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THS6214
SBOS431A – MAY 2009 – REVISED MARCH 2017
THS6214 Dual-Port, Differential, VDSL2 Line Driver Amplifiers
1 Features
3 Description
•
The THS6214 is a dual-port, current-feedback
architecture, differential line driver amplifier system
ideal for xDSL systems. The device is targeted for
use in very-high-bit-rate digital subscriber line 2
(VDSL2) line driver systems that enable greater than
14.5-dBm line power, supporting the G.993.2 VDSL2
17a profile. The device is also fast enough to support
central-office transmissions of 14.5-dBm line power
up to 30 MHz. The device is also targeted for use as
a broadband or wideband power line communications
(PLC) amplifier for line driver applications.
1
•
•
•
•
•
•
•
•
Low Power Consumption:
– Full Bias Mode: 21 mA per Port
– Mid Bias Mode: 16.2 mA per Port
– Low Bias Mode: 11.2 mA per Port
– Low-Power Shutdown Mode
– IADJ Pin for Variable Bias
Low Noise:
– Voltage Noise: 2.7 nV/√Hz
– Inverting Current Noise: 17 pA/√Hz
– Noninverting Current Noise: 1.2 pA/√Hz
Low MTPR Distortion:
– 70 dB with 20.5 dBm G.993.2—Profile 8b
–93 dBc HD3 (1 MHz, 100-Ω Differential)
High Output Current: > 416 mA (25-Ω Load)
Wide Output Swing: 43.2 VPP (±12 V, 100-Ω
Differential Load)
Wide Bandwidth: 150 MHz (GDIFF = 10 V/V)
PSRR: 50 dB at 1 MHz for Good Isolation
Wide Power-Supply Range: 10 V to 28 V
The unique architecture of the THS6214 uses
minimal quiescent current and still achieves very high
linearity. Differential distortion, under full bias
conditions, is –93 dBc at 1 MHz and reduces to only
–73 dBc at 10 MHz. Fixed multiple bias settings of
the amplifiers allow for enhanced power savings for
line lengths where the full performance of the
amplifier is not required. To allow for even more
flexibility and power savings, an adjustable current
pin (IADJ) is available to further lower the bias
currents.
2 Applications
The wide output swing of 43.2 VPP (100-Ω differential
load) with ±12-V power supplies, coupled with over
416-mA current drive (25-Ω load), allows for wide
dynamic headroom, keeping distortion minimal.
•
•
The THS6214 is available in a VQFN-24 or a
HTSSOP-24 PowerPAD™ package.
•
Ideal For VDSL2 Systems
Backwards-Compatible with ADSL, ADSL2+,
ADSL2++ Systems
Broadband Power Line Communications
Device Information(1)
PART NUMBER
THS6214
PACKAGE
BODY SIZE (NOM)
VQFN (24)
5.00 mm × 4.00 mm
HTSSOP (24)
7.80 mm × 4.40 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical VDSL2 Line Driver Circuit Using One Port of the THS6214
12 V
RS
RT
RF
RP
RG
100 W
RP
RF
RS
IADJ
RT
12 V
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
THS6214
SBOS431A – MAY 2009 – REVISED MARCH 2017
www.ti.com
Table of Contents
1
2
3
4
5
6
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
6.11
6.12
6.13
1
1
1
2
3
4
Absolute Maximum Ratings ...................................... 4
ESD Ratings.............................................................. 5
Recommended Operating Conditions....................... 5
Thermal Information .................................................. 5
Electrical Characteristics: VS = ±12 V....................... 6
Electrical Characteristics: VS = ±6 V......................... 8
Timing Requirements .............................................. 10
Typical Characteristics: VS = ±12 V, Full Bias ........ 11
Typical Characteristics: VS = ±12 V, Mid Bias ........ 14
Typical Characteristics: VS = ±12 V, Low Bias ..... 16
Typical Characteristics: VS = ±6 V, Full Bias ........ 18
Typical Characteristics: VS = ±6 V, Mid Bias ........ 21
Typical Characteristics: VS = ±6 V, Low Bias ....... 23
7
Detailed Description ............................................ 25
7.1
7.2
7.3
7.4
8
Overview .................................................................
Functional Block Diagram .......................................
Feature Description.................................................
Device Functional Modes........................................
25
25
25
28
Application and Implementation ........................ 29
8.1 Application Information............................................ 29
8.2 Typical Applications ................................................ 29
9 Power Supply Recommendations...................... 35
10 Layout................................................................... 36
10.1 Board Layout Guidelines....................................... 36
10.2 Layout Example .................................................... 37
11 Device and Documentation Support ................. 38
11.1
11.2
11.3
11.4
11.5
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
38
38
38
38
38
12 Mechanical, Packaging, and Orderable
Information ........................................................... 38
4 Revision History
Changes from Original (May 2009) to Revision A
Page
•
Added Device Information table, Pin Functions table, ESD Ratings table, Recommended Operating Conditions
table, Thermal Information table, Timing Requirements table, Overview section, Functional Block Diagram section,
Feature Description section, Device Functional Modes section, Application and Implementation section, Power
Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical,
Packaging, and Orderable Information section ...................................................................................................................... 1
•
Added last Applications bullet ................................................................................................................................................ 1
•
Added last sentence to first paragraph of Description section .............................................................................................. 1
•
Changed QFN to VQFN and TSSOP to HTSSOP throughout document ............................................................................. 1
•
Deleted Ordering Information table ....................................................................................................................................... 3
•
Deleted Dissipation Ratings table .......................................................................................................................................... 5
•
Changed second paragraph of Distortion Performance section for clarity........................................................................... 26
2
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SBOS431A – MAY 2009 – REVISED MARCH 2017
5 Pin Configuration and Functions
VS+
D1 OUT
PWP Package
24-Pin HTSSOP
Top View
20
22
21
VS-
BIAS-1/D1D2
23
24
BIAS-2/D1D2
RHF Package
24-Pin VQFN
Top View
VS-
1
24
VS+
BIAS-1/D1D2
2
23
D1 OUT
BIAS-2/D1D2
3
22
D1 FB
D1 IN+
4
21
D2 FB
D2 IN+
5
20
D2 OUT
GND
6
19
NC
D1 IN+
1
19
D1 FB
D2 IN+
2
18
D2 FB
GND
3
17
D2 OUT
IADJ
7
18
NC
IADJ
4
16
NC
D3 IN+
8
17
D3 OUT
NC
5
15
D3 OUT
D4 IN+
9
16
D3 FB
D3 IN+
6
14
D3 FB
BIAS-2/D3D4
10
15
D4 FB
D4 IN+
7
13
D4 FB
BIAS-1/D3D4
11
14
D4 OUT
VS-
12
13
VS+
8
9
10
11
12
BIAS-2/D3D4
BIAS-1/D3D4
VS-
VS+
D4 OUT
PowerPAD
PowerPAD
(1)
The PowerPAD is electrically isolated from all other pins and can be connected to any potential voltage range from
VS– to VS+. Typically, the PowerPAD is connected to the GND plane because this plane tends to physically be the
largest and is able to dissipate the most amount of heat.
(2)
The THS6214 defaults to the shutdown (disable) state if no signal is present on the bias pins.
(3)
The GND pin range is from VS– to (VS+ – 5 V).
NOTE: NC = no connection.
Pin Functions (1)
PIN
NAME
NO.
RHF
I/O
DESCRIPTION
PWP
BIAS-1/D1D2
23
2
I
Bias mode parallel control for port A, LSB
BIAS-1/D3D4
9
11
I
Bias mode parallel control for port B, LSB
BIAS-2/D1D2
24
3
I
Bias mode parallel control for port A, MSB
BIAS-2/D3D4
8
10
I
Bias mode parallel control for port B, MSB
D1 FB
19
22
I
Amplifier D1 inverting input
D2 FB
18
21
I
Amplifier D2 inverting input
D3 FB
14
16
I
Amplifier D3 inverting input
D4 FB
13
15
I
Amplifier D4 inverting input
D1 IN+
1
4
I
Amplifier D1 noninverting input
D2 IN+
2
5
I
Amplifier D2 noninverting input
D3 IN+
6
8
I
Amplifier D3 noninverting input
D4 IN+
7
9
I
Amplifier D4 noninverting input
D1 OUT
20
23
O
Amplifier D1 output
D2 OUT
17
20
O
Amplifier D2 output
(1)
The THS6214 defaults to the shutdown (disable) state if no signal is present on the bias pins.
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Pin Functions(1) (continued)
PIN
NO.
NAME
I/O
DESCRIPTION
RHF
PWP
D3 OUT
15
17
O
Amplifier D3 output
D4 OUT
12
14
O
Amplifier D4 output
GND
(2)
3
6
I/O
Control pin ground reference
IADJ
4
7
I/O
Bias current adjustment pin
NC
5, 16
18, 19
—
No internal connection
VS–
10, 22
1, 12
I/O
Negative power-supply connection
VS+
11, 21
11, 24
I/O
Positive power-supply connection
(2)
The GND pin range is from VS– to (VS+ – 5 V).
Table 1. BIAS-1, BIAS-2 Logic Table
BIAS-1
BIAS-0
FUNCTION
DESCRITPION
0
0
Full bias mode (100%)
Amplifiers on with lowest distortion possible (default state)
1
0
Mid bias mode (75%)
Amplifiers on with power savings and a reduction in distortion performance
0
1
Low bias mode (50%)
Amplifiers on with enhanced power savings and a reduction of overall
performance
1
1
Shutdown mode
Amplifiers off and output has high impedance
6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
MIN
Supply voltage, VS– to VS+
Input voltage, VI
Differential input voltage, VID
Output current, IO
Static dc
(2)
Continuous power dissipation
Storage temperature, Tstg
(2)
(3)
(4)
4
28
V
±VS
V
±2
V
±500
mA
150
Continuous operation, long-term reliability (4),
RHF package only
Continuous operation, long-term reliability
PWP package only
(1)
UNIT
See Thermal Information
Under any condition (3)
Maximum junction temperature, TJ
MAX
130
°C
(4)
,
140
–65
150
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
The THS6214 incorporates a PowerPAD on the underside of the chip. This pad functions as a heatsink and must be connected to a
thermally dissipating plane for proper power dissipation. Failure to do so may result in exceeding the maximum junction temperature,
which can permanently damage the device. See PowerPAD™ Thermally Enhanced Package (SLMA002) for more information about
using the PowerPAD thermally-enhanced package. Under high-frequency ac operation (greater than 10 kHz), the short-term output
current capability is much greater than the continuous dc output current rating. This short-term output current rating is approximately 8.5
times the dc capability, or approximately ±850 mA.
