AD604AN-AD604AR-AD604ARS Fast Delivery |IC PHOENIX CO.,LIMITED

AD604AR ,Dual, Ultralow Noise Variable Gain Amplifierapplications; however ing the 2nd channel’s preamplifier. However, in multiple channelit will suppo ..
AD604AR ,Dual, Ultralow Noise Variable Gain AmplifierCHARACTERISTICSPreamplifierInput Resistance 300 kΩInput Capacitance 8.5 pFInput Bias Current –27 μA ..
AD604ARS ,Dual, Ultralow Noise Variable Gain AmplifierFEATURESFUNCTIONAL BLOCK DIAGRAMUltralow Input Noise at Maximum Gain:0.80 nV/√Hz, 3.0 pA/√Hz PAO –D ..
AD604ARZ-RL , Dual, Ultralow Noise Variable Gain Amplifier
AD605 ,Accurate, Low Noise, Dual Channel Linear-In-dB Variable Gain Amplifier, Optimized For Any Application Requiring High PerformanceCHARACTERISTICS–3 dB Bandwidth Constant with Gain 40 40 MHzSlew Rate VGN = 1.5 V, Output = 1 V Step ..
AD605AR ,Dual, Low Noise, Single-Supply Variable Gain AmplifierFEATURES FUNCTIONAL BLOCK DIAGRAMTwo Independent Linear-in-dB ChannelsInput Noise at Maximum Gain: ..
AD9883KST-110 ,110 MSPS Analog Interface for Flat Panel DisplaysSPECIFICATIONSAnalog Interface (V = 3.3 V, V = 3.3 V, ADC Clock = Maximum Conversion Rate)D DDTest ..
AD9884 ,Triple 8-Bit, 140 MSPS ADC, RGB Graphics Digitizer for SXGA LCD MonitorsSPECIFICATIONSTest AD9884AKS-100 AD9884AKS-140Parameter Temp Level Min Typ Max Min Typ Max UnitRESO ..
AD9884A ,100 MSPS/140 MSPS Analog Flat Panel InterfaceCHARACTERISTICSq –Junction-to-CaseJCThermal Resistance V 8.4 8.4

AD604AN-AD604AR-AD604ARS
Dual, Ultralow Noise Variable Gain Amplifier
REV.0Dual, Ultralow Noise
Variable Gain Amplifier
FEATURES
Ultralow Input Noise at Maximum Gain:
0.80 nV/√Hz, 3.0pA/√Hz
Two Independent Linear-in-dB Channels
Absolute Gain Range per Channel Programmable:dB to +48dB (Preamp Gain = +14dB), throughdB to +54dB (Preamp Gain = +20dB)
61.0dB Gain Accuracy
Bandwidth:40 MHz (–3dB)
300 kV Input Resistance
Variable Gain Scaling:20dB/V through 40dB/V
Stable Gain with Temperature and Supply Variations
Single-Ended Unipolar Gain Control
Power Shutdown at Lower End of Gain Control
Can Drive A/D Converters Directly
APPLICATIONS
Ultrasound and Sonar Time-Gain Control
High Performance AGC Systems
Signal Measurement
PRODUCT DESCRIPTION
The AD604 is an ultralow noise, very accurate, dual channel,
linear-in-dB variable gain amplifier (VGA) optimized for time-
based variable gain control in ultrasound applications; however
it will support any application requiring low noise, wide bandwidth
variable gain control. Each channel of the AD604 provides a
300 kΩ input resistance and unipolar gain control for ease of
use. User determined gain ranges, gain scaling (dB/V) and dc
level shifting of output further optimize application performance.
Each channel of the AD604 utilizes a high performance pre-
amplifier that provides an input referred noise voltage of
0.8nV/√Hz. The very accurate linear-in-dB response of the
AD604 is achieved with the differential input exponential amplifier
(DSX-AMP) architecture. Each of the DSX-AMPs comprise a
variable attenuator of 0dB to 48.36dB followed by a high speed
fixed gain amplifier. The attenuator is based on a seven stage
R-1.5R ladder network. The attenuation between tap points
is 6.908dB and 48.36dB for the ladder network.
