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LT1789-1/LT1789-10

1789fb

The LT

1789-1/LT1789-10 are micropower, precision

instrumentation ampliﬁ ers that are optimized for single

supply operation from 2.2V to 36V. The quiescent current

is 95μA max, the inputs common mode to ground and the

output swings within 110mV of ground. The gain is set

with a single external resistor for a gain range of 1 to 1000

for the LT1789-1 and 10 to 1000 for the LT1789-10.

The high accuracy of the LT1789-1 (40ppm maximum non-

linearity and 0.25% max gain error) is unmatched by other

micropower instrumentation ampliﬁ ers. The LT1789-10

maximizes both the input common mode range and dynamic

output range when an ampliﬁ cation of 10 or greater is required,

allowing precise signal processing where other instrumenta-

tion ampliﬁ ers fail to operate. The LT1789-1/LT1789-10 are

laser trimmed for very low input offset voltage, low input

offset voltage drift, high CMRR and high PSRR. The output

can handle capacitive loads up to 400pF (LT1789-1), 1000pF

(LT1789-10) in any gain conﬁ guration while the inputs are

ESD protected up to 10kV (human body).

The LT1789-1/LT1789-10 are offered in the 8-pin SO

package, requiring signiﬁ cantly less PC board area than

discrete multi op amp and resistor designs.

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Micropower,

Single Supply Rail-to-Rail

Output Instrumentation Ampliﬁ ers

0.5A to 4A Voltage Controlled Current Source

Micropower: 95μA Supply Current Max

Low Input Offset Voltage: 100μV Max

Low Input Offset Voltage Drift: 0.5μV/°C Max

Single Gain Set Resistor:

G = 1 to 1000 (LT1789-1)

G = 10 to 1000 (LT1789-10)

Inputs Common Mode to V

–

Wide Supply Range: 2.2V to 36V Total Supply

CMRR at G = 10: 96dB Min

Gain Error: G = 10, 0.25% Max

Gain Nonlinearity: G = 10, 40ppm Max

Input Bias Current: 40nA Max

PSRR at G = 10: 100dB Min

1kHz Voltage Noise: 48nV/√Hz

0.1Hz to 10Hz Noise: 1.5μV

P-P

Portable Instrumentation

Bridge Ampliﬁ ers

Strain Gauge Ampliﬁ ers

Thermocouple Ampliﬁ ers

Differential to Single-Ended Converters

Medical Instrumentation

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other

trademarks are the property of their respective owners.

* ENSURE ADEQUATE POWER

DISSIPATION CAPABILITY AT

HIGHER VOLTAGES,

CURRENTS AND DUTY CYCLES

LOAD

1789 TA01

SENSE

0.1Ω

TIP127*

10k

3300pF

100Ω

0.1μF

4700pF

10k

90.9k

–

120Ω

= 3.3V TO 32V

= 1A PER VOLT AS SHOWN

LOAD

RISE TIME ≈ 250μs, 10% TO 90%,

1A TO 2A OUTPUT STEP INTO 0.25Ω LOAD

SENSE

• 10

LT1636

–

REF

LT1789-1

Summary of content (24 pages)