The absolute maximum junction temperature under any condition is limited by the constraints of the silicon process.
The absolute maximum junction temperature for continuous operation is limited by the package constraints. Operation above this
temperature may result in reduced reliability and/or lifetime of the device.
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6.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2000
Charged-device model (CDM), per JEDEC specification JESD22-C101 (2)
±500
Machine model (MM)
±100
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
VS
Supply voltage, VS– to VS+
TJ
Operating junction temperature
TA
Ambient operating air temperature
NOM
MAX
10
25
UNIT
28
V
130
°C
85
°C
6.4 Thermal Information
THS6214
THERMAL METRIC
(1)
RHF (VQFN)
PWP (HTSSOP)
24 PINS
24 PINS
UNIT
RθJA
Junction-to-ambient thermal resistance
33.2
35.7
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
31.7
22.9
°C/W
RθJB
Junction-to-board thermal resistance
11.3
10.1
°C/W
ψJT
Junction-to-top characterization parameter
0.4
0.4
°C/W
ψJB
Junction-to-board characterization parameter
11.3
10.3
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
3.9
1.7
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
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6.5 Electrical Characteristics: VS = ±12 V
at TA = 25°C, GDIFF = 10 V/V with RL = 100-Ω differential load, RADJ = 0 Ω, active impedance circuit configuration, and full bias
(unless otherwise noted); each port is independently tested
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
TEST
LEVEL (1)
AC PERFORMANCE
GDIFF = 5 V/V , RF = 1.5 kΩ, VO = 2 VPP
Small-signal bandwidth, –3 dB
160
GDIFF = 10 V/V , RF = 1.5 kΩ, VO = 2 VPP
120
Over –40°C to +85°C temperature range
100
C
150
MHz
B
0.1-dB bandwidth flatness
GDIFF = 10 V/V , RF = 1.24 kΩ
114
MHz
C
Large-signal bandwidth
GDIFF = 10 V/V , RF = 1.24 kΩ, VO = 20 VPP
120
MHz
C
Slew rate (10% to 90% level)
Rise and fall time
GDIFF = 10 V/V, VO = 20-V step, differential
3200
TA = –40°C to +85°C
3000
GDIFF = 10 V/V, VO = 2 VPP
3800
5
Full bias, f = 1 MHz
–100
TA = –40°C to +85°C
2nd-order harmonic distortion
GDIFF = 10 V/V,
VO = 2 VPP,
RL = 100-Ω differential
Low bias, f = 1 MHz
–96
Full bias, f = 10 MHz
–75
Low bias, f = 10 MHz
–72
Full bias, f = 1 MHz
–89
Low bias, f = 1 MHz
–85
Full bias, f = 10 MHz
–73
Differential inverting current noise
dBc
2.7
TA = –40°C to +85°C
1.2
TA = –40°C to +85°C
–65
B
B
dBc
17
TA = –40°C to +85°C
C
B
B
C
3.2
1.4
1.6
f = 1 MHz
B
B
–85
3.5
f = 1 MHz
C
C
–58
f = 1 MHz, input-referred
B
C
B
–53
Low bias, f = 10 MHz
Differential noninverting current
noise
–70
B
B
–80
TA = –40°C to +85°C
Differential input voltage noise
–95
–65
TA = –40°C to +85°C
3rd-order harmonic distortion
ns
–90
TA = –40°C to +85°C
GDIFF = 10 V/V,
VO = 2 VPP,
RL = 100-Ω differential
V/µs
20
24
nV/√Hz
pA/√Hz
pA/√Hz
B
B
B
B
B
B
DC PERFORMANCE
Open-loop transimpedance gain
Input offset voltage
Input offset voltage drift
Input offset voltage matching
Noninverting input bias current
Noninverting input bias current drift
Inverting input bias current
Inverting input bias current drift
Inverting input bias current
matching
(1)
(2)
6
330 (2)
RL = 100 Ω
700
kΩ
300
±15
±50 (2)
TA = –40°C to +85°C
±60
TA = –40°C to +85°C
±155
±0.5
TA = –40°C to +85°C
±5 (2)
±7
±1
±3.5
±5.5
TA = –40°C to +85°C
±30 (2)
±45 (2)
TA = –40°C to +85°C
±55
TA = –40°C to +85°C
±154
±8
TA = –40°C to +85°C
µV/°C
mV
(2)
TA = –40°C to +85°C
±8
mV
±30 (2)
±40
µA
nA/°C
µA
nA/°C
µA
A
B
A
B
B
A
B
A
B
B
A
B
B
A
B
Test levels: (A) 100% tested at 25°C. Overtemperature limits set by characterization and simulation. (B) Limits set by characterization
and simulation. (C) Typical value only for information.
This specification is 100% tested at 25°C.
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Electrical Characteristics: VS = ±12 V (continued)
at TA = 25°C, GDIFF = 10 V/V with RL = 100-Ω differential load, RADJ = 0 Ω, active impedance circuit configuration, and full bias
(unless otherwise noted); each port is independently tested
PARAMETER
TEST CONDITIONS
MIN
TYP
Each input
±9 (2)
±9.5
TA = –40°C to +85°C
±8.6
Each input
53 (2)
MAX
UNIT
TEST
LEVEL (1)
INPUT CHARACTERISTICS
Common-mode input range
Common-mode rejection ratio
TA = –40°C to +85°C
V
65
dB
49
Noninverting input resistance
500 || 2
Inverting input resistance
50
A
B
A
B
kΩ || pF
C
Ω
C
OUTPUT CHARACTERISTICS (3)
RL = 100 Ω, each output
RL = 50 Ω, each output
Output voltage swing
TA = –40°C to +85°C
RL = 25 Ω, each output
TA = –40°C to +85°C
Output current
(sourcing and sinking)
RL = 25 Ω, based on VO tests
TA = –40°C to +85°C
±10.9
±10.6 (2)
C
±10.8
A
±10.4
±10.2 (2)
V
±10.4
A
±10
±408
(2)
B
±416
mA
±400
Short-circuit output current
B
1
A
B
A
C
Output impedance
f = 1 MHz, differential
0.2
Ω
C
Crosstalk
f = 1 MHz, VO = 2 VPP, port 1 to port 2
–90
dB
C
POWER SUPPLY
Operating voltage
±5 (2)
TA = –40°C to +85°C
Per port, full bias (BIAS-1 = 0, BIAS-2 = 0)
TA = –40°C to +85°C
IS+ quiescent current
±5
19.5 (2)
15 (2)
TA = –40°C to +85°C
12.8
Per port, low bias (BIAS-1 = 0, BIAS-2 = 1)
10 (2)
21
16.2
11.2
0.4
TA = –40°C to +85°C
IS– quiescent current
18.5 (2)
20
16
A
B
17.4 (2)
A
12.4 (2)
A
1
B
21.5 (2)
A
23
B
16.4 (2)
A
11.8
17.6
(2)
(2)
9
7.1
Per port, bias off (BIAS-1 = 1, BIAS-2 = 1)
10.2
0.1
TA = –40°C to +85°C
Current through GND pin
+PSRR Positive power-supply rejection ratio
Negative power-supply rejection
–PSRR
ratio
(3)
1
54 (2)
Differential
TA = –40°C to +85°C
TA = –40°C to +85°C
66
52
52 (2)
Differential
11.6
mA
50
65
B
A
11.4
B
0.3 (2)
A
0.8
Per port, full bias (BIAS-1 = 0, BIAS-2 = 0)
A
B
TA = –40°C to +85°C
TA = –40°C to +85°C
B
0.8 (2)
14 (2)
Per port, low bias (BIAS-1 = 0, BIAS-2 = 1)
mA
13.2
Per port, mid bias (BIAS-1 = 1, BIAS-2 = 0)
15.2
A
C
24
TA = –40°C to +85°C
Per port, full bias (BIAS-1 = 0, BIAS-2 = 0)
V
22.5 (2)
18.6
8.1
Per port, bias off (BIAS-1 = 1, BIAS-2 = 1)
±14 (2)
±14
17
Per port, mid bias (BIAS-1 = 1, BIAS-2 = 0)
TA = –40°C to +85°C
±12
B
mA
dB
dB
C
A
B
A
B
Test circuit is shown in Figure 1.
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Electrical Characteristics: VS = ±12 V (continued)
at TA = 25°C, GDIFF = 10 V/V with RL = 100-Ω differential load, RADJ = 0 Ω, active impedance circuit configuration, and full bias
(unless otherwise noted); each port is independently tested
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
TEST
LEVEL (1)
LOGIC
Bias control pin logic threshold
Logic 1, with respect to GND (4),
TA = –40°C to +85°C
1.9
Logic 0, with respect to GND ,
TA = –40°C to +85°C
BIAS-1, BIAS-2 = 0.5 V (logic 0)
Bias pin quiescent current
B
V
(4)
20
TA = –40°C to +85°C
BIAS-1, BIAS-2 = 3.3 V (logic 1)
0.3
A
30
1 (2)
µA
1.2
Bias pin input impedance
(4)
B
(2)
35
TA = –40°C to +85°C
Amplifier output impedance
0.8
50
Off bias (BIAS-1 = 1, BIAS-2 = 1)
10 || 5
B
A
B
kΩ
C
kΩ || pF
C
The GND pin usable range is from VS– to (VS+ – 5 V).
