STMICROELECTRONICS TS636I

TS636
DIFFERENTIAL VARIABLE GAIN AMPLIFIER
FOR ADSL LINE INTERFACE
■
■
■
■
LOW NOISE : 4.7nV/√Hz
LOW DISTORTION
HIGH SLEW RATE : 90V/µs
WIDE BANDWIDTH : 52MHz @ -3dB &
18dB gain
■ GAIN PROGRAMMABLE from -9dB to +30dB
with 3dB STEPS
■ POWER DOWN FUNCTION
D
SO14
(Plastic Micropackage)
DESCRIPTION
This TS636 is particularly intended for applications such as preamplification in telecommunication systems using multiple carriers. It has been
minly designed to fit with ADSL chip-sets such as
ASCOT ADSL chip-set for CPE.
PIN CONNECTIONS (top view)
The TS636 is a differential digitally controled variable gain amplifier featuring a high slew rate of
90V/µs, a large bandwidth, a very low distortion
and a very low current and voltage noise.
The gain can be set from -9dB to +30dB through a
4bit digital word, with 3dB steps.
+Vcc1 1
14 +Vcc2
Input 1 2
13 Output 1
Input 2 3
12 Output 2
The gain monotonicity is guaranteed by design.
APPLICATION
LSB GC1
■ Preamplifier with automatic gain control for
Asymmetric Digital Subscriber Line (ADSL).
5
GC3 6
ORDER CODE
Package
Part Number
GC2
4
Temperature Range
MSB GC4
7
11 Power Down
Gain Control
Logic Decoder
The TS636 comes in SO-14 plastic packages.
10 -Vcc
9 AGND
8 DGND
D
TS636I
-40, +85°C
•
D = Small Outline Package (SO) - also available in Tape & Reel (DT)
January 2001
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TS636
ABSOLUTE MAXIMUM RATINGS
Symbol
VCC
Vi
Parameter
Supply voltage
1)
2)
Value
Unit
14
V
0 to 14
V
Toper
Operating Free Air Temperature Range TS636ID
-40 to + 85
°C
Tstd
Storage Temperature
-65 to +150
°C
150
°C
Tj
Input Voltage
Maximum Junction Temperature
Rthjc
Thermal Resistance Junction to Case
22
°C/W
Rthja
Thermal Resistance Junction to Ambiante Area
125
°C/W
Output Short Circuit Duration
Infinite
1. All voltages values are with respect to network terminal.
2. The magnitude of input and output voltages must never exceed VCC +0.3V.
OPERATING CONDITIONS
Symbol
Parameter
Value
VCC
Supply Voltage
5 to 12
V
Vicm
Common Mode Input Voltage
VCC/2
V
APPLICATION: ADSL LINE INTERFACE
ASCOT ADSL
CHIP-SET
TX
emission LP filter
(analog
signal)
ST70135
upstream
TS634 or TS635
Line Driver
ST70134
HYBRID
Power Down
CIRCUIT
twisted-pair
telephone
line
RX
reception
(analog signal)
4-bit Gain Control
2/9
Unit
VGA
downstream
TS636
Receiver
TS636
ELECTRICAL CHARACTERISTICS. VCC = ±6Volts, Tamb = 25°C (unless otherwise specified).
Symbol
Parameter
Test Condition
Min.
Typ.
Max
Unit
DC PERFORMANCE
Iib
ICC
∆VOFFSET
SVR
Input Bias Current (AGND pin)
Total Supply Current
Differential Input Offset Voltage
Supply Voltage Rejection Ratio
No load, Vout = 0
Vin = 0, AV = 30dB
AV = 0dB
8
28
6
50
80
100kΩ
150kΩ//5pF
µA
mA
mV
dB
POWER DOWN MODE
Iccpdw
Zout
Power Down Total Consumption Power Down Mode
Power Down Output Impedance Power Down Mode
150
µA
AC PERFORMANCE
Zin
VOH
VOL
AV
PAV
Avstep
Avmis
Bw
Rbw
Io
SR
Input Impedance
High Level Output Voltage
RL = 500Ω
RL connected to GND
Low Level Output Voltage
RL = 500Ω
RL connected to GND
Voltage Gain
F= 1MHz
Gain monotonicity guaranteed by design
Precision of the Voltage Gain
F= 1MHz
Step Value
F= 1MHz
Gain Mismatch between Both
F= 1MHz
Channels
AV = -9dB
Bandwidth @ -3dB
RL = 500Ω, CL = 15pF
AV = +30dB
AV = +30dB, F = 1MHz
Bandwidth Roll-off
|Source|
Bandwidth @ -3dB
RL = 500Ω, CL = 15pF
Sink
Vo = 2Vpeak
Slew Rate (gain independent)
100kΩ//5pF
4
4.5
-4.5
-9
-1.4
2.4
45
9
17
17
40
3
V
-4
V
30
dB
1.4
3.6
dB
dB
1
dB
100
17
0.08
28
22
90
MHz
MHz
dB
V/µs
1.6
pA/√Hz
4.7
nV/√Hz
mA
NOISE AND DISTORTION
in
Equivalent Input Noise Current
en
Equivalent Input Noise Voltage
THD30
Harmonic Distorsion
IM3_1
Third Order Intermodulation
Product
F1 = 180kHz, F2 = 280kHz
IM3_2
Third Order Intermodulation
Product
F1 = 70kHz, F2 = 80kHz
F = 100kHz
F = 100kHz
AV = 30dB
1Vpeak, F = 150kHz,
AV = +30dB, RL = 500Ω//15pF
H2
H3
H4
H5
Vout = 1Vpeak, AV = +30dB
RL = 500Ω//15pF
@ 80kHz
@ 380kHz
@640kHz
@740kHz
Vout = 1Vpeak, AV = +30dB
RL = 500Ω//15pF
@ 60kHz
@ 90kHz
@220kHz
@230kHz
-70
-93
-98
-99
-77
-85
-86
-87
-77
-79
-83
-84
dBc
dBc
dBc
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TS636
DIGITAL INPUTS
Pin
GC1, GC2, GC3
and GC4
Power Down
Parameter
Min.
