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LT1189 Low Power Video Difference Amplifier
FEATURES
s s s s s s s s s s s
DESCRIPTIO
Differential or Single-Ended Gain Block (Adjustable) -3dB Bandwidth, AV = 10 35MHz Slew Rate 220V/s Low Supply Current 13mA Output Current 20mA CMRR at 10MHz 48dB LT1193 Pin Out Low Cost Single 5V Operation Drives Cables Directly Output Shutdown
The LT1189 is a difference amplifier optimized for operation on 5V, or a single 5V supply, and gain 10. This versatile amplifier features uncommitted high input impedance (+) and (-) inputs, and can be used in differential or single-ended configurations. Additionally, a second set of inputs give gain adjustment and DC control to the difference amplifier. The LT1189's high slew rate, 220V/s, wide bandwidth, 35MHz, and 20mA output current require only 13mA of supply current. The shutdown feature reduces the power dissipation to a mere 15mW, and allows multiple amplifiers to drive the same cable. The LT1189 is a low power, gain of 10 stable version of the popular LT1193, and is available in 8-pin miniDIPs and SO packages. For lower gain applications see the LT1187 data sheet.
APPLICATI
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Line Receivers Video Signal Processing Cable Drivers Tape and Disc Drive Systems
TYPICAL APPLICATI
Cable Sense Amplifier for Loop Through Connections with DC Adjust
VIN 5V 3 CABLE VDC 2 1 8 - LT1189 + - 4 -5V 909
Closed-Loop Gain vs Frequency
50 VS = 5V RL = 1k
40
VOLTAGE GAIN (dB)
+
7 6 VOUT
30
20
10
100
0 0.1
LT1189 * TA01
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1 10 FREQUENCY (MHz) 100
LT1189 * TA02
UO
UO
1
LT1189 ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW +/REF -IN +IN V- 1 2 3 4 8 7 6 5 -/FB V+ OUT S/D
Total Supply Voltage (V + to V -) ............................. 18V Differential Input Voltage ........................................ 6V Input Voltage .......................................................... VS Output Short Circuit Duration (Note 1) ........ Continuous Operating Temperature Range LT1189M ..................................... - 55C to 150C LT1189C............................................. 0C to 70C Junction Temperature (Note 2) Plastic Package (CN8,CS8) ......................... 150C Ceramic Package (CJ8,MJ8) ....................... 175C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec.)................ 300C
ORDER PART NUMBER LT1189MJ8 LT1189CJ8 LT1189CN8 LT1189CS8 S8 PART MARKING 1189
J8 PACKAGE N8 PACKAGE 8-LEAD HERMETIC DIP 8-LEAD PLASTIC DIP S8 PACKAGE 8-LEAD PLASTIC SOIC
LT1189 * POI01
TJMAX = 175C, JA = 100C/W (J8) TJMAX = 150C, JA = 100C/W (N8) TJMAX = 150C, JA = 150C/W (S8)
+5V ELECTRICAL CHARACTERISTICS -
SYMBOL VOS IOS IB en in RIN CIN VIN LIM CMRR PSRR VOUT PARAMETER Input Offset Voltage Input Offset Current Input Bias Current Input Noise Voltage Input Noise Current Input Resistance Input Capacitance Input Voltage Limit Input Voltage Range Common-Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing
TA = 25C, (Note 3) VS = 5V, VREF = 0V, RFB1 = 900 from pins 6 to 8, RFB2 = 100 from pin 8 to ground, RL = RFB1 + RFB2 = 1k, CL 10pF, pin 5 open.