6.6 Electrical Characteristics: VS = ±6 V
at TA = 25°C, GDIFF = 5 V/V with RL = 100-Ω differential load, RADJ = 0 Ω, active impedance circuit configuration, and full bias
(unless otherwise noted); each port is independently tested
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
TEST
LEVEL (1)
AC PERFORMANCE
GDIFF = 5 V/V , RF = 1.5 kΩ, VO = 2 VPP
Small-signal bandwidth, –3 dB
140
GDIFF = 10 V/V , RF = 1.5 kΩ, VO = 2 VPP
110
Over –40°C to +85°C temperature range
95
MHz
GDIFF = 10 V/V , RF = 1.24 kΩ
100
MHz
C
Large-signal bandwidth
GDIFF = 10 V/V , RF = 1.24 kΩ, VO = 20 VPP
120
MHz
C
Rise and fall time
GDIFF = 10 V/V, VO = 20-V step, differential
1200
TA = –40°C to +85°C
1000
GDIFF = 10 V/V, VO = 2 VPP
Full bias
1600
2nd-order harmonic distortion
GDIFF = 10 V/V,
VO = 2 VPP,
RL = 100-Ω differential
–98
Low bias
–93
Full bias
–80
Low bias
–74
Full bias
–93
–89
Full bias
–66
TA = –40°C to +85°C
Differential input voltage noise
Differential noninverting current
noise
Differential inverting current noise
f = 1 MHz, input-referred
TA = –40°C to +85°C
TA = –40°C to +85°C
B
B
–84
–60
B
B
dBc
C
B
B
C
3.0
1.4
1.6
17
C
C
3.3
1.2
f = 1 MHz
dBc
–55
2.5
B
C
B
–54
TA = –40°C to +85°C
f = 1 MHz
–75
B
B
–79
Low bias
Low bias
–92
–68
TA = –40°C to +85°C
3rd-order harmonic distortion
ns
–87
TA = –40°C to +85°C
GDIFF = 10 V/V,
VO = 2 VPP,
RL = 100-Ω differential
V/µs
5
TA = –40°C to +85°C
8
B
0.1-dB bandwidth flatness
Slew rate (10% to 90% level)
(1)
C
140
20
24
nV/√Hz
pA/√Hz
pA/√Hz
B
B
B
B
B
B
Test levels: (A) 100% tested at 25°C. Overtemperature limits set by characterization and simulation. (B) Limits set by characterization
and simulation. (C) Typical value only for information.
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SBOS431A – MAY 2009 – REVISED MARCH 2017
Electrical Characteristics: VS = ±6 V (continued)
at TA = 25°C, GDIFF = 5 V/V with RL = 100-Ω differential load, RADJ = 0 Ω, active impedance circuit configuration, and full bias
(unless otherwise noted); each port is independently tested
PARAMETER
TEST CONDITIONS
MIN
TYP
330 (2)
650
MAX
UNIT
TEST
LEVEL (1)
DC PERFORMANCE
Open-loop transimpedance gain
Input offset voltage
Input offset voltage drift
Input offset voltage matching
Noninverting input bias current
Noninverting input bias current drift
Inverting input bias current
Inverting input bias current drift
Inverting input bias current
matching
RL = 100 Ω
TA = –40°C to +85°C
kΩ
300
±10
±45 (2)
TA = –40°C to +85°C
±55
TA = –40°C to +85°C
±155
Channels 1 to 2 and 3 to 4 only
±0.5
TA = –40°C to +85°C
±5 (2)
±7
±1
±3.5 (2)
TA = –40°C to +85°C
±5.5
TA = –40°C to +85°C
±30 (2)
±8
TA = –40°C to +85°C
±45 (2)
±55
TA = –40°C to +85°C
±135
±8
TA = –40°C to +85°C
±30 (2)
±40
mV
µV/°C
mV
µA
nA/°C
µA
nA/°C
µA
A
B
A
B
B
A
B
A
B
B
A
B
B
A
B
INPUT CHARACTERISTICS
Common-mode input range
Common-mode rejection ratio
±2.9 (2)
Each input
TA = –40°C to +85°C
±2.7
Each input
51 (2)
TA = –40°C to +85°C
±3.0
62
47
Noninverting input resistance
500 || 2
Inverting input resistance
55
V
dB
A
B
A
B
kΩ || pF
C
Ω
C
OUTPUT CHARACTERISTICS (3)
RL = 100 Ω, each output
RL = 50 Ω, each output
Output voltage swing
TA = –40°C to +85°C
RL = 25 Ω, each output
TA = –40°C to +85°C
Output current
(sourcing and sinking)
RL = 25 Ω, based on VO tests
TA = –40°C to +85°C
Short-circuit output current
(2)
(3)
±4.9
±4.75 (2)
±4.6
±4.55 (2)
C
±4.9
A
V
±4.7
A
±4.4
±182 (2)
B
B
±188
±176
mA
A
B
±1
A
C
Output impedance
f = 1 MHz, differential
0.2
Ω
C
Crosstalk
f = 1 MHz, VO = 2 VPP, port 1 to port 2
–90
dB
C
This specification is 100% tested at 25°C.
Test circuit is shown in Figure 1.
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Electrical Characteristics: VS = ±6 V (continued)
at TA = 25°C, GDIFF = 5 V/V with RL = 100-Ω differential load, RADJ = 0 Ω, active impedance circuit configuration, and full bias
(unless otherwise noted); each port is independently tested
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
±5 (2)
±6
±14 (2)
UNIT
TEST
LEVEL (1)
POWER SUPPLY
Operating voltage
TA = –40°C to +85°C
±5
Per port, full bias (BIAS-1 = 0, BIAS-2 = 0)
TA = –40°C to +85°C
13 (2)
17
TA = –40°C to +85°C
10.2 (2)
13.2
9.3
Per port, low bias (BIAS-1 = 0, BIAS-2 = 1)
TA = –40°C to +85°C
9.4
6.7
A
B
16.2 (2)
A
11.4 (2)
IS– quiescent current
TA = –40°C to +85°C
A
0.9
B
20 (2)
A
9
21
B
(2)
(2)
A
12 (2)
9.2
16
12.2
8.3
Per port, low bias (BIAS-1 = 0, BIAS-2 = 1)
TA = –40°C to +85°C
15.2
15.4
6.4 (2)
8.4
5.7
Per port, bias off (BIAS-1 = 1, BIAS-2 = 1)
0.1
10.4 (2)
+PSRR Positive power-supply rejection ratio
Negative power-supply rejection
–PSRR
ratio
mA
B
A
1
54 (2)
Differential
TA = –40°C to +85°C
64
52 (2)
TA = –40°C to +85°C
B
mA
dB
52
Differential
A
0.3 (2)
0.5
Per port, full bias (BIAS-1 = 0, BIAS-2 = 0)
B
10.6
TA = –40°C to +85°C
Current through GND pin
A
B
TA = –40°C to +85°C
Per port, mid bias (BIAS-1 = 1, BIAS-2 = 0)
B
0.8 (2)
0.5
TA = –40°C to +85°C
mA
11.6
Per port, bias off (BIAS-1 = 1, BIAS-2 = 1)
Per port, full bias (BIAS-1 = 0, BIAS-2 = 0)
A
C
22
16.4
7.4 (2)
V
21 (2)
10
Per port, mid bias (BIAS-1 = 1, BIAS-2 = 0)
IS+ quiescent current
±14
63
dB
50
C
A
B
A
B
LOGIC
Bias control pin logic threshold
Logic 1, with respect to GND (4),
TA = –40°C to +85°C
1.9
B
V
(4)
Logic 0, with respect to GND ,
TA = –40°C to +85°C
BIAS-1, BIAS-2 = 0.5 V (logic 0)
Bias pin quiescent current
20
0.8
B
30 (2)
A
TA = –40°C to +85°C
35
BIAS-1, BIAS-2 = 3.3 V (logic 1)
1 (2)
0.3
TA = –40°C to +85°C
1.2
Bias pin input impedance
Amplifier output impedance
(4)
50
Off bias (BIAS-1 = 1, BIAS-2 = 1)
µA
10 || 5
B
A
B
kΩ
C
kΩ || pF
C
The GND pin usable range is from VS– to (VS+ – 5 V).