Typ.
Max.
0
0.8
Low Level
High Level
2
3.3
0
Thershold Voltage for Power
Down Mode (high level active)
2
0.8
3.3
Unit
V
V
SIMPLIFIED SCHEMATIC
The TS636 consists of two independent channels.
Each channel has two stages. The first is a very low noise digitally controlled variable gain amplifier (range
0 to 18dB).
The TS636 features a high input impedance and a low noise current. To minimize the overall noise figure,
the source impedance must be less than 3kΩ.
This value gives an equal contribution of voltage and current noises.
The second stage is a gain/attenuation stage (+12dB to -9dB) featuring a low output impedance.
This output stage can drive loads as low as 500Ω.
v
Input1
_
+
Ouput1
_
+
+Vcc1
-Vcc
v
Analog GND
(AGND)
v
+
+
Ouput2
_
_
Input2
+Vcc2
vv
GC1
GC2
GC3
GC4
GAIN CONTROL
LOGIC DECODER
Power
Down
Digital GND
(DGND)
POWER DOWN MODE POSITION
+Vcc
+Vcc
Power Down
Input
Output
-Vcc
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-Vcc
TS636
BANDWIDTH
The small signal bandwidth is almost constant for gains between +18dB to 0dB and is in the order of
52MHz to 70MHz respectively. For 30dB gain the bandwidth is around 18MHz.
The power bandwidth is typically equal to 30MHz for 2V peak to peak signals.
MAXIMUM INPUT LEVEL
The input level must not exceed the following values :
negative peak value: must be greater than -VCC + 1.5V
positive peak value: must be less than +V CC - 1.5V
For example, if a ±6V power supply is used, the input signal can swing between -4.5V and +4.5V.
These values are due to common mode input range limitations of the input stage of the first amplifier.
Some other limitations may occur, due to the slew rate of the first operational amplifier (typically in the order of 300V/µs). This means that the maximum input signal decreases at high frequency.
SINGLE SUPPLY OPERATION
The incoming signal is AC coupled to the inputs.
The TS636 can be used either with a dual or a single supply. If a single supply is used, the inputs are biased to the mid supply voltage (+VCC/2). This bias network must be carefully designed, in order to reject
any noise present on the supply rail.
The AGND pin (9) must be connected to +VCC/2. The bias current of the second stage (inverting structure)
is 8µA for both amplifiers. A resistor divider structure can be used. Two resistances should be chosen by
considering 8µA as the 1% of the total current through these resistances. For a single +12V supply voltage, two resistances of 7.5kΩ can be used. The differential input consists of a high pass circuit, formed by
the 1µF capacitor and a 1kΩ resistance and gives a break frequency of 160Hz.