PAGE 1
LT1789-1/LT1789-10 Micropower, Single Supply Rail-to-Rail Output Instrumentation Amplifiers FEATURES DESCRIPTION n The LT®1789-1/LT1789-10 are micropower, precision instrumentation ampliﬁers that are optimized for single supply operation from 2.2V to 36V. The quiescent current is 95μA max, the inputs common mode to ground and the output swings within 110mV of ground. The gain is set with a single external resistor for a gain range of 1 to 1000 for the LT1789-1 and 10 to 1000 for the LT1789-10.
PAGE 2
LT1789-1/LT1789-10 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) Supply Voltage (V+ to V–)..........................................36V Input Differential Voltage...........................................36V Input Current (Note 3)..........................................±20mA Output Short-Circuit Duration .......................... Indeﬁnite Operating Temperature Range.................. –40°C to 85°C Speciﬁed Temperature Range (Note 4) LT1789C-1, LT1789C-10 ......................
PAGE 3
LT1789-1/LT1789-10 3V AND 5V ELECTRICAL CHARACTERISTICS supply, TA = 25°C, unless otherwise noted. VS = 3V, 0V; VS = 5V, 0V; RL = 20k, VCM = VREF = half LT1789-1 SYMBOL PARAMETER CONDITIONS TYP MAX TYP MAX UNITS G = 1000 15 100 20 160 μV Output Offset Voltage G = 1 (LT1789-1), G =10 (LT1789-10) 150 750 650 3000 μV IOS Input Offset Current (Note 6) 0.2 4 0.2 4 nA IB Input Bias Current en Input Noise Voltage, RTI (Referred to Input) (Note 6) 19 40 19 40 G = 1, fO = 0.
PAGE 4
LT1789-1/LT1789-10 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the temperature range of 0°C ≤ TA ≤ 70°C. VS = 3V, 0V; VS = 5V, 0V; RL = 20k, VREF = half supply, unless otherwise noted. (Note 4) LT1789-1 SYMBOL PARAMETER Gain Error (Note 6) Gain Nonlinearity (Note 6) CONDITIONS MIN TYP LT1789-10 MAX G = 1, VO = 0.3V to (+VS) – 1V l 0.25 VO = 0.3V to (+VS) – 0.5V G = 10 (Note 2) G = 100 (Note 2) l l 0.53 0.55 G = 1, VO = 0.
PAGE 5
LT1789-1/LT1789-10 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the temperature range of –40°C ≤ TA ≤ 85°C. VS = 3V, 0V; VS = 5V, 0V; RL = 20k, VREF = half supply, unless otherwise noted. (Note 4) LT1789-1 SYMBOL PARAMETER Gain Error (Note 6) Gain Nonlinearity (Note 6) CONDITIONS MIN TYP LT1789-10 MAX G = 1, VO = 0.3V to (+VS) – 1V l 0.30 VO = 0.3V to (+VS) – 0.5V G = 10 (Note 2) G = 100 (Note 2) l l 0.57 0.59 G = 1, VO = 0.
PAGE 6
LT1789-1/LT1789-10 ELECTRICAL CHARACTERISTICS VS = ±15V, RL = 20k, VCM = VOUT = 0V, TA = 25°C, unless otherwise noted.
PAGE 7
LT1789-1/LT1789-10 ELECTRICAL CHARACTERISTICS VS = ±15V, RL = 20k, VCM = VOUT = 0V, TA = 25°C, unless otherwise noted. LT1789-1 SYMBOL PARAMETER CONDITIONS BW Slew Rate G=1 G = 10 G = 100 G = 1000 VOUT = ±10V Settling Time to 0.01% 10V Step SR Bandwidth RREFIN Reference Input Resistance IREFIN Reference Input Current AVREF Reference Gain to Output MIN TYP LT1789-10 MAX MIN 60 30 3 0.2 0.012 VREF = 0V 0.026 0.028 TYP MAX UNITS 25 12 1.5 kHz kHz kHz kHz 0.
PAGE 8
LT1789-1/LT1789-10 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the temperature range of 0°C ≤ TA ≤ 70°C. VS = ±15V, RL = 20k, VCM = VREF = 0V, unless otherwise noted. (Note 4) LT1789-1 SYMBOL PARAMETER CONDITIONS PSRR LT1789-1, VS = ±1.25V to ±16V LT1789-10, VS = ±1.50V to ±16V G=1 G = 10 G = 100, 1000 Power Supply Rejection Ratio MIN l l l TYP LT1789-10 MAX 92 102 104 MIN TYP MAX UNITS dB dB dB 98 104 Minimum Supply Voltage l ±1.25 ±1.
PAGE 9
LT1789-1/LT1789-10 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the temperature range of –40°C ≤ TA ≤ 85°C. VS = ±15V, RL = 20k, VCM = VREF = 0V, unless otherwise noted. (Note 4) LT1789-1 SYMBOL PARAMETER CONDITIONS PSRR LT1789-1, VS = ±1.25V to ±16V LT1789-10, VS = ±1.50V to ±16V G=1 G = 10 G = 100, 1000 Power Supply Rejection Ratio IS VO SR MIN l l l UNITS dB dB dB 96 102 ±1.50 V Supply Current l 160 160 µA Output Voltage Swing l ±14.15 ±14.
PAGE 10
LT1789-1/LT1789-10 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage Swing vs Load Current Gain vs Frequency 4.4 1.4 4.2 1.2 VS = 5V, 0V VREF = 2.5V 4.0 1.0 125°C 0.8 25°C 0.6 0.4 SINK –55°C 0.2 60 50 40 G = 100 30 20 G = 10 10 0 1k 10k FREQUENCY (Hz) 100k 1789 G04 COMMON MODE REJECTION RATIO (dB) 120 VS = 5V, 0V VREF = 2.
PAGE 11
LT1789-1/LT1789-10 TYPICAL PERFORMANCE CHARACTERISTICS Voltage Noise Density vs Frequency Current Noise Density vs Frequency G=1 G = 10 100 G = 100, 1000 1000 CURRENT NOISE DENSITY (fA/√Hz) VS = 5V, 0V VREF = 2.5V INPUT REFERRED 10 VS = 5V, 0V VREF = 2.5V 100 RS LT1789-1 10 1 10 100 FREQUENCY (Hz) 1k 10 100 FREQUENCY (Hz) 1 1k 1789 G13 1789 G14 0.1Hz to 10Hz Noise Voltage, G=1 0.1Hz to 10Hz Noise Voltage, RTI, G = 1000 VS = 5V, 0V VREF = 2.5V NOISE VOLTAGE (2μV/DIV) NOISE VOLTAGE (0.
PAGE 12
LT1789-1/LT1789-10 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage Swing vs Load Current Gain vs Frequency SOURCE 25°C 1.4 4.2 4.0 1.2 VS = 5V, 0V VREF = 2.5V 1.0 125°C 0.8 25°C 0.6 0.4 SINK –55°C 0.2 60 0.01 0.1 1 OUTPUT CURRENT (mA) 40 G = 100 30 20 G = 10 10 110 VS = 5V, 0V VREF = 2.5V G = 10 100 90 80 70 60 50 40 10 100 1k FREQUENCY (Hz) 10k 20k –20 100 1k 10k FREQUENCY (Hz) Negative Power Supply Rejection Ratio vs Frequency 140 G = 1000 120 100 VS = 5V, 0V VREF = 2.
PAGE 13
LT1789-1/LT1789-10 TYPICAL PERFORMANCE CHARACTERISTICS Voltage Noise Density vs Frequency Current Noise Density vs Frequency G = 10 100 G = 100 G = 1000 1000 CURRENT NOISE DENSITY (fA/√Hz) VS = 5V, 0V VREF = 2.5V INPUT REFERRED 10 VS = 5V, 0V VREF = 2.5V 100 RS LT1789-10 10 1 10 100 FREQUENCY (Hz) 1k 10 100 FREQUENCY (Hz) 1 1k 1789 G30 1789 G31 0.1Hz to 10Hz Noise Voltage, RTI, G = 10 0.1Hz to 10Hz Noise Voltage, RTI, G = 1000 VS = 5V, 0V VREF = 2.
PAGE 14
LT1789-1/LT1789-10 TYPICAL PERFORMANCE CHARACTERISTICS Large-Signal Transient Response G = 1, 10, 100 (LT1789-1) Large-Signal Transient Response G = 1000 5V/DIV 5V/DIV VS = ±15V RL = 20k CL = 50pF 500μs/DIV 1789 G38 VS = ±15V RL = 20k CL = 50pF Small-Signal Transient Response G=1 2ms/DIV 1789 G39 Small-Signal Transient Response G = 10 20mV/DIV 20mV/DIV VS = 5V, 0V VREF = 2.5V RL = 20k CL = 50pF 100μs/DIV 1789 G40 VS = 5V, 0V VREF = 2.
PAGE 15
LT1789-1/LT1789-10 TYPICAL PERFORMANCE CHARACTERISTICS Large-Signal Transient Response G = 10, 100 5V/DIV (LT1789-10) Large-Signal Transient Response G = 1000 20mV/DIV 5V/DIV VS = ±15V RL = 20k CL = 50pF 500μs/DIV 1789 G44 Small-Signal Transient Response G = 10 VS = ±15V RL = 20k CL = 50pF 500μs/DIV Small-Signal Transient Response G = 100 20mV/DIV 1789 G45 VS = 5V, 0V VREF = 2.5V RL = 20k CL = 50pF 100μs/DIV 1789 G46 Small-Signal Transient Response G = 1000 20mV/DIV VS = 5V, 0V VREF = 2.
PAGE 16
LT1789-1/LT1789-10 TYPICAL PERFORMANCE CHARACTERISTICS Valid Output Voltage vs Input Common Mode Voltage VS = ±15V 3.0 TA = 25°C G=1 2.5 10 VALID OUTPUT VOLTAGE (V) VALID OUTPUT VOLTAGE (V) G≥2 Valid Output Voltage vs Input Common Mode Voltage VS = ±2.5V 5 0 –5 –10 Valid Output Voltage vs Input Common Mode Voltage VS = ±1.5V 1.5 TA = 25°C AV = 10 2.0 AV = 1 1.5 VALID OUTPUT VOLTAGE (V) 15 (LT1789-1) AV = 2 1.0 0.5 0 –0.5 –1.0 –1.5 TA = 25°C AV = 1 1.0 AV = 2 AV = 10 0.5 0 –0.5 –1.
PAGE 17
LT1789-1/LT1789-10 TYPICAL PERFORMANCE CHARACTERISTICS Valid Output Voltage vs Input Common Mode Voltage VS = ±15V Valid Output Voltage vs Input Common Mode Voltage VS = ±2.5V 15 2.5 5 0 –5 –10 Valid Output Voltage vs Input Common Mode Voltage VS = ±1.5V AV = 100 1.5 1.5 TA = 25°C AV = 10 VALID OUTPUT VOLTAGE (V) G = 100 2.0 VALID OUTPUT VOLTAGE (V) 10 TA = 25°C 1.0 0.5 0 –0.5 –1.0 –1.5 TA = 25°C AV = 10 1.0 AV = 100 0.5 0 –0.5 –1.0 –2.
PAGE 18
LT1789-1/LT1789-10 BLOCK DIAGRAM V+ V+ 100k V+ 5.7k +IN 3 – RG 1 V– V– V+ V+ + R1 R2 110k/10k* 110k/100k* A1 5 REF VB V– + RG 8 A3 100k – 5.7k V+ –IN 2 – V– + V– R3 R4 110k/10k* 110k/100k* A2 6 OUT 7 V+ VB *LT1789-1/LT1789-10 V– 4 V– 1789 F01 Figure 1.
PAGE 19
LT1789-1/LT1789-10 APPLICATIONS INFORMATION Setting the Gain The gain of the LT1789-1 and LT1789-10 is set by the value of resistor RG, applied across pins 1 and 8. For the LT1789-1, the gain G will be: G = 1+ 200k/RG voltage dominates, whereas at low gains the output offset voltage dominates.
PAGE 20
LT1789-1/LT1789-10 APPLICATIONS INFORMATION Input Bias Current Return Path Output Voltage vs Input Common Mode Voltage The low input bias current of the LT1789-1/LT1789-10 (19nA) and the high input impedance (1.6GΩ) allow the use of high impedance sources without introducing signiﬁcant offset voltage errors, even when the full common mode range is required. However, a path must be provided for the input bias currents of both inputs when a purely differential signal is being ampliﬁed.
PAGE 21
LT1789-1/LT1789-10 APPLICATIONS INFORMATION 3) The input voltage range of the output ampliﬁer A3 (internal node). 4) The output swing of the output ampliﬁer A3. These limits can be determined using the relationships below. 1) The input voltage range limits can be found in the electrical tables. 2) The output voltages of the input ampliﬁers A1 and A2 can be found by the following formulas: single supplies, where both the reference voltage and input common mode voltage are near V+.
PAGE 22
LT1789-1/LT1789-10 TYPICAL APPLICATIONS Single Supply Positive Integrator 3 VIN VS + 7 LT1789-1 REF 1 2 – VS R1 6 10k 8 5 3 + C1 100μF 4 R2 10Ω + 1 LT1636 2 – VOUT 4 RESET 1789 TA02 VS = 2.
PAGE 23
LT1789-1/LT1789-10 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 .045 ±.005 .050 BSC 8 .245 MIN 7 6 5 .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) .030 ±.005 TYP 1 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 3 4 .053 – .069 (1.346 – 1.752) .004 – .010 (0.101 – 0.254) 0°– 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1.
PAGE 24
LT1789-1/LT1789-10 TYPICAL APPLICATION Voltage Controlled Current Source 3V TO 32V 3 VIN + 7 8 RG 1 2 6 LT1789-1 REF 5 – R1 1k 4 IL LOAD IL = AV • VIN/R1 1789 TA03 AV = 1 + 200k RG 10°C to 40°C Thermometer VS+ 4 LT1790 6 –1.25 1 2 29.4k 1% 3 6 LT1789-10 1 2 100k @ 25°C 7 8 36.5k 0.5% THERMISTOR THERMOMETRICS DC95G104V VS+ + 5 – 4 866k 1% 56.2k 1% VOUT = 2.5V AT 25°C + 50mV/°C OVER 10°C TO 40°C LINEARITY = 0.