE THRESHOLD VOLTAGE 2.0 IDS = +1A VDS = +0.1V VD = 0.1V THRESHOLD VOLTAGE (V) 0.2 0.1 0 25C -0.2 -0.3 -0.4 10000 55C 1.0 VGS(th) = 0.0V 0.0 VGS(th) = -0.4V -1.0 VGS(th) = -1.3V -2.0 -3.0 VGS(th) = -3.5V -4.0 1000 100 10 1 0.1 -25 DRAIN-SOURCE CURRENT (nA) ALD110800/ALD110900/ ALD1108xx/ALD1109xx/ALD1148xx/ALD1149xx 125 THRESHOLD VOLTAGES vs. AMBIENT TEMPERATURES 0.3 -0.1 100 AMBIENT TEMPERATURE (C) DRAIN -SOURCE ON CURRENT(mA) GATE-SOURCE VOLTAGE - THRESHOLD VOLTAGE (V) VGS - VGS(th) 2 GATE-SOURCE VOLTAGE (V) DRAIN SOURCE ON CURRENT (A) 25 75 125 AMBIENT TEMPERATURE (OC) Advanced Linear Devices 5