Each independent channel of the AD604 provides a gain range
of 48dB which can be optimized for the application by program-
ming the preamplifier with a single external resistor in the
preamp feedback path. The linear-in-dB gain response of the
AD604 can be described by the equation:G (dB) = (Gain
Scaling (dB/V) × VGN (V)) + (Preamp Gain (dB) – 19 dB).
Preamplifier gains between 5 and 10 (+14dB and +20dB)
FUNCTIONAL BLOCK DIAGRAM
OUT
VOCM
PAO
PAI
+DSX–DSXVGN
VREF
provide overall gain ranges per channel of 0dB through +48dB
and +6dB through +54dB. The two channels of the AD604
can be cascaded to provide greater levels of gain range by bypass-
ing the 2nd channel’s preamplifier. However, in multiple channel
systems, cascading the AD604 with other devices in the AD60x
VGA family, which do not include a preamplifier may provide
a more efficient solution. The AD604 provides access to the
output of the preamplifier allowing for external filtering be-
tween the preamplifier and the differential attenuator stage.
The gain control interface provides an input resistance of
approximately 2 MΩ and scale factors from 20dB/V todB/V for a VREF input voltage of 2.5V to 1.67V respect-
ively. Note that scale factors up to 40dB/V are achievable
with reduced accuracy for scales above 30 dB/V. The gain scales
linear-in-dB with control voltages of 0.4V to 2.4V with thedB/V scale. Below and above this gain control range, the gain
begins to deviate from the ideal linear-in-dB control law. The
gain control region below 0.1V is not used for gain control. In
fact when the gain control voltage is <50mV the amplifier
channel is powered down to 1.9 mA.
The AD604 is available in a 24-pin plastic SSOP, SOIC and DIP,
and is guaranteed for operation over the –40°C to +85°C
temperature range.
AD604–SPECIFICATIONS
Distortion (IMD)
ACCURACY
(Each Amplifier Channel at TA = +258C, VS = 65V, RS = 50V, RL = 500V, CL = 5pF, VREF = 2.50V (Scaling = 20dB/V), 0dB to +48dB gain
range (preamplifier gain = +14dB), VOCM = 2.5 V, C1 and C2 = 0.1 mF (see Figure 35) unless otherwise noted)
AD604
POWER SUPPLY
ABSOLUTE MAXIMUM RATINGS
Supply Voltage ±VS
Pins 17, 18, 19, 20 (with Pins 16, 22 = 0 V) . . . . . . ±6.5 V
Input Voltages
Pins 1, 2, 11, 12 . . . . . . . . . . . . .VPOS/2 ±2 V Continuous
Pins 4, 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±2 V
Pins 5, 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . VPOS, VNEG
Pins 6, 7, 13, 14, 23, 24 . . . . . . . . . . . . . . . . . . . . VPOS, 0
Internal Power Dissipation
Plastic (N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.2 W
Small Outline (R) . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.7 W
Shrink Small Outline (RS) . . . . . . . . . . . . . . . . . . . . .1.1 W
Operating Temperature Range . . . . . . . . . . . –40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature, Soldering 60 seconds . . . . . . . . . +300°C
NOTESStresses above those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only and functional opera-
tion of the device at these or any other conditions above those indicated in the
operational section of this specification is not implied. Exposure to absolute maxi-
mum rating conditions for extended periods may affect device reliability.Pins 1, 2, 11, 12, 13, 14, 23, 24 are part of a single-supply circuit and the part will
most likely be damaged if any of these pins are accidentally connected to VN.When driven from an external low impedance source.
ORDERING GUIDE
*N = Plastic DIP, R = Small Outline IC (SOIC), RS = Shrink Small Outline
Package (SSOP).
