TI1 LMH6517SQNOPB Low power, low noise, if and baseband, dual 16 bit adc driver with digitally controlled gain Datasheet

LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
Low Power, Low Noise, IF and Baseband, Dual 16 bit ADC Driver With Digitally Controlled
Gain
Check for Samples: LMH6517
FEATURES
DESCRIPTION
•
•
•
•
•
•
•
•
•
The LMH6517 contains two high performance,
digitally controlled variable gain amplifiers (DVGA). It
has been designed for use in narrowband and
broadband IF sampling applications. Typically the
LMH6517 drives a high performance ADC in a broad
range of mixed signal and digital communication
applications such as mobile radio and cellular base
stations where automatic gain control (AGC) is
required to increase system dynamic range.
1
2
•
•
Accurate, 0.5dB Gain Steps
200Ω Resistive, Differential Input
Low Impedance, Differential Output
Disable Function for Each Channel
Parallel Gain Control
SPI Compatible Serial Bus
Two Wire, Pulse Mode Control
On Chip Register Stores Gain Setting
Low Sensitivity of Linearity and Phase to Gain
Setting
Single 5V Supply Voltage
Small Footprint WQFN Package
The LMH6517 digitally controlled attenuator provides
precise 0.5dB gain steps over a 31.5dB range. On
chip digital latches are provided for local storage of
the gain setting. Both serial and parallel programming
options are provided. A Pulse mode is also offered
where simple up or down commands can change the
gain one step at a time.
APPLICATIONS
•
•
•
•
•
Cellular Base Stations
IF Sampling Receivers
Instrumentation
Modems
Imaging
The output amplifier has a differential output allowing
large signal swings on a single 5V supply. The low
impedance output provides maximum flexibility when
driving filters or analog to digital converters.
KEY SPECIFICATIONS
•
•
•
•
•
•
Each channel of LMH6517 has an independent,
digitally controlled attenuator and a high linearity,
differential output amplifier. Each block has been
optimized for low distortion and maximum system
design flexibility. Each channel can be individually
disabled for power savings.
OIP3: 43dBm @ 200MHz
Noise figure 5.5dB
Gain step size of 0.5dB
Gain step accuracy: 0.05dB
Frequency Range of 1200 MHz
Supply current 80mA per channel
The LMH6517 operates over the industrial
temperature range of −40°C to +85°C. The LMH6517
is available in a 32-Pin, thermally enhanced, WQFN
package.
Typical Application: IF Sampling Receiver
VCC
RF
200
LO
½ LMH6517
ADC
6
GAIN 0-5
LATCH
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2008–2011, Texas Instruments Incorporated
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Absolute Maximum Ratings
ESD Tolerance
(1) (2)
(3)
Human Body Model
2 kV
Machine Model
100V
Charged Device Model
750V
−0.6V to 5.5V
Positive Supply Voltage (Pin 3)
Differential Voltage between Any Two Grounds
<200 mV
−0.6V to V+
Analog Input Voltage Range
−0.6V to 3.6V
Digital Input Voltage Range
Output Short Circuit Duration
(one pin to ground)
Infinite
Junction Temperature
+150°C
−65°C to +150°C
Storage Temperature Range
Soldering Information
Infrared or Convection (30 sec)
(1)
(2)
(3)
260°C
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications, see the
Electrical Characteristics tables.
If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and
specifications.
Human Body Model, applicable std. MIL-STD-883, Method 3015.7. Machine Model, applicable std. JESD22-A115-A (ESD MM std. of
JEDEC)Field-Induced Charge-Device Model, applicable std. JESD22-C101-C (ESD FICDM std. of JEDEC).
Operating Ratings
(1)
Supply Voltage (Pin 3)
4.5V to 5.25V
Differential Voltage Between Any Two Grounds
<10 mV
Analog Input Voltage Range,
AC Coupled
Temperature Range
0V to V+
(2)
−40°C to +85°C
Package Thermal Resistance (θJA)
32-Pin WQFN
(1)
(2)
2
42°C/W
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications, see the
Electrical Characteristics tables.
The maximum power dissipation is a function of TJ(MAX), θJA. The maximum allowable power dissipation at any ambient temperature is
PD = (TJ(MAX) – TA)/ θJA. All numbers apply for packages soldered directly onto a PC Board.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
5V Electrical Characteristics
(1)
The following specifications apply for single supply with V+ = 5V, Maximum Gain , RL = 100Ω, VOUT = 2 VPP, fin = 150 MHz.
Boldface limits apply at temperature extremes.
Parameter
Test Conditions
Min
(2)
Typ
(3)
Max
(2)
Units
Dynamic Performance
SSBW
OIP3
IMD3
P1dB
Frequency Range
1200
MHz
Maximum Voltage Gain
f = 200 MHz
22
dB
Input Noise Voltage
Maximum Gain, f > 1MHz, RIN= 0 Ω
1.1
nV/√Hz
Output Noise Voltage
Maximum Gain, f > 1MHz
22
nV/√Hz
Noise Figure
Maximum Gain
5.5
dB
Output Third Order Intercept Point
f = 150 MHz, V OUT = 4dBm per tone
43
dBm
Output Third Order Intercept Point
f = 200 MHz, V OUT = 4dBm per tone
43
Third Order Intermodulation
Products
f = 150 MHz, V OUT = 4dBm per tone
−78
Third Order Intermodulation
Products
f = 200 MHz, V OUT = 4dBm per tone
−78
1dB Compression Point
f = 150 MHz, RL= 100Ω
18.3
1dB Compression Point
f= 150 MHz, RL= 200Ω
15.5
Input Resistance
Differential
dBc
dBm
Analog I/O
170
Input Capacitance
200
220
2
Input Common Mode Voltage
Self Biased
2.42
2.24
Input Common Mode Voltage
Range
Externally Driven, CMRR > 40dB
1.5
Maximum Input Voltage Swing
Volts peak to peak, differential
Output Common Mode Voltage
Self Biased
Maximum DIfferential Output
Voltage Swing
Differential
2.55
2.71
2.79
V
3.5
V
5.5
2.4
2.55
Ω
pF
V
2.7
5.9
V
VPP
Output Voltage Swing
Single ended (each output)
1.05
1V to 4V
4.00
V
VOS
Output Offset Voltage
All Gain Settings
−25
-30
−2
25
30
mV
CMRR
Common Mode Rejection Ratio
Maximum Gain, f=100MHz
PSRR
Power Supply Rejection Ratio
Maximum Gain, f=100MHz
60
dB
XTLK
Channel to Channel Crosstalk
Maximum Gain, f=100MHz
−85
dBc
XTLK
Channel to Channel Crosstalk
Maximum Gain, f=300MHz
−72
dBc
60
dB
Gain Parameters
(1)
(2)
(3)
Maximum Gain
Gain Code 000000,
DC Voltage Gain
21.7
21.65
21.85
22
22.05
dB
Minimum Gain
Gain Code 111111,
DC Voltage Gain
−9.25
−9.1
−9.5
−9.78
−9.8
dB
Gain Adjust Range
31.5
dB
Gain Step Size
0.5
dB
dB
Channel Matching
Gain Error between A and B channel.