6.7 Timing Requirements
MIN
NOM
MAX
UNIT
tON
Turn-on time delay: time for IS to reach 50% of final value
1
µs
tOFF
Turn-off time delay: time for IS to reach 50% of final value
1
µs
10
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SBOS431A – MAY 2009 – REVISED MARCH 2017
6.8 Typical Characteristics: VS = ±12 V, Full Bias
at TA = 25°C, GDIFF = 10 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.24 kΩ, and RL = 100 Ω (unless otherwise noted)
3
0
-3
-6
GDIFF = 10 V/V
RF = 1.24 kW
-9
Full Bias
Normalized Gain (dB)
0
Normalized Gain (dB)
3
GDIFF = 5 V/V
RF = 1.5 kW
-12
-3
-6
75% Bias
-9
-12
50% Bias
-15
-15
-18
10M
100M
-18
10M
400M
100M
VO = 2 VPP
VO = 2 VPP
Figure 1. Small-Signal Frequency Response
Figure 2. Small-Signal Frequency Response vs Bias Mode
12
1.2
0
8
0.8
-3
VO = 4 VPP
-6
VO = 2 VPP
VO = 20 VPP
-9
-12
VO = 8 VPP
Output Voltage (V)
3
4
0
0
-4
-0.4
Large-Signal Pulse Response
(±10 VP) Left Scale
-8
-15
-18
0.4
Small-Signal ±500 mVP
Right Scale
-0.8
-12
0
120
60
180
240
Output Voltage (V)
Normalized Gain (dB)
400M
Frequency (Hz)
Frequency (Hz)
-1.2
300
Time (10 ns/div)
Frequency (MHz)
Figure 4. Pulse Response
Figure 3. Large-Signal Frequency Response
23
100
22 pF
20
470 pF
Gain (dB)
RS (W)
17
10
100 pF
14
THS6214
10
100
1000
CL
VIN
1 kW
VOUT
Optional
RS
5
1
47 pF
11
8
1
39 pF
RS
THS6214
2
10M
100M
300M
Frequency (Hz)
Capacitive Load (pF)
RS optimized for 100% bias
Figure 5. Recommended RS vs Capacitive Load
Figure 6. Frequency Response vs Capacitive Load
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Typical Characteristics: VS = ±12 V, Full Bias (continued)
at TA = 25°C, GDIFF = 10 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.24 kΩ, and RL = 100 Ω (unless otherwise noted)
-60
-60
Third Harmonic
-70
-80
Second Harmonic
-90
-100
-110
400k
-70
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
-50
Third Harmonic
-80
-90
-100
Second Harmonic
-110
-120
10M
1M
40M
0.5
1
10
Frequency (Hz)
VO = 2 VPP
f = 1 MHz
Figure 7. Harmonic Distortion vs Frequency
Figure 8. Harmonic Distortion vs Output Voltage
-70
-80
-82
Third Harmonic
-84
-86
-88
-90
Third Harmonic
-92
-94
-96
-80
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
20
Output Voltage (VPP)
Second Harmonic
-90
-100
Second Harmonic
-110
-98
-120
-100
4
5
6
7
8
9
10
11
50
12
100
1k
Resistance (W)
Supply Voltage (±VS)
VO = 2 VPP, f = 1 MHz
VO = 2 VPP, f = 1 MHz
Figure 10. Harmonic Distortion vs Load Resistance
Figure 9. Harmonic Distortion vs Supply Voltage
-85
55
Third Harmonic
Intercept Point (dBm)
Harmonic Distortion (dBc)
50
-90
-95
-100
Second Harmonic
-105
45
40
35
30
25
20
-110
15
1
10
30
0
Gain (V/V)
5
10
15
20
25
30
Frequency (MHz)
VO = 2 VPP, f = 1 MHz
Figure 11. Harmonic Distortion vs Noninverting Gain
12
Figure 12. Two-Tone, Third-Order Intermodulation Intercept
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SBOS431A – MAY 2009 – REVISED MARCH 2017
Typical Characteristics: VS = ±12 V, Full Bias (continued)
Output Voltage (V)
12
10
8
6
4
2
0
-2
1-W Internal
-4
Power Dissipation
-6
-8
-10
-12
-14
-600
-400
-200
Output Voltage Noise Density (nV/ÖHz)
Input Current Noise Density (pA/ÖHz)
at TA = 25°C, GDIFF = 10 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.24 kΩ, and RL = 100 Ω (unless otherwise noted)
1-W Internal
Power Dissipation
50-W Load Line
100-W Load Line
1000
100
Inverting Current Noise
(17.4 pA/ÖHz)
Voltage Noise
(2.7 nV/ÖHz)
10
Noninverting Current Noise
(1.2 pV/ÖHz)
1
0
200
1k
100
600
400
10k
100k
1M
10M
Frequency (Hz)
Output Current (mA)
Voltage and current noise contributing to differential noise
Figure 14. Input Voltage and Current Noise Density
Figure 13. Output Voltage and Current Limitations
60
Power-Supply Rejection Ratio (dB)
Quiescent Current (±IQ, mA)
25
20
15
+IQ
10
-IQ
5
-PSRR
50
+PSRR
40
30
20
10
0
0
0
1
2
3
4
5
1k
6
10k
100k
1M
10M
100M
Frequency (Hz)
RADJ (kW)
Figure 16. PSRR vs Frequency
Figure 15. Quiescent Current for Full Bias Setting vs RADJ
140
0
10
-45
100
-90
Phase
80
-135
60
-180
40
-225
20
-270
0
-315
10k
100k
1M
10M
100M
1G
Output Impedance (W)
120
Transimpedance Phase (°)
Transimpedance Gain (dBW)
Gain
1
0.1
0.01
0.001
100k
Frequency (Hz)
1M
10M
100M
Frequency (Hz)
Figure 17. Open-Loop Gain and Phase
Figure 18. Closed-Loop Output Impedance
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6.9 Typical Characteristics: VS = ±12 V, Mid Bias
at TA = 25°C, GDIFF = 10 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.24 kΩ, and RL = 100 Ω (unless otherwise noted)
3
0
Normalized Gain (dB)
0
Normalized Gain (dB)
3
GDIFF = 5 V/V
RF = 1.5 kW
-3
-6
GDIFF = 10 V/V
RF = 1.24 kW
-9
-12
-3
VO = 20 VPP
VO = 4 VPP
-6
-9
VO = 8 VPP
-12
VO = 2 VPP
-15
-15
-18
-18
10M
100M
0
400M
20 40 60 80 100 120 140 160 180 200 220 240 260
Frequency (MHz)
Frequency (Hz)
VO = 2 VPP
Figure 19. Small-Signal Frequency Response
Figure 20. Large-Signal Frequency Response
12
1.2
8
0.8
18
0.4
Small-Signal ±500 mVP
Right Scale
0
0
-4
-0.4
Large-Signal Pulse Response
(±10 VP) Left Scale
-8
-12
-0.8
Quiescent Current (±IQ, mA)
4
Output Voltage (V)
Output Voltage (V)
16
14
12
10
8
+IQ
6
-IQ
4
2
-1.2
0
Time (10 ns/div)
0
1
2
3
4
5
6
RADJ (kW)
Figure 21. Pulse Response
Figure 22. Quiescent Current for Mid Bias Setting vs RADJ
23
100
22 pF
20
470 pF
Gain (dB)
RS (W)
17
10
100 pF
14
THS6214
10
100
1000
CL
VIN
5
1
47 pF
11
8
1
39 pF
RS
2
10M
1 kW
VOUT
Optional
RS
THS6214
100M
300M
Frequency (Hz)
Capacitive Load (pF)
RS optimized for 100% bias
Figure 23. Recommended RS vs Capacitive Load
14
Figure 24. Frequency Response vs Capacitive Load
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SBOS431A – MAY 2009 – REVISED MARCH 2017
Typical Characteristics: VS = ±12 V, Mid Bias (continued)
at TA = 25°C, GDIFF = 10 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.24 kΩ, and RL = 100 Ω (unless otherwise noted)
-70
-50
-70
Second Harmonic
-80
Third Harmonic
-75
-60
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
Third Harmonic
-90
-100
-80
-85
-90
-95
Second Harmonic
-100
-105
-110
400k
-110
10M
1M
40M
0
4
2
Frequency (Hz)
VO = 2 VPP
Figure 25. Harmonic Distortion vs Frequency
10
12
14
16
Figure 26. Harmonic Distortion vs Output Voltage
-60
-85
Third Harmonic
-90
-95
-70
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
8
f = 1 MHz
-80
Second Harmonic
-100
Third Harmonic
-80
-90
-100
Second Harmonic
-110
-120
-105
4
5
6
7
8
9
10
11
10
12
100
1k
Resistance (W)
Supply Voltage (±VS)
VO = 2 VPP, f = 1 MHz
VO = 2 VPP, f = 1 MHz
Figure 28. Harmonic Distortion vs Load Resistance
Figure 27. Harmonic Distortion vs Supply Voltage
-85
60
50
-90
Third Harmonic
Intercept Point (dBm)
Harmonic Distortion (dBc)
6
Output Voltage (VPP)
-95
Second Harmonic
-100
-105
40
30
20
10
0
-110
1
10
20
0
5
10
15
20
25
30
Frequency (MHz)
Gain (V/V)
VO = 2 VPP, f = 1 MHz
Figure 29. Harmonic Distortion vs Noninverting Gain
Figure 30. Two-Tone, Third-Order Intermodulation Intercept
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6.10 Typical Characteristics: VS = ±12 V, Low Bias
at TA = 25°C, GDIFF = 10 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.24 kΩ, and RL = 100 Ω (unless otherwise noted)
6
3
GDIFF = 5 V/V
RF = 1.5 kW
0
0
Normalized Gain (dB)
Normalized Gain (dB)
3
-3
-6
GDIFF = 10 V/V
RF = 1.24 kW
-9
-12
-3
VO = 20 VPP
-6
VO = 4 VPP
VO = 8 VPP
-9
-12
-15
-15
-18
10M
-18
VO = 2 VPP
100M
300M
0
20
40
60
80
Frequency (Hz)
100 120 140 160 180 200 220
Frequency (MHz)
VO = 2 VPP
Figure 32. Large-Signal Frequency Response
1.2
14
8
0.8
12
4
0.4
Small-Signal ±500 mVP
Right Scale
0
0
-4
-0.4
Large-Signal Pulse Response
(±10 VP) Left Scale
-8
-12
-0.8
Quiescent Current (±IQ, mA)
12
Output Voltage (V)
Output Voltage (V)
Figure 31. Small-Signal Frequency Response
-1.2
10
8
6
+IQ
4
-IQ
2
0
Time (10 ns/div)
0
1
2
3
4
5
6
RADJ (kW)
Figure 33. Pulse Response
Figure 34. Supply Current for Low Bias Setting vs RADJ
100
26
22 pF
23
Gain (dB)
RS (W)
20
10
100 pF
17
470 pF
THS6214
14
11
39 pF
RS
47 pF
CL
VIN
1 kW
VOUT
Optional
8
RS
5
1
1
10
100
1000
THS6214
2
10M
Capacitive Load (pF)
100M
200M
Frequency (Hz)
RS optimized for 100% bias
Figure 35. Recommended RS vs Capacitive Load
16
Figure 36. Frequency Response vs Capacitive Load
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SBOS431A – MAY 2009 – REVISED MARCH 2017
Typical Characteristics: VS = ±12 V, Low Bias (continued)
at TA = 25°C, GDIFF = 10 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.24 kΩ, and RL = 100 Ω (unless otherwise noted)
-60
-50
-70
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
-40
Third Harmonic
-60
-70
-80
Second Harmonic
-90
-80
-90
Second Harmonic
-100
-110
-100
-110
100k
Third Harmonic
-120
10M
1M
30M
0
4
2
Frequency (Hz)
VO = 2 VPP
Figure 37. Harmonic Distortion vs Frequency
10
12
14
16
Figure 38. Harmonic Distortion vs Output Voltage
-80
Third Harmonic
-90
Second Harmonic
-95
-85
Harmonic Distortion (dBc)
-85
-100
Third Harmonic
-90
-95
Second Harmonic
-100
-105
-110
-105
4
5
6
7
8
9
10
11
50
12
100
1k
Resistance (W)
Supply Voltage (±VS)
VO = 2 VPP, f = 1 MHz
VO = 2 VPP, f = 1 MHz
Figure 40. Harmonic Distortion vs Load Resistance
Figure 39. Harmonic Distortion vs Supply Voltage
-85
55
Third Harmonic
50
-90
Intercept Point (dBm)
Harmonic Distortion (dBc)
8
f = 1 MHz
-80
Harmonic Distortion (dBc)
6
Output Voltage (VPP)
-95
