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LTC6943 Micropower, Dual Precision Instrumentation Switched Capacitor Building Block DESCRIPTIO
The LTC(R)6943 is a monolithic, charge-balanced, dual switched capacitor instrumentation building block. A pair of switches alternately connects an external capacitor to an input voltage and then connects the charged capacitor across an output port. The internal switches have a break-before-make action. An internal clock is provided and its frequency can be adjusted with an external capacitor. The LTC6943 can also be driven with an external CMOS clock. The LTC6943, when used with low clock frequencies, provides ultra precision DC functions without requiring precise external components. Such functions are differential voltage to single-ended conversion, voltage inversion, voltage multiplication and division by 2, 3, 4, 5, etc. The LTC6943 is manufactured using Linear Technology's enhanced LTCMOSTM silicon gate process, and it is functionally compatible with the LTC1043.
FEATURES

Low Power, IS = 60A(Max) Robust, Latch Up Proof Instrumentation Front End with 120dB CMRR Precise, Charge-Balanced Switching Operates from 5V to 18V Internal or External Clock Operates up to 5MHz Clock Rate Two Independent Sections with One Clock Tiny SSOP-16 Package
APPLICATIO S

Ultra Precision Voltage Inverters, Multipliers and Dividers V-F and F-V Converters Sample-and-Hold Current Sources Precision Instrumentation Amplifiers
, LTC and LT are registered trademarks of Linear Technology Corporation. LTCMOS is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
5V INPUT 0V TO 3.7V 3
Precision Voltage Controlled Current Source with Ground Referred Input and Output Precision Current Sensing in Supply Rails
1
+ -
5
LTC2050 4 2 0.68F 5V 1k 7 3 1/2 LTC6943
POSITIVE OR NEGATIVE RAIL
I
E RSHUNT 1/2 LTC6943 11 12
6
9 1F 10 1F 1k
12 15 0.001F
11 14
IOUT =
VIN 1000
OPERATES FROM A SINGLE 5V SUPPLY
6943 * TA01a
U
U
U
10 1F 9 1F E I= E RSHUNT
6
7
14 0.01F
15
6943 * TA01b
6943f
1
LTC6943
ABSOLUTE
(Note 1)
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW CB+ 1 CB- 2 V+ 3 S2B 4 S1B 5 S1A 6 S2A 7 SHA 8 16 S3B 15 V- 14 COSC 13 S4B 12 S4A 11 S3A 10 CA- 9 CA+
Supply Voltage ........................................................ 18V Input Voltage at Any Pin .......... -0.3V VIN V+ + 0.3V Operating Temperature Range (Note 2) ............................................ -40C to 125C Specified Temperature Range (Note 2) .............................................-40C to 125C Storage Temperature Range ................. -65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C
ORDER PART NUMBER LTC6943CGN LTC6943IGN LTC6943HGN GN PART MARKING 6943C 6943I 6943H
GN PACKAGE 16-LEAD NARROW PLASTIC SSOP TJMAX = 125C, JA = 110C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS +
SYMBOL PARAMETER IS Power Supply Current CONDITIONS
The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. V = 10V, V- = 0V
LTC6943C LTC6943I MIN TYP MAX 40
MIN
LTC6943H TYP MAX 40 80 6 240 400 185 30 40 25 75 5 120 60 90 150 170 100 200 400 700 700 1 50 75 70 100
UNITS A A A A pA nA k kHz kHz kHz A A ns ns MHz dB
Pin 14 Connected High or Low COSC (Pin 14 to V -) = 100pF
60 90 150 170 100 40 400 700 700 1 50 75 70 100 20 10
80
II RON RON fOSC
OFF Leakage Current ON Resistance ON Resistance Internal Oscillator Frequency
Any Switch, Test Circuit 1 (Note 3)
6 240
Test Circuit 2, VIN = 7V, 1 = 0.5mA V+ = 10V, V - = 0V Test Circuit 2, VIN = 3.1V, 1 = 0.5mA V + = 5V, V - = 0V COSC (Pin 14 to V -) = 0pF COSC (Pin 14 to V -) = 100pF Test Circuit 3 Pin 14 at V+ or V -
400

20 12
185 30 40 25
IOSC
Pin Source or Sink Current Break-Before-Make Time Clock to Switching Delay
COSC Pin Externally Driven V+ = 5V, V - = -5V, -5V < VCM < 5V DC to 400Hz
75 5 120
fM CMRR
Maximum External CLK Frequency COSC Pin Externally Driven with CMOS Levels Common Mode Rejection Ratio
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: All versions of the LTC6943 are guaranteed functional over the operating temperature range of -40C to 125C. The LTC6943CGN is guaranteed to meet 0C to 70C specifications and is designed, characterized and expected to meet the specified performance from -40C
to 85C but it is not tested or QA sampled at these temperatures. The LTC6943IGN is guaranteed to meet specified performance from -40C to 85C. The LTC6943HGN is guaranteed to meet specified performance from -40C to 125C. Note 3: OFF leakage current at 25C is guaranteed by design and it is not 100% tested in production.
6943f
2
U
W
U
U
WW
W
LTC6943 TYPICAL PERFOR A CE CHARACTERISTICS
Power Supply Current vs Power Supply Voltage
0.50 0.45 0.40
SUPPLY CURRENT (mA)
0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 0
COSC = 0pF, TA = -55C COSC = 0pF, TA = 25C COSC = 0pF, TA = 125C COSC = 4700pF, TA = -55C COSC = 4700pF, TA = 25C COSC = 4700pF, TA = 125C
RON ()
RON ()
2
4
6
8 10 12 VSUPPLY (V)
14
RON vs VIN
260 240 220 V IN 200 RON () 180 160 140 120 100 80 0 2 4 6 8 10 12 14 16 18 20 VIN (V)
LTC1043 * TPC04
RON (PEAK) I = 100A
V+ = 15V V - = 0V TA = 25C
RON ()
I = 100A I = mA
500 400 300 200 100 0 0
RON ()
Oscillator Frequency, fOSC vs COSC
1000 TA = 25C
250 225 200
OSCILLATOR FREQUENCY NORMALIZED TO fOSC AT 5V SUPPLY
100
fOSC (kHz)
IOSC (kHz)
10
VS = 5V VS = 10V
1
VS = 15V
0.1 0 1000 2000 3000 COSC (pF) 4000 5000
6943 TPC07
UW
16 18
6943 TPC01
(Test Circuits 2 through 4)
RON vs VIN
550 500 450 V IN 400 350 300 250 200 150 100 0 1 2 VIN (V)
LTC1043 * TPC02
RON vs VIN
V+ = 5V V - = 0V TA = 25C 280 260 240 VIN 220 200 180 160 140 120 100 3 4 5 0 1 2 3 4 56 VIN (V) 7 8 9 10 I = 100A I = mA RON (PEAK) I = 100A V+ = 10V V - = 0V TA = 25C
RON (PEAK) I = 100A
I = 100A I = mA
LTC1043 * TPC03
RON (Peak) vs Power Supply Voltage
1000 900 800 700 600 VIN 3.2V VIN 7V 3V V+ + 18V V - = 0V TA = 25C 2 4 6 VIN = 1.6V VIN RON (PEAK) I = 100A 1100 1000 900 800 700 600 500 400 300 200 100
RON (Peak) vs Power Supply Voltage and Temperature
RON (PEAK) VIN I = 100A
TA = 125C
VIN 11V
TA = 70C TA = -55C 0 2 4 6 8 10 12 14 16 18 20 VSUPPLY (V)
LTC1043 * TPC06
VIN 15.1V 8 10 12 14 16 18 20 VSUPPLY (V)
LTC1043 * TPC05
Oscillator Frequency, fOSC vs Supply Voltage
TA = 25C
Normalized Oscillator Frequency, fOSC vs Supply Voltage
1.5 TA = 25C
1.3 COSC = 0pF 1.0 COSC = 100pF 0.5 COSC = 10,000pF 0.3 COSC = 1,000pF
175 150 125 100 75 50 25 0 0 2 4 6 8
COSC = 0pF
COSC = 100pF
10 12 VSUPPLY (V)
14
16
18
0
0
2
4
6
8 10 12 VSUPPLY (V)
14
16
18
6943 TPC08
6943 TPC09
6943f
3
LTC6943 TYPICAL PERFOR A CE CHARACTERISTICS
Oscillator Frequency, fOSC vs Ambient Temperature
350 300 VS = 5V 250
fOSC (kHz)
PIN 14 SOURCE OR SINK CURRENT (A)
COSC = 0pF
50
ISOURCE, TA = -55C ISOURCE, TA = 25C
tNOV (ns)
200 150 100 50
VS = 10V VS = 15V
0 -50 -25
50 25 75 0 TEMPERATURE (C)
BLOCK DIAGRA
4
UW
100
6943 TPC10
(Test Circuits 2 through 4) Break-Before-Make Time, tNOV, vs Supply Voltage
80 TA = 25C 70 60 50 40 30
COSC Pin ISINK, ISOURCE vs Supply Voltage
100 ISINK, TA = -55C 75 ISINK, TA = 25C
25 ISINK, TA = 125C ISOURCE, TA = 125C 0 0 2 4 6 8 10 12 14 16 18
20 10 0 2 4 6 8 10 12 14 16 18 20 VSUPPLY (V)
LTC1043 * TPC12
125
LTC1043 * TPC11
W
S1A 6 7 S2A SHA 8 9 CA+ 10 CA- S3A 11 CHARGE BALANCING CIRCUITRY S1B 5 4 S2B 12 S4A 1 CB+ 2 CB- S3B 16 CHARGE BALANCING CIRCUITRY 13 S4B NON-OVERLAPPING CLOCK V+ V- COSC 14 OSCILLATOR 15 V- 3 V+ THE CHARGE BALANCING CIRCUITRY SAMPLES THE VOLTAGE AT S3 WITH RESPECT TO S4 (PIN 14 HIGH) AND INJECTS A SMALL CHARGE AT THE C+ PIN (PIN 14 LOW). THIS BOOSTS THE CMRR WHEN THE LTC6943 IS USED AS AN INSTRUMENTATION AMPLIFIER FRONT END. FOR MINIMUM CHARGE INJECTION IN OTHER TYPES OF APPLICATIONS, S3A AND S3B SHOULD BE GROUNDED THE SWITCHES ARE TIMED AS SHOWN WITH PIN 14 HIGH
6943 * BD01
6943f
LTC6943
TEST CIRCUITS
Test Circuit 1. Leakage Current Test
(6, 11, 5, 16) (7, 12, 4, 13) NOTE: TO OPEN SWITCHES, S1 AND S3 PIN 14, SHOULD BE CONNECTED TO V -. TO OPEN S2, S4, THE COSC PIN 14 SHOULD BE CONNECTED TO V+ COSC
6943 * TC01
Test Circuit 2. RON Test
(6, 11, 5, 16) (7, 12, 4, 13)
A
+
0V TO 10V
+
(9, 10, 1, 2)
VIN (9, 10, 1, 2) 100A to 1mA CURRENT SOURCE A
6943 * TC02
Test Circuit 3. Oscillator Frequency, fOSC
6
(TEST PIN) 1 V+ V- COSC
Test Circuit 4. CMRR Test
7 VOUT
15
8
14
9 1F 1F CAPACITORS ARE NOT ELECTROLYTIC
+
3
LTC6943
4
10
+
5 IV
6943 * TC03
11
12
+
V- VCM V+ CMRR = 20 LOG
()
VCM VOUT
6943 * TC04
NOTE: FOR OPTIMUM CMRR, THE COSC SHOULD BE LARGER THAN 0.0047F, AND THE SAMPLING CAPACITOR ACROSS PINS 9 AND 10 SHOULD BE PLACED OVER A SHIELD TIED TO PIN 8
APPLICATIO S I FOR ATIO
Common Mode Rejection Ratio (CMRR)
The LTC6943, when used as a differential to single-ended converter rejects common mode signals and preserves differential voltages (Figure 1). Unlike other techniques, the LTC6943's CMRR does not degrade with increasing common mode voltage frequency. During the sampling mode, the impedance of Pins 1, 2 (and 9, 10) should be balanced, otherwise, common mode signals will appear differentially. The value of the CMRR depends on the value of the sampling and holding capacitors (CS, CH) and on the sampling frequency. Since the common mode voltages are not sampled, the common mode signal frequency can well exceed the sampling frequency without experiencing aliasing phenomena. The CMRR of Figure 1 is measured by shorting Pins 6 and 11 and by observing, with a
U
1/2 LTC6943 6 7 C+ VD 9
W
UU
+
+
CS C- 10 VD CH
11 VCM
12
+
CS, CH ARE MYLAR OR POLYPROPYLENE
6943 * AI01
Figure 1. Differential to Single-Ended Converter
6943f
5
LTC6943
APPLICATIO S I FOR ATIO
precision DVM, the change of the voltage across CH with respect to an input CM voltage variation. During the sampling and holding mode, charges are being transferred and minute voltage transients will appear across the holding capacitor. Although the RON on the switches is low enough to allow fast settling, as the sampling frequency increases, the rate of charge transfer increases and the average voltage measured with a DVM across it will increase proportionally; this causes the CMRR of the sampled data system, as seen by a "continuous" instrument (DVM), to decrease (Figure 2). Switch Charge Injection Figure 3 shows one out of the eight switches of the LTC6943, configured as a basic sample-and-hold circuit. When the switch opens, a ``hold step'' is observed and its magnitude depends on the value of the input voltage. Figure 4 shows charge injected into the hold capacitor. For instance, a 2pCb of charge injected into a 0.01F capacitor causes a 200V hold step. As shown in Figure 4, there is a predictable and repeatable charge injection cancellation when the input voltage is close to half the supply voltage of the LTC6943. This is a unique feature of this product, containing charge-balanced switches fabricated with a self-aligning gate CMOS process. Any switch of the LTC6943, when powered with symmetrical dual supplies, will sample-and-hold small signals around ground without any significant error.
140 120 100 CMRR (dB) CS = CH = 1F CS = 1F, CH = 0.1F
80 60 40
20 100
1k fOSC (Hz)
10k
100k
6943 * AI02
Figure 2. CMRR vs Sampling Frequency
6
U
Shielding the Sampling Capacitor for Very High CMRR Internal or external parasitic capacitors from the C + pin(s) to ground affect the CMRR of the LTC6943 (Figure 1). The common mode error due to the internal junction capacitances of the C + Pin(s) 1 and 9 is cancelled through internal circuitry. The C + pin, therefore, should be used as the top plate of the sampling capacitor. A shield placed underneath the sampling capacitor and connected to C - helps to boost the CMRR to 120dB (Figure 5). Excessive external parasitic capacitance between the C - pins and ground indirectly degrades CMRR; this becomes visible especially when the LTC6943 is used with clock frequencies above 2kHz. Because of this, if a shield is used, the parasitic capacitance between the shield and circuit ground should be minimized. It is recommended that the outer plate of the sampling capacitor be connected to the C - pin(s). COSC Pin (14) The COSC pin can be used with an external capacitor, COSC, connected from Pin 14 to Pin 15, to modify the internal oscillator frequency. If Pin 16 is floating, the internal 24pF capacitor, plus any external interpin capacitance, set the oscillator frequency around 190kHz with 5V supply. The typical performance characteristics curves provide the necessary information to set the oscillator frequency for various power supply ranges. Pin 14 can also be driven with an external CMOS level clock to override the internal oscillator.
5V 1 1/8 LTC6943 VIN 1000pF 5
W
UU
+
1/2 LTC1013 VOUT
-
-5V
V+ 0V
SAMPLE HOLD TO PIN 14
6943 * AI03
Figure 3
6943f
LTC6943
APPLICATIO S I FOR ATIO
12 10 V+ = 15V V- = 0V
CHARGE INJECTION (pCb)
8 6 4 2 0 0 2 4 6
V+ = 10V V- = 0V
V+ = 5V V- = 0V
10 8 VIN (V)
12
14
16
6943 * AI04
Figure 4. Individual Switch Charge Injection vs Input Voltage
TYPICAL APPLICATIO S
Divide by 2 Multiply by 2 Ultra Precision Voltage Inverter
1/2 LTC6943
1/2 LTC6943 VIN 6 7 VOUT = VIN /2 VOUT 1F 9 1F 10 1F 6
11
12
14 0.01F
15
VOUT = VIN /2 1ppm 0 VIN V+ 3 V+ 18V
6943 * TA03
U
OUTSIDE FOIL CS 1 2 PRINTED CIRCUIT BOARD AREA LTC6943
6943 * AI05
W
U
UU
Figure 5. Printed Circuit Board Layout Showing Shielding the Sampling Capacitor
1/2 LTC6943 7 VIN
6
7
VOUT = -VIN
9
9
1F 1F
1F
10
10
VIN 11 12
11
12
14
15 0.01F
14 0.01F
15
VOUT = 2VIN 5ppm 0 VIN V+ /2 3 V+ 18V
VOUT = -VIN 2ppm V - < VIN < V + V + = +5V, V - = -5V
6943 * TA02
6943 * TA03
6943f
7
LTC6943
TYPICAL APPLICATIO S
Precision Multiply by 3
VIN
LTC6943 6 7
9 1F 10
11
VOUT
5
2 1F 3 1F 1F
16
14 0.01F
VOUT = 3VIN 10ppm 0 < VIN < V+/3 3V < V+ < 18V
VIN 0V TO 3V
8
U
Divide by 3
LTC6943 VIN 6 7
9 1F 10
11
12
12
VOUT
1F
4
5
4
2 1F 3
VOUT
13
16
13
1F 14 15 0.01F
15
VOUT = VIN /3 3ppm 0 VIN V+
6943 * TA07
6943 * TA06
0.01% V/F Converter
-5V 1k LT1009 2.5V
15 5V 7 1/2 LTC6943 6 1F
9 12 11
fOUT: 0kHz TO 30kHz
3 GAIN 2.5k 6.19k** 1F 3 5V 2
10 0.01F* 6
14
- +
7 LT1056 4 -5V
*POLYPROPYLENE **1% FILM RESISTOR
22k Q1 2N2907A -5V
30pF
330k
1F
6943 * TA08
6943f
LTC6943
TYPICAL APPLICATIO S
0.01% Analog Multiplier
1/4 LTC6943 12 11 LT1004-1.2V 10 5V YINPUT 7.5k* 2 1F 0.001F
- +
7 LT1056 6 14 1/4 LTC6943 XINPUT 30pF 5 4 2 5V 7 LT1056 330k OPERATE LTC6943 FROM 5V POLYPROPYLENE, MOUNT CLOSE *1% FILM RESISTOR ADJUST OUTPUT TRIM SO X * Y = OUTPUT 0.01% 3 1 0.001F
3
4 -5V
22k 2N2907A (FOR START-UP)
-5V
+
INPUT 10
-
43k
V+ = 5V
1N914 2
U
1k -5V 1F 20k OUTPUT TRIM 0.01F
80.6k*
- +
6
OUTPUT XY 0.01%
4 -5V
1F
6943 * TA09
Single 5V Supply, Ultra Precision Low Power with True Rail-to-Rail In/Out Instrumentation Amplifier
5V LTC6943 6 7 3 5 1 OUTPUT AV = 1000
+ -
LTC2054CS 4 9 1F 1F 2
100 11 12
99.9k
5
4 0.22F 10k 1 1F 1F NONPOLARIZED
16
13 -0.5V
14
15
3 5V INPUT AND OUTPUT VOLTAGE RANGE INCLUDES GROUND. INPUT REFERRED OFFSET ERRORS ARE TYPICALLY 3V WITH 2V OF PEAK-TO-PEAK DC TO 10Hz NOISE CMRR ~ 120dB
6943 * TA10
0.0047
6943f
9
LTC6943
TYPICAL APPLICATIO S
Voltage Controlled Current Source with Ground Referred Input and Output
5V INPUT 0V TO 2V 3 8 1
THERMISTOR BRIDGE IS THE SIGNAL SOURCE 10k* T1 500Hz SINE DRIVE 4 1 6.19k 6.19k 3 3 6.19k 2 5V
RT
PHASE TRIM 0.002 2 5V 5V 8 LT1011 3 7 4 1 -5V ZERO CROSSING DETECTOR 1k
50k 10k
10
U
+ -
1/2 LT1013 2 4
0.68F
5V 1k 3
7
6
9 1F 10 1F 100
12 1/2 LTC6943 15
11 IOUT = 14 VIN 100
0.001F OPERATES FROM A SINGLE 5V SUPPLY
6943 * TA11
Lock-In Amplifier (= Extremely Narrow-Band Amplifier)
SYNCHRONOUS DEMODULATOR 10k* 5V 2
+
LT1007 6 11
-
LT1056
1/4 LTC6943 10 100k 3
5V 2 1M
-
-5V
+
-5V
-
LT1012 6 VOUT = 1000 * DC BRIDGE SIGNAL
12 100
14 1F
3
+
4 -5V
+
0.01F 47F
T1 = TF5SX17ZZ, TOROTEL RT = YSI THERMISTOR 44006 6.19k AT 37.5C *MATCH 0.05% 6.19k = VISHAY S-102 OPERATE LTC6943 WITH 5V SUPPLIES LOCK-IN AMPLIFIER TECHNIQUE USED TO EXTRACT VERY SMALL SIGNALS BURIED INTO NOISE
6943 * TA13
+ -
6943f
LTC6943
TYPICAL APPLICATIO S
50MHz Thermal RMS/DC Converter
5V 5V 3 30k** 30k** 5 10k 1 1F 2 0.01F 10k 16 300mV- 10VRMS INPUT BRN T1 GRN RED RED T2 GRN 2% ACCURACY DC-50MHZ 100:1 CREST FACTOR CAPABILITY T1 - T2 = YELLOW SPRINGS INST. CO. THERMISTOR COMPOSITE ENCLOSE T1 AND T2 IN STYROFOAM *1% RESISTOR **0.1% RESISTOR 1F 15 BRN 13 0.01F 1F 14 301* 10k 10k 1F 2 1/2 LTC6943 4 3 5V
Single Supply Precision Linearized Platinum RTD Signal Conditioner
250k* 5V 3 10k* (LINEARITY CORRECTION LOOP)
+ -
8 1 2.74k* 50k ZERO ADJUST 8.25k*
1/2 LT1013 2 4
0.1F 2k 6 1/2 LTC6943 7
9 1F 10 1F 887*
11
12 1mA
Rp 100 AT 0C
U
+ -
8 LT1013 4 1
CALIBRATION ADJUST 20k 5 100k*
5V
+
LT1013 7 DC OUTPUT 0V TO 3.5V 10k
6
-
6943 * TA13
2.4k LT1009 2.5V
5V
3 1/2 LTC6943 4 5 5
+
1/2 LT1013
0V TO 4V = 0C TO 400C 0.05C 7 5k LINEARITY ADJUST
6 1 1F 2 1F
-
1k GAIN ADJUST 8.06k*
13
16
1k* Rp = ROSEMOUNT 118MFRTD * 1% FILM RESISTOR TRIM SEQUENCE: SET SENSOR TO 0C VALUE. ADJUST ZERO FOR 0V OUT SET SENSOR TO 100C VALUE. ADJUST GAIN FOR 1000V OUT SET SENSOR TO 400C VALUE. ADJUST LINEARITY FOR 4000V OUT 6943 * TA14 REPEAT AS REQUIRED
14 0.01F
15
6943f
11
LTC6943
TYPICAL APPLICATIO S
0.01% F/V Converter
10k GAIN TRIM 1F 75k*
1k -5V LT1004-1.2C 1F 11
FREQUENCY IN 0kHz TO 30kHz
GAIN CONTROL 0kHz TO 10kHz = GAIN 0 TO 1000
VIN FOR DIFFERENTIAL INPUT, GROUND PIN 7A AND USE PINS 11A AND 6A FOR INPUTS fIN * 0.01F GAIN = ; GAIN IS NEGATIVE AS SHOWN 1kHz * 100pF FOR SINGLE-ENDED INPUT AND POSITIVE GAIN, GROUND PIN 8A AND USE PIN 7A FOR INPUT OPERATES THE LTC6943'S WITH 5V SUPPLIES 5V 2 0.01F 6 7 LT1056 3 VOUT
12
U
1/4 LTC6943 12 2
5V
- +
7 LT1056 6 0V TO 3V OUTPUT
3 10 1000pF** 14
4 -5V
3 15
5V -5V * 1% FILM RESISTOR ** POLYPROPYLENE
6943 * TA15
Frequency-Controlled Gain Amplifier
11A 1/2 LTC6943A
12A
11B 1/2 LTC6943B
12B
14A
10A 0.01F 9A 1kHz
14B
10B 100pF 9B
6A
7A
6B
7B
3 5V
15 -5V
- +
4 -5V
6943 * TA16
6943f
LTC6943
TYPICAL APPLICATIO S
Battery Powered Relative Humidity Sensor Signal Conditioner
0.1 100pF +9 4.7k 2.32k* 10k 0.1 1.8k* LT1004 1.2V 90% TRIM 500 11 10 0.1F SENSOR RESPONSE RH% 5 25 50 75 90 CAPACITANCE 379.3pF 413.3pF 455.8pF 498.3pF 523.8pF 6 0.1 SENSOR 22M - A1 LT1006 + OUTPUT 0-1.00V = 0-100% RH LTC6943 12 +9 1 10pF 5% TRIM 16 2 13
5V Powered, Frequency Output, Relative Humidity Sensor Signal Conditioner
80.6k* OUT 1N4148 125kHz 4V LTC6943 14 13.3k* 4V 0.1F SENSOR 10 CHARGE PUMP 5V 200 TO ALL 4V POINTS 1k* 11 1F 12 562k* 100k RH = 25% TRIM (204.5pF) 4V 1N5712 110k* * = 1% METAL FILM RESISTOR = WIMA, TYPE MKP-2 SENSOR = PANAMETRICS MC-2 0% RH = 196.7pF 100% RH = 227.8pF 0.31pF/RH 20k RH = 100% TRIM (227.8pF)
6943 TA20
1F
LT1634 4V
U
6
+9 3 15 4 5
9 7 * = 1% FILM RESISTOR = POLYPROPYLENE SENSOR = PANAMETRICS TYPE RHS 500pF AT RH = 76% 1.7pF/RH
6943 TA17
RSET LTC1799 O1 VIN CLOCK
5V
GND 10k BAT85 Q1 VN2222L 4V
5V
15
10k
7 9 3 1000pF 5V 4V S D RESET COMPARATOR
-
A1 LTC1050
L
+
300k* 4V
5V Q
+
INTEGRATOR
C1 +V LT1671
-
Q OUT 0% TO 100% RH = 0Hz TO 1kHz
300pF
6943f
13
LTC6943
TYPICAL APPLICATIO S
Linear Variable Differential Transformer (LVDT), Signal Conditioner
1/4 LTC6943 6 5V 30k 3 5V 1 1.5kHz YEL-BLK 4 - 5V BLUE GRN 10k 4.7k 1N914 LT1004 1.2V YEL-RED BLK LVDT 10 10F 7.5k 11 1/4 LTC6943 LVDT = SCHAEVITZ E-100 5V 100k 0.01F 3 100k PHASE TRIM 5V 1k 7 1 4 -5V
6943 * TA18
0.005F
30k
0.005F
+ -
8 LT1013
2 AMPLITUDE STABLE SINE WAVE SOURCE
Q1 2N4338 1.2k
+15V 1
5
500k
549k*
49.9k*
Q1 2N3906 1M 10k
Q2 TEMPERATURE SENSOR TRANSISTOR
*0.1% FILM RESISTOR SENSOR TRANSISTOR MAY BE ANY SMALL SIGNAL NPN-2N2222, 3904, ETC. DO NOT USE GOLD DOPED TRANSISTORS.
14
U
7
3 9 RD-BLUE
100k 1F
5
+
1/2 LT1013 7
6
-
OUTPUT 0V 2.5V 0mm 2.50mm 200k
15 12
-5V 10k GAIN TRIM
+ -
8 LT1011
TO PIN 14, LTC6943
2
VBE Based Thermometer Requires No Calibration
C1 1F 2 14
LTC6943 16 C2 1F
+15
+
A1 LTC1150
13 0.01 +15 10k
-
0-10VOUT = 0-100C, 1C ACCURACY
C3 0.1 86k*
1M*
2.019k*
LT1009 2.5V
6943 TA21
6943f
LTC6943
PACKAGE DESCRIPTIO
.254 MIN
.0165 .0015
RECOMMENDED SOLDER PAD LAYOUT
.007 - .0098 (0.178 - 0.249)
.016 - .050 (0.406 - 1.270)
NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) 3. DRAWING NOT TO SCALE *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
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.
U
GN Package 16-Lead Plastic SSOP (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1641)
.045 .005
.189 - .196* (4.801 - 4.978) 16 15 14 13 12 11 10 9
.009 (0.229) REF
.150 - .165
.229 - .244 (5.817 - 6.198)
.150 - .157** (3.810 - 3.988)
.0250 TYP
1
23
4
56
7
8
.004 - .0098 (0.102 - 0.249)
.015 .004 x 45 (0.38 0.10)
0 - 8 TYP
.053 - .068 (1.351 - 1.727)
.008 - .012 (0.203 - 0.305)
.0250 (0.635) BSC
GN16 (SSOP) 0502
6943f
15
LTC6943
TYPICAL APPLICATIO S
5V Powered Voltage-to-Frequency Converter
5VIN 16 3 22k 5 4 LTC6943 fOUT 0kHz TO 13 3kHz 2 15
INPUT 0V TO 2V
RELATED PARTS
PART NUMBER LTC1043 LTC1152 LTC2050 LTC2051 LTC2052 LTC2053 LTC2054 LTC6800 LTC6915 DESCRIPTION Dual Precision Instrumentation Switched Cap, Building Block Rail-to-Rail In/Out, Zero Drift Op Amp Zero Drift Op Amp Zero Drift Dual Op Amp Zero Drift Quad Op Amp Precision, Rail-to-Rail Zero Drift I.A. Low Power, Zero Drift Op Amp Low Cost, Rail-to-Rail I.A. Precision Instrumentation Amplifier with Digitally Programmable Gain COMMENTS 120dB CMRR, 3V to 18V Operation Operates Up to 14V Supply Voltage Single Supply Operation on 2.7V to 11V, SOT-23 Package Dual LTC2050, 8-Lead DFN, MS8 Packages Dual LTC2050, GN16 Package 120dB CMRR at Low Gains 150A Supply Current, SOT-23 Package VOS(MAX) = 100V, DFN 8 Package 14 Levels of Programmable Gain, 125dB CMRR
16
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 FAX: (408) 434-0507
U
+
22F
1 LT1034 1.2V 2 16
C1** 0.01 F 13 14
10k FULL SCALE TRIM
5VIN 75k* 1F
-
A1 1/2 LT1017
D1 1N4148
C2 560pF
+
1N5712 50k
120pF 1.6M (10Hz TRIM)
6943 TA19
10k * = 1% FILM RESISTOR, TYPE TRW-MTR+120ppm/C ** = POLYPROPYLENE
6943f LT/TP 0804 1K * PRINTED IN USA
www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 2004

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