2162Q16-U - THAT - Datasheet.Directory

EC-

EC+

SYM

OUT VCA1

INOUT VCA2

12345678

910111213141516

OUT 1

OUT 2

SY M 1 EC- 1 V EE E C+ 1 IN 1 GND

NCIN 2EC+ 2VCC

EC- 2SYM 2

Figure 1. THAT 2162 Block Diagram

FEATURES

• Two Independent Channels

• Wide Dynamic Range: >118 dB

• Wide Gain Range: >130 dB

• Exponential (dB) Gain Control

• Low Distortion: 0.05% typ.

• Wide Supply Voltage Range:

±2.25V ~ ±16V

• Low Supply Current: 5.2 mA typ. (±15V)

3 mA typ. (±5V)

• Dual Control Ports (pos/neg)

• Low Cost

• Small Package (16-pin QSOP)

APPLICATIONS

• Faders

• Panners

• Compressors & Limiters

• Gates & Expanders

• Mixers

• Equalizers

• Filters

• Oscillators

THAT 2162

16NC 15OUT 2 14SYM 2 13Ec- 2 12VCC

11Ec+ 2 10IN 2 9NC 8GND 7IN 1 6Ec+ 1 5VEE

4Ec- 1 3SYM 1 2OUT 1 1NC Pin NumberPin Name

Table 1. Pin Assignments

2162Q16-U16 pin QSOP Order NumberPackage

Table 2. Ordering Information

Dual Pre-trimmed Blackmer®

Voltage Controlled Amplifier

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; US

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

THAT 2162 contains two high-performance

Blackmer® voltage-controlled amplifiers (VCAs).

With two opposing-polarity, voltage-sensitive

control ports, they offer wide-range exponential

control of gain and attenuation with low signal

distortion. Both VCAs are trimmed at wafer stage

to deliver low distortion and control-voltage

feedthrough without further adjustment.

However, external symmetry adjustment is possi-

ble to further optimize distortion and control

feedthrough for critical applications.

The 2162 operates from a split power supply

up to ±16 Vdc, drawing only 5.2mA at ±15V and

3 mA at ±5V. The part can also operate at supply

voltages as low as ±2.25V, making it suitable for

battery-operated applications.

The two VCAs are independent of each other,

sharing only their power supply connections.

The 2162 is extremely flexible and capable of

being configured for a wide range of stereo or

multichannel applications. It is available in a

RoHS-compliant 16-pin QSOP package.