CONDITIONS Either Input, (Note 4) SOIC Package Either Input Either Input fO = 10kHz fO = 10kHz Differential Either Input (Note 5) -2.5 VCM = -2.5V to 3.5V VS = 2.375V to 8V VS = 5V, RL = 1k, AV = 50 VS = 8V, RL = 1k, AV = 50 VS = 8V, RL = 300, AV = 50, (Note 3) GE SR FPBW BW tr, tf tPD ts Diff AV Diff Ph IS Gain Error Slew Rate Full Power Bandwidth Small Signal Bandwidth Rise Time, Fall Time Propagation Delay Overshoot Settling Time Differential Gain Differential Phase Supply Current Shutdown Supply Current Pin 5 at V - VO = 1.0V, AV = 10 (Note 6, 10) VO = 2VP-P, (Note 7) AV = 10 AV = 50, VO = 1.5V, 20% to 80% (Note 10) RL= 1k, VO = 125mV, 50% to 50% VO = 50mV 3V Step, 0.1%, (Note 8) RL = 1k, AV = 10, (Note 9) RL = 1k, AV = 10, (Note 9) 35 80 75 3.8 6.7 6.4 150 105 90 4.0 7.0 6.8 1.0 220 35 35 50 12 10 1 0.6 0.75 13 0.8 16 1.5 75 3.5 % V/s MHz MHz ns ns % s % DEGP-P mA mA MIN LT1189M/C TYP MAX 1.0 3.0 1.0 4.0 0.2 0.5 30 1.25 30 2.0 170 3.5 1.0 2.0 UNITS mV mV A A nV/Hz pA/Hz k pF mV V dB dB V
2
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W
U
U
WW
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LT1189 +5V ELECTRICAL CHARACTERISTICS -
SYMBOL IS/D ton toff PARAMETER Shutdown Pin Current Turn On Time Turn Off Time CONDITIONS Pin 5 at V - Pin 5 from V - to Ground, RL = 1k Pin 5 from Ground to V -, RL = 1k
TA = 25C, (Note 3) VS = 5V, VREF = 0V, RFB1 = 900 from pins 6 to 8, RFB2 = 100 from pin 8 to ground, RL = RFB1 + RFB2 = 1k, CL 10pF, pin 5 open.
MIN LT1189M/C TYP MAX 5 500 600 25 UNITS A ns ns
5V ELECTRICAL CHARACTERISTICS + -
SYMBOL VOS IOS IB CMRR VOUT SR BW IS IS/D PARAMETER Input Offset Voltage Input Offset Current Input Bias Current Input Voltage Range Common-Mode Rejection Ratio Output Voltage Swing Slew Rate Small-Signal Bandwidth Supply Current Shutdown Supply Current Shutdown Pin Current Pin 5 at V - Pin 5 at V - CONDITIONS
TA = 25C, (Note 3) VS = 5V, VS = 0V, VREF = 2.5V, RFB1 = 900 from pins 6 to 8, RFB2 = 100 from pin 8 to VREF, RL = RFB1 + RFB2 = 1k, CL 10pF, pin 5 open.
MIN LT1189M/C TYP MAX 1.0 1.0 0.2 0.5 2.0 VCM = 2.0V to 3.5V RL = 300 to Ground (Note 3) VO = 1.5V to 3.5V AV = 10 VOUT High VOUT Low 80 3.6 100 4.0 0.15 175 30 12 0.8 5 15 1.5 25 0.4 V/s MHz mA mA A 3.0 5.0 1.0 2.0 3.5 UNITS mV mV A A V dB V Either Input, (Note 4) SOIC Package Either Input Either Input
+5V ELECTRICAL CHARACTERISTICS -55C TA 125C, (Note 3) - V = 5V, V = 0V, R = 900 from pins 6 to 8, R = 100 from pin 8 to ground, R = R + R
S REF FB1 FB2 L FB1
FB2 =
1k, CL 10pF, pin 5 open.