SINGLE +12V SUPPLY OF THE TS636
10nF
1µF
100nF
TS636
IN+
12V
+Vcc1 1
14 +Vcc2
1k
47k
Input 1
13 Output 1
1k
47k
2
Input 2 3
1µF
GC2 5
INGC3 6
1µF
GC4 7
10nF
100nF
10µF
Output 2
11 Power Down
GC1 4
Gain Control
Logic Decoder
10nF
12
12V
12V
10 -Vcc
7.5k
9
AGND
8 DGND
10nF
7.5k
1µF
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TS636
GAIN CONTROL
The gain and the power down mode is programmed with a 4 bit digital word :
Digital
Control
Total Gain
(dB)
First Stage
Gain
(dB)
Second Stage
Gain
(dB)
Maximum
Input Level
Bandwidth
Small Signal
Eq. Input
Noise
(nV/√Hz)
$0000
-9
0
-9
2.8Vrms
110MHZ
29
$0001
-6
0
-6
2.8Vrms
100MHz
26
$0010
-3
0
-3
2.8Vrms
85MHz
23
$0011
0
0
0
2.8Vrms
69MHz
22
$0100
3
3
0
2Vrms
63MHz
16
$0101
6
6
0
1.4Vrms
58MHz
12
$0110
9
9
0
1Vrms
56MHz
9
$0111
12
12
0
0.7Vrms
55MHz
7
$1000
15
15
0
0.5Vrms
54MHz
6
$1001
18
18
0
0.35Vrms
52MHz
4.8
$1010
21
21
3
0.25Vrms
42MHz
4.7
$1011
24
24
6
175mVrms
30MHz
4.7
$1100
27
27
9
125mVrms
24MHz
4.6
$1101
30
30
12
88mVrms
18MHz
4.6
$1110
30
30
12
88mVrms
18MHz
4.6
$1111
30
30
12
88mVrms
18MHz
4.6
GC4....GC1
MSB
LSB
The gain is the same for both channels.
The digital inputs are CMOS compatible. The supply voltage of the logic decoder used to transcode the digital word can be either 3.3V or 5V or VCC.
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TS636
Bandwidth vs. Gain
Closed Loop Gain vs. Frequency
100
30
90
BANDWIDTH (MHz)
40
20
Gain (dB)
10
0
-10
-20
80
70
60
50
40
30
20
-30
10
-40
10kHz
100kHz
1MHz
10MHz
-9
100MHz
-6 -3
0
3
Frequency
110
VOLTAGE NOISE (nV/VHz)
SLEW RATE (V/µs)
SR-
95
SR+
85
80
75
70
-9
-6
-3
0
3
6
9
12 15 18 21 24
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
-9
27 30
-6
-3
Gain Switching (+15dB to -9dB)
3
6
9
12 15 18 21 24 27 30
Gain Switching (+30dB to +9dB)
6
6
GC4 command
5
5
4
4
Ouput Signal (V)
Ouput Signal (V)
0
GAIN (dB)
GAIN (dB)
3
2
1
0
-1
GC1 command
3
2
1
0
-1
Ouput Signal
-2
-2
Ouput Signal
-3
-4
12 15 18 21 24 27 30
Equivalent Input Voltage Noise vs. Gain
105
90
9
GAIN (dB)
Negative & Positive Slew Rate vs. Gain
100
6
-3
0
5µs
10µs
15µs
20µs
Time
-4
0
5µs
10µs
15µs
20µs
Time
measurement conditions: Vcc=±6V, Rload=500Ω, Tamb=25°C
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TS636
Output/Input Isolation in Power Down Mode vs.
Frequency
3rd Order Intermodulation
(2 tones : 180kHz and 280kHz)
-50
-70
-60
Isolation (dB)
-75
60kHZ
IM3 (dBc)
-70
-80
90kHZ
-80
220kHZ
-90
-85
230kHZ
-100
-110
-90
10kHz
100kHz
10MHz
1MHz
Frequency
-70
-75
IM3 (dBc)
80kHZ
-80
380kHZ
640kHZ
740kHZ
-90
0
1
2
3
4
5
Vout peak (V)
measurement conditions: Vcc=±6V, Rload=500Ω, Tamb=25°C
8/9
1
2
3
Vout peak (V)
3rd Order Intermodulation
(2 tones : 180kHz and 280kHz)
-85
0
4
5
TS636
PACKAGE MECHANICAL DATA
14 PINS - PLASTIC MICROPACKAGE (SO)
Millimeters
Inches
Dim.
Min.
A
a1
a2
b
b1
C
c1
D (1)
E
e
e3
F (1)
G
L
M
S
Typ.
Max.
Min.
1.75
0.2
1.6
0.46
0.25
0.1
0.35
0.19
Typ.
0.069
0.008
0.063
0.018
0.010
0.004
0.014
0.007
0.5
Max.
0.020
45° (typ.)
8.55
5.8
8.75
6.2
0.336
0.228
1.27
7.62
3.8
4.6
0.5
0.344
0.244
0.050
0.300
4.0
5.3
1.27
0.68
0.150
0.181
0.020
0.157
0.208
0.050
0.027
8° (max.)
Note : (1) D and F do not include mold flash or protrusions - Mold flash or protrusions shall not exceed 0.15mm (.066 inc) ONLY FOR DATA BOOK.
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from
its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications
mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information
previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of STMicroelectronics.
© The ST logo is a registered trademark of STMicroelectronics
© 2001 STMicroelectronics - Printed in Italy - All Rights Reserved
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