Descri

tion

Document 600087 Rev 02 Page 2

of 11 2162

Dual Pre-trimmed Blackmer®

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

Operating Temperature Range (TOP) -40 to +85 ºC

Junction Temperature (TJ) +125 ºC

Storage Temperature Range (TST) -40 to +125 ºC

Supply Voltages (VCC, VEE) ±18V

VCA Control Voltage ±0.6 V

Input or Output Voltage ±0.5 V

Absolute Maximum Ratings2

SPECIFICATIONS1

Parameter Symbol Conditions Min Typ Max Units

Positive Supply Voltage VCC Referenced to GND +2.25 —+16 V

Negative Supply Voltage VEE Referenced to GND -2.25 —-16 V

Supply Current No Signal

ICC VCC=+15V, VEE= -15V —5.2 7 mA

IEE VCC=+15V, VEE= -15V —-5.2 -7 mA

ICC VCC=+5V, VEE= -5V —3—mA

IEE VCC=+5V, VEE= -5V —-3 —mA

Equivalent Input Bias Current IB0 dB Gain —3—nA

Input Offset Voltage VOFF(IN) 0 dB Gain —-7 —mV

Output Offset Voltage Change4 Δ VOFF(OUT) ROUT = 20 kΩ

0 dB gain —± 1 ± 5 mV

+15 dB gain —± 3 ± 20 mV

Gain Cell Idling Current IIDLE 0 dB Gain 20 µA

Power Supply Rejection Ratio PSRR 0 dB Gain, Rin = Rout = 20 kΩ, 100 Hz

Positive supply, 100 Hz —80 —dB

Negative supply, 100 Hz —75 —dB

Max. I/O Signal Current iIN(VCA) + iOUT(VCA) VCC=+15V, VEE= -15V ± 1.5 mApeak

VCC=+5V, VEE= -5V ± 815 µApeak

VCA Gain Range -70 —+60 dB

Gain-Control Constant EC+/Gain (dB) -60 dB < gain < +60 dB

VCC = +15V, VEE = -15V —6.4 —mV/dB

VCC = +5V, VEE = -5V —6.1 —mV/dB

Gain-Control Tempco ΔEC/ΔTCHIP Ref TCHIP=27ºC —+0.33 —%/ºC

Gain Control Linearity -60 dB to +40 dB Gain —1—%

Off Isolation 1 kHz, Ec+ = -0.45 V, Ec- = +0.45 V —130 —dB

Output Noise eN(OUT) 22Hz~22kHz, RIN = ROUT = 20 kΩ

0 dB gain —-97.5 -95 dBV

+15 dB gain —-86 -84 dBV

Crosstalk 1 kHz, 0 dB Gain, Rin = Rout = 20 kΩ—110 — dB

Electrical Characteristics3

1All specifications are subject to change without notice.

2If the devices are subjected to stress above the Absolute Maximum Ratings, permanent damage may result. Sustained operation at or near the Absolute Maximum Ratings

conditions is not recommended. In particular, like all semiconductor devices, device reliability declines as operating temperature increases.

3Unless otherwise noted, TA=25ºC, VCC=+15V, VEE= -15V.

4Reference is to output offset with -40 dB VCA gain.

2162 Dual Pre-trimmed Blackme

® VC

Page 3

of 11 Document 600087 Rev 02

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; US

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

VCC

VEE

+CE 6

-CE 4

MYS 3

OUT

VCA1

THAT2162

20k0 R4

6k8 3

NJM4580

20k0

100p

NP0

22p

10u

100n

+15V

N/C

-15V

Out 1

In 1

Ec - 1

+CE 11

-CE 13

MYS 14

OUT

VCA2

THAT2162

20k0 R8

6k8 5

NJM4580

20k0

100p

NP0

22p

10u Ou t 2

In 2

Ec- 2

Figure 2. Typical Application Circuit

Parameter Symbol Conditions Min Typ Max Units

Total Harmonic Distortion THD VIN= 0dBV, 1kHz, EC+ = EC- = 0V —0.05 0.12 %

VIN= -5dBV, 1kHz, EC+ = 0V, EC- = -90mV —0.09 0.15 %

VIN= +10dBV, 1kHz, EC+ = 0V, EC- = 90mV —0.09 0.15 %

Slew Rate 0 dB Gain, Rin = Rout = 20 kΩ—6.5 —V/μs

Gain at 0V Control G0EC+ = EC- = 0V -1.0 0 +1.0 dB

Electrical Characteristics (con’t)3

+40dB

0dB

+20dB

-2

-1

100k20 100 1k 10k Hz

Figure 3. 2162 Frequency Response Vs. Gain

-120

-60

-110

-100

-90

-80

-70

+30-90 0-30-60

Gai

dBV

Figure 4. 2162 Noise (22 kHz NBW) Vs. Gain

The THAT 2162 VCA is designed for high

performance in audio-frequency applications requir-

ing exponential gain control, wide dynamic range,

low control-voltage feedthrough, and low cost. This

part controls gain by converting an input current

signal to a bipolar logged voltage, adding a dc control

voltage, and re-converting the summed voltage back

to a current through a bipolar antilog circuit.

Figure 5 presents a considerably simplified

internal circuit diagram of the IC. The ac input signal

current flows in pin 7 [10]1, the input pin. An inter-

nal operational transconductance amplifier (OTA)

works to maintain pin 7 [10] at a virtual ground

potential by driving the emitters of Q1 and (through

the Voltage Bias Generator) Q3. Q3/D3 and Q1/D1

act to log the input current, producing a voltage, V3,

which represents the bipolar logarithm of the input

current. The voltage at the junction of D1 and D2 is

the same as V3, but shifted by four forward Vbe

drops.

Gain Control

Since pin 2 [15], the output, is usually connected

to a virtual ground, Q2/D2 and Q4/D4 take the

bipolar antilog of V3, creating an output current

which is a precise replica of the input current. If pin

6 [11] (EC+) and pin 4 [13] (EC-) are held at ground,

the output current will equal the input current. For

pin 6 [11] positive or pin 4 [13] negative, the output

current will be scaled larger than the input current.

