View LT1206CT7_1154530.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

LT1206 250mA/60MHz Current Feedback Amplifier FEATURES

DESCRIPTION
The LT(R)1206 is a current feedback amplifier with high output current drive capability and excellent video characteristics. The LT1206 is stable with large capacitive loads, and can easily supply the large currents required by the capacitive loading. A shutdown feature switches the device into a high impedance, low current mode, reducing dissipation when the device is not in use. For lower bandwidth applications, the supply current can be reduced with a single external resistor. The low differential gain and phase, wide bandwidth, and the 250mA minimum output current drive make the LT1206 well suited to drive multiple cables in video systems. The LT1206 is manufactured on Linear Technology's proprietary complementary bipolar process.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
250mA Minimum Output Drive Current 60MHz Bandwidth, AV = 2, RL = 100 900V/s Slew Rate, AV = 2, RL = 50 0.02% Differential Gain, AV = 2, RL = 30 0.17 Differential Phase, AV = 2, RL = 30 High Input Impedance, 10M Wide Supply Range, 5V to 15V Shutdown Mode: IS < 200A Adjustable Supply Current Stable with CL = 10,000p Available in 8-Pin DIP and SO and 7-Pin DD and TO-220 Packages
APPLICATIONS

Video Amplifiers Cable Drivers RGB Amplifiers Test Equipment Amplifiers Buffers
TYPICAL APPLICATION
Noninverting Amplifier with Shutdown
15V VIN
Large-Signal Response, CL = 10,000pF
+
LT1206 COMP CCOMP - S/D** 0.01F* -15V RF 15V 5V RG 24k 74C906
LT1206 * TA01
VOUT
*OPTIONAL, USE WITH CAPACITIVE LOADS **GROUND SHUTDOWN PIN FOR NORMAL OPERATION
ENABLE VS = 15V RL = RG = 3k RL = 500ns/DIV
1206 TA02
1206fa
1
LT1206 ABSOLUTE MAXIMUM RATINGS
(Note 1)
Supply Voltage ........................................................18V Input Current........................................................15mA Output Short-Circuit Duration (Note 2) .........Continuous Specified Temperature Range (Note 3) ........ 0C to 70C
Operating Temperature Range ................. -40C to 85C Junction Temperature ........................................... 150C Storage Temperature Range................... -65C to 150C Lead Temperature (Soldering, 10 sec) .................. 300C
PACKAGE/OERDER INFORMATION
TOP VIEW NC 1 -IN 2 +IN 3 S/D* 4 8 7 6 5 V+ OUT V- COMP V+ 1 -IN 2 +IN 3 S/D* 4 TOP VIEW 8 7 6 5 V+ OUT V- COMP
N8 PACKAGE 8-LEAD PLASTIC DIP JA = 100C/W
S8 PACKAGE 8-LEAD PLASTIC SO JA = 60C/W
ORDER PART NUMBER LT1206CN8**
FRONT VIEW 7 6 5 4 3 2 1 OUT V- COMP V+ S/D* +IN -IN
ORDER PART NUMBER LT1206CS8**
FRONT VIEW 7 6 5 4 3 2 1
S8 PART MARKING 1206
OUT V- COMP V+ S/D* +IN -IN
TAB IS V+
TAB IS V+
R PACKAGE 7-LEAD PLASTIC DD JA = 30C/W
T7 PACKAGE 7-LEAD PLASTIC TO-220 JA = 5C/W
ORDER PART NUMBER LT1206CR**
Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/
ORDER PART NUMBER LT1206CT7**
Consult LTC Marketing for parts specified with wider operating temperature ranges. *Ground shutdown pin for normal operation. ** See Note 3.
ELECTRICAL CHARACTERISTICS
SYMBOL VOS PARAMETER Input Offset Voltage Input Offset Voltage Drift IIN
+
The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCM = 0, 5V VS 15V, pulse tested, VS/D = 0V, unless otherwise noted.
CONDITIONS

MIN
TYP 3 10 2 10
MAX 10 15 8 25 60 100
UNITS mV mV V/C A A A A
1206fa
Noninverting Input Current Inverting Input Current
IIN-
2
LT1206 ELECTRICAL CHARACTERISTICS
SYMBOL en +in -in RIN CIN PARAMETER Input Noise Voltage Density Input Noise Current Density Input Noise Current Density Input Resistance Input Capacitance Input Voltage Range CMRR Common Mode Rejection Ratio Inverting Input Current Common Mode Rejection Power Supply Rejection Ratio Noninverting Input Current Power Supply Rejection Inverting Input Current Power Supply Rejection Large-Signal Voltage Gain Transresistance, VOUT/IIN- Maximum Output Voltage Swing
The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCM = 0, 5V VS 15V, pulse tested, VS/D = 0V, unless otherwise noted.