Second Harmonic
-100
-105
45
40
35
30
25
20
15
-110
1
10
20
0
Gain (V/V)
5
10
15
20
25
30
Frequency (MHz)
VO = 2 VPP, f = 1 MHz
Figure 41. Harmonic Distortion vs Noninverting Gain
Figure 42. Two-Tone, Third-Order Intermodulation Intercept
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6.11 Typical Characteristics: VS = ±6 V, Full Bias
at TA = 25°C, GDIFF = 5 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.82 kΩ, and RL = 100 Ω (unless otherwise noted)
3
6
GDIFF = 5 V/V
RF = 1.82 kW
0
3
Normalized Gain (dB)
Normalized Gain (dB)
Full Bias
-3
GDIFF = 10 V/V
RF = 1.5 kW
-6
-9
-12
-15
0
75% Bias
-3
-6
50% Bias
-9
-12
-15
-18
10M
100M
-18
10M
400M
100M
VO = 2 VPP
VO = 2 VPP
Figure 43. Small-Signal Frequency Response
Figure 44. Small-Signal Frequency Response vs Bias
7.5
Large-Signal Pulse Response
(±5 VP) Left Scale
6
-3
VO = 4 VPP
-6
VO = 16 VPP
-9
VO = 2 VPP
-12
VO = 20 VPP
-15
Output Voltage (V)
0
50
100
150
200
250
300
1.6
4.5
1.2
3
0.8
1.5
0.4
Small-Signal
Pulse Response
(±500 mVP) Right Scale
0
-1.5
0
-0.4
-3
-0.8
-4.5
-1.2
-6
-1.6
-2
-7.5
-18
2
Output Voltage (V)
Normalized Gain (3 dB/div)
3
0
400M
Frequency (Hz)
Frequency (Hz)
350
Time (10 ns/div)
Frequency (MHz)
Figure 46. Pulse Response
Figure 45. Large-Signal Frequency Response
100
17
14
Gain (dB)
RS (W)
470 pF
10
22 pF
11
RS
THS6214
100 pF
39 pF
8
CL
VIN
5
1 kW
VOUT
Optional
47 pF
RS
THS6214
1
1
10
100
1000
2
10M
Capacitive Load (pF)
100M
300M
Frequency (Hz)
RS optimized for 100% bias
Figure 47. Recommended RS vs Capacitive Load
18
Figure 48. Frequency Response vs Capacitive Load
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Typical Characteristics: VS = ±6 V, Full Bias (continued)
at TA = 25°C, GDIFF = 5 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.82 kΩ, and RL = 100 Ω (unless otherwise noted)
-50
-55
-65
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
-60
-60
Third Harmonic
-70
-80
-90
Second Harmonic
-100
Third Harmonic
-70
-75
-80
-85
Second Harmonic
-90
-95
-100
-110
400k
-105
10M
1M
40M
0
4
2
VO = 2 VPP
8
10
12
14
16
VO = 2 VPP, f = 1 MHz
Figure 49. Harmonic Distortion vs Frequency
Figure 50. Harmonic Distortion vs Output Voltage
-75
-80
-85
Third Harmonic
-90
-95
-80
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
6
Output Voltage (VPP)
Frequency (Hz)
Second Harmonic
-100
-85
-90
Third Harmonic
-95
Second Harmonic
-100
-105
-110
-105
4
5
6
7
8
9
10
11
50
12
100
1k
Supply Voltage (±VS)
Resistance (W)
VO = 2 VPP, f = 1 MHz
VO = 2 VPP, f = 1 MHz
Figure 51. Harmonic Distortion vs Supply Voltage
Figure 52. Harmonic Distortion vs Load Resistance
-80
60
Intercept Point (dBm)
Harmonic Distortion (dBc)
55
-85
Third Harmonic
-90
-95
Second Harmonic
-100
50
45
40
35
30
25
-105
20
1
10
20
0
5
10
15
20
25
30
Frequency (MHz)
Gain (V/V)
VO = 2 VPP, f = 1 MHz
Figure 53. Harmonic Distortion vs Noninverting Gain
Figure 54. Two-Tone, Third-Order Intermodulation Intercept
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Typical Characteristics: VS = ±6 V, Full Bias (continued)
at TA = 25°C, GDIFF = 5 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.82 kΩ, and RL = 100 Ω (unless otherwise noted)
20
Quiescent Current (±IQ, mA)
18
16
14
12
10
8
+IQ
6
-IQ
4
2
0
0
1
2
3
4
5
6
RADJ (kW)
Figure 55. Quiescent Current for Full Bias Setting vs RADJ
20
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6.12 Typical Characteristics: VS = ±6 V, Mid Bias
at TA = 25°C, GDIFF = 5 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.82 kΩ, and RL = 100 Ω (unless otherwise noted)
3
0
Normalized Gain (dB)
0
Normalized Gain (dB)
3
GDIFF = 5 V/V
RF = 1.82 kW
-3
GDIFF = 10 V/V
RF = 1.5 kW
-6
-9
-12
-3
VO = 4 VPP
-6
VO = 16 VPP
VO = 2 VPP
-9
-12
VO = 20 VPP
-15
-15
-18
10M
-18
100M
300M
0
50
100
150
200
250
300
Frequency (MHz)
Frequency (Hz)
VO = 2 VPP
Figure 56. Small-Signal Frequency Response
Large-Signal Pulse Response
(±5 VP) Left Scale
2
16
1.6
14
4.5
1.2
3
0.8
1.5
0.4
Small-Signal
Pulse Response
(±500 mVP) Right Scale
0
-1.5
0
-0.4
Output Voltage (V)
Output Voltage (V)
6
Quiescent Current (±IQ, mA)
7.5
Figure 57. Large-Signal Frequency Response
12
10
8
-3
-0.8
-4.5
-1.2
-6
-1.6
2
-2
0
-7.5
+IQ
6
-IQ
4
0
Time (10 ns/div)
1
2
3
4
5
6
RADJ (kW)
Figure 58. Pulse Response
Figure 59. Quiescent Current for Mid Bias Setting vs RADJ
100
17
22 pF
14
470 pF
39 pF
Gain (dB)
RS (W)
RS
10
11
8
THS6214
CL
VIN
1 kW
VOUT
Optional
100 pF
RS
5
THS6214
47 pF
1
1
10
100
1000
2
10M
Capacitive Load (pF)
100M
200M
Frequency (Hz)
RS optimized for 100% bias
Figure 60. Recommended RS vs Capacitive Load
Figure 61. Frequency Response vs Capacitive Load
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Typical Characteristics: VS = ±6 V, Mid Bias (continued)
at TA = 25°C, GDIFF = 5 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.82 kΩ, and RL = 100 Ω (unless otherwise noted)
-60
-65
-50
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
-40
Third Harmonic
-60
-70
-80
-90
Second Harmonic
-70
Third Harmonic
-75
-80
-85
Second Harmonic
-90
-100
-95
-110
400k
-100
10M
1M
40M
0
4
2
VO = 2 VPP
Figure 62. Harmonic Distortion vs Frequency
10
12
14
16
Figure 63. Harmonic Distortion vs Output Voltage
-80
-85
Harmonic Distortion (dBc)
-85
Third Harmonic
-90
Second Harmonic
-95
-90
Third Harmonic
-95
Second Harmonic
-100
-105
-110
-100
4
5
6
7
8
9
10
11
50
12
100
1k
Supply Voltage (±VS)
Resistance (W)
VO = 2 VPP, f = 1 MHz
VO = 2 VPP, f = 1 MHz
Figure 64. Harmonic Distortion vs Supply Voltage
Figure 65. Harmonic Distortion vs Load Resistance
-86
60
55
-88
Third Harmonic
Intercept Point (dBm)
Harmonic Distortion (dBc)
8
f = 1 MHz
-80
Harmonic Distortion (dBc)
6
Output Voltage (VPP)
Frequency (Hz)
-90
-92
-94
Second Harmonic
-96
50
45
40
35
30
25
-98
20
1
10
20
0
5
10
15
20
25
30
Frequency (MHz)
Gain (V/V)
VO = 2 VPP, f = 1 MHz
Figure 66. Harmonic Distortion vs Noninverting Gain
22
Figure 67. Two-Tone, Third-Order Intermodulation Intercept
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6.13 Typical Characteristics: VS = ±6 V, Low Bias
at TA = 25°C, GDIFF = 5 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.82 kΩ, and RL = 100 Ω (unless otherwise noted)
6
6
GDIFF = 5 V/V
RF = 1.82 kW
3
3
-3
GDIFF = 10 V/V
RF = 1.5 kW
-6
0
Normalized Gain (dB)
Normalized Gain (dB)
0
-9
-12
-3
VO = 16 VPP
VO = 4 VPP
-6
-9
VO = 2 VPP
VO = 20 VPP
-12
-15
-15
-18
10M
-18
100M
300M
0
20 40 60 80 100 120 140 160 180 200 220 240 260
Frequency (MHz)
Frequency (Hz)
VO = 2 VPP
Figure 69. Large-Signal Frequency Response
Figure 68. Small-Signal Frequency Response
Large-Signal Pulse Response
(±5 VP) Left Scale
2
1.6
4.5
1.2
3
0.8
1.5
0.4
Small-Signal
Pulse Response
(±500 mVP) Right Scale
0
-1.5
0
-0.4
-3
-0.8
-4.5
-1.2
-6
-1.6
Output Voltage (V)
Output Voltage (V)
6
Quiescent Current (±IQ, mA)
7.5
12
8
6
+IQ
4
-IQ
2
0
-2
-7.5
10
0
Time (10 ns/div)
1
2
3
4
5
6
RADJ (kW)
Figure 70. Pulse Response
Figure 71. Quiescent Current for Low Bias Setting vs RADJ
100
20
17
100 pF
Gain (dB)
RS (W)
14
10
22 pF
470 pF
RS
THS6214
11
39 pF
8
CL
VIN
1 kW
VOUT
Optional
47 pF
RS
5
THS6214
1
1
10
100
1000
2
10M
Capacitive Load (pF)
100M
200M
Frequency (Hz)
RS optimized for 100% bias
Figure 72. Recommended RS vs Capacitive Load
Figure 73. Frequency Response vs Capacitive Load
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Typical Characteristics: VS = ±6 V, Low Bias (continued)
at TA = 25°C, GDIFF = 5 V/V, GCM = 1 V/V, RADJ = 0 Ω, RF = 1.82 kΩ, and RL = 100 Ω (unless otherwise noted)
-60
-50
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
-40
-60
-70
Third Harmonic
-80
Second Harmonic
-70
Third Harmonic
-80
Second Harmonic
-90
-90
-100
-100
100k
1M
10M
0
100M
4
2
Frequency (Hz)
VO = 2 VPP
8
10
12
14
16
f = 1 MHz
Figure 74. Harmonic Distortion vs Frequency
Figure 75. Harmonic Distortion vs Output Voltage
-80
-80
-85
-85
Harmonic Distortion (dBc)
Harmonic Distortion (dBc)
6
Output Voltage (VPP)
Third Harmonic
-90
Second Harmonic
-95
Second Harmonic
-90
-95
-100
Third Harmonic
-105
-100
-110
4
5
6
7
8
9
10
11
12
50
100
1k
Resistance (W)
Supply Voltage (±VS)
VO = 2 VPP, f = 1 MHz
VO = 2 VPP, f = 1 MHz
Figure 77. Harmonic Distortion vs Load Resistance
Figure 76. Harmonic Distortion vs Supply Voltage
60
-80
Intercept Point (dBm)
Harmonic Distortion (dBc)
55
-85
Third Harmonic
-90
-95
Second Harmonic
50
45
40
35
30
25
-100
20
1
10
20
0
5
10
15
20
25
30
Frequency (MHz)
Gain (V/V)
VO = 2 VPP, f = 1 MHz
Figure 78. Harmonic Distortion vs Noninverting Gain
24
Figure 79. Two-Tone, Third-Order Intermodulation Intercept
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7 Detailed Description
7.1 Overview
The THS6214 is a differential line-driver amplifier with a current-feedback architecture. The device is targeted for
use in line-driver applications (such as xDSL and wide-band, power-line communications) and is fast enough to
support transmissions of 14.5-dBm line power up to 30 MHz. The architecture of the THS6214 is designed to
provide maximum flexibility with multiple bias settings that are selectable based on application performance
requirements, and also provides an external current pin (IADJ) to further adjust the bias current to the device. The
wide output swing (43.2 VPP) and high current drive (416 mA) of the THS6214 make the device ideally suited for
high-power, line-driving applications.