For pin 6 [11] negative or pin 4 [13] positive, the

output current is scaled smaller than the input.

The scale factor between the output and input

currents is the gain of the VCA. Either pin 6 [11]

(EC+) or pin 4 [13] (EC-), or both, may be used to

control gain. Gain is exponentially proportional to

the voltage at pin 6 [11], and exponentially

proportional to the negative of the voltage at pin 4

[13]. Therefore, pin 6 [11] (EC+) is the positive

control port, while pin 4 [13] (EC-) is the negative

control port. Because of the exponential characteris-

tic, the control voltage sets gain linearly in decibels.

Figure 6 shows the decibel current gain of a 2162

versus the voltage at EC+, while Figure 7 shows gain

versus EC-.

Temperature Effects

The logging and antilogging in the VCA depends

on the logarithmic relationship between voltage and

current in a semiconductor junction (in particular,

between a transistor's Vbe and Ic). As is well known,

this relationship is temperature dependent. There-

fore, the gain of any log-antilog VCA depends on its

temperature.

Document 600087 Rev 02 Page 4

of 11 2162

Dual Pre-trimmed Blackmer®

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

-100

-80

-60

-40

-20

+20

+40

-576 +256-512 -384 -256 -128 +0 +128 mVd

dBr

Figure 6. Gain Vs. Control Voltage (Ec+) @ 1 kHz

-100

-80

-60

-40

-20

+20

+40

-256 +576-128 0 +128 +256 +384 +512 mVd

dBr

Figure 7. Gain Vs. Control Voltage (Ec-) @ 1 kHz

Figure 8. Gain Vs. Control Voltage (Ec-) with Temp (ºC)

-50

-40

-30

-20

-10

-256 -192 -128 -64 0 64

+50

+25

128 192 256

mVdc

heory of Operation

Q4Q3

Icell

Iadj

3[14]

2[15]

4[13]

7[10]

6[11]

V+

IN OUT

SYM

Ec-

Ec+

30 30

V-

V+

Voltage

Bias

Generator

Iin

Figure 5. Simplified internal circuit

1Pin number references are for VCA1, with VCA2 shown in brackets.

Figure 8 shows the effect of temperature on the

negative control port. (The positive control port

behaves in the same manner.) Note that the gain at

EC = 0 V is 0 dB, regardless of temperature. Chang-

ing temperature changes the scale factor of the gain

by 0.33%/C, which pivots the curve about the 0 dB

point.

Mathematically, the 2162's gain characteristic is

, Eq. 1

Gain =EC+−EC−

(0.0064)(1+0.0033T)

where ΔT is the difference between room

temperature (25ºC) and the actual temperature, and

Gain is the gain in decibels. At room temperature,

this reduces to

, Eq. 2

Gain =EC+−EC−

0.0064

If only the positive control port is used, this

becomes

, Eq. 3

Gain =EC+

0.0064

If only the negative control port is used, this

becomes

. Eq. 4

Gain =−EC−

0.0064

DC Bias Currents

The 2162 current consumption is determined by

an internal bias generator (ICELL), which varies its

current based on the power supply voltage. At

VCC=-VEE=15V, ICELL is approximately 2.25 mA; at

VCC=-VEE=5V, ICELL is approximately 1.15 mA.

Another ~ 350 μA is used to bias each OTA. ICELL is

split in two parts: about 250 μA is necessary for the

bias generator, the rest is available for the sum of

input and output signal current.