CONDITIONS f = 10kHz, RF = 1k, RG = 10, RS = 0 f = 10kHz, RF = 1k, RG = 10, RS = 10k f = 10kHz, RF = 1k, RG = 10, RS = 10k VIN = 12V, VS = 15V VIN = 2V, VS = 5V VS = 15V VS = 15V VS = 5V VS = 15V, VCM = 12V VS = 5V, VCM = 2V VS = 15V, VCM = 12V VS = 5V, VCM = 2V VS = 5V to 15V VS = 5V to 15V VS = 5V to 15V VS = 15V, VOUT = 10V, RL = 50 VS = 5V, VOUT = 2V, RL = 25 VS = 15V, VOUT = 10V, RL = 50 VS = 5V, VOUT = 2V, RL = 25 VS = 15V, RL = 50 VS = 15V, RL = 25 IOUT Maximum Output Current Supply Current Supply Current, RS/D = 51k (Note 4) Positive Supply Current, Shutdown Output Leakage Current, Shutdown SR Slew Rate (Note 5) Differential Gain (Note 6) Differential Phase (Note 6) BW Small-Signal Bandwidth RL = 1 VS = 15V, VS/D = 0V VS = 15V VS = 15V, VS/D = 15V VS = 15V, VS/D = 15V AV = 2 VS = 15V, RF = 560, RG = 560, RL = 30 VS = 15V, RF = 560, RG = 560, RL = 30 VS = 15V, Peaking 0.5dB, RF = RG = 620, RL = 100 VS = 15V, Peaking 0.5dB, RF = RG = 649, RL = 50 VS = 15V, Peaking 0.5dB, RF = RG = 698, RL = 30 VS = 15V, Peaking 0.5dB, RF = RG = 825, RL = 10

MIN
TYP 3.6 2 30
MAX
UNITS nV/Hz pA/Hz pA/Hz M M pF V V dB dB A/V A/V dB nA/V A/V dB dB k k V V V V mA mA mA mA A A V/s % Deg MHz MHz MHz MHz
1.5 0.5 12 2 55 50
10 5 2 13.5 3.5 62 60 0.1 0.1 77 30 0.7
10 10 500 5
PSRR
60
AV ROL VOUT
55 55 100 75 11.5 10.0 2.5 2.0 250
71 68 260 200 12.5 3.0 500 20 12 1200 30 35 17 200 10
IS
400
900 0.02 0.17 60 52 43 27
Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Applies to short circuits to ground only. A short circuit between the output and either supply may permanently damage the part when operated on supplies greater than 10V.
Note 3: Commercial grade parts are designed to operate over the temperature range of -40C to 85C but are neither tested nor guaranteed beyond 0C to 70C. Industrial grade parts tested over -40C to 85C are available on special request. Consult factory. Note 4: RS/D is connected between the shutdown pin and ground. Note 5: Slew rate is measured at 5V on a 10V output signal while operating on 15V supplies with RF = 1.5k, RG = 1.5k and RL = 400. Note 6: NTSC composite video with an output level of 2V.
1206fa
3
LT1206 SMALL-SIGNAL BANDWIDTH
IS = 20mA Typical, Peaking 0.1dB AV -1 RL 150 30 10 150 30 10 150 30 10 150 30 10 RF 562 649 732 619 715 806 576 649 750 442 511 649 RG 562 649 732 - - - 576 649 750 48.7 56.2 71.5 -3dB BW (MHz) 48 34 22 54 36 22.4 48 35 22.4 40 31 20 -0.1dB BW (MHz) 21.4 17 12.5 22.3 17.5 11.5 20.7 18.1 11.7 19.2 16.5 10.2 AV -1 RL 150 30 10 150 30 10 150 30 10 150 30 10 RF 681 768 887 768 909 1k 665 787 931 487 590 768 RG 681 768 887 - - - 665 787 931 536 64.9 84.5 -3dB BW (MHz) 50 35 24 66 37 23 55 36 22.5 44 33 20.7 -0.1dB BW (MHz) 19.2 17 12.3 22.4 17.5 12 23 18.5 11.8 20.7 17.5 10.8
VS = 5V, RS/D = 0
VS = 15V, RS/D = 0
1
1
2
2
10
10
IS = 10mA Typical, Peaking 0.1dB AV -1 RL 150 30 10 150 30 10 150 30 10 150 30 10 RF 576 681 750 665 768 845 590 681 768 301 392 499 RG 576 681 750 - - - 590 681 768 33.2 43.2 54.9 -3dB BW (MHz) 35 25 16.4 37 25 16.5 35 25 16.2 31 23 15 -0.1dB BW (MHz) 17 12.5 8.7 17.5 12.6 8.2 16.8 13.4 8.1 15.6 11.9 7.8 AV -1 RL 150 30 10 150 30 10 150 30 10 150 30 10 RF 634 768 866 768 909 1k 649 787 931 301 402 590 RG 634 768 866 - - - 649 787 931 33.2 44.2 64.9 -3dB BW (MHz) 41 26.5 17 44 28 16.8 40 27 16.5 33 25 15.3 -0.1dB BW (MHz) 19.1 14 9.4 18.8 14.4 8.3 18.5 14.1 8.1 15.6 13.3 7.4