LT1189M TYP MAX 1.0 10 0.2 0.5 7.5 1.5 3.5 3.5 105 90 4.0 7.0 6.6 1.0 13 0.8 5 6.0 17 1.5 25 % mA mA A UNITS mV V/C A A V dB dB V
SYMBOL VOS VOS /T IOS IB CMRR PSRR VOUT
PARAMETER Input Offset Voltage Input VOS Drift Input Offset Current Input Bias Current Input Voltage Range Common-Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing
CONDITIONS Either Input, (Note 4) Either Input Either Input
MIN
-2.5 VCM = -2.5V to 3.5V VS = 2.375V to 8V VS = 5V, RL = 1k, AV = 50 VS = 8V, RL = 1k, AV = 50 VS = 8V, RL = 300, AV = 50, (Note 3) 80 65 3.7 6.6 6.4
GE IS IS/D
Gain Error Supply Current Shutdown Supply Current Shutdown Pin Current
VO = 1V, AV = 10, RL = 1k Pin 5 at V -, (Note 11) Pin 5 at V -
3
LT1189 +5V ELECTRICAL CHARACTERISTICS 0C TA 70C, (Note 3) - V = 5V, V = 0V, R = 900 from pins 6 to 8, R = 100 from pin 8 to ground, R = R
S REF FB1 FB2 L FB1
+ RFB2 = 1k, CL 10pF, pin 5 open.
MIN LT1189C TYP MAX 1.0 1.0 5.0 0.2 0.5 -2.5 80 70 3.7 6.6 6.4 105 90 4.0 7.0 6.6 1.0 13 0.8 5 3.5 17 1.5 25 % mA mA A 3.0 6.0 1.5 3.5 3.5 UNITS mV mV V/C A A V dB dB V
SYMBOL VOS VOS /T IOS IB CMRR PSRR VOUT
PARAMETER Input Offset Voltage (Note 4) Input VOS Drift Input Offset Current Input Bias Current Input Voltage Range Common-Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing
CONDITIONS Either Input SOIC Package Either Input Either Input VCM = - 2.5V to 3.5V VS = 2.375V to 8V VS = 5V, RL = 1k, AV = 50 VS = 8V, RL = 1k, AV = 50 VS = 8V, RL = 300, AV = 50, (Note 3)
GE IS IS/D
Gain Error Supply Current Shutdown Supply Current Shutdown Pin Current
VO = 1V, AV = 10, RL = 1k Pin 5 at V -, (Note 11) Pin 5 at V -
5V ELECTRICAL CHARACTERISTICS + -
SYMBOL VOS VOS /T IOS IB CMRR VOUT IS IS/D PARAMETER Input Offset Voltage, (Note 4) Input VOS Drift Input Offset Current Input Bias Current Input Voltage Range Common-Mode Rejection Ratio Output Voltage Swing Supply Current Shutdown Supply Current Shutdown Pin Current Either Input Either Input CONDITIONS Either Input
0C TA 70C, (Note 3) VS = +5V, VS = 0V, VREF = 2.5V, RFB1 = 900 from pins 6 to 8, RFB2 = 100 from pin 8 to VREF, RL = RFB1 + RFB2 = 1k, CL 10pF, pin 5 open.
MIN LT1189C TYP MAX 1.0 5.0 0.2 0.5 2.0 VCM = 2.0V to 3.5V RL = 300 to Ground (Note 3) Pin 5 at V, (Note 11) Pin 5 at V - VOUT High VOUT Low 80 3.5 100 4.0 0.15 12 0.8 5 0.4 16 1.5 25 mA mA A 1.5 3.5 3.5 3.0 UNITS mV V/C A A V dB V
Note 1: A heat sink may be required to keep the junction temperature below absolute maximum when the output is shorted continuously. Note 2: TJ is calculated from the ambient temperature T A and power dissipation PD according to the following formulas: LT1189MJ8, LT1189CJ8: TJ = TA + (PD x 100C/W) LT1189CN8: TJ = TA + (PD x 100C/W) LT1189CS8: TJ = TA + (PD x 150C/W) Note 3: When RL = 1k is specified, the load resistor is RFB1 + RFB2, but when RL = 300 is specified, then an additional 430 is added to the output such that (RFB1 + RFB2) in parallel with 430 is RL = 300. Note 4: VOS measured at the output (pin 6) is the contribution from both input pair, and is input referred. Note 5: VIN LIM is the maximum voltage between -V IN and +VIN (pin 2 and pin 3) for which the output can respond.
Note 6: Slew rate is measured between 1V on the output, with a VIN step of 0.5V, AV = 10 and RL = 1k. Note 7: Full power bandwidth is calculated from the slew rate measurement: FPBW = SR/2Vp. Note 8: Settling time measurement techniques are shown in "Take the Guesswork Out of Settling Time Measurements," EDN, September 19, 1985. Note 9: NTSC (3.58MHz). Note 10: AC parameters are 100% tested on the ceramic and plastic DIP packaged parts (J8 and N8 suffix) and are sample tested on every lot of the SO packaged parts (S8 suffix). Note 11: See Application section for shutdown at elevated temperatures. Do not operate shutdown above T J > 125C.
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LT1189
TYPICAL PERFOR A CE CHARACTERISTICS
Input Bias Current vs Common-Mode Voltage
3.0 VS = 5V 2.5
INPUT BIAS CURRENT (A) INPUT BIAS CURRENT (nA)
2.0 1.5 -55C 1.0 0.5 0 25C 125C
COMMON-MODE RANGE (V)
- 0.5 - 5 - 4 -3 -2 -1 0 1 2 3 COMMON-MODE VOLTAGE (V) 4 5
Equivalent Input Noise Voltage vs Frequency
180 160 140 120 100 80 60 40 20 0 10 100 1k 10k FREQUENCY (Hz) 100k V S = 5V T A = 25C RS = 0
EQUIVALENT INPUT NOISE CURRENT (pA/Hz)
EQUIVALENT INPUT NOISE VOLTAGE (nV/Hz)
200
8 6 4 2 0 10 100 1k 10k FREQUENCY (Hz) 100k
SUPPLY CURRENT (mA)
Shutdown Supply Current vs Temperature
6.0
SHUTDOWN SUPPLY CURRENT (mA)
VS = 5V 5.0 -1.4
GAIN ERROR (%)
4.0 3.0 2.0 1.0
VS/D = -VEE + 0.6V VS/D = -VEE + 0.4V VS/D = -VEE + 0.2V
-1.6 -1.8 -2.0 -2.2
OPEN-LOOP GAIN (kV/V)
VS/D = -VEE 0 -50 -25 0 25 75 50 TEMPERATURE (C) 100 125 -2.4 -50 -25 0 25 50 75 TEMPERATURE (C) 100 125 0 -50 -25 25 75 0 50 TEMPERATURE (C) 100 125
UW
LT1189 * TPC01
Input Bias Current vs Temperature
100 VS = 5V 0 +IB
Common-Mode Voltage vs Temperature
V+ -0.5 -1.0 -1.5 -2.0 V + = 1.8V TO 9V
-100 IOS -200
-IB
2.0 1.5 1.0 0.5 V- - 50 -25 V + = -1.8V TO -9V
-300
-400 -50
-25
0 25 75 50 TEMPERATURE (C)
100
125
0 25 50 75 TEMPERATURE (C)
100
125
LT1189 * TPC02
LT1189 * TPC03
Equivalent Input Noise Current vs Frequency
12 10 VS = 5V TA = 25C RS = 100k
16
Supply Current vs Supply Voltage
14
-55C 25C
12 125C 10
8 0 2 4 6 8 SUPPLY VOLTAGE (V) 10
LT1189 * TPC04
LT1189 * TPC05
LT1189 * TPC06
Gain Error vs Temperature
-1.2 VS = 5V VOUT = 1V AV = 10 RL = 1k 16 14 12 10 8 6 4 2
Open-Loop Gain vs Temperature
VS = 5V VO = 3V RL = 1k
RL = 500
LT1189 * TPC07
LT1189 * TPC08
LT1189 * TPC09
5
LT1189
TYPICAL PERFOR A CE CHARACTERISTICS
Gain, Phase vs Frequency
100 80 PHASE VS = 5V TA = 25C RL = 1k 100 80
OPEN-LOOP VOLTAGE GAIN (kV/V)
GAIN BANDWIDTH PRODUCT (MHz)
VOLTAGE GAIN (dB)
60 40 20 0 -20 100k GAIN
1M 10M FREQUENCY (Hz)
Gain Bandwidth Product and Phase Margin vs Temperature
250
GAIN BANDWIDTH PRODUCT (MHz)
COMMON-MODE REJECTION RATIO (dB)
OUTPUT IMPEDANCE ( )
VS = 5V R L = 1k AV = 20dB
PHASE MARGIN (DEG)
200
GAIN BANDWIDTH PRODUCT
150 PHASE MARGIN
100 -50
-25
25 75 0 50 TEMPERATURE (C)
Power Supply Rejection Ratio vs Frequency
80
OUTPUT SHORT CIRCUIT CURRENT (mA)
POWER SUPPLY REJECTION RATIO (dB)
OUTPUT SATURATION VOLTAGE (V)
60
VS = 5V TA = 25C VRIPPLE = 300mV
40
+PSRR -PSRR
20
0
-20 1k 10k 1M 100k FREQUENCY (Hz) 10M 100M
6
UW
100M
LT1189 * TPC11
Open-Loop Voltage Gain vs Load Resistance
30 VS = 5V VO = 3V TA = 25C 20 250
Gain Bandwidth Product vs Supply Voltage
AV = 20dB TA = -55C
PHASE MARGIN (DEG)
60 40 20 0 -20
200
TA = 25C
TA = 125C 150
10
0 100
100 1k LOAD RESISTANCE () 10k
LT1189* TPC10
0
2
4 8 6 SUPPLY VOLTAGE (V)
10
LT1189 * TPC12
Output Impedance vs Frequency
85 100 VS = 5V TA = 25C AV = 10 75 10
Common-Mode Rejection Ratio vs Frequency
90 80 70 60 50 40 30 100k VS = 5V TA = 25C RL = 1k
65
1
100
55 125
0.1
1k
10k
100k 1M FREQUENCY (Hz)
10M
100M
1M 10M FREQUENCY (Hz)
100M
LT1189 * TPC15
LT1189 * TPC13
LT1189 * TPC14
Output Short Circuit Current vs Temperature
36 VS = 5V 35 34 33 32 31 30 -50
V+ - 0.7 -0.8 -0.9 -1.0 -1.1 0.5 0.4 0.3 0.2
Output Swing vs Supply Voltage
125C 25C -55C RL = 1k 1.8V VS 9V 125C 25C -55C
-25
50 0 25 75 TEMPERATURE (C)
100
125
0.1 V- 0
2
4 6 8 SUPPLY VOLTAGE (V)
10
LT1189 * TPC16
LT1189 * TPC17
LT1189 * TPC18
LT1189
TYPICAL PERFOR A CE CHARACTERISTICS
Output Voltage Swing vs Load Resistance
5 VS = 5V -SLEW RATE OUTPUT VOLTAGE SWING (V) 3 TA = -55C TA = 25C TA = 25C
SLEW RATE (V/s)
1
-1 TA = 25C
-3
-5 10 100 LOAD RESISTANCE () 1000
LT1189 * TPC19
Output Voltage Step vs Settling Time, AV = 10
4 VS = 5V TA = 25C RL = 1k 0 -10
DISTORTION (dBc)
OUTPUT VOLTAGE STEP (V)
2
0
-2
10mV
-4 100
140
180 220 260 SETTLING TIME (ns)
Large-Signal Transient Reponse
AV = 10, RL = 1k, +SR = 223V/s, -SR = 232V/s
LT1189 * TPC23
UW
Slew Rate vs Temperature
300
+SLEW RATE 250
TA = -55C TA = 25C
VS = 5V RL = 1k VO = 2V AV = 10 200 -50 -25 0 25 50 75 TEMPERATURE (C) 100 125
LT1189 * TPC20
Harmonic Distortion vs Output Level
VS = 5V TA = 25C RL = 1k f = 10MHz AV = 10
10mV
-20 -30 -40 -50 -60
HD3
HD2
300
340
0
3 1 2 OUTPUT VOLTAGE (VP-P)
4
LT1189 * TPC22
LT1189 * TPC21
Small-Signal Transient Reponse
AV = 10, RL = 1k, tr = 9.40ns
LT1189 * TPC24
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LT1189
APPLICATI S I FOR ATIO U
Power Supply Bypassing The LT1189 is quite tolerant of power supply bypassing. In some applications a 0.1F ceramic disc capacitor placed 1/2 inch from the amplifier is all that is required. In applications requiring good settling time, it is important to use multiple bypass capacitors. A 0.1F ceramic disc in parallel with a 4.7F tantalum is recommended. Calculating the Output Offset Voltage Both input stages contribute to the output offset voltage at pin 6. The feedback correction forces balance in the input stages by introducing an Input VOS at pin 8. The complete expression for the output offset voltage is: VOUT = (VOS + IOS(RS) + IB(RREF)) x (RFB + RG)/RG + IB(RFB) RS represents the input source resistance, typically 75, and RREF represents finite source impedance from the DC reference voltage, for VREF grounded, RREF = 0 the IOS is normally a small contributor and the expression simplifies to: VOUT = VOS(RFB + RG)/RG + IB(RFB) If RFB is limited to 1k, the last term of the equation contributes only 2mV since IB is less than 2A.
RFB + RG RG 6 VOUT
The primary use of the LT1189 is in converting high speed differential signals to a single-ended output. The LT1189 video difference amplifier has two uncommitted high input impedance (+) and (-) inputs. The amplifier has another set of inputs which can be used for reference and feedback. Additionally, this set of inputs give gain adjust, and DC control to the differential amplifier. The voltage gain of the LT1189 is set like a conventional operational amplifier. Feedback is applied to pin 8, and it is optimized for gains of 10 or greater. The amplifier can be operated singleended by connecting either the (+) or (-) inputs to the +/REF (pin 1). The voltage gain is set by the resistors: (RFB + RG)/RG. Like the single-ended case, the differential voltage gain is set by the external resistors: (RFB + RG)/RG. The maximum input differential signal for which the output will respond is approximately 170mV.
S/D 5 VIN V+ V IN V+ 5 3 7 + 2 - LT1189 1 +/REF 8 -/FB 4 V- RFB RFB + RG RG S/D
3 7 + 2 - LT1189 1 +/REF 8 -/FB 4 V- RFB AV = +
6
VOUT
RG
S/D V+ 5 3 7 + 2 - LT1189 1 +/REF 8 -/FB 4 V- RFB RFB + RG RG
VIN DIFF VIN
6
VIN DIFF VOUT V IN RG
RG
VO = (VIN DIFF + VIN)
VO =
(
8
W
RG
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AV = -
7 V+
6
S/D V+ 5 3 7 + 2 - LT1189 1 +/REF 8 -/FB 4 V- RFB RFB + RG RG
RFB
6 VOUT
Q1 3
Q2 RE 300
Q3
Q4 RE 300
8 RG
+
RS
2
-
RS
+
1 REF RREF
345A
350A 4 V-
LT1189 * AI02
(V
IN DIFF -
( R (V
G
RFB
IN
LT1189 * AI01
Figure 1. Simplified Input Stage Schematic
LT1189
APPLICATI
S I FOR ATIO
Instrumentation Amplifier Rejects High Voltage Instrumentation amplifiers are often used to process slowly varying outputs from transducers. With the LT1189 it is easy to make an instrumentation amplifier that can respond to rapidly varying signals. Attenuation resistors in front of the LT1189 allow very large common-mode signals to be rejected while maintaining good frequency response. The input common-mode and differential-mode signals are reduced by 100:1, while the closed-loop gain is set to be 100, thereby maintaining unity-gain input to output. The unique topology allows for frequency response boost by adding 150pF to pin 8 as shown.
3.5MHz Instrumentation Amplifier Rejects 120VP-P
5V 2 1 10k* 100* 3 8
VOLTAGE GAIN (dB)
10k* VIN VCM 120VP-P
100*
+
REF
7 LT1189 4 -5V 10k 6
-
FB
150pF * 0.1% RESISTORS WORST CASE CMRR = 48dB
100
LT1189 * AI03
Output of Instrumentation Amplifier with 1MHz Square Wave Riding on 120VP-P at the Input
LT1189 * AI04
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High Voltage Instrumentation Amplifier Response
20 0 DIFFERENTIAL-MODE RESPONSE -20 -40 COMMON-MODE RESPONSE - 60 100k 1M 10M FREQUENCY (Hz) 100M
LT1189 * AI05
W
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Operating with Low Closed-Loop Gain The LT1189 has been optimized for closed-loop gains of 10 or greater. The amplifier can be operated at much lower closed-loop gains with the aid of a capacitor CFB across the feedback resistor, (feedback zero). This capacitor lowers the closed-loop 3dB bandwidth. The bandwidth cannot be made arbitrarily low because CFB is a short at high frequency and the amplifier will appear configured unity-gain. As an approximate guideline, make BW x AVCL = 200MHz. This expression expands to:
A VCL = 200MHz 2(RFB )(C FB )
or:
C FB =
A VCL (200MHz)(2)(RFB )
The effect of the feedback zero on the transient and frequency response is shown for AV = 4.
9
LT1189
APPLICATI
30
S I FOR ATIO
Closed-Loop Voltage Gain vs Frequency
CLOSED-LOOP VOLTAGE GAIN (dB)
20
CFB = 0pF
10
CFB = 5pF
0 VS = 5V TA = 25C AV = 4 RFB = 900 RG = 300 1M 10M FREQUENCY (Hz) 100M
LT1189 * AI06
-10
-20 100k
Small-Signal Transient Response
AV = 4, RFB = 910, RG = 300
LT1189 * AI07
Small-Signal Transient Response
AV = 4, RFB = 910, RG = 300, CFB = 5pF
LT1189 * AI08
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Reducing the Closed-Loop Bandwidth Although it is possible to reduce the closed-loop bandwidth by using a feedback zero, instability can occur if the bandwidth is made too low. An alternate technique is to do differential filtering at the input of the amplifier. This technique filters the differential input signal, and the differential noise, but does not filter common-mode noise. Common-mode noise is rejected by the LT1189's CMRR.
10MHz Bandwidth Limited Amplifier
R1 110 SIG eND C1 68pF 5V 3 2 1 8 R2 110 100 + - LT1189 REF FB 4 -5V 909 AV = 10 f -3dB = VOUT = 1 2(R1 + R2)C1 SIG + eND eNCM + CMR FILTER
LT1189 * AI09
W
U
UO
7 6 VOUT
eNCM
Using the Shutdown Feature The LT1189 has a unique feature that allows the amplifier to be shutdown for conserving power, or for multiplexing several amplifiers onto a common cable. The amplifier will shutdown by taking pin 5 to V -. In shutdown, the amplifier dissipates 15mW while maintaining a true high impedance output state of about 20k in parallel with the feedback resistors. For MUX applications, the amplifiers may be configured inverting, non-inverting, or differential. When the output is loaded with as little as 1k from the amplifier's feedback resistors, the amplifier shuts off in 600ns. This shutoff can be under the control of HC CMOS operating between 0V and - 5V.
LT1189
APPLICATI
S I FOR ATIO
1MHz Sine Wave Gated Off with Shutdown Pin
SHUTDOWN
VOUT
AV = 10, RFB = 900, RG = 100
LT1189 * AI10
TYPICAL APPLICATI
Differential Receiver MUX for Power Down Applications
15k 1.5k 15k 1.5k CMOS IN CHANNEL SELECT 1k 3 2
CABLE 1
1k -5V 15k 1.5k 15k 1.5k 3 + 2 - VDC 1 REF 8 FB 5 5V 7 LT1189 4 -5V 1k 100 1% RESISTORS WORST CASE CMRR = 28dB TYPICALLY 35dB
LT1189 * TA03
CABLE 2
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.
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The ability to maintain shutoff is shown on the curve Shut down Supply Current vs Temperature in the Typical Performance Characteristics section. At very high elevated temperature it is important to hold the shutdown pin close to the negative supply to keep the supply current from increasing.
+ -
5 5V 7 LT1189 4 -5V 6 VDC 1 REF 8 FB 1k 100 74HC04 74HC04 VOUT 6
W
UO
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UO
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LT1189
SI PLIFIED SCHE ATIC
7 V+ VBIAS VBIAS
+3 C FF -2 +V +V
5 S/D 1 +/REF 8 -/FB * SUBSTRATE DIODE, DO NOT FORWARD BIAS
PACKAGE DESCRIPTIO
0.290 - 0.320 (7.366 - 8.128)
J8 Package 8-Lead Hermetic DIP
0.008 - 0.018 (0.203 - 0.460) 0.385 0.025 (9.779 0.635)
0.300 - 0.320 (7.620 - 8.128)
N8 Package 8-Lead Plastic DIP
0.009 - 0.015 (0.229 - 0.381)
(
+0.025 0.325 -0.015 +0.635 8.255 -0.381
)
0.010 - 0.020 x 45 (0.254 - 0.508)
S8 Package 8-Lead Plastic SOIC
0- 8 TYP 0.016 - 0.050 0.406 - 1.270
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977
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W
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CM
6 VOUT
*
4 V-
LT1189 * SS
Dimensions in inches (millimeters) unless otherwise noted.
0.405 (10.287) MAX 8 7 6 5
CORNER LEADS OPTION (4 PLCS)
0.200 (5.080) MAX 0.015 - 0.060 (0.381 - 1.524)
0.005 (0.127) MIN
0.023 - 0.045 (0.58 - 1.14) HALF LEAD OPTION 0 - 15 0.045 - 0.065 (1.14 - 1.65) FULL LEAD OPTION
0.025 (0.635) RAD TYP 1 2 3
0.220 - 0.310 (5.588 - 7.874)
4
0.045 - 0.065 (1.14 - 1.65) 0.014 - 0.026 (0.360 - 0.660)
0.125 3.175 0.100 0.010 MIN (2.540 0.254)
0.045 - 0.065 (1.143 - 1.651)
0.130 0.005 (3.302 0.127)
0.400 (10.160) MAX 8 7 6 5
0.065 (1.651) TYP 0.125 (3.175) MIN 0.020 (0.508) MIN
0.250 0.010 (6.350 0.254)
0.045 0.015 (1.143 0.381) 0.100 0.010 (2.540 0.254)
1
2
3
4
0.018 0.003 (0.457 0.076) 0.189 - 0.197 (4.801 - 5.004)
0.053 - 0.069 (1.346 - 1.752) 0.004 - 0.010 (0.101 - 0.254) 0.228 - 0.244 (5.791 - 6.197)
8
7
6
5
0.008 - 0.010 (0.203 - 0.254)
0.014 - 0.019 (0.355 - 0.483)
0.050 (1.270) BSC
0.150 - 0.157 (3.810 - 3.988)
1
2
3
4
BA/LT/GP 0293 10K REV 0
(c) LINEAR TECHNOLOGY CORPORATION 1993

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