±0.05
Channel Matching
Phase Shift between A and B channel.
±0.1
Gain Step Error
Any two steps
−0.3
±0.05
0.3
dB
Gain Step Error
Maximum Gain to Maximum Gain −12dB
−0.5
±0.1
0.5
dB
°
Electrical Table values apply only for factory testing conditions at the temperature indicated. No guarantee of parametric performance is
indicated in the electrical tables under conditions different than those tested
Limits are 100% production tested at 25°C. Limits over the operating temperature range are guaranteed through correlation using
Statistical Quality Control (SQC) methods.
Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary
over time and will also depend on the application and configuration. The typical values are not tested and are not guaranteed on
shipped production material.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
3
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
5V Electrical Characteristics (1) (continued)
The following specifications apply for single supply with V+ = 5V, Maximum Gain , RL = 100Ω, VOUT = 2 VPP, fin = 150 MHz.
Boldface limits apply at temperature extremes.
Parameter
Gain Step Phase Shift
Test Conditions
Min
(2)
between any two steps
Gain Step Switching Time
Typ
(3)
Max
(2)
Units
0.5
°
15
ns
Power Requirements
ICC
Supply Current
Each channel (two channels per package)
80
P
Power
Each Channel
400
91
mW
mA
ICC
Disabled Supply Current
Each Channel
7.5
mA
All Digital Inputs
Logic Compatibility
TTL, 2.5V CMOS, 3.3V CMOS
VIL
Logic Input Low Voltage
0
0.4
VIH
Logic Input High Voltage
2.0
3.6
V
V
IIH
Logic Input High Input Current
Digital Input Voltage = 3.3V
−110
110
μA
IIL
Logic Input Low Input Current
Digital Input Voltage = 0V
−110
110
μA
Parallel and Pulse Mode Timing
tGS
Setup Time
3
ns
tGH
Hold Time
3
ns
tLP
Latch Low Pulse Width
7
ns
tPG
Pulse Gap between Pulses
20
ns
tPW
Minimum Latch Pulse Width
20
ns
tRW
Reset Width
10
ns
Serial Mode Timing and AC Characteristics
SPI Compatible
fSCLK
Serial Clock Frequency
10.5
MHz
tPH
SCLK High State Duty Cycle
% of SCLK Period
40
60
%
tPL
SCLK Low State Duty cycle
% of SCLK Period
40
60
tSU
Serial Data In Setup Time
tH
Serial Data In Hold Time
tODZ
Serial Data Out Driven-to- Tri-State
Time
Referenced to Positive edge of CS
40
50
ns
tOZD
Serial Data Out Tri-State-to-Driven
Time
Referenced to Negative edge of SCLK
15
20
ns
tOD
Serial Data Out Output Delay TIme
Referenced to Negative edge of SCLK
15
20
ns
tCSS
Serial Chip Select Setup TIme
Referenced to Positive edge of SCLK
10
5
tCSH
Serial Chip Select Hold TIme
Referenced to Positive edge of SCLK
10
5
tIAG
Inter-Access Gap
Minimum time Serial Chip Select pin must
be asserted between accesses.
4
0.5
5
Submit Documentation Feedback
3
%
ns
ns
Cycles of
SCLK
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
CONNECTION DIAGRAM
A2/CS/S1A
A1/SDO/S0A
IPA+
IPA-
GND
+5V
GND
A0
32
31
30
29
28
27
26
25
Top View
A3/SDI/DNA
1
24
OPA+
A4/CLK/UPA
2
23
OPA-
22
ENA
LMH6517
A5
3
MOD0
4
21
LATA
MOD1
5
20
LATB
B5
6
19
ENB
B4/UPB
7
18
OPB-
17
OPB+
9
10
11
12
13
14
15
16
B1/S0B
IPB+
IPB-
GND
+5V
GND
B0
8
B2/S1B
B3/DNB
GND
Figure 1. 32-Pin WQFN Package
See Package Number RTV0032A
PIN DESCRIPTIONS
Pin Number
Pin Name
Description
Analog I/O
30, 11
IPA+, IPB+
Amplifier non—inverting input. Internally biased to mid supply. Input voltage should not exceed
V+ or go below GND by more than 0.5V.
29, 12
IPA−, IPB−
Amplifier inverting input. Internally biased to mid supply. Input voltage should not exceed V+ or
go below GND by more than 0.5V.
24, 17
OPA+, OPB+
Amplifier non—inverting output. Internally biased to mid supply.
23, 18
OPA−, OPB−
Amplifier inverting output. Internally biased to mid supply.
13, 15, 26, 28,
center pad
GND
Ground pins. Connect to low impedance ground plane. All pin voltages are specified with
respect to the voltage on these pins. The exposed thermal pad is internally bonded to the
ground pins.
14, 27
+5V
Power supply pins. Valid power supply range is 4.5V to 5.25V.
Power
Common Control Pins
4, 5
MOD0, MOD1
Digital Mode control pins. These pins float to the logic hi state if left unconnected. See below
for Mode settings.
22, 19
ENA, ENB
Enable pins. Logic 1 = enabled state. See Application Information for operation in serial mode.
Digital Inputs Parallel Mode (MOD1 = 1, MOD0 = 1)
25, 16
A0, B0
Gain bit zero = 0.5dB step. Gain steps down from maximum gain (000000 = Maximum Gain)
31, 10
A1, B1
Gain bit one = 1dB step
32, 9
A2, B2
Gain bit two = 2dB step
1, 8
A3, B3
Gain bit three = 4dB step
2, 7
A4, B4
Gain bit four = 8dB step
3, 6
A5, B5
Gain bit five = 16dB step
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
5
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
PIN DESCRIPTIONS (continued)
Pin Number
21, 20
6
Pin Name
LATA, LATB
Description
Latch pins. Logic zero = active, logic 1 = latched. Gain will not change once latch is high.
Connect to ground if the latch function is not desired.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
PIN DESCRIPTIONS (continued)
Pin Number
Pin Name
Description
Digital Inputs Serial Mode (MOD1 =1 , MOD0 = 0)
2
CLK
Serial Clock
1
SDI
Serial Data In (SPI Compatible) See Application Information for more details.
32
CS
Serial Chip Select (SPI compatible)
31
SDO
Serial Data Out (SPI compatible)
3, 4, 6 — 10, 16, 20, GND
21, 25
Pins unused in Serial Mode, connect to DC ground.
Digital Inputs Pulse Mode (MOD1 = 0 , MOD0 = 1)
2, 7
UPA, UPB
Up pulse pin. A logic 0 pulse will increase gain one step.
1, 8
DNA, DNB
Down pulse pin. A logic 0 pulse will decrease gain one step.
1 & 2 or 7 & 8
Pulsing both pins together will reset the gain to maximum gain.