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD604 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
AD604
PIN DESCRIPTIONS
PIN CONFIGURATION
–DSX1
+DSX1
PAI1
FBK1
PAO1
COM1
COM2
PAI2
FBK2
PAO2
+DSX2
–DSX2
VGN1
VREF
VPOS
GND1
OUT1
VNEG
VNEG
VPOS
GND2
OUT2
VOCM
VGN2
(Unless otherwise noted G (preamp) = +14 dB, VREF = 2.5 V (20 dB/V Scaling), f = 1 MHz, RL = 500V, CL = 5 pF, TA = +258C, VSS = 65V)
VGN – Volts
GAIN – dB
Figure 1.Gain vs. VGN
GAIN SCALING – dB/V
VREF – Volts
Figure 4.Gain Scaling vs. VREF
VGN – Volts
GAIN ERROR – dB
0.71.21.72.22.7
Figure 7.Gain Error vs. VGN for
Different Gain Scalings
VGN – Volts
GAIN – dB
Figure 2.Gain vs. VGN for Different
Preamp Gains
VGN – Volts
GAIN ERROR – dB
0.71.21.72.22.7
Figure 5.Gain Error vs. VGN at
Different Temperatures
DELTA GAIN – dB
PERCENTAGE
–0.8–0.6–0.4–0.20.10.30.50.70.9
Figure 8.Gain Match; VGN1 = VGN2 =
1.0 V
Figure 3.Gain vs. VGN for Different
Gain Scalings
Figure 6.Gain Error vs. VGN at
Different Frequencies
Figure 9.Gain Match: VGN1 = VGN2 =
2.50 V
AD604–Typical Performance Characteristics (per Channel)
(Unless otherwise noted G (preamp) = +14 dB, VREF = 2.5 V (20 dB/V Scaling), f = 1 MHz, RL = 500V, CL = 5 pF, TA = +258C, VSS = 65V)
FREQUENCY – Hz
GAIN – dB
–50100k1M10M100M
–40
Figure 10.AC Response
NOISE –
VGN – Volts
0.50.91.31.72.12.5
Figure 13.Input Referred Noise vs.
VGN
NOISE –
RSOURCE – Ω
1101k100
Figure 16.Input Referred Noise vs.
RSOURCE
Figure 12.Output Referred Noise vs.
VGN
Figure 15. Input Referred Noise vs.
Frequency
Figure 18.Noise Figure vs. VGN
VGN – Volts
OUT
– Volts
2.47
Figure 11.Output Offset vs. VN
NOISE –
TEMPERATURE – °C
–40–2020406090
Figure 14.Input Referred Noise vs.
Temperature
RIN
11010k1001k
4
Figure 17.Noise Figure vs. RSOURCE
VGN – Volts
HARMONIC DISTORTION – dBc
–75
Figure 20.Harmonic Distortion vs.
VGN
VGN – Volts
– dBm
2.52.9
Figure 23.1 dB Compression vs. VGN
100ns / DIV
40mV / DIV
253ns1.253µs
TRIG'D
Figure 26.Small Signal Pulse
Response
FREQUENCY – Hz
HARMONIC DISTORTION – dBc
100k
–6510M100M
Figure 19.Harmonic Distortion vs.
Frequency
FREQUENCY – MHz
OUT
– dBm
–20
Figure 22.Intermodulation Distortion
100ns / DIV
400mV / DIV
–2V
253ns1.253µs
Figure 25.Large Signal Pulse
Response
Figure 21.Harmonic Distortion vs.
RSOURCE
Figure 24.3rd Order Intercept vs.
VGN
Figure 27.Power-Up/Down Response
AD604
FREQUENCY – Hz
CROSSTALK – dB
100k1M100M10M
Figure 29.Crosstalk (CH1 to CH2) vs.
Frequency
TEMPERATURE – °C
INPUT BIAS CURRENT – µA
27.4
Figure 32.Input Bias Current vs.
Temperature
FREQUENCY – Hz
100k1M100M10M
DELAY – ns
Figure 34.Group Delay vs. Frequency
FREQUENCY – Hz
CMRR – dB
100k1M100M10M
Figure 30.DSX Common-Mode
Rejection vs. Frequency
Figure 33.Supply Current (One
Channel) vs. Temperature
2.9V
0.1V
VGN – Volts
Figure 28.Gain Response
FREQUENCY – Hz1M100M
100k
10k
10k100k
INPUT IMPEDANCE –
10M
Figure 31.Input Impedance vs.