VS = 5V, RS/D = 10.2k
VS = 15V, RS/D = 60.4k
1
1
2
2
10
10
IS = 5mA Typical, Peaking 0.1dB AV -1 RL 150 30 10 150 30 10 150 30 10 150 30 10 RF 604 715 681 768 866 825 634 750 732 100 100 100 RG 604 715 681 - - - 634 750 732 11.1 11.1 11.1 -3dB BW (MHz) 21 14.6 10.5 20 14.1 9.8 20 14.1 9.6 16.2 13.4 9.5 -0.1dB BW (MHz) 10.5 7.4 6.0 9.6 6.7 5.1 9.6 7.2 5.1 5.8 7.0 4.7 AV -1 RL 150 30 10 150 30 10 150 30 10 150 30 10 RF 619 787 825 845 1k 1k 681 845 866 100 100 100 RG 619 787 825 - - - 681 845 866 11.1 11.1 11.1 -3dB BW (MHz) 25 15.8 10.5 23 15.3 10 23 15 10 15.9 13.6 9.6 -0.1dB BW (MHz) 12.5 8.5 5.4 10.6 7.6 5.2 10.2 7.7 5.4 4.5 6 4.5
1206fa
VS = 5V, RS/D = 22.1k
VS = 15V, RS/D = 121k
1
1
2
2
10
10
4
LT1206 TYPICAL PERFORMANCE CHARACTERISTICS
Bandwidth vs Supply Voltage
100 90 - 3dB BANDWIDTH (MHz) 80 70 60 50 40 30 20 10 0 4 6 14 12 10 8 SUPPLY VOLTAGE (V) 16 18 RF = 1k RF = 1.5k 0 4 6 14 12 10 8 SUPPLY VOLTAGE (V) 16 18 100 1 RF = 750 RF = 470 RF = 560 RF = 680 PEAKING 0.5dB PEAKING 5dB AV = 2 RL = 100 -3dB BANDWIDTH (MHz) 40 RF = 560 30 RF = 750 RF = 1k RF = 2k 10 50 PEAKING 0.5dB PEAKING 5dB AV = 2 RL = 10 FEEDBACK RESISTOR ()
Bandwidth vs Supply Voltage
10k
Bandwidth and Feedback Resistance vs Capacitive Load for 0.5dB Peak
100 BANDWIDTH -3dB BANDWIDTH (MHz)
1k FEEDBACK RESISTOR AV = 2 RL = VS = 15V CCOMP = 0.01F 100 10 1000 CAPACITIVE LOAD (pF)
10
20
1 10000
LT1206 * TPC01
LT1206 * TPC02
LT1206 * TPC03
Bandwidth vs Supply Voltage
100 90 -3dB BANDWIDTH (MHz) 80 70 60 50 40 30 20 10 0 4 6 14 12 10 8 SUPPLY VOLTAGE (V) 16 18 RF = 680 RF = 1.5k 0 RF = 470 RF =390 RF = 330 PEAKING 0.5dB PEAKING 5dB AV = 10 RL = 100 - 3dB BANDWIDTH (MHz) 40 50
Bandwidth vs Supply Voltage
PEAKING 0.5dB PEAKING 5dB 10k AV = 10 RL = 10 FEEDBACK RESISTOR ()
Bandwidth and Feedback Resistance vs Capacitive Load for 5dB Peak
100 BANDWIDTH -3dB BANDWIDTH (MHz)
30
RF = 560 RF = 680 RF = 1k
1k
10
20
10
RF = 1.5k 100 0 4 6 14 12 10 8 SUPPLY VOLTAGE (V) 16 18 1
FEEDBACK RESISTOR
AV = +2 RL = VS = 15V CCOMP = 0.01F
10 100 1k CAPACITIVE LOAD (pF)
1 10k
LT1206 * TPC04
LT1206 * TPC05
LT1206 * TPC06
Differential Phase vs Supply Voltage
0.50 RL = 15 DIFFERENTIAL GAIN (%) 0.10
Differential Gain vs Supply Voltage
100 SPOT NOISE (nV/Hz OR pA/Hz) RF = RG = 560 AV = 2 N PACKAGE
Spot Noise Voltage and Current vs Frequency
DIFFERENTIAL PHASE (DEG)
0.40
0.08
RL = 15
-in
0.30
0.20
RF = RG = 560 AV = 2 N PACKAGE
0.06 RL = 30 0.04 RL = 50
10 en in 1 10
RL = 30 RL = 50 RL = 150
0.10
0.02 RL = 150 0 5 7 11 13 9 SUPPLY VOLTAGE (V) 15
0 5 7 11 13 9 SUPPLY VOLTAGE (V) 15
100
1k 10k FREQUENCY (Hz)
100k
LT1206 * TPC09
LT1206 * TPC07
LT1206 * TPC08
1206fa
5
LT1206 TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
24 VS/D = 0V 22 SUPPLY CURRENT (mA) 20 TJ = 25C 18 16 14 TJ = 125C 12 10 4 6 14 12 10 8 SUPPLY VOLTAGE (V) 16 18 0 -50 -25 0 -50 -25 TJ = 85C TJ = -40C 20 SUPPLY CURRENT (mA) 25 RSD = 0 AV = 1 RL = N PACKAGE SUPPLY CURRENT (mA)
Supply Current vs Ambient Temperature, VS = 5V
25
Supply Current vs Ambient Temperature, VS = 15V
RSD = 0 20 AV = 1 RL = N PACKAGE
15 RSD = 10.2k 10 RSD = 22.1k
15 RSD = 60.4k 10 RSD = 121k 5
5