Trimming

The VCA symmetry (actually, the combined VBE

offsets of the gain cell transistors) is trimmed for low

distortion and control-voltage feedthrough during

wafer probe. However, limited trim resolution and

shifts during IC packaging limit the ultimate

pre-trimmed performance of the finished part. In

general, the second harmonic distortion and offset

change with gain can be reduced via external

trimming, as shown in the circuit of Figure 14. Pin 3

[14] (SYM) allows this adjustment. The 2162

includes on-chip 30Ω resistors between the SYM pins

and their respective EC+ pins. The external trim

circuitry shown provides for up to ± 880 μV offset

across these pins. Symmetry should be trimmed for

2162 Dual Pre-trimmed Blackme

® VC

Page 5

of 11 Document 600087 Rev 02

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; US

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

0.001

0.01

0.1

%THD+N

0.5 5 101

Vin

rms

Figure 13. THD+Noise Vs. Input Level, -15 dB Gain

0.001

0.01

0.1

%THD+N

0.1 10.5 2

Vin

rms

Figure 12. THD+Noise Vs. Input Level, +15 dB Gain

0.001

0.01

0.1

%THD+N

0.5 101

Vin

rm s

Figure 11. THD+Noise Vs. Input Level, 0 dB Gain

-0.02

+0.02

-0.01

+0.01

+30

-90 0-30-60 d

Vdc

Figure 10. Offset Vs. Gain (Ec-)

-0.02

+0.02

-0.01

+0.01

-90 +30-60 -30 0 d

Vdc

Figure 9. Offset Vs. Gain (Ec+)

minimum THD with a modest level (e.

., ~1

Vrms),

middle-frequency (e.g., ~1 kHz) sine wave input.

The parameter that is being trimmed here (the

combined VBE offset of the gain cell transistors) is a

constant that varies depending on the specific IC

involved. It is substantially independent of power

supply voltage, though the setting will vary slightly

with power supply voltage. Note that the on-board

trim is set with ±15 V power supply rails. Typically,

the 1 kHz THD+N at 0 dB gain and 1 Vrms input will

vary by approximately 0.003% - 0.005% per 5

change in the supply voltage from ±15 V.

Most parts will require less than 600 μV of trim

adjustment. But, in the circuit of Figure 14, the avail-

able range of adjustment is directly proportional to

the power supply voltage. For best results, R1 should

be scaled proportional to the supply voltage.

If the external symmetry circuitry is omitted,

pins 3 and 14 should be left open, as shown in

Figure 2.

DC Feedthrough

Normally, a small dc error term flows in pin

2 [15] (the output). When the gain is changed, the dc

term changes. This control-voltage feedthrough

increases with gain. See Figures 9 and 10 for typical

curves for dc offset vs. gain. As noted above, dc

feedthrough is affected by the symmetry trim.

Audio Performance

The 2162 VCA design, fabrication and testing

ensure good audio performance when used as

recommended. In particular, the 2162 maintains low

distortion over a wide range of gain, cut and signal

levels. Figures 11 through 13 show typical distortion

performance for representative samples of the part.

Document 600087 Rev 02 Page 6

of 11 2162

Dual Pre-trimmed Blackmer®

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

7[10]

+CE 6[11]

-CE

4[13]

MYS 3[14]

2[15]

OUT

VCA

THAT2162

20k0 R4

6k8 3

NJM4580

20k0

100p

NP0

22p

10u

-15V

+15V

cw VR1

50k Symmetry

Trim

Out 1

In 1

Ec - 1

510k

Figure 14. External trimming circuit

Input

Input signals are currents in pin 7 [10] -- the

2162’s VCA IN pins. These pins are virtual grounds

with negative feedback provided internally. The

input resistor R3 (R7) in Figure 2 should be scaled to

convert the available ac input voltage to a current

within the linear range of the device. Generally, peak

input currents should be kept under 750 μA for best

distortion performance.

Refer to Figures 11 through 13 to see how

distortion typically varies with signal level for 0 dB,

+15 dB and -15 dB gain. The circuit of Figure 2,

Page 3 was used to generate these curves.

For a specific application, the acceptable distor-

tion will usually determine the maximum signal

current level which may be used. Note that, with

20 kΩ current-to-voltage converting resistors, distor-

tion remains low even at 10 V rms input at 0 dB or

-15 dB gain, and at 1.7 V rms input at +15 dB gain

(~10 V rms output).

AC Coupling

Pin 7 [10], the VCA IN pin will also have a small

dc offset away from ground. It is important to

prevent this dc offset from becoming a dc current in

the input, since any dc input currents will be

modulated by gain changes, thereby becoming

audible as thumps. To prevent the dc input offset

voltage and the previous stage’s dc output offset from

causing dc input currents, the input pins are

normally ac-coupled (C2, C7 in Figure 2). This blocks

such offset currents and reduces dc offset variation

with gain. Choose a capacitor which will give accept-

able low frequency performance for the application.