Frequency
THEORY OF OPERATION
The AD604 is a dual channel, variable gain amplifier with an
ultralow noise preamplifier. Figure 35 shows the simplified
block diagram of one channel. Each channel consists of:
(1) a preamplifier with gain setting resistors R5, R6 and R7
(2) a single-supply X-AMP (hereafter called, DSX, Differential
Single-supply X-AMP) made up of:
(a)a precision passive attenuator (differential ladder)
(b)a gain control block
(c)a VOCM buffer with supply splitting resistors R3 and R4
(d)an Active Feedback Amplifier1 (AFA) with gain setting
resistors R1 and R2
The preamplifier is powered by a ±5 V supply, while the DSX
uses a single +5 V supply. The linear-in-dB gain response of the
AD604 can generally be described by Equation 1:
G (dB) = (Gain Scaling (dB/V)) × (Gain Control (V)) +
((Preamp Gain (dB)) – 19 dB)(1)
Each channel provides between 0 dB to +48.4 dB through +6 dB
to +54.4 dB of gain depending on the user determined pream-
plifier gain. The center 40 dB of gain is exactly linear-in-dB
while the gain error increases at the top and bottom of the
range. The gain of the preamplifier is typically either +14 dB or
+20dB, but can be set to intermediate values by a single exter-
nal resistor (see PREAMPLIFIER section for details). The gain
of the DSX can vary from –14dB to +34.4dB which is deter-
mined by the gain control voltage (VGN). The VREF input
establishes the gain scaling – the useful gain scaling range is
between 20 dB/V and 40 dB/V for a VREF voltage of 2.5 V and
1.25 V respectively. For example, if the preamp gain was set to
+14 dB and VREF was set to 2.50V (to establish a gain scaling
of 20dB/V), the gain equation would simplify to:
G (dB) = (20 (dB/V)) × (VGN (V)) – 5dB
The desired gain can then be achieved by setting the unipolar
gain control (VGN) to a voltage within its nominal operating
range of 0.25V to 2.65V (for 20dB/V gain scaling). The gain is
monotonic for a complete gain control voltage range of 0.1V to
2.9V. Maximum gain can be achieved at a VGN of 2.9 V.
Since the two channels are identical, only Channel 1 will be
used to describe their operation. VREF and VOCM are the only
inputs that are shared by the two channels, and since they are
normally ac grounds, crosstalk between the two channels is
minimized. For highest gain scaling accuracy, VREF should
have an external low impedance voltage source. For low accu-
racy 20 dB/V applications, the VREF input can be decoupled
with a capacitor to ground. In this mode the gain scaling will be
determined by the midpoint between +VCC and GND, so care
should be taken to control the supply voltage to +5 V. The in-
put resistance looking into the VREF pin is 10 kΩ ± 20%.
The DSX portion of the AD604 is a single-supply circuit and
the VOCM pin is used to establish the dc level of the midpoint
of this portion of the circuit. VOCM needs only an external
decoupling capacitor to ground to center the midpoint between
the supply voltages (+5 V, GND); however, if the dc level of the
output is important to the user (see APPLICATIONS section
for AD9050 example), then VOCM can be specifically set. The
input resistance looking into the VOCM pin is 45 kΩ ± 20%.
Preamplifier
The input capability of the following single-supply DSX (2.5 ±V for a +5 V supply) limits the maximum input voltage of the
preamplifier to ±400 mV for the 14 dB gain configuration or
±200 mV for the 20 dB gain configuration.
The preamplifier’s gain can be programmed to +14 dB or
+20dB; by either shorting the FBK1 node to PAO1 (+14 dB),
or leaving node FBK1 open (+20 dB). These two gain settings
are very accurate since they are set by the ratio of on-chip resis-
tors. Any intermediate gain can be achieved by connecting the
appropriate resistor value between PAO1 and FBK1 according
to Equations 2 and 3: =VOUTIN(R7iREXT)+R5+R6(2)
REXT=[R6×G−(R5+R6)]×R7−(R6×G)+(R5+R6)(3)
VREF
VGN
PAI
VOCM
OUTEXT.
Figure 35. Simplified Block Diagram of a Single Channel of the AD604
AD604
Since the internal resistors have an absolute tolerance of ±20%,
the gain can be in error by as much as 0.33 dB when REXT is
30 Ω, where it was assumed that REXT is exact.
Figure 36 shows how the preamplifier is set to gains of +14,
+17.5 and +20 dB. The gain range of a single channel of the
AD604 is 0 dB to +48 dB when the preamplifier is set to
+14dB (Figure 36a), 3.5 dB to +51.5 dB for a preamp gain of
+17.5 dB (Figure 36b), and 6 dB to 54 dB for the highest
preamp gain of +20 dB (Figure 36c).
