Part A
AD8227ARMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7701 PCS
- Package
- MSOP-8
- Series
- Linear - Amplificadores - Instrumentação, OP Amps, Buffer Amps
Replacement verdict
Compatible functional replacement candidate
The AD8227ARMZ and AD8220ARMZ-RL are both single-channel instrumentation amplifiers in the same 8-lead MSOP package, making them a viable functional replacement candidate. However, the AD8220ARMZ-RL offers a JFET input stage with significantly lower input bias current and wider bandwidth, while the AD8227ARMZ provides a rail-to-rail output with higher gain bandwidth. Designers should validate gain-setting resistor networks, input bias current budgets, and bandwidth requirements before substituting one for the other in precision instrumentation signal chains.
Package Type
High match
Channel Count
High match
Input Bias Current
Validation required
Gain Bandwidth Product
Validation required
Parts at a glance
Part B
AD8220ARMZ-RL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3523 PCS
- Package
- TSSOP-8
- Series
- Linear - Amplificadores - Instrumentação, OP Amps, Buffer Amps
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8227ARMZ | AD8220ARMZ-RL | Why it matters |
|---|---|---|---|
| Amplifier Type | Instrumentation Amplifier | Instrumentation Amplifier (JFET input) | Both are in-amps, but the AD8220 uses a JFET input stage while the AD8227 uses a bipolar input stage, which affects input bias current and noise characteristics. |
| Number of Channels | 1 | 1 | Both are single-channel devices, so channel count is not a differentiator for substitutability. |
| Input Bias Current (typ) | ~1.5 nA | ~10 pA | The JFET input of the AD8220 provides dramatically lower bias current, making it preferable for high-impedance sensor interfaces. |
| Input Offset Voltage (max) | ~200 µV | ~250 µV | Offset voltage directly impacts DC accuracy; the AD8227 offers slightly better guaranteed offset performance. |
| Gain Bandwidth Product | ~250 kHz (G=1) | ~1.5 MHz (G=1) | The AD8220 supports higher bandwidth, enabling use in faster signal-conditioning applications. |
| Supply Voltage Range | ±2.25 V to ±18 V (4.5 V to 36 V) | ±2.25 V to ±18 V (4.5 V to 36 V) | Identical supply flexibility means both can operate in the same power rails, easing substitution. |
| Supply Current per Amplifier (typ) | ~350 µA | ~750 µA | The AD8227 draws less supply current, which is advantageous for low-power designs. |
| Input Voltage Noise (typ, 1 kHz) | ~22 nV/√Hz | ~14 nV/√Hz | Lower voltage noise in the AD8220 improves signal-to-noise ratio for low-level signal amplification. |
| CMRR (min, G=10) | ~80 dB | ~80 dB | Comparable common-mode rejection supports similar performance in rejecting interference in both parts. |
| Package | 8-Lead MSOP (RMZ) | 8-Lead MSOP (RMZ) | Identical package and pinout allow drop-in replacement on the same PCB footprint. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8227ARMZ | AD8220ARMZ-RL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Part Status | Active | Obsolete |