31, 32
S0A, S1A
Step size zero and step size 1. (0,0) = 0.5dB; (0, 1)= 1dB; (1,0) = 2dB, and (1, 1)= 6dB
10, 9
S0B, S1B
Step size zero and step size 1. (0,0) = 0.5dB; (0, 1)= 1dB; (1,0) = 2dB, and (1, 1)= 6dB
3, 5, 6, 16, 25
GND
Pins unused in Pulse Mode, connect to DC ground.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
7
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
Typical Performance Characteristics
VCC = 5V
Frequency Response 2dB Gain Steps
Transformer Coupled
Frequency Response 2dB Gain Steps
30
RL = 120Ö
& 5 pF
25
20
15
GAIN (dB)
GAIN (dB)
20
15
10
10
5
5
0
0
-5
-5
-10
-10
10
100
1000
1
10k
10
FREQUENCY (MHz)
Figure 2.
-40 °C
0 °C
20 °C
50 °C
80 °C
0.75
GROUP DELAY (ns)
22.4
GAIN (dB)
Group Delay
1.00
22.6
22.2
22.0
21.8
21.6
21.4
0
50
100 150 200 250
FREQUENCY (MHz)
0.00
-0.25
ATT = 16 dB
-0.50
150 250 350 450 550 650 750 850
FREQUENCY (MHz)
Figure 4.
Figure 5.
Third Order Intercept Point
vs
Frequency
Third Order Intermodulation Products
vs
Frequency
-40
-50
ATT = 8 dB
ATT = 16 dB
-55
IMD3 (dBc)
40
35
POUT = 6 dBm
-45
ATT = 0 dB
45
OIP3 (dBm)
ATT = 31.5 dB
0.25
-1.00
50
300
55
ATT = 24 dB
ATT = 24 dB
-60
-65
-70
-75
ATT = 16 dB
-80
30
-85
POUT = 6 dBm
100
ATT = 8 dB
ATT = 0 dB
200
300
400
500
-90
0
FREQUENCY (MHz)
100
200
300
400
500
FREQUENCY (MHz)
Figure 6.
8
ATT = 0 dB
0.50
-0.75
21.2
25
0
1000
Figure 3.
Gain Flatness over Temperature
22.8
50
100
FREQUENCY (MHz)
Figure 7.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
Typical Performance Characteristics (continued)
VCC = 5V
Third Order Intercept Point at Various Attenuator Settings
f = 150 MHz
Third Order Intercept Point at Various Attenuator Settings
f = 200 MHz
46
46
44
44
ATT = 0 dB
42
42
OIP3 (dBm)
OIP3 (dBm)
ATT = 8 dB
40 ATT = 16 dB
38
ATT = 0 dB
ATT = 8 dB
40
ATT = 16 dB
38
ATT = 24 dB
36
34
32
-2
36
RL = 100:
f = 150 MHz
0
34
2
4
6
8
32
-2
10
ATT = 24dB
RL = 100:
f = 200 MHz
0
OUTPUT POWER (dBm/tone)
2
4
6
8
10
OUTPUT POWER (dBm/tone)
Figure 8.
Figure 9.
Third Order Intercept Point at Various Attenuator Settings
f = 250 MHz
Third Order Intermodulation at Various Attenuator Settings
f = 200 MHz
46
-30
ATT = 0 dB
42
ATT = 8 dB
OIP3 (dBm)
ATT = 16 dB
40
ATT = 24 dB
38
36
34
32
-2
RL = 100:
f = 250 MHz
0
2
4
-40
Third Order IMD Products (dBc)
44
6
8
RL = 100:
f = 200 MHz
-50
-60
-70
-80
-90
ATT = 16 dB
ATT = 0 dB
-100
-2
10
ATT = 24 dB
ATT = 8 dB
0
OUTPUT POWER (dBm/tone)
2
4
6
8
10
OUTPUT POWER (dBm/tone)
Figure 10.
Figure 11.
OIP3
vs
Temperature
Gain Shift
vs
Temperature
0.3
50
POUT = 3 dBm / TONE
0.2
GAIN SHIFT (dB)
OIP (dBm)
48 f = 200 MHz
MAXIMUM GAIN
46
44
42
40
ATT=0 dB
0.1
ATT=31 dB
ATT=16 dB
0
38
36
34
-40 -20
0
20
40
60
80
100 120
TEMPERATURE (°C)
-0.1
-40
-10
20
50
80
105
TEMPERATURE (°C)
Figure 12.
Figure 13.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
9
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
Typical Performance Characteristics (continued)
VCC = 5V
Cumulative Gain Error
vs
Attenuator Setting
Cumulative Gain Error over Temperature
0.4
f = 200 MHz
0.3
0.3
0.2
GAIN ERROR (dB)
CUMULATIVE GAIN ERROR (dB)
0.4
0.2
CH A
0.1
CH B
0.0
0.1
TEMP = -40
0
TEMP = 25
-0.1
-0.2
-0.1
-0.3
TEMP = 85
-0.2
0
6
13
19
26
-0.4
32
5
0
25
Phase Shift
vs
Attenuator Setting
Noise Figure
vs
Attenuator Setting
30
30
f = 200 MHz
CH B
2
f = 350MHz
25
1
0
-1
CH A
-2
-3
20
f = 150 MHz
15
f = 70 MHz
10
-4
5
0
6
13
19
26
32
0
ATTENUATION (0 = MAX GAIN)
5
10
15
20
25
30
ATTENUATOR SETTING (0 = MAX GAIN)
Figure 16.
Figure 17.
Noise Figure
vs.
Temperature
Noise Figure
vs
Frequency
9
10
8
8
350 MHz
NOISE FIGURE
NOISE FIGURE (dB)
20
Figure 15.
-5
250 MHz
7
6
5
4
-40
6
4
2
150 MHz
0
40
80
40 MHz
0
50
120
TEMPERATURE (°C)
100
150
200
250
300
350
400
FREQUENCY (MHz)
Figure 18.
10
15
Figure 14.
NOISE FIGURE (dB)
NORMALIZED PHASE (DEGREES)
3
10
DVGA ATTENUATOR SETTING (dB)
ATTENUATION (0 = MAX GAIN)
Figure 19.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
Typical Performance Characteristics (continued)
VCC = 5V
Second Order Harmonic Distortion
at 10 MHz
Third Order Harmonic Distortion
at 10 MHz
-40
-20
RL = 100:
f = 10MHz
RL = 100:
f = 10MHz
-50
-38
ATT = 24 dB
ATT = 0 dB
-60
HD3 (dBc)
HD2 (dBc)
ATT = 24 dB
ATT = 16 dB
-70
-80
ATT = 16 dB
-56
-74
ATT = 0 dB
-92
ATT = 16 dB
ATT = 16 dB
-90
-4
0
5
9
14
-110
-4
18
0
OUTPUT POWER (dBm)
9
Second Order Harmonic Distortion
at 75 MHz
Third Order Harmonic Distortion
at 75 MHz
-20
ATT = 0 dB
RL = 100:
f = 75 MHz
-38
HD3 (dBc)
-50
-60
ATT = 24 dB
-70
ATT = 24 dB
-56
ATT = 16 dB
-74
ATT = 0 dB
ATT = 16 dB
-90
-4
ATT = 8 dB
0
-92
5
9
14
-110
-4
18
ATT = 16 dB
0
OUTPUT POWER (dBm)
9
14
18
OUTPUT POWER (dBm)
Figure 23.