The mean offset voltage is slightly negative, so if a

polarized capacitor is used, it should be oriented

with the negative side toward the VCA input.

Summing Multiple Input Signals

Multiple signals may be summed via multiple

resistors, just as with an inverting opamp configura-

tion. In such a case, a single coupling capacitor may

be located next to pin 1 rather than multiple capaci-

tors at the driven ends of the summing resistors.

However, take care that the capacitor does not pick

up stray signals.

Stability

In order to guarantee stability at low gains, the

source impedance seen at the VCA IN terminal must

be less than 5 kΩ above approximately 250 kHz.

The R4-C4 and R8-C8 networks in Figure 2 ensure

this.

Output

The VCA output signal, at pin 2 (15), is also a

current, inverted with respect to the input current. In

normal operation, the output current is connected to

a virtual ground node, and converted to a voltage via

an external op-amp. The current-to-voltage conver-

sion ratio is determined by the feedback resistor, R2

[R6] in Figure 2 connected between the op-amp's

output and its inverting input. The resulting signal

path through the VCA plus op-amp is non-inverting.

R3 [R7] -- the input resistor -- determines the

voltage-to-current conversion at the input, and R2

(R6) -- the output resistor -- determines the current-

to-voltage conversion rate at the output. As a result,

the familiar ratio of Rf /Ri for an inverting opamp will

determine the overall voltage gain when the 2162 is

set for 0 dB current gain. Since the VCA performs

best at settings near unity gain, use the input and

feedback resistors to provide design-center gain or

loss, if necessary.

A small feedback capacitor around the output

opamp is needed to cancel the output capacitance of

the VCA. Without it, this capacitance will destabilize

most opamps. The capacitance at pin 2 [15] is

typically 3 pF The 22 pF capacitor shown at C1 (C6)

ensures stability.

Voltage Control

The VCA gain is controlled by the voltage applied

between pin 6 [11] -- EC+ and pin 4 [13] -- EC-. Note

that any unused control ports should be connected to

ground (as EC+ is in Figure 2). The gain (in decibels)

is proportional to (EC+ - EC-). The constant of propor-

tionality is 6.4 mV/dB for the voltage at EC+ (relative

to EC-). See Figure 6 through 8. Note that neither EC+

or EC- should be driven more than ±0.6 V away from

ground.

Positive and Negative

Note for Figures 9 and 10 that the EC- port yields

lower offset change at very low gains than the EC+

port. For best performance with large attenuations

both control ports can be utilized simultaneously

with differential drives.

Symmetry

As described more fully in the Theory section

under “Trimming”, Pin 3 [14] -- the SYM pin -- can be

used to improve the preprogrammed distortion

setting, allowing for finer resolution than available

on-chip, and for shifts that may occur during IC

packaging. The recommended additional trim

circuitry is shown in Figure 14. The wiper resistor

R1, shown as 510 kΩ, is recommended for the ±15V

supplies shown. For other power supply voltages,

scale R1 directly proportional to the supply voltage.

Adjust the Symmetry control for minimum THD

with a modest level (e.g., ~1 Vrms), low-frequency

(e.g., ~1 kHz) sine wave input. Since the SYM pins

are connected to internal bias generators, if an exter-

nal symmetry adjustment is omitted, leave the SYM

pins open.

2162 Dual Pre-trimmed Blackme

® VC

Page 7

of 11 Document 600087 Rev 02

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; US

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

Applications

Control Port Drive Impedance

The control ports are connected directly to the

bases of the logging and/or antilogging transistors.

The accuracy of the logging and antilogging is

dependent on the EC+ and EC- voltages being exactly

as desired to control gain. The base current in the

core transistors will follow the collector currents, of

course. Since the collector currents are

signal-related, the base currents are therefore also

signal-related. Should the source impedance of the

control voltage(s) be large, the signal-related base

currents will cause signal-related voltages to appear

at the control ports, which will interfere with precise

logging and antilogging, in turn causing distortion.

The 2162 VCAs are designed to be operated with

zero source impedance at pins 4 [13] and 6 [11], and

a high (> 100 kΩ) source impedance at pin 3 [14].

To realize all the performance designed into a 2162,

keep the source impedance of the control voltage

driver well under 50 Ω.