7.2 Functional Block Diagram
VS+
D1 IN+
D1
THS6214
D1 OUT
D1 FB
D2 FB
D2
THS6214
D2 OUT
D2 IN+
BIAS-1/D1D2
BIAS-2/D1D2
IADJ
BIAS-2/D3D4
BIAS-1/D3D4
D3 IN+
BIAS
D3
THS6214
GND
D3 OUT
D3 FB
D4 FB
D4
THS6214
D4 OUT
D4 IN+
VS-
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7.3 Feature Description
7.3.1 Output Current and Voltage
The THS6214 provides output voltage and current capabilities that are unsurpassed in a low-cost, dual
monolithic op amp. Under no-load conditions at 25°C, the output voltage typically swings closer than 1.1 V to
either supply rail; tested at 25°C, the swing limit is within 1.4 V of either rail into a 100-Ω differential load. Into a
25-Ω load (the minimum tested load), the amplifier delivers more than ±408-mA continuous and greater than ±1A peak output current.
The specifications described in the previous paragraph, though familiar in the industry, consider voltage and
current limits separately. In many applications, the voltage times current (or V-I product) is more relevant to
circuit operation. See the Output Voltage and Current Limitations plot (Figure 13) in the Typical Characteristics
section. The X- and Y-axes of this graph show the zero-voltage output current limit and the zero-current output
voltage limit, respectively. The four quadrants give a more detailed view of the THS6214 output drive capabilities,
noting that the graph is bounded by a safe operating area of 1-W maximum internal power dissipation (in this
case, for one channel only). Superimposing resistor load lines onto the plot illustrates that the THS6214 can drive
±10.9 V into 100 Ω or ±10.5 V into 50 Ω without exceeding the output capabilities or the 1-W dissipation limit. A
100-Ω load line (the standard test circuit load) illustrates the full ±12-V output swing capability, as provided in the
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Feature Description (continued)
Electrical Characteristics tables. The minimum specified output voltage and current over temperature are set by
worst-case simulations at the cold temperature extreme. Only at cold startup do the output current and voltage
decrease to the numbers provided in the Electrical Characteristics tables. When the output transistors deliver
power, the junction temperature increases, decreasing the VBEs (increasing the available output voltage swing),
and increasing the current gains (increasing the available output current). In steady-state operation, the available
output voltage and current are always greater than that shown in the overtemperature specifications, because
the output stage junction temperatures are higher than the minimum specified operating ambient temperature. To
maintain maximum output stage linearity, no output short-circuit protection is provided. This absence of shortcircuit protection is normally not a problem because most applications include a series-matching resistor at the
output that limits the internal power dissipation if the output side of this resistor is shorted to ground. However,
shorting the output pin directly to the adjacent positive power-supply pin (24-pin package), in most cases
destroys the amplifier. If additional short-circuit protection is required, a small series resistor can be included in
the supply lines. Under heavy output loads, this additional resistor reduces the available output voltage swing. A
5-Ω series resistor in each power-supply lead limits the internal power dissipation to less than 1 W for an output
short-circuit, and decreases the available output voltage swing only 0.5 V for up to 100-mA desired load currents.
Always place the 0.1-µF power-supply decoupling capacitors after these supply current limiting resistors, directly
on the supply pins.
7.3.2 Driving Capacitive Loads
One of the most demanding and yet very common load conditions for an op amp is capacitive loading. Often, the
capacitive load is the input of an ADC—including additional external capacitance that may be recommended to
improve the ADC linearity. A high-speed, high open-loop gain amplifier such as the THS6214 can be very
susceptible to decreased stability and closed-loop response peaking when a capacitive load is placed directly on
the output pin. When the amplifier open-loop output resistance is considered, this capacitive load introduces an
additional pole in the signal path that can decrease the phase margin. Several external solutions to this problem
have been suggested below.
When the primary considerations are frequency response flatness, pulse response fidelity, and distortion, the
simplest and most effective solution is to isolate the capacitive load from the feedback loop by inserting a series
isolation resistor between the amplifier output and the capacitive load. This series resistor does not eliminate the
pole from the loop response, but shifts the pole and adds a zero at a higher frequency. The additional zero
functions to cancel the phase lag from the capacitive load pole, thus increasing the phase margin and improving
stability. The Typical Characteristics illustrate the recommended RS versus capacitive load (see Figure 5,
Figure 23, Figure 35, Figure 47, Figure 60, and Figure 72) and the resulting frequency response at the load.
Parasitic capacitive loads greater than 2 pF can begin to degrade device performance. Long printed-circuit board
(PCB) traces, unmatched cables, and connections to multiple devices can easily cause this value to be
exceeded. Always consider this effect carefully, and add the recommended series resistor as close as possible to
the THS6214 output pin (see the Board Layout Guidelines section).
7.3.3 Distortion Performance
The THS6214 provides good distortion performance into a 100-Ω load on ±12-V supplies. Relative to alternative
solutions, the amplifier provides exceptional performance into lighter loads and operation on a dual ±6-V supply.
Generally, until the fundamental signal reaches very high frequency or power levels, the second harmonic
dominates the distortion with a negligible third-harmonic component. Focusing then on the second harmonic,
increasing the load impedance improves distortion directly. Remember that the total load includes the feedback
network—in the noninverting configuration (see Figure 81), this value is the sum of RF + RG, whereas in the
inverting configuration this value is just RF. Also, providing an additional supply decoupling capacitor (0.01 µF)
between the supply pins (for bipolar operation) improves the second-order distortion slightly (from 3 dB to 6 dB).
In most op amps, increasing the output voltage swing directly increases harmonic distortion. The Typical
Characteristics illustrate the second harmonic increasing at a little less than the expected 2x rate, whereas the
third harmonic increases at a little less than the expected 3x rate. Where the test power doubles, the second
harmonic decreases less than the expected 6 dB, and the third harmonic decreases by less than the expected
12 dB. This difference also appears in the two-tone, third-order intermodulation spurious (IM3) response curves.
The third-order spurious levels are extremely low at low-output power levels, and the output stage continues to
hold them low even when the fundamental power reaches very high levels.
26
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Feature Description (continued)
7.3.4 Differential Noise Performance
The THS6214 is designed to be used as a differential driver in xDSL applications. Therefore, analyzing the noise
in such a configuration is important. Figure 80 shows the op amp noise model for the differential configuration.
IN
EN
RS
IN
ERS
RF
4 kTRF
4 kTRS
RG
2
EO
4 kTRG
RF
4 kTRF
IN
EN
RS
IN
ERS
4 kTRS
Figure 80. Differential Op Amp Noise Analysis Model
As a reminder, the differential gain is expressed as given in Equation 1:
2 ´ RF
GD = 1 +
RG
(1)
The output noise can be expressed as shown in Equation 2:
EO =
2
2
2
2 ´ GD2 ´ eN + (iN ´ RS) + 4 kTRS + 2(iIRF) + 2(4 kTRFGD)
(2)
Dividing this expression by the differential noise gain [GD = (1 + 2RF / RG)] gives the equivalent input-referred
spot noise voltage at the noninverting input, as shown in Equation 3.
EO =
2
2
2 ´ eN + (iN ´ RS) + 4 kTRS + 2
iIRF
GD
2
+2
4 kTRF
GD
(3)
Evaluating these equations for the THS6214 ADSL circuit and component values of Figure 84 gives a total output
spot noise voltage of 38.9 nV/√Hz and a total equivalent input spot noise voltage of 7 nV/√Hz.
In order to minimize the output noise as a result of the noninverting input bias current noise, keeping the
noninverting source impedance as low as possible is recommended.