Second Order Harmonic Distortion
at 150 MHz
Third Order Harmonic Distortion
at 150 MHz
-10
ATT = 0 dB
RL = 100:
f = 150 MHz
RL = 100:
f = 150 MHz
-28
HD3 (dBc)
-50
HD2 (dBc)
5
Figure 22.
-40
-60
-70
ATT = 16 dB
-80
ATT = 16 dB
-46
ATT = 24 dB
-64
-82
ATT = 8 dB
-90
-4
18
Figure 21.
RL = 100:
f = 75 MHz
-80
14
Figure 20.
-40
HD2 (dBc)
5
OUTPUT POWER (dBm)
0
ATT = 24 dB
5
9
14
ATT = 8 dB
18
-100
-4
OUTPUT POWER (dBm)
0
5
ATT = 0 dB
9
14
18
OUTPUT POWER (dBm)
Figure 24.
Figure 25.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
11
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
Typical Performance Characteristics (continued)
VCC = 5V
Second Order Harmonic Distortion
at 200 MHz
Third Order Harmonic Distortion
at 200 MHz
-30
-10
RL = 100:
-40 f = 200 MHz
RL = 100:
-20 f = 200 MHz
ATT = 0 dB
ATT = 8 dB
-30
-50
ATT = 8 dB
-40
HD3 (dBc)
HD2 (dBc)
ATT = 16 dB
-60
-70
-80
-50
ATT = 24 dB
-60
ATT = 24 dB
-70
ATT = 16 dB
-90
-100
-4
ATT = 0 dB
-80
0
5
9
14
-90
-4
18
0
OUTPUT POWER (dBm)
Third Order Harmonic Distortion
at 250 MHz
-10
RL = 100:
-20 f = 250 MHz
-60
-70
-50
-70
ATT = 24 dB
0
5
ATT = 24 dB
-60
ATT = 16 dB
-90
ATT = 8 dB
-40
HD3 (dBc)
ATT = 8 dB
-80
ATT = 16 dB
-30
-50
HD2 (dBc)
18
Second Order Harmonic Distortion
at 250 MHz
RL = 100:
-40 f = 250 MHz
ATT = 0 dB
-80
9
14
-90
-4
18
OUTPUT POWER (dBm)
0
5
9
14
18
OUTPUT POWER (dBm)
Figure 28.
Figure 29.
Max Gain
vs.
Temperature
Supply Current
vs
Temperature
180
23.00
RL = 120:
22.75 and 4.7 pF
450 MHz
75 MHz
22.00
21.75
200 MHz
21.50
150 MHz
SUPPLY CURRENT (mA)
300 MHz
22.50
22.25
14
Figure 27.
-30
-100
-4
9
Figure 26.
ATT = 0 dB
MAXIMUM GAIN (dB)
5
OUTPUT POWER (dBm)
170
160
150
140
21.25
21.00
-40
-20
0
20
40
60
130
-40 -20
80
0
20 40 60 80
TEMPERATURE (°C)
100 120
TEMPERATURE (°C)
Figure 30.
12
Figure 31.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
Typical Performance Characteristics (continued)
VCC = 5V
Output Offset Voltage
vs.
Temperature
Pulse Response
4
RL = 200: and 4.7 pF
ATT = 0 dB
3
DIFFERENTIAL VOUT (V)
5
ATT = 8 dB
0
ATT = 24 dB
-5
2
1
0
-1
-2
-3
ATT = 16 dB
ATT = 31 dB
-10
-40 -20
0
20
40
60
80
-4
0
100 120
TEMPERATURE (°C)
25
Enable Timing Maximum Gain
ENABLE
3.0
0.3
0.2
2.5
0.2
0.1
2.0
1.5
-0.1
1.0
VOUT
0.1
VOUT (V)
0
GAIN BIT A5 (V)
VOUT (V)
20
0.4
A5
0.3
VOUT
2
0
1
-0.1
0
-0.3
0
-0.4
-0.5
0
10 20 30 40 50 60 70 80 90 100
TIME (ns)
ATT = 0 dB
-1
10 20 30 40 50 60 70 80 90 100
TIME (ns)
Figure 34.
Figure 35.
Enable Timing Minimum Gain
Channel To Channel Crosstalk
3.5
-30
0.3
3.0
-40
0.2
2.5
0.4
3
-0.2
0.5
-0.3
-0.4
0
15
Figure 33.
Gain Change Timing
-0.2
10
TIME (ns)
Figure 32.
0.4
5
ENABLE (V)
OUTPUT OFFSET VOLTAGE (mV)
10
2.0
0
1.5
-0.1
1.0
-0.2
0.5
0.0
-0.3
CROSSTALK (dBc)
VOUT (V)
VOUT
0.1
ENABLE (V)
ENABLE
-50
-60
CHB TO CHA
-70
-80
-90
CHA to CHB
ATT = 32.5 dB
-0.4
0
-0.5
10 20 30 40 50 60 70 80 90 100
-100
10
TIME (ns)
100
1000
FREQUENCY (MHz)
Figure 36.
Figure 37.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
13
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
Typical Performance Characteristics (continued)
VCC = 5V
Input Impedance (S11)
Output Impedance (S22)
250
50
|Z|
40
OUTPUT IMPEDANCE (:)
INPUT IMPEDANCE (:)
200
150
R
100
50
jX
|Z|
30
R
20
10
0
0
jX
-50
10
100
1000
-10
10
FREQUENCY (MHz)
1000
FREQUENCY (MHz)
Figure 38.
14
100
Figure 39.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
APPLICATION INFORMATION
The LMH6517 is a fully differential amplifier optimized for signal path applications up to 400 MHz. The LMH6517
has a 200Ω input and a low impedance output. The gain is digitally controlled over a 31.5 dB range from +22dB
to −9.5dB. The LMH6517 is optimized for accurate gain steps and minimal phase shift combined with low
distortion products. This makes the LMH6517 ideal for voltage amplification and an ideal ADC driver where high
linearity is necessary. The LMH6517 was designed for differential signal inputs only. Single ended inputs require
a balun or transformer as shown on the evaluation board.
VCC
RF
½ LMH6517
200
LO
ADC
6
GAIN 0-5
LATCH
Figure 40. LMH6517 Typical Application
5
OUT +
VOUT (V)
4
3
COMMON MODE
= 2.5V
1.25 VP
2
1
OUT 0
0
45
90
135 180 225 270 315 360
PHASE (°)
Figure 41. Output Voltage with Respect to the Output Common Mode
In order to help with system design National Semiconductor offers the SP16160CH1RB High IF Receiver
reference design board. This board combines the LMH6517 DVGA with the ADC16DV160 ADC and provides a
ready made solution for many IF receiver applications. The SP16160CH1RB delivers an IF chain receiver
sensitivity of -105 dBm, with a 9 dB carrier-to-noise ratio in a 200 kHz channel, at 192 MHz input IF. With the
digitally-controlled variable gain amplifier (DVGA) set at a maximum gain of 22 dB, the sensitivity is limited
primarily by the noise contribution of the DVGA. In the presence of a strong blocker, with the DVGA gain set at
12 dB and blocker level kept at 1.6 dBm input to the ADC, the SP16160CH1RB board delivers sensitivity of -86
dBm. In this blocking condition, the receiver sensitivity is determined by the ADC’s high spurious-free dynamic
range (SFDR).
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
15
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
Channel A
0 to - 31.5 dB
Attenuator
22 dB
Attenuator
0 to - 31.5 dB
22 dB
Channel B
Figure 42. LMH6517 Block Diagram
INPUT CHARACTERISTICS
The LMH6517 input impedance is set by internal resistors to a nominal 200Ω. Process variations will result in a
range of values as shown in the 5V Electrical Characteristics table. At higher frequencies parasitic reactances
will start to impact the impedance. This characteristic will also depend on board layout and should be verified on
the customer’s system board.
At maximum gain the digital attenuator is set to 0 dB and the input signal will be much smaller than the output. At
minimum gain the output is 9 dB or more smaller than the input. In this configuration the input signal will begin to
clip against the ESD protection diodes before the output reaches maximum swing limits. The input signal cannot
swing more than 0.5V below the negative supply voltage (normally 0V) nor should it exceed the positive supply
voltage. The input signal will clip and cause severe distortion if it is too large. Because the input stage self biases
to approximately mid rail the supply voltage will impose the limit for input voltage swing.
At the frequencies where the LMH6517 is the most useful the input impedance is not exactly 200 Ω and it may
not be purely resistive. For many AC coupled applications the impedance can be easily changed using LC
circuits to transform the actual impedance to the desired impedance.
SOURCE IMPEDANCE = 100:
f = 200 MHz
5V
C1
LMH6517
ZAMP
VIN
L1
ZIN
C2
L1 = 160 nH
5
C1 = 16 pF
C2 = 16 pF
GAIN 1-5
LATCH
ZAMP = (200):
ZIN = (100):
Figure 43. Differential 200Ω LC Conversion Circuit
In Figure 43 a circuit is shown that matches the amplifier 200Ω input with source is 100Ω. This would be the
case when connecting the LMH6517 directly to many common types of 50Ω test equipment. For an easy way to
calculate the L and C circuit values there are several options for online tools or down-loadable programs. The
following tool might be helpful.
http://www.circuitsage.com/matching/matcher2.html
16
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
Excel can also be used for simple circuits; however, the “Analysis ToolPak” add-in must be installed to calculate
complex numbers.
OUTPUT CHARACTERISTICS
The LMH6517 has a low impedance output very similar to a traditional Op-amp output. This means that nearly
any load can be driven with minimal gain loss. Matching load impedance for proper termination of filters is as
easy as inserting the proper value of resistor between the filter and the amplifier. This flexibility makes system
design and gain calculations very easy. The LMH6517 was designed to run from a single 5V supply. In spite of
this low supply voltage the LMH6517 is still able to deliver very high power gains when driving low impedance
loads.
The ability of the LMH6517 to drive low loads creates an opportunity to greatly increase power gain, if required.
One example of using power gain to offset filter loss is shown in Figure 59. A graph showing power gain over
various load conditions is shown below in Figure 44. This graph clearly shows the reduction in power gain
caused by back termination. While many RF amplifiers have internal resistance and deliver maximum power into
a matched load the LMH6517 has an output resistance very near to zero Ohms. The graph shows that maximum
power transfer does indeed occur with a load of nearly zero Ohms. Another useful feature of the graph is the
ability to determine how much gain can be recovered by dropping load resistance when it is necessary to back
terminate either a transmission line or a filter.
40
NON TERMINATED
POWER GAIN (dB)
35
30
25
20
BACK TERMINATED
15
10
5
1
10
100
1000
LOAD RESISTANCE (:)
Figure 44. Power Gain vs Load
Note 6dB power loss when adding load matching resistors.
Here is an example of how to use the chart in Figure 44. In a system it is desired to have at least 20dB of
maximum gain from the amplifier input to output. The system noise and harmonic distortion requirements dictate
a 200 Ohm filter between the amplifier and the ADC. Using the chart we can see that a back terminated 200
Ohm filter will result in a net 16 dB of gain at the filter input. To recover this loss it is possible to use a 1:4 balun
to drop the load condition of the filter to 50 Ohms at the amplifier output. This gives an additional 6dB of power
gain. Since the transformer has a power loss of approximately 1dB we end up with 21dB of gain at the filter
output instead of 16dB. See Figure 59 for an example where the filter performs the impedance transformation
function.
The LMH6517, like most high frequency amplifiers, is sensitive to loading conditions on the output. Load
conditions that include small amounts of capacitance connected directly to the output can cause stability
problems. In order to ensure output stability resistors should be connected directly at the amplifier output
followed by a small capacitor. This circuit sets a dominant pole that will cancel out board parasitics in most
applications. An example of this is shown in figure Figure 45 . In this example the amplifier and ADC are less
than 0.1 wavelength apart and do not require a terminated transmission line. A more sophisticated filter may
require better impedance matching. Some example filters are shown later.
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
17
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
10
f = 140 MHz
0.01P
+
200:
4.7p
LMH6517
220n
10
.
-
+IN
12p
100
100
12p
VRM ADC16DV160
-IN
0.01P
Figure 45. Output Configuration
DIGITAL CONTROL
The LMH6517 will support three modes of control, parallel mode, serial mode (SPI compatible) and pulse mode.
Parallel mode is fastest and requires the most board space for logic line routing. Serial mode is compatible with
existing SPI compatible systems. The pulse mode is both fast and compact, but must step through intermediate
gain steps when making large gain changes.
The LMH6517 has gain settings covering a range of 31.5 dB. To avoid undesirable signal transients the
LMH6517 should not be powered on with large inputs signals present. Careful planning of system power on
sequencing is especially important to avoid damage to ADC inputs.
The LMH6517 was designed to interface with 3.3V CMOS logic circuits. If operation with 5V logic is required a
simple voltage divider at each logic pin will allow for this. To properly terminate 100Ω transmission lines a divider
with a 66.5Ω resistor to ground and a 33.2Ω series resistor will properly terminate the line as well as give the
3.3V logic levels. Care should be taken not to exceed the 3.6V absolute maximum voltage rating of the logic
pins.
Some pins on the LMH6517 have different functions depending on the digital control mode. These functions will
be described in the sections to follow.
Control Mode
MOD1 Pin Value
MOD0 Pin Value
Parallel
1
1
Serial
1
0
Pulse
0
1
Reserved
0
0
PARALLEL MODE (MOD1= 1, MOD0 = 1)
Parallel mode offers the fastest gain update capability with the drawback of requiring the most board space
dedicated to control lines. When designing a system that requires very fast gain changes parallel mode is the
best selection.
18
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
A2
A1
IPA+
IPA-
GND
+5V
GND
A0
31
30
29
28
27
26
25
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
32
www.ti.com
A3
1
24
OPA+
A4
2
23
OPA-
A5
3
22
ENA
+3.3/NC
4
21
LATA
+3.3/NC
5
20
LATB
B5
6
19
ENB
B4
7
18
OPB-
B3
8
17
OPB+
LMH6517
13
14
GND
+5V
16
12
IPB-
B0
11
IPB+
15
10
B1
GND
9
B2
GND
Figure 46. Pin Functions for Parallel Mode
The LMH6517 has a 6-bit gain control bus as well as a Latch pin. When the Latch pin is low, data from the gain
control pins is immediately sent to the gain circuit (i.e. gain is changed immediately). When the Latch pin
transitions high the current gain state is held and subsequent changes to the gain set pins are ignored. To
minimize gain change glitches multiple gain control pins should not change while the latch pin is low. In order to
achieve the very fast gain step switching time of 5 ns the internal gain change circuit is very fast. Gain glitches
could result from timing skew between the gain set bits. This is especially the case when a small gain change
requires a change in state of three or more gain control pins. If continuous gain control is desired the Latch pin
can be tied to ground. This state is called transparent mode and the gain pins are always active. In this state the
timing of the gain pin logic transitions should be planned carefully to avoid undesirable transients
ENA and ENB pins are provided to reduce power consumption by disabling the highest power portions of the
LMH6517. The gain register will preserve the last active gain setting during the disabled state. These pins will
float high and can be left disconnected if they won't be used. If the pins are left disconnected a 0.01uF capacitor
to ground will help prevent external noise from coupling into these pins. See Typical Performance Characteristics
for disable and enable timing information.
DVGA
FPGA/DSP/PC/ASIC
latcha
ga[5:0]
gb[5:0]
latchb
pd
latcha
6
6
cmode
VSS
ga[5:0]
gb[5:0]
latchb
pd
Pins: 15
MSPS: 125
Low Skew
Figure 47. Parallel Mode Connection for Fastest Response
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
19
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
FPGA/DSP/PC/ASIC
DVGA
VSS
6
ga[5:0]
6
gb[5:0]
VSS
latcha
cmode
ga[5:0]
gb[5:0]
Pins: 13
MSPS: 333
High Skew
latchb
pd
pd
VSS
Figure 48. Parallel Mode Connection Not Using Latch Pins (Latch pins tied to logic low state)
FPGA/DSP/PC/ASIC
DVGA
latcha
ga/gb[5:0]
latcha
6
cmode
VSS
ga[5:0]
gb[5:0]
latchb
pd
latchb
pd
Pins: 9
MSPS: 62.5
Low Skew
Figure 49. Parallel Mode Connection Using Latch Pins to Mulitplex Digital Data
SPI COMPATIBLE SERIAL INTERFACE (MOD1= 1, MOD0 = 0)
Serial interface allows a great deal of flexibility in gain programming and reduced board complexity. Using only 4
wires for both channels allows for significant board space savings. The trade off for this reduced board
complexity is slower response time in gain state changes. For systems where gain is changed only infrequently
or where only slow gain changes are required serial mode is the best choice.
20
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
CS
SDO
IPA+
IPA-
GND
+5V
GND
GND
31
30
29
28
27
26
25
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
32
www.ti.com
SDI
1
24
OPA+
CLK
2
23
OPA-
GND
3
22
ENA
GND
4
21
GND
+3.3/NC
5
20
GND
GND
6
19
ENB
GND
7
18
OPB-
GND
8
17
OPB+
LMH6517
9
10
11
12
13
14
15
16
GND
GND
IPB+
IPB-
GND
+5V
GND
GND
GND
Figure 50. Pin Functions for Serial Mode
The LMH6517 has a serial interface that allows access to the control registers. The serial interface is a generic
4-wire synchronous interface that is compatible with SPI type interfaces that are used on many microcontrollers
and DSP controllers.
The serial mode is active when the two mode pins are set as follows: MOD1=1, MOD0=0). In this configuration
the pins function as shown in the pin description table. The SPI interface uses the following signals: clock input
(CLK), serial data in (SDI), serial data out, and serial chip select (CS)
ENA and ENB pins are active in the serial mode. For fast disable capability these pins can be used and the serial
register will hold the last active gain state. These pins will float high and can be left disconnected for serial mode.
The serial control bus can also disable the DVGA channels, but at a much slower speed. The serial enable
function is an AND function. For a channel to be active both the Enable pin and the serial control register must
be in the enabled state. To disable a channel either method will suffice. See Typical Performance Characteristics
for disable and enable timing information.
LATA and LATB pins are not active during serial mode.
CLK: This pin is the serial clock pin. It is used to register the input data that is presented on the SDI pin on the
rising edge; and to source the output data on the SDO pin on the falling edge. User may disable clock and hold it
in the low state, as long as the clock pulse-width minimum specification is not violated when the clock is enabled
or disabled.
CS: This pin is the chip select pin. Each assertion starts a new register access - i.e., the SDATA field protocol is
required. The user is required to deassert this signal after the 16th clock. If the SCSb is deasserted before the
16th clock, no address or data write will occur. The rising edge captures the address just shifted-in and, in the
case of a write operation, writes the addressed register. There is a minimum pulse-width requirement for the
deasserted pulse - which is specified in Electrical Characteristics.
SDI: This pin is an input for the serial data. It must observe setup/hold requirements with respect to the SCLK.
Each cycle is 16-bits long
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
21
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
SDO: This is the data output pin. Ths SDO pin is an open drain output and requires an external bias resistor.
See Figure 51 for resistor sizing guidance. This output is normally at TRI-STATE and is driven only when SCSb
is asserted. Upon SCSb assertion, contents of the register addressed during the first byte are shifted out with the
second 8 SCLK falling edges. Upon power-up, the default register address is 00h.
Each serial interface access cycle is exactly 16 bits long as shown in Figure 52. Each signal's function is
described below. the read timing is shown in Figure 53, while the write timing is shown in figure Figure 54.
FPGA/DSP/uC/ASIC
LMH6517
Clock out
Chip Select out
Data Out
Data In
CLK
CS
SDI (MOSI)
SDO (MISO)
R
V+ (Logic High)
SDO
For SDO (MISO) pin only:
VOH = V+,
25:
VOL = (V+) - (R/(R+25)) * V+
Recommended:
R = 300 Ohms to 2000 Ohms
V+ (Logic) = 2.5V to 3.3V
Figure 51. SDO Pin External Bias Resistor Configuration
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
D2
D1
D0
(LSB)
D2
D1
17
SCLK
SCSb
COMMAND FIELD
SDI
C7
C6
C5
C4
R/Wb
0
0
0
Reserved (3-bits)
DATA FIELD
C3
C2
C1
C0
A3
A2
A1
A0
D7
D6
(MSB)
D5
D4
D3
Write DATA
Address (4-bits)
D7
D6
(MSB)
D5
D4
D3
D0
(LSB)
Hi-Z
Read DATA
SDO
Data (8-bits)
Single Access Cycle
Figure 52. Serial Interface Protocol (SPI compatible)
22
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
R/Wb
Read / Write bit. A value of 1 indicates a read operation, while a
value of 0 indicates a write operation.
Reserved
Not used. Must be set to 0.
ADDR:
Address of register to be read or written.
DATA
In a write operation the value of this field will be written to the
addressed register when the chip select pin is deasserted. In a read
operation this field is ignored.
st
th
1 clock
th
8 clock
16
clock
SCLK
tCSH
tCSS
tCSH
tCSS
CSb
tOZD
SDO
tODZ
tOD
D7
D1
D0
Figure 53. Read Timing
Table 1. Read Timing
Data Output on SDO Pin
Parameter
Description
tCSH
Chip select hold time
tCSS
Chip select setup time
tOZD
Initial output data delay
tODZ
High impedance delay
tOD
Output data delay
tPL
tPH
16th clock
SCLK
tSU
SDI
tH
Valid Data
Valid Data
Figure 54. Write Timing
Data Written to SDI Pin
Table 2. Write Timing
Data Input on SDI Pin
Parameter
Description
tPL
Minimum clock low time (clock duty dycle)
tPH
Minimum clock high time (clock duty cycle)
tSU
Input data setup time
tH
Input data hold time
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
23
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
Table 3. Serial Word Format for LMH6517
C7
1= read
0=write
C6
0
C5
C4
0
C3
0
C2
0
C1
0
0
C0
0=Ch A
1=Ch B
Table 4. Serial Word Format for LMH6517 (cont)
Enable
1=On
0=Off
Gb5
1=+16dB
Gb4
Gb3
1=+8dB
Gb2
1=+4dB
Gb1
1=+2dB
Gb0
1=+1dB
1=+0.5dB
RES
0
PULSE MODE (MOD1= 0, MOD0 = 1)
S1A
S0A
IPA+
IPA-
GND
+5V
GND
GND
32
31
30
29
28
27
26
25
Pulse mode is a simple yet fast way to adjust gain settings. Using only two control lines per device the LMH6517
gain can be changed by simple up and down signals. Gain steps are selectable either by hard wiring the board
or using two additional logic inputs. For a system where gain changes can be stepped from one gain to the next
and where board space is limited this mode may be the best choice. The ENA and ENB pins are fully active
during pulse mode, and the channel gain state is preserved during the disabled state. See Typical Performance
Characteristics for disable and enable timing information.
DNA
1
24
OPA+
UPA
2
23
OPA-
GND
3
22
ENA
GND
4
21
GND
+3.3/NC
5
20
GND
GND
6
19
ENB
UPB
7
18
OPB-
DNB
8
17
OPB+
LMH6517
9
10
11
12
13
14
15
16
S1B
S0B
IPB+
IPB-
GND
+5V
GND
GND
GND
Figure 55. Pin Functions for Pulse Mode
The LMH6517 supports a simple pulse up or pulse down control mode. In this mode the gain step size can be
selected from a choice of 0.5, 1, 2 or 6dB steps. In operation the gain can be quickly adjusted either up of down
one step at a time by a negative pulse on the UP or DN pins. This mode of operation is most suitable for
applications where board space is at a premium and high speed gain changes are desired. As shown in
Figure 56 each gain step pulse must have a logic high state of at least tPW= 20 ns and a logic low state of at
least tPG 20 ns for the pulse to register as a gain change signal.
To provide a known gain state there is a reset feature in pulse mode. To reset the gain to maximum gain both
the UP and DN pins must be strobed low together as shown in Figure 56. There must be an overlap of at least
tRW= 20 ns for the reset to register.
24
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
PULSE TIMING
tPW
tPG
UP/DN
RESET TIMING
UP
tRW
DN
Figure 56. Pulse Mode Timing
EXPOSED PAD WQFN PACKAGE
The LMH6517 is packaged in a thermally enhanced package. The exposed pad is connected to the GND pins. It
is recommended, but not necessary, that the exposed pad be connected to the supply ground plane. In any
case, the thermal dissipation of the device is largely dependent on the attachment of this pad. The exposed pad
should be attached to as much copper on the circuit board as possible, preferably external copper. However, it is
also very important to maintain good high speed layout practices when designing a system board. Please refer to
the LMH6517 evaluation board for suggested layout techniques.
Package information is available on the Texas Instruments web site.
http://www.ti.com/packaging/
INTERFACING TO ADC
The LMH6517 was designed to be used with high speed ADCs such as the ADC16DV160. As shown in
Applications, AC coupling provides the best flexibility especially for IF sub-sampling applications. For DC coupled
applications the use of a level shifting amplifier or a resistive biasing network may be possible.
The inputs of the LMH6517 will self bias to the optimum voltage for normal operation. The internal bias voltage
for the inputs is approximately mid rail which is 2.5V with the typical 5V power supply condition. In most
applications the LMH6517 input will need to be AC coupled.
The output common mode voltage is also self biasing to mid supply. This means that for driving most ADCs AC
coupling is required. Since most often a band pass filter is desired between the amplifier and ADC the bandpass
filter can be configured to block the DC voltage of the amplifier output from the ADC input.
3 pF
41 pF
27 nH
ADC IN
390 nH
AMP OUT
100:
200:
390 nH
100:
A.
Center
Frequency
is
Designed for 200Ω Impedance
200
3 pF
140
MHz
with
a
20
MHz
Bandwidth
Figure 57. Bandpass Filter
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
25
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
ADC Noise Filter
Below are filter schematics and a table of values for some common IF frequencies. The filter shown in Figure 58
offers a good compromise between bandwidth, noise rejection and cost. This filter topology is the same as is
used on the ADC14V155KDRB High IF Receiver reference design board. This filter topology works best with the
12 and 14 bit sub-sampling analog to digital converters shown in the Table 6 table.
Table 5. Filter Component Values
Filter Component Values
75 MHz
140 MHz
170 MHz
250 MHz
BW
40 MHz
20 MHz
25 MHz
Narrow Band
R1, R2
100Ω
200Ω
100Ω
499Ω
L1, L2
390 nH
39 0nH
560 nH
—
C1, C2
10 pF
3 pF
1.4 pF
47 pF
C3
22 pF
41 pF
32 pF
11 pF
L5
220 nH
27 nH
30 nH
22 nH
R3, R4
100Ω
200Ω
100Ω
499Ω
R1
AMP VOUT -
L1
C1
L5
C2
L2
AMP VOUT +
ADC ZIN
C3
AMP ZOUT
R3
ADC VIN +
R4
Components
Fc
ADC VIN -
R2
ADC VCM
Figure 58. Sample Filter
While the filters shown above have excellent performance in most respects they have one very large drawback,
and that is voltage loss. There is a 6dB loss right up front from the matching resistors (R1 and R2 in Figure 58)
and there are additional losses in the filter, primarily due to the resistive losses of the inductors. One solution is
to use larger inductors with higher Q ratings. An even better solution is to use the filter as an impedance
transforming circuit. Designing a filter with a low impedance input and a high impedance output will result in a
voltage gain that can be used to offset the voltage losses. While this solution won't work with high impedance
amplifiers, the LMH6517's low impedance output stage is perfectly suited for it. In essence the additional power
gained from driving a given voltage into a lower value load impedance is used to offset the power lost in the filter
and matching resistors.
The filter shown in Figure 59 uses both an impedance transform as well as a slight input impedance mismatch to
reduce the voltage loss from the amplifier to the ADC input. This configuration makes use of the strengths of the
LMH6517 output stage to deliver the best linearity possible. Due to the low impedance output stage the
LMH6517 can drive a lot of current into a low impedance load and still deliver high linearity signals.
26
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
LMH6517
www.ti.com
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
AMP VOUT -
5
91n
240n
18n
ADC VIN +
4.7p
ADC ZIN
100
27p
5.2p
100
ADC VIN 5
AMP VOUT +
91n
240n
ADC VCM
Figure 59. Impedance Transforming Filter
25 Ω Input 200 Ω Output, 210 MHz Center Frequency
POWER SUPPLIES
The LMH6517 was designed primarily to be operated on 5V power supplies. The voltage range for VCC is 4.5V to
5.25V. A 5V supply provides the best performance while lower supplies will result in less power consumption.
Power supply regulation of 2.5% or better is advised. When operated on a board with high speed digital signals it
is important to provide isolation between digital signal noise and the LMH6517 inputs. The SP16160CH1RB
reference board provides an example of good board layout.
Of special note is that the digital circuits are powered from an internal supply voltage of 3.3V. The logic pins
should not be driven above the absolute maximum value of 3.6V. See DIGITAL CONTROL for details.
Table 6. Compatible High Speed Analog To Digital Converters
Product Number
Max Sampling Rate (MSPS)
Resolution
Channels
ADC12L063
62
12
SINGLE
ADC12DL065
65
12
DUAL
ADC12L066
66
12
SINGLE
ADC12DL066
66
12
DUAL
CLC5957
70
12
SINGLE
ADC12L080
80
12
SINGLE
ADC12DL080
80
12
DUAL
ADC12C080
80
12
SINGLE
ADC12C105
105
12
SINGLE
ADC12C170
170
12
SINGLE
ADC12V170
170
12
SINGLE
ADC14C080
80
14
SINGLE
ADC14C105
105
14
SINGLE
ADC14DS105
105
14
DUAL
ADC14155
155
14
SINGLE
ADC14V155
155
14
SINGLE
ADC16V130
130
16
SINGLE
ADC16DV160
160
16
DUAL
ADC08D500
500
8
DUAL
ADC08500
500
8
SINGLE
ADC08D1000
1000
8
DUAL
ADC081000
1000
8
SINGLE
ADC08D1500
1500
8
DUAL
ADC081500
1500
8
SINGLE
ADC08(B)3000
3000
8
SINGLE
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
27
LMH6517
SNOSB19J – NOVEMBER 2008 – REVISED NOVEMBER 2011
www.ti.com
Table 6. Compatible High Speed Analog To Digital Converters (continued)
Product Number
Max Sampling Rate (MSPS)
Resolution
Channels
ADC08L060
60
8
SINGLE
ADC08060
60
8
SINGLE
ADC10DL065
65
10
DUAL
ADC10065
65
10
SINGLE
ADC10080
80
10
SINGLE
ADC08100
100
8
SINGLE
ADCS9888
170
8
SINGLE
ADC08(B)200
200
8
SINGLE
ADC11C125
125
11
SINGLE
ADC11C170
170
11
SINGLE
28
Submit Documentation Feedback
Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Links: LMH6517
PACKAGE OPTION ADDENDUM
www.ti.com
24-Jan-2013
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package Qty
Drawing
Eco Plan
Lead/Ball Finish
(2)
MSL Peak Temp
Op Temp (°C)
Top-Side Markings
(3)
(4)
LMH6517SQ/NOPB
ACTIVE
WQFN
RTV
32
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 85
L6517SQ
LMH6517SQE/NOPB
ACTIVE
WQFN
RTV
32
250
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 85
L6517SQ
LMH6517SQX/NOPB
ACTIVE
WQFN
RTV
32
4500
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 85
L6517SQ
(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)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
Only one of markings shown within the brackets will appear on the physical device.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
Samples
PACKAGE MATERIALS INFORMATION
www.ti.com
17-Nov-2012
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
LMH6517SQ/NOPB
WQFN
RTV
32
LMH6517SQE/NOPB
WQFN
RTV
LMH6517SQX/NOPB
WQFN
RTV
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
1000
178.0
12.4
5.3
5.3
1.3
8.0
12.0
Q1
32
250
178.0
12.4
5.3
5.3
1.3
8.0
12.0
Q1
32
4500
330.0
12.4
5.3
5.3
1.3
8.0
12.0
Q1
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
17-Nov-2012
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
LMH6517SQ/NOPB
WQFN
RTV
32
1000
203.0
190.0
41.0
LMH6517SQE/NOPB
WQFN
RTV
32
250
203.0
190.0
41.0
LMH6517SQX/NOPB
WQFN
RTV
32
4500
358.0
343.0
63.0
Pack Materials-Page 2
MECHANICAL DATA
RTV0032A
SQA32A (Rev B)
www.ti.com
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other
changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest
issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and
complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale
supplied at the time of order acknowledgment.
TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms
and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary
to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily
performed.
TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and
applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or
other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information
published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or
endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the
third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration
and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered
documentation. Information of third parties may be subject to additional restrictions.
Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service
voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.
TI is not responsible or liable for any such statements.
Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements
concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support
that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which
anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause
harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use
of any TI components in safety-critical applications.
In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to
help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and
requirements. Nonetheless, such components are subject to these terms.
No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties
have executed a special agreement specifically governing such use.
Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in
military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components
which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and
regulatory requirements in connection with such use.
TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of
non-designated products, TI will not be responsible for any failure to meet ISO/TS16949.
Products
Applications
Audio
www.ti.com/audio
Automotive and Transportation
www.ti.com/automotive
Amplifiers
amplifier.ti.com
Communications and Telecom
www.ti.com/communications
Data Converters
dataconverter.ti.com
Computers and Peripherals
www.ti.com/computers
DLP® Products
www.dlp.com
Consumer Electronics
www.ti.com/consumer-apps
DSP
dsp.ti.com
Energy and Lighting
www.ti.com/energy
Clocks and Timers
www.ti.com/clocks
Industrial
www.ti.com/industrial
Interface
interface.ti.com
Medical
www.ti.com/medical
Logic
logic.ti.com
Security
www.ti.com/security
Power Mgmt
power.ti.com
Space, Avionics and Defense
www.ti.com/space-avionics-defense
Microcontrollers
microcontroller.ti.com
Video and Imaging
www.ti.com/video
RFID
www.ti-rfid.com
OMAP Applications Processors
www.ti.com/omap
TI E2E Community
e2e.ti.com
Wireless Connectivity
www.ti.com/wirelessconnectivity
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2013, Texas Instruments Incorporated
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Texas Instruments:
LMH6517EVAL-R1/NOPB

Open as PDF

Similar pages