FBK1
PAO1
COM1
PAI1
a. Preamp Gain = 14 dB
R10
40Ω
FBK1
COM1
PAI1
b. Preamp Gain = 17.5 dB
FBK1
PAO1
COM1
PAI1
c. Preamp Gain = 20 dB
Figure 36. Preamplifier Gain Programmability
For a preamplifier gain of +14 dB, the preamplifier’s –3 dB
small-signal bandwidth is 130 MHz; when the gain is at the high
end (+20 dB), the bandwidth will be reduced by a factor of two
to 65 MHz. Figure 37 shows the ac responses for the three preamp
gains discussed above; note that the gain for an REXT of 40Ω
should be 17.5 dB, but the mismatch between the internal resis-
tors and the external resistor has caused the actual gain for this
particular preamplifier to be 17.7 dB. The –3dB small-signal
bandwidth of one complete channel of the AD604 (preamplifier
and DSX) is 40MHz and is independent of gain.
GAIN
– dB
To achieve its optimum specifications, power and ground man-
agement are critical to the AD604. Large dynamic currents
result because of the low resistances needed for the desired
noise performance. Most of the difficulty is with the very low
gain setting resistors of the preamplifier that allow for a total
input referred noise, including the DSX, as low as 0.8 nV/√Hz.
The consequently large dynamic currents have to be carefully
handled to maintain performance even at large signal levels.
To accommodate these large dynamic currents as well as a
ground referenced input, the preamplifier is operated from a
dual ±5 V supply. This causes the preamplifiers output to also
be ground referenced, which requires a common-mode level
shift into the single-supply DSX. The two external coupling ca-
pacitors (C1, C2 in Figure 35) connected to nodes PAO1 and
+DSX, and –DSX and ground, respectively, perform this func-
tion (see AC Coupling Section). In addition, they eliminate any
offset that would otherwise be introduced by the preamplifier. It
should be noted that an offset of 1 mV at the input of the DSX
will get amplified by +34.4 dB (× 52.5) when the gain-control
voltage is at its maximum, this equates to 52.5 mV at the out-
put. AC coupling is consequently required to keep the offset
from degrading the output signal range.
The internal feedback resistors setting the gain of the preampli-
fier are so small (nominally 8 Ω and 32 Ω) that even an addi-
tional 1 Ω in the “ground” connection at pin COM1, which
serves as the input common-mode reference, will seriously
degrade gain accuracy and noise performance. This node is very
sensitive and careful attention is necessary to minimize the
ground impedance. All connections to node COM1 should be
as short as possible.
The preamplifier including the gain setting resistors has a noise
performance of 0.71nV/√Hz and 3 pA/√Hz. Note that a signifi-
cant portion of the total input referred voltage noise is due to
the feedback resistors. The equivalent noise resistance presented
by R5 and R6 in parallel is nominally 6.4 Ω, which contributes
0.33 nV/√Hz to the total input referred voltage noise. The larger
portion of the input referred voltage noise is coming from the
amplifier with 0.63 nV/√Hz. The current noise is independent of
gain and depends only on the bias current in the input stage of
the preamplifier—it is 3 pA/√Hz.
The preamplifier can drive 40 Ω (the nominal feedback resis-
tors) and the following175 Ω ladder load of the DSX with low
distortion. For example, at 10 MHz and ±1 V at the output, the
preamplifier has less than –45 dB of second and third harmonic
distortion when driven from a low (25 Ω) source resistance.
In some cases one may need more than 48 dB of gain range, in
which case two AD604 channels could be cascaded. Since the
preamplifier has limited input signal range, consumes over half
(120 mW) of the total power (220 mW), and its ultralow noise
is not necessary after the first AD604 channel, a shutdown
mechanism that disables only the preamplifier is built in. All
that is required to shut down the preamplifier is to tie the
COM1 and/or COM2 pin to the positive supply. The DSX will
be unaffected and can be used as before (see APPLICATIONS
section for further details).

Partno	Mfg	Dc	Qty	Available	Descript
AD604AN	AD	N/a	2	avai	Dual, Ultralow Noise Variable Gain Amplifier
AD604AR	AD	N/a	35	avai	Dual, Ultralow Noise Variable Gain Amplifier
AD604AR	ADI	N/a	2	avai	Dual, Ultralow Noise Variable Gain Amplifier
AD604ARS	AD	N/a	2	avai	Dual, Ultralow Noise Variable Gain Amplifier