50 25 0 75 TEMPERATURE (C)
100
125
50 25 0 75 TEMPERATURE (C)
100
125
LT1206 * TPC10
LT1206 * TPC11
LT1206 * TPC12
Supply Current vs Shutdown Pin Current
20 18 16 SUPPLY CURRENT (mA) 14 12 10 8 6 4 2 0 0 100 300 400 200 SHUTDOWN PIN CURRENT (A) 500 VS = 15V COMMON-MODE RANGE (V) V+ - 0.5 -1.0 -1.5 -2.0 2.0 1.5 1.0 0.5
Input Common Mode Limit vs Junction Temperature
1.0 OUTPUT SHORT-CIRCUIT CURRENT (A) 0.9 0.8
Output Short-Circuit Current vs Junction Temperature
SOURCING 0.7 0.6 SINKING 0.5 0.4 0.3 -50 -25
V- -50
-25
0 75 25 50 TEMPERATURE (C)
100
125
50 25 75 0 TEMPERATURE (C)
100
125
LT1206 * TPC13
LT1206 * TPC14
LT1206 * TPC15
Output Saturation Voltage vs Junction Temperature
V+ OUTPUT SATURATION VOLTAGE (V) -1 -2 -3 -4 4 3 2 1 V- -50 -25 0 75 25 50 TEMPERATURE (C) 100 125 RL = 50 VS = 15V 70 RL = 2k POWER SUPPLY REJECTION (dB) 60 50 40 30 20 10
Power Supply Rejection Ratio vs Frequency
60 NEGATIVE POSITIVE RL = 50 VS = 15V RF = RG = 1k SUPPLY CURRENT (mA)
Supply Current vs Large-Signal Output Frequency (No Load)
AV = 2 RL = VS = 15V VOUT = 20VP-P
50
RL = 50
40
30
RL = 2k
20
0 10k
100k
1M 10M FREQUENCY (Hz)
100M
LT1206 * TPC17
10 10k
100k
1M
10M
LT1206 * TPC18
FREQUENCY (Hz)
LT1206 * TPC16
1206fa
6
LT1206 TYPICAL PERFORMANCE CHARACTERISTICS
Output Impedance vs Frequency
100 VS = 15V IO = 0mA RS/D = 121k 100k AV = 1 RF = 1k VS = 15V OUTPUT IMPEDANCE () 10k DISTORTION (dBc) -50 -60 -70 -80 0.01 100k 10 100k -90 1M 10M 100M
LT1206 * TPC20
Output Impedance in Shutdown vs Frequency
-30 -40
2nd and 3rd Harmonic Distortion vs Frequency
VS = 15V VO = 2VP-P RL = 10 2nd 3rd 2nd
OUTPUT IMPEDANCE ()
10
1
RS/D = 0
1k
RL = 30
0.1
100
3rd
1M
10M
100M
LT1206 * TPC19
1
3 2 45 FREQUENCY (MHz)
6 7 8 9 10
LT1206 * TPC21
FREQUENCY (Hz)
FREQUENCY (Hz)
3rd Order Intercept vs Frequency
60 VS = 15V RL = 50 RF = 590 RG = 64.9
Test Circuit for 3rd Order Intercept +
LT1206 PO
3rd ORDER INTERCEPT (dBm)
50
-
40 590 65 MEASURE INTERCEPT AT PO 20
LT1206 * TPC23
30
50
10
0
5
10 15 20 FREQUENCY (MHz)
25
30
LT1206 * TPC22
1206fa
7
LT1206 SIMPLIFIED SCHEMATIC
V+ TO ALL CURRENT SOURCES Q2 Q18 Q17 1.25k +IN Q1 Q6 Q9 V- RC 50 COMP OUTPUT V+ V+ Q12 Q8 Q4 Q7 D2 Q13 Q16 Q14
Q5 D1 Q15
Q10 Q11
V- -IN CC
SHUTDOWN
Q3
V-
LT1206 * SS
APPLICATIONS INFORMATION
The LT1206 is a current feedback amplifier with high output current drive capability. The device is stable with large capacitive loads and can easily supply the high currents required by capacitive loads. The amplifier will drive low impedance loads such as cables with excellent linearity at high frequencies. Feedback Resistor Selection The optimum value for the feedback resistors is a function of the operating conditions of the device, the load impedance and the desired flatness of response. The Typical AC Performance tables give the values which result in the highest 0.1dB and 0.5dB bandwidths for various resistive loads and operating conditions. If this level of flatness is not required, a higher bandwidth can be obtained by use of a lower feedback resistor. The characteristic curves of Bandwidth vs Supply Voltage indicate feedback resistors for peaking up to 5dB. These curves use a solid line when the response has less than 0.5dB of peaking and a dashed line when the response has 0.5dB to 5dB