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Feature Description (continued)
7.3.5 DC Accuracy and Offset Control
A current-feedback op amp such as the THS6214 provides exceptional bandwidth in high gains, giving fast pulse
settling but only moderate dc accuracy. The Electrical Characteristics describe an input offset voltage
comparable to high-speed, voltage-feedback amplifiers; however, the two input bias currents are somewhat
higher and are unmatched. Although bias current cancellation techniques are very effective with most voltagefeedback op amps, these techniques do not generally reduce the output dc offset for wideband current-feedback
op amps. Because the two input bias currents are unrelated in both magnitude and polarity, matching the input
source impedance to reduce error contribution to the output is ineffective. Evaluating the configuration of
Figure 81, using a worst-case condition at 25°C input offset voltage and the two input bias currents, gives a
worst-case output offset range equal to Equation 4:
RS
§
·
VOFF r NG u VOS MAX
¨ IBN u 2 u NG ¸ r IBI u RF
©
¹
r 10 u 5 mV
3.5 PA u 25 : u 10 r 1.24 k: u 45 PA
r50 mV 0.875 mV r 55.5 mV
VOFF
104.92 mV to 106.67 mV
where
•
NG = noninverting signal gain
(4)
7.4 Device Functional Modes
The THS6214 has four different functional modes for each port set by the BIAS-1/xxxx and BIAS-2/xxxx pins.
Table 2 shows the truth table for the device mode pin configuration and the associated description of each mode.
Table 2. Bias Logic Table
28
BIAS-1/XXXX
BIAS-2/XXXX
FUNCTION
DESCRIPTION
0
0
Full-bias mode (100%)
Amplifiers on with lowest distortion possible (default state)
1
0
Mid-bias mode (75%)
Amplifiers on with power savings and a reduction in
distortion performance
0
1
Low-bias mode (50%)
Amplifiers on with enhanced power savings and a
reduction of overall performance
1
1
Shutdown mode
Amplifiers off and output has high impedance
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The THS6214 is typically used to drive high output power applications with various load conditions. In the Typical
Applications section, the amplifier is presented in a general-purpose, wideband, current-feedback configuration,
and a more specific 100-Ω twisted pair cable line driver. However, the amplifier is also applicable for many
different general-purpose and specific cable line-driving scenarios beyond what is described in the Typical
Applications section.
8.2 Typical Applications
8.2.1 Wideband Current-Feedback Operation
The THS6214 provides the exceptional ac performance of a wideband current-feedback op amp with a highly
linear, high-power output stage. Requiring only 21-mA/port quiescent current, the THS6214 swings to within
1.9 V of either supply rail on a 100-Ω load and delivers in excess of 416 mA at room temperature. This lowoutput headroom requirement, along with supply voltage independent biasing, provides remarkable ±6-V supply
operation. The THS6214 delivers greater than 140-MHz bandwidth driving a 2-VPP output into 100 Ω on a ±6-V
supply. Previous boosted output stage amplifiers typically suffer from very poor crossover distortion when the
output current goes through zero. The THS6214 achieves a comparable power gain with much better linearity.
The primary advantage of a current-feedback op amp over a voltage-feedback op amp is that ac performance
(bandwidth and distortion) is relatively independent of signal gain. Figure 81 shows the dc-coupled, gain of
10 V/V, dual power-supply circuit configuration used as the basis of the ±12-V Electrical Characteristics and
Typical Characteristics. For test purposes, the input impedance is set to 50 Ω with a resistor to ground and the
output impedance is set to 50 Ω with a series output resistor. Voltage swings reported in the Electrical
Characteristics are taken directly at the input and output pins, whereas load powers (dBm) are defined at a
matched 50-Ω load.
For the circuit of Figure 81, the total effective load is 100 Ω || 1.24 kΩ || 1.24 kΩ = 86.1 Ω.
12 V
D1
THS6214
RF
1.24 kW
VIN
RG
274 W
RF
1.24 kW
VOUT
RL
D2
THS6214
GDIFF = 1 +
-12 V
2 ´ RF
RG
=
VOUT
VIN
Figure 81. Noninverting Differential I/O Amplifier
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Typical Applications (continued)
8.2.1.1 Design Requirements
The main design requirements for wideband current-feedback operation are to choose power supplies that satisfy
common-mode requirements at the input and output of the device, and also to use a feedback resistor value that
allows for the proper bandwidth when maintaining stability. These requirements and the proper solutions are
described in the Detailed Design Procedure section. Using transformers and split power supplies can be required
for certain applications.
8.2.1.2 Detailed Design Procedure
For ease of test purposes in this design, the THS6214 input impedance is set to 50 Ω with a resistor to ground
and the output impedance is set to 50 Ω with a series output resistor. Voltage swings reported in the Electrical
Characteristics tables are taken directly at the input and output pins, whereas load powers (dBm) are defined at
a matched 50-Ω load. For the circuit of Figure 81, the total effective load is 100 Ω || 1.24 kΩ || 1.24 kΩ = 86.1 Ω.
This approach allows a source termination impedance to be set at the input that is independent of the signal
gain. For instance, simple differential filters can be included in the signal path right up to the noninverting inputs
with no interaction with the gain setting. The differential signal gain for the circuit of Figure 81 is given by
Equation 5:
RF
AD = 1 + 2 ´
RG
where
•
AD = differential gain
(5)
A value of 274 Ω for the AD = 10-V/V design is given by Figure 81. The device bandwidth is primarily controlled
with the feedback resistor value because the THS6214 is a current-feedback (CFB) amplifier; the differential
gain, however, can be adjusted with considerable freedom using just the RG resistor. In fact, RG can be reduced
by a reactive network that provides a very isolated shaping to the differential frequency response.
Various combinations of single-supply or ac-coupled gain can also be delivered using the basic circuit of
Figure 81. Common-mode bias voltages on the two noninverting inputs pass on to the output with a gain of 1 V/V
because an equal dc voltage at each inverting node does not create current through RG. This circuit does show a
common-mode gain of 1 V/V from the input to output. The source connection must either remove this commonmode signal if undesired (using an input transformer can provide this function), or the common-mode voltage at
the inputs can be used to set the output common-mode bias. If the low common-mode rejection of this circuit is a
problem, the output interface can also be used to reject that common-mode signal. For instance, most modern
differential input analog-to-digital converters (ADCs) reject common-mode signals very well, and a line-driver
application through a transformer also attenuates the common-mode signal through to the line.
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Typical Applications (continued)
8.2.1.3 Application Curves
3
-50
0
-60
Harmonic Distortion (dBc)
Normalized Gain (dB)
Figure 82 and Figure 83 show the frequency response and distortion performance of the circuit in Figure 81. The
measurements are made with a load resistor (RL) of 100 Ω, and at room temperature. Figure 82 is measured
using the three different device power modes, and the distortion measurements in Figure 83 are made at an
output voltage level of 2 VPP.
-3
-6
-9
-12
Full-Bias (100%) Mode
Mid-Bias (75%) Mode
Low-Bias (50%) Mode
-15
-70
-80
-90
-100
-18
1
HD2
HD3
10
Frequency (MHz)
100
-110
0.4
400
1
10
Frequency (MHz)
D002
Figure 82. Frequency Response
40
D007
Figure 83. Harmonic Distortion
8.2.2 Dual-Supply VDSL Downstream Driver
Figure 84 shows an example of a dual-supply downstream driver with a synthesized output impedance circuit.
The THS6214 is configured as a differential gain stage to provide a signal drive to the primary winding of the
transformer (a step-up transformer with a turns ratio of 1:n is shown in Figure 84). The main advantage of this
configuration is the cancellation of all even harmonic-distortion products. Another important advantage is that
each amplifier must only swing half of the total output required driving the load.
12 V
20 W
D1
THS6214
RF
2.2 kW
0.1 mF
RP
2.9 kW
2 kW
AFE
2 VPP
Max
Assumed
RG
1.4 kW
2 kW
0.1 mF
20 W
IP = 159 mA
RM
10 W
1:1.1
ZLINE
RP
2.9 kW
RF
2.2 kW
D2
THS6214
RL
100 W
RM
10 W
IP = 159 mA
-12 V
Figure 84. Dual-Supply VDSL Downstream Driver
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Typical Applications (continued)
The analog front-end (AFE) signal is ac-coupled to the driver, and the noninverting input of each amplifier is
biased to the mid-supply voltage (ground in this case). In addition to providing the proper biasing to the amplifier,
this approach also provides a high-pass filtering with a corner frequency that is set at 5 kHz in this example.
Because the signal bandwidth starts at 26 kHz, this high-pass filter does not generate any problems and has the
advantage of filtering out unwanted lower frequencies.
8.2.2.1 Design Requirements
The main design requirements for Figure 84 are to match the output impedance correctly, satisfy headroom
requirements, and ensure that the circuit meets power driving requirements. These requirements are described in
the Detailed Design Procedure section and include the required equations to properly implement the design. The
design must be fully worked through before physical implementation because small changes in a single
parameter can often have large effects on performance.
8.2.2.2 Detailed Design Procedure
For Figure 84, the input signal is amplified with a gain set by Equation 6:
2 ´ RF
GD = 1 +
RG
(6)
The two back-termination resistors (RM = 10 Ω, each) added at each terminal of the transformer make the
impedance of the amplifier match the impedance of the line, and also provide a means of detecting the received
signal for the receiver. The value of these resistors (RM) is a function of the line impedance and the transformer
turns ratio (n), given by Equation 7:
ZLINE
RM =
2n2
(7)
8.2.2.2.1 Line Driver Headroom Model Requirements
The first step in a transformer-coupled, twisted-pair driver design is to compute the peak-to-peak output voltage
from the target specifications. This calculation is done using Equation 8 to Equation 11:
VRMS2
PL = 10 ´ log
(1 mW) ´ RL
where
•
•
•
PL = power at the load
VRMS = voltage at the load
RL = load impedance
(8)
These values produce the following:
VRMS =
(1 mW) ´ RL ´ 10
PL
10
(9)
VP = Crest Factor ´ VRMS = CF ´ VRMS
where
•
•
VP = peak voltage at the load
CF = crest factor
(10)
VLPP = 2 ´ CF ´ VRMS
where
•
32
VLPP = peak-to-peak voltage at the load
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Typical Applications (continued)
Consolidating Equation 8 to Equation 11 allows the required peak-to-peak voltage at the load to be expressed as
a function of the crest factor, the load impedance, and the power at the load, as given by Equation 12:
VLPP = 2 ´ CF ´
(1 mW) ´ RL ´ 10
PL
10
(12)
VLPP is usually computed for a nominal line impedance and can be taken as a fixed design target.
The next step in the design is to compute the individual amplifier output voltage and currents as a function of
peak-to-peak voltage on the line and transformer-turns ratio.
When this turns ratio changes, the minimum allowed supply voltage also changes. The peak current in the
amplifier output is given by Equation 13:
2 ´ VLPP
1
1
±IP =
´
´
n
2
4 RM
where
•
•
VPP is as defined in Equation 12, and
RM is as defined in Equation 7 and Figure 85
(13)
RM
VPP =
2 VLPP
n
VLPP
n
RL
VLPP
RM
Copyright © 2016, Texas Instruments Incorporated
Figure 85. Driver Peak Output Voltage
With the previous information available, a supply voltage and the turns ratio desired for the transformer can now
be selected, and the headroom for the THS6214 can be calculated.
The model illustrated in Figure 86 can be described with Equation 14 and Equation 15 as:
1. The available output swing:
VPP = VCC - (V1 + V2) - IP ´ (R1 + R2)
2. Or as the required supply voltage:
VCC = VPP + (V1 + V2) + IP ´ (R1 + R2)
(14)
(15)
The minimum supply voltage for power and load requirements is given by Equation 15.
V1, V2, R1, and R2 are given in Table 3 for the ±12-V operation.
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Typical Applications (continued)
VCC
R1
V1
VOUT
IP
V2
R2
Figure 86. Line Driver Headroom Model
Table 3. Line Driver Headroom Model Values
VS
V1
R1
V2
R2
±12 V
1V
0.6 Ω
1V
1.2 Ω
When using a synthetic output impedance circuit (see Figure 84), a significant drop in bandwidth occurs from the
specification provided in the Electrical Characteristics tables. This apparent drop in bandwidth for the differential
signal is a result of the apparent increase in the feedback transimpedance for each amplifier. This feedback
transimpedance equation is given by Equation 16:
1+2´
ZFB = RF ´
1+2´
RS
RL
RS
RP
RL
+
RS
+
RS
RF
-
RP
RP
(16)
To increase the 0.1-dB flatness to the frequency of interest, adding a serial RC in parallel with the gain resistor
may be needed, as shown in Figure 87.
RS
D1
THS6214
RF
RP
RM
ZLINE
VIN
RG
RP
100 W
CM
RF
D2
THS6214
RS
Figure 87. 0.1-dB Flatness Compensation Circuit
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8.2.2.2.2 Total Driver Power for xDSL Applications
The total internal power dissipation for the THS6214 in an xDSL line driver application is the sum of the
quiescent power and the output stage power. The THS6214 holds a relatively constant quiescent current versus
supply voltage—giving a power contribution that is simply the quiescent current times the supply voltage used
(the supply voltage is greater than the solution given in Equation 15). The total output stage power can be
computed with reference to Figure 88.
VCC
IAVG =
IP
CF
RT
Figure 88. Output Stage Power Model
The two output stages used to drive the load of Figure 85 are shown as an H-Bridge in Figure 88. The average
current drawn from the supply into this H-Bridge and load is the peak current in the load given by Equation 13
divided by the crest factor (CF) for the xDSL modulation. This total power from the supply is then reduced by the
power in RT, leaving the power dissipated internal to the drivers in the four output stage transistors. That power is
simply the target line power used in Equation 8 plus the power lost in the matching elements (RM). In the
following examples, a perfect match is targeted giving the same power in the matching elements as in the load.
The output stage power is then set by Equation 17.
IP
POUT =
´ VCC - 2PL
CF
(17)
The total amplifier power is then given by Equation 18:
IP
PTOT = IQ ´ VCC +
´ VCC - 2PL
CF
(18)
For the ADSL CO driver design of Figure 84, the peak current is 159 mA for a signal that requires a crest factor
of 5.6 with a target line power of 20.5 dBm into a 100-Ω load (115 mW).
With a typical quiescent current of 21 mA and a nominal supply voltage of ±12 V, the total internal power
dissipation for the solution of Figure 84 is given by Equation 19:
159 mA
PTOT = 21 mA (24 V) +
(24 V) - 2(115 mW) = 955 mW
5.6
(19)
9 Power Supply Recommendations
The THS6214 is designed to operate optimally using split power supplies. The device has a very wide supply
range of ±5 V to ±14 V to accommodate many different application scenarios. Choose power-supply voltages
that allow for adequate swing on both the inputs and outputs of the amplifier to prevent affecting device
performance. The ground pin provides the ground reference for the control pins and must be within VS– to (VS+ –
5 V) for proper operation.
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10 Layout
10.1 Board Layout Guidelines
Achieving optimum performance with a high-frequency amplifier such as the THS6214 requires careful attention
to board layout parasitic and external component types. Recommendations that optimize performance include:
a. Minimize parasitic capacitance to any ac ground for all signal I/O pins. Parasitic capacitance on the output
and inverting input pins can cause instability; on the noninverting input, this capacitance can react with the
source impedance to cause unintentional band limiting. To reduce unwanted capacitance, a window around
the signal I/O pins must be opened in all ground and power planes around these pins. Otherwise, ground
and power planes must be unbroken elsewhere on the board.
b. Minimize the distance (less than 0.25 in, or 6.35 mm) from the power-supply pins to high-frequency 0.1-µF
decoupling capacitors. At the device pins, the ground and power plane layout must not be in close proximity
to the signal I/O pins. Avoid narrow power and ground traces to minimize inductance between the pins and
the decoupling capacitors. The power-supply connections must always be decoupled with these capacitors.
An optional supply decoupling capacitor across the two power supplies (for bipolar operation) improves
second-harmonic distortion performance. Larger (2.2 µF to 6.8 µF) decoupling capacitors, effective at lower
frequencies, must also be used on the main supply pins. These capacitors can be placed somewhat farther
from the device and can be shared among several devices in the same area of the PCB.
c. Careful selection and placement of external components preserve the high-frequency performance of the
THS6214. Resistors must be of a very low reactance type. Surface-mount resistors work best and allow a
tighter overall layout. Metal film and carbon composition, axially-leaded resistors can also provide good highfrequency performance.
Again, keep leads and PCB trace length as short as possible. Never use wire-wound type resistors in a highfrequency application. Although the output pin and inverting input pin are the most sensitive to parasitic
capacitance, always position the feedback and series output resistor, if any, as close as possible to the
output pin. Other network components, such as noninverting input termination resistors, must also be placed
close to the package. Where double-side component mounting is allowed, place the feedback resistor
directly under the package on the other side of the board between the output and inverting input pins. The
frequency response is primarily determined by the feedback resistor value as described previously.
Increasing the value reduces the bandwidth, whereas decreasing the value leads to a more peaked
frequency response. The 1.24-kΩ feedback resistor used in the Typical Characteristics at a gain of 10 V/V on
±12-V supplies is a good starting point for design. Note that a 1.5-kΩ feedback resistor, rather than a direct
short, is recommended for a unity-gain follower application. A current-feedback op amp requires a feedback
resistor to control stability even in the unity-gain follower configuration.
d. Connections to other wideband devices on the board can be made with short direct traces or through
onboard transmission lines. For short connections, consider the trace and the input to the next device as a
lumped capacitive load. Relatively wide traces (50 mils to 100 mils [0.050 in to 0.100 in, or 1.27 mm to 2.54
mm]) must be used, preferably with ground and power planes opened up around them. Estimate the total
capacitive load and set RS from the recommended RS versus capacitive load plots (see Figure 5, Figure 23,
Figure 35, Figure 47, Figure 60, and Figure 72). Low parasitic capacitive loads (less than 5 pF) may not
need an isolation resistor because the THS6214 is nominally compensated to operate with a 2-pF parasitic
load. If a long trace is required, and the 6-dB signal loss intrinsic to a doubly-terminated transmission line is
acceptable, implement a matched-impedance transmission line using microstrip or stripline techniques
(consult an ECL design handbook for microstrip and stripline layout techniques). A 50-Ω environment is not
necessary on board; in fact, a higher impedance environment improves distortion (see the distortion versus
load plots). With a characteristic board trace impedance defined based on board material and trace
dimensions, a matching series resistor into the trace from the output of the THS6214 is used, as well as a
terminating shunt resistor at the input of the destination device. Remember also that the terminating
impedance is the parallel combination of the shunt resistor and the input impedance of the destination
device.
This total effective impedance must be set to match the trace impedance. The high output voltage and
current capability of the THS6214 allows multiple destination devices to be handled as separate transmission
lines, each with their own series and shunt terminations. If the 6-dB attenuation of a doubly-terminated
transmission line is unacceptable, a long trace can be series-terminated at the source end only.
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Board Layout Guidelines (continued)
Treat the trace as a capacitive load in this case and set the series resistor value as shown in the
recommended RS versus capacitive load plots. However, this configuration does not preserve signal integrity
as well as a doubly-terminated line. If the input impedance of the destination device is low, there is some
signal attenuation as a result of the voltage divider formed by the series output into the terminating
impedance.
e. Socketing a high-speed part such as the THS6214 is not recommended. The additional lead length and pinto-pin capacitance introduced by the socket can create an extremely troublesome parasitic network, and can
make achieving a smooth, stable frequency response almost impossible. Best results are obtained by
soldering the THS6214 directly onto the board.
f. Use the –VS plane to conduct heat out of the VQFN-24 and HTSSOP-24 PowerPAD packages. These
packages attach the die directly to an exposed thermal pad on the bottom, and must be soldered to the
board. This pad must be connected electrically to the same voltage plane as the most negative supply
applied to the THS6214 (in Figure 84, this supply is –12 V).
10.2 Layout Example
Figure 89. Example Layout
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11 Device and Documentation Support
11.1 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me to register and receive a weekly digest of any product information that has
changed. For change details, review the revision history included in any revised document.
11.2 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.3 Trademarks
PowerPAD, E2E are trademarks of Texas Instruments.
All other trademarks are the property of their respective owners.
11.4 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
11.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
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10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
THS6214IPWP
ACTIVE
HTSSOP
PWP
24
60
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
THS6214
THS6214IPWPR
ACTIVE
HTSSOP
PWP
24
2000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
THS6214
THS6214IRHFR
ACTIVE
VQFN
RHF
24
3000
RoHS & Green NIPDAU | NIPDAUAG
Level-2-260C-1 YEAR
-40 to 85
6214
THS6214IRHFT
ACTIVE
VQFN
RHF
24
250
RoHS & Green NIPDAU | NIPDAUAG
Level-2-260C-1 YEAR
-40 to 85
6214
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of