Noise Considerations

The VCA's noise performance varies with gain in

a predictable way (shown in Figure 4), but due to the

way internal bias currents vary with gain, noise at the

output is not strictly the product of a static input

noise times the voltage gain commanded. At large

attenuation, the noise floor is usually limited by the

input noise of the output op-amp and its feedback

resistor. At 0 dB gain, the noise floor of ~ -97.5 dBV

is the result of the VCA’s output noise current,

converted to a voltage by the typical 20 kΩ I-V

converter resistor (R2 [R6] in Figure 2). In the vicinity

of 0 dB gain, the noise increases more slowly than

the gain: approximately 7.5 dB noise increase for

every 10 dB gain increase. Finally, as gain

approaches 30 dB, output noise begins to increase

directly with gain.

Another factor that influences noise is that the

2162 VCAs act like multipliers: when no signal is

present at the signal input, noise at the control input

is rejected. So, when measuring noise (in the absence

of signal – as most everyone does), even very noisy

control circuitry often goes unnoticed. However,

noise at the control port of these parts will cause

noise modulation of the signal. This can become

significant if care is not taken to drive the control

ports with quiet signals.

The 2162 VCA has a small amount of inherent

noise modulation because of its class AB biasing

scheme, where the shot noise in the core transistors

reaches a minimum with no signal, and increases

with the square root of the instantaneous signal

current. However, in an optimum circuit, the noise

floor rises only to -93.5 dBV with a 50 μA rms signal

at unity gain — 4 dB of noise modulation. By

contrast, if a unity-gain connected, non-inverting

5534 opamp is used to directly drive the control

port, the noise floor will rise to 91.5 dBV — 6 dB of

noise modulation.

To avoid excessive noise, one must take care to

use quiet electronics throughout the control-voltage

circuitry. One useful technique is to process control

voltages at a multiple of the eventual control constant

(e.g., 64 mV/dB — ten times higher than the VCA

requires), and then attenuate the control signal just

before the final drive amplifier. With careful attention

to impedance levels, relatively noisy opamps may be

used for all but the final stage.

Stray Signal Pickup

It is also common practice among audio design-

ers to design circuit boards to minimize the pickup

of stray signals within the signal path. As with noise

in the control path, signal pickup in the control path

can adversely effect the performance of an otherwise

good VCA. Because it is a multiplier, the 2162

produces second harmonic distortion if the audio

signal itself is present at the control port. Only a

small voltage at the control port is required: as little

as 10 μV of signal can increase distortion by over

0.01%. This can frequently be seen at high frequen-

cies, where capacitive coupling between the signal

and control paths can cause stray signal pickup.

Because the signal levels involved are very small,

this problem can be difficult to diagnose. One clue to

the presence of this problem is that the symmetry

null for minimum THD varies with frequency. It is

often possible to counteract a small amount of pure

fundamental picked up in the control path by

"misadjusting" the symmetry setting. Since the

amount of pickup usually varies with frequency, the

optimum trim setting will vary with frequency and

level. A useful technique to confirm this problem is

to temporarily bypass the control port to ground via

a modest-sized capacitor (e.g., 10 μF). If the distor-

tion diminishes, signal pickup in the control path is

the likely cause.

Temperature Sensitivity

As shown by Equation 1 (Page 5), the gain of a

2162 VCA is sensitive to temperature in proportion

to the amount of gain or loss commanded. The

constant of proportionality is 0.33% of the decibel

gain commanded, per degree Celsius, referenced to

27°C (300°K). This means that at 0 dB gain, there is

no change in gain with temperature. However, at

-122 mV, the gain will be +20 dB at room tempera-

ture, but will be 20.66 dB at a temperature 10 °C

lower.

For most audio applications, this change with

temperature is of little consequence. However, if

necessary, it may be compensated by a resistor

embedded in the control voltage path whose value

varies with temperature at the same rate of 0.33%/°C.

Such parts are available from RCD Components, Inc,

Manchester, NH, USA [+1(603)669-0054],

[www.rcd-comp.com] and KOA/Speer Electronics,

Bradford, PA, 16701 USA [+1(814)362-5536],

[www.koaspeer.com].

Document 600087 Rev 02 Page 8

of 11 2162

Dual Pre-trimmed Blackmer®

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

Differences Between 2162 and 2180-series

VCAs

While the 2162's VCA circuitry is very similar to

that of the THAT 2180 Series VCAs, there are several

important differences, as follows.

1. As noted in the Theory section under “DC

Bias Currents,” supply current for the 2162 VCA

depends on the supply voltage. At ±5 V, approxi-

mately 850 μA is available for the sum of input and

output signal currents. This increases to about 1.8

mA at ±15 V. (Compare this to ~1.8 mA for a 2180

Series VCA when biased as recommended.)

2. The control-voltage constant is approximately

6.4 mV/dB when operating from ±15V supplies (it is

~6.1mV/dB in the 2180-series). This difference is

due primarily to the higher internal operating

temperature of the 2162 compared to that of the

2180 Series.

3. As noted in the Applications section under

“Stability,” the source impedance seen at the VCA

input must be less than 5 kΩ at frequencies above

250 kHz. In typical applications using a 20 kΩ input

resistor, this is accomplished via a series network

consisting of a 6.8 kΩ resistor and a 100 pF capaci-

tor to ground.

Closing Thoughts

THAT Corporation welcomes comments,

questions and suggestions regarding these devices,

their design and application. Our engineering staff

includes designers who have decades of experience in

applying our parts. Please feel free to contact us to

discuss your applications in detail.

2162 Dual Pre-trimmed Blackme

® VC

Page 9

of 11 Document 600087 Rev 02

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; US

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

The THAT 2162 is available in a 16-pin QSOP

package. The package dimensions are shown in

Figure 15 below, while the pinout is given in Table 1

on page 1.

The 2162 is available only in a lead-free, "green"

package. The lead frame is copper, plated with

successive layers of nickel palladium, and gold. This

approach makes it possible to solder these devices

using lead-free and lead-bearing solders. The plastic

mold compound, and the material in which the parts

are packaged, contains no hazardous substances as

specified in the RoHS directive. For more informa-

tion, including MDDS forms which disclose the

substances contained in our ICs and their packaging,

please visit: www.thatcorp.com/RoHShome.html.

The package has been qualified using reflow

temperatures as high as 250°C for 10 seconds. This

makes it suitable for use in a 100% tin solder

process. Furthermore, the 2162 has been qualified to

a JEDEC moisture sensitivity level of MSL1. No

special humidity precautions are required prior to

flow soldering the parts.

Document 600087 Rev 02 Page 10

of 11 2162

Dual Pre-trimmed Blackmer®

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

Package and Soldering Information

0-8º

ITEM MILLIMETERS INCHES

A 4.80 - 4.98 0.189 - 0.196

B3.81 - 3.99 0.150 - 0.157

C5.79 - 6.20 0.228 - 0.244

D0.20 - 0.30 0.008 - 0.012

E0.635 BSC 0.025 BSC

G1.35 - 1.75 0.0532 - 0.0688

H0.10 - 0.25 0.004 - 0.010

I0.40 - 1.27 0.016 - 0.050

J0.19 - 0.25 0.0075 - 0.0098

Figure 15. QSOP-16 surface mount package

Parameter Symbol Conditions Min Typ Max Units

Package Style See Fig. 15 for dimensions 16 Pin QSOP

Thermal Resistance θJA SO package soldered to board 150 ºC/W

Environmental Regulation Compliance Complies with RoHS requirements

Soldering Reflow Profile JEDEC JESD22-A113-D (250 ºC)

Package Characteristics

2162 Dual Pre-trimmed Blackme

® VC

Page 11

of 11 Document 600087 Rev 02

THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; US

Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com

Revision Histor

-Added footnote 1 “All specifications are subject to change without notice

”

and renumbered existing footnotes sequentially.

-Added Revision History table.

Oct. 201002

2-Changed THD spec as follows:

Under Vin = 0 dBV, Changed Typ. from 0.04 to 0.05 and Max. from

0.09 to 0.12

Under Vin = -5 dBV, Changed Typ. from 0.075 to 0.09 and Max. from

0.1 to 0.15

Under Vin = +10 dBV, Changed Typ. from 0.075 to 0.09 and Max. from

0.1 to 0.15

Jun. 201001

ReleaseSept. 200800

PageChangesDateRevision