of peaking. The curves stop where the response has more than 5dB of peaking. For resistive loads, the COMP pin should be left open (see section on capacitive loads). Capacitive Loads The LT1206 includes an optional compensation network for driving capacitive loads. This network eliminates most of the output stage peaking associated with capacitive loads, allowing the frequency response to be flattened. Figure 1 shows the effect of the network on a 200pF load. Without the optional compensation, there is a 5dB peak at 40MHz caused by the effect of the capacitance on the output stage. Adding a 0.01F bypass capacitor between the output and the COMP pins connects the compensation and completely eliminates the peaking. A lower value feedback resistor can now be used, resulting in a response which
1206fa
8
LT1206 APPLICATIONS INFORMATION
12 10 8 VOLTAGE GAIN (dB) 6 4 2 0 -2 -4 -6 -8 1 10 FREQUENCY (MHz) 100
LT1206 * F01
VS = 15V RF = 1.2k COMPENSATION
RF = 2k NO COMPENSATION RF = 2k COMPENSATION
Figure 1
is flat to 0.35dB to 30MHz. The network has the greatest effect for CL in the range of 0pF to 1000pF. The graph of Maximum Capacitive Load vs Feedback Resistor can be used to select the appropriate value of feedback resistor. The values shown are for 0.5dB and 5dB peaking at a gain of 2 with no resistive load. This is a worst case condition, as the amplifier is more stable at higher gains and with some resistive load in parallel with the capacitance. Also shown is the - 3dB bandwidth with the suggested feedback resistor vs the load capacitance. Although the optional compensation works well with capacitive loads, it simply reduces the bandwidth when it is connected with resistive loads. For instance, with a 30 load, the bandwidth drops from 55MHz to 35MHz when the compensation is connected. Hence, the compensation was made optional. To disconnect the optional compensation, leave the COMP pin open. Shutdown/Current Set If the shutdown feature is not used, the SHUTDOWN pin must be connected to ground or V -. The shutdown pin can be used to either turn off the biasing for the amplifier, reducing the quiescent current to less than 200A, or to control the quiescent current in normal operation. The total bias current in the LT1206 is controlled by the current flowing out of the shutdown pin. When the shutdown pin is open or driven to the positive supply, the part is shut down. In the shutdown mode, the output looks like a 40pF
capacitor and the supply current is typically 100A. The shutdown pin is referenced to the positive supply through an internal bias circuit (see the simplified schematic). An easy way to force shutdown is to use open drain (collector) logic. The circuit shown in Figure 2 uses a 74C904 buffer to interface between 5V logic and the LT1206. The switching time between the active and shutdown states is less than 1s. A 24k pull-up resistor speeds up the turn-off time and insures that the LT1206 is completely turned off. Because the pin is referenced to the positive supply, the logic used should have a breakdown voltage of greater than the positive supply voltage. No other circuitry is necessary as the internal circuit limits the shutdown pin current to about 500A. Figure 3 shows the resulting waveforms.
15V VIN
+
LT1206 VOUT
- S/D
-15V RF
15V 5V ENABLE 74C906 24k
RG
LT1206 * F02
Figure 2. Shutdown Interface
VOUT
ENABLE
AV = 1 RF = 825 RL = 50 RPU = 24k VIN = 1VP-P
1s/DIV
1206 F03
Figure 3. Shutdown Operation
1206fa
9
LT1206 APPLICATIONS INFORMATION
For applications where the full bandwidth of the amplifier is not required, the quiescent current of the device may be reduced by connecting a resistor from the shutdown pin to ground. The quiescent current will be approximately 40 times the current in the shutdown pin. The voltage across the resistor in this condition is V + - 3VBE. For example, a 60k resistor will set the quiescent supply current to 10mA with VS = 15V. The photos (Figures 4a and 4b) show the effect of reducing the quiescent supply current on the large-signal response. The quiescent current can be reduced to 5mA in the inverting configuration without much change in response. In noninverting mode, however, the slew rate is reduced as the quiescent current is reduced. Slew Rate Unlike a traditional op amp, the slew rate of a current feedback amplifier is not independent of the amplifier gain configuration. There are slew rate limitations in both the input stage and the output stage. In the inverting mode, and for higher gains in the noninverting mode, the signal amplitude on the input pins is small and the overall slew rate is that of the output stage. The input stage slew rate is related to the quiescent current and will be reduced as the supply current is reduced. The output slew rate is set by the value of the feedback resistors and the internal capacitance. Larger feedback resistors will reduce the slew rate as will lower supply voltages, similar to the way the bandwidth is reduced. The photos (Figures 5a, 5b and 5c) show the large-signal response of the LT1206 for various gain configurations. The slew rate varies from 860V/s for a gain of 1, to 1400V/s for a gain of - 1.
RF = 750 RL = 50 IQ = 5mA, 10mA, 20mA VS = 15V
50ns/DIV
1206 F04a
Figure 4a. Large-Signal Response vs IQ, AV = -1
RF = 825 RL = 50 VS = 15V
20ns/DIV
1206 F05a
Figure 5a. Large-Signal Response, AV = 1
RF = 750 RL = 50 IQ = 5mA, 10mA, 20mA VS = 15V
50ns/DIV
1206 F04b
Figure 4b. Large-Signal Response vs IQ, AV = 2
RF = RG = 750 RL = 50 VS = 15V
20ns/DIV
1206 F05b
Figure 5a. Large-Signal Response, AV = -1
1206fa
10
LT1206 APPLICATIONS INFORMATION
the maximum allowable input voltage. To allow for some margin, it is recommended that the input signal be less than 5V when the device is shut down. Capacitance on the Inverting Input Current feedback amplifiers require resistive feedback from the output to the inverting input for stable operation. Take care to minimize the stray capacitance between the output and the inverting input. Capacitance on the inverting input to ground will cause peaking in the frequency response (and overshoot in the transient response), but it does not degrade the stability of the amplifier. Power Supplies The LT1206 will operate from single or split supplies from 5V (10V total) to 15V (30V total). It is not necessary to use equal value split supplies, however the offset voltage and inverting input bias current will change. The offset voltage changes about 500V per volt of supply mismatch. The inverting bias current can change as much as 5A per volt of supply mismatch, though typically the change is less than 0.5A per volt. Thermal Considerations The LT1206 contains a thermal shutdown feature which protects against excessive internal (junction) temperature. If the junction temperature of the device exceeds the protection threshold, the device will begin cycling between normal operation and an off state. The cycling is not harmful to the part. The thermal cycling occurs at a slow rate, typically 10ms to several seconds, which depends on the power dissipation and the thermal time constants of the package and heat sinking. Raising the ambient temperature until the device begins thermal shutdown gives a good indication of how much margin there is in the thermal design. For surface mount devices heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces. Experiments have shown that the heat spreading copper layer does not need to be electrically connected to the tab of the device. The PCB material can be very effective at transmitting heat between the pad area attached to the tab of the device, and a ground or
1206fa
RF = 750 RL = 50
20ns/DIV
1206 F05c
Figure 5c. Large-Signal Response, AV = 2
When the LT1206 is used to drive capacitive loads, the available output current can limit the overall slew rate. In the fastest configuration, the LT1206 is capable of a slew rate of over 1V/ns. The current required to slew a capacitor at this rate is 1mA per picofarad of capacitance, so 10,000pF would require 10A! The photo (Figure 6) shows the large signal behavior with CL = 10,000pF. The slew rate is about 60V/s, determined by the current limit of 600mA.
VS = 15V RL = RG = 3k RL =
500ns/DIV
1206 TA02
Figure 6. Large-Signal Response, CL = 10,000pF
Differential Input Signal Swing The differential input swing is limited to about 6V by an ESD protection device connected between the inputs. In normal operation, the differential voltage between the input pins is small, so this clamp has no effect; however, in the shutdown mode the differential swing can be the same as the input swing. The clamp voltage will then set
11
LT1206 APPLICATIONS INFORMATION
power plane layer either inside or on the opposite side of the board. Although the actual thermal resistance of the PCB material is high, the length/area ratio of the thermal resistance between the layer is small. Copper board stiffeners and plated through holes can also be used to spread the heat generated by the device. Tables 1 and 2 list thermal resistance for each package. For the TO-220 package, thermal resistance is given for junction-to-case only since this package is usually mounted to a heat sink. Measured values of thermal resistance for several different board sizes and copper areas are listed for each surface mount package. All measurements were taken in still air on 3/32" FR-4 board with 1oz copper. This data can be used as a rough guideline in estimating thermal resistance. The thermal resistance for each application will be affected by thermal interactions with other components as well as board size and shape.
Table 1. R Package, 7-Lead DD COPPER AREA THERMAL RESISTANCE TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)
Calculating Junction Temperature The junction temperature can be calculated from the equation: TJ = (PD x JA) + TA where: TJ = Junction Temperature TA = Ambient Temperature PD = Device Dissipation JA = Thermal Resistance (Junction-to Ambient) As an example, calculate the junction temperature for the circuit in Figure 7 for the N8, S8, and R packages assuming a 70C ambient temperature.
15V I 39mA
+
330
12V 0.01F 2k 300pF f = 2MHz -12V
-
LT1206 S/D
2500 sq. mm 2500 sq. mm 2500 sq. mm 1000 sq. mm 2500 sq. mm 2500 sq. mm 125 sq. mm 2500 sq. mm 2500 sq. mm *Tab of device attached to topside copper
25C/W 27C/W 35C/W
-15V
2k
LT1206 * F07
Figure 7. Thermal Calculation Example
Table 2. S8 Package, 8-Lead Plastic SO COPPER AREA THERMAL RESISTANCE TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)
2500 sq. mm 2500 sq. mm 2500 sq. mm 1000 sq. mm 2500 sq. mm 2500 sq. mm 225 sq. mm 2500 sq. mm 2500 sq. mm 100 sq. mm 2500 sq. mm 2500 sq. mm 100 sq. mm 1000 sq. mm 2500 sq. mm 100 sq. mm 225 sq. mm 2500 sq. mm 100 sq. mm 100 sq. mm 2500 sq. mm *Pins 1 and 2 attached to topside copper
Y Package, 7-Lead TO-220 Thermal Resistance (Junction-to-Case) = 5C/W N8 Package, 8-Lead DIP Thermal Resistance (Junction-to-Ambient) = 100C/W
60C/W 62C/W 65C/W 69C/W 73C/W 80C/W 83C/W
The device dissipation can be found by measuring the supply currents, calculating the total dissipation, and then subtracting the dissipation in the load and feedback network. PD = (39mA x 30V) - (12V)2/(2k||2k) = 1.03W Then: TJ = (1.03W x 100C/W) + 70C = 173C for the N8 package TJ = (1.03W x 65C/W) x + 70C = 137C for the S8 with 225 sq. mm topside heat sinking TJ = (1.03W x 35C/W) x + 70C = 106C for the R package with 100 sq. mm topside heat sinking Since the Maximum Junction Temperature is 150C, the N8 package is clearly unacceptable. Both the S8 and R packages are usable.
1206fa
12
LT1206 TYPICAL APPLICATIONS
Precision x10 Hi Current Amplifier CMOS Logic to Shutdown Interface
15V VIN
+
LT1097
+
LT1206 COMP - S/D 500pF 330 3k 5V 10k 10k
LT1206 * TA03
-
OUT 0.01F
+ -
LT1206 S/D 24k
LT1206 * TA05
-15V 2N3904
OUTPUT OFFSET: < 500V SLEW RATE: 2V/s BANDWIDTH: 4MHz STABLE WITH CL < 10nF
1k
Low Noise x10 Buffered Line Driver
15V 1F 15V 1F
Distribution Amplifier
+
LT1115
+ + +
1F
VIN 75 OUTPUT 0.01F RL
+ -
LT1206 S/D RF
+
LT1206 S/D
75
75 CABLE
75 75
LT1206 * TA06
-
-15V
-
-15V 560 909
LT1206 * TA04
560
100
RL = 32 VO = 5VRMS THD + NOISE = 0.0009% AT 1kHz = 0.004% AT 20kHz SMALL SIGNAL 0.1dB BANDWIDTH = 600kHz
VIN
+ -
LT1206 COMP S/D VOUT 0.01F* *OPTIONAL, USE WITH CAPACITIVE LOADS **VALUE OF RF DEPENDS ON SUPPLY VOLTAGE AND LOADING. SELECT FROM TYPICAL AC PERFORMANCE TABLE OR DETERMINE EMPIRICALLY
+ Buffer AV = 1
RF**
LT1206 * TA07
68pF
1F
RG 75
1206fa
13
LT1206 PACKAGE DESCRIPTION
N8 Package 8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
.300 - .325 (7.620 - 8.255) .045 - .065 (1.143 - 1.651) .130 .005 (3.302 0.127) .400* (10.160) MAX 8 7 6 5
.008 - .015 (0.203 - 0.381) +.035 .325 -.015 +0.889 8.255 -0.381
.065 (1.651) TYP .120 (3.048) .020 MIN (0.508) MIN .018 .003 (0.457 0.076)
.255 .015* (6.477 0.381)
1
2
3
4
N8 1002
(
)
.100 (2.54) BSC
INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
NOTE: 1. DIMENSIONS ARE
R Package 7-Lead Plastic DD Pak
(Reference LTC DWG # 05-08-1462)
.256 (6.502) .060 (1.524)
.060 (1.524) TYP .390 - .415 (9.906 - 10.541) 15 TYP .165 - .180 (4.191 - 4.572)
.045 - .055 (1.143 - 1.397)
.060 (1.524)
.183 (4.648)
.330 - .370 (8.382 - 9.398)
.059 (1.499) TYP
(
+.008 .004 -.004 +0.203 0.102 -0.102
)
.075 (1.905) .300 (7.620) BOTTOM VIEW OF DD PAK HATCHED AREA IS SOLDER PLATED COPPER HEAT SINK .050 (1.27) BSC .013 - .023 (0.330 - 0.584)
.095 - .115 (2.413 - 2.921) .050 .012 (1.270 0.305)
R (DD7) 0502
(
+.012 .143 -.020 +0.305 3.632 -0.508
)
.026 - .035 (0.660 - 0.889) TYP
.420 .420 .080 .276
.350 .205 .565
.325 .565
.320 .090 .050 .035 .050 .090 .035
RECOMMENDED SOLDER PAD LAYOUT NOTE: 1. DIMENSIONS IN INCH/(MILLIMETER) 2. DRAWING NOT TO SCALE
RECOMMENDED SOLDER PAD LAYOUT FOR THICKER SOLDER PASTE APPLICATIONS
1206fa
14
LT1206 PACKAGE DESCRIPTION
S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
.189 - .197 (4.801 - 5.004) NOTE 3 8 7 6 5
.045 .005 .050 BSC
.245 MIN
.160 .005 .228 - .244 (5.791 - 6.197)
.150 - .157 (3.810 - 3.988) NOTE 3
.030 .005 TYP RECOMMENDED SOLDER PAD LAYOUT
.010 - .020 x 45 (0.254 - 0.508) .008 - .010 (0.203 - 0.254) 0- 8 TYP
1
2
3
4
.053 - .069 (1.346 - 1.752)
.004 - .010 (0.101 - 0.254)
.016 - .050 (0.406 - 1.270) NOTE: 1. DIMENSIONS IN
INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
.014 - .019 (0.355 - 0.483) TYP
.050 (1.270) BSC
SO8 0303
T7 Package 7-Lead Plastic TO-220 (Standard)
(Reference LTC DWG # 05-08-1422)
.147 - .155 (3.734 - 3.937) DIA .230 - .270 (5.842 - 6.858) .460 - .500 (11.684 - 12.700) .570 - .620 (14.478 - 15.748) .330 - .370 (8.382 - 9.398) .620 (15.75) TYP .700 - .728 (17.780 - 18.491) .165 - .180 (4.191 - 4.572)
.390 - .415 (9.906 - 10.541)
.045 - .055 (1.143 - 1.397)
SEATING PLANE .152 - .202 .260 - .320 (3.860 - 5.130) (6.604 - 8.128)
.050 (1.27) .026 - .036 (0.660 - 0.914)
.095 - .115 (2.413 - 2.921) .155 - .195* (3.937 - 4.953)
BSC
.135 - .165 (3.429 - 4.191)
.013 - .023 (0.330 - 0.584) *MEASURED AT THE SEATING PLANE
T7 (TO-220) 0801
1206fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LT1206 RELATED PARTS
PART NUMBER LT1010 LT1207 LT1210 LT1395 LT1815 LT1818 DESCRIPTION High Speed Buffer Dual 250mA Out, 900V/s, 60MHz Current Feedback Amplifier 1.1A, 35MHz, 900V/s Current Feedback Amplifier Single 400MHz Current Feedback Amplifier 6.5mA, 220MHz, 1.5V/ns Operational Amplifier with Programmable Current 400MHz, 2500V/s, 9mA Single Operational Amplifier COMMENTS High Power, High Speed Buffer Adjustable Supply Current, Shutdown Adjustable Supply Current, Shutdown 0.1dB Gain Flatness to 100MHz S6 Version Features Programmable Supply Current High Speed, Low Noise, Low Distortion, Low Offset
1206fa
16 Linear Technology Corporation
(408) 432-1900 FAX: (408) 434-0507
LT 0307 REV A * PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 1993

▲Up To Search▲

Price & Availability of LT1206CT7

	To Download LT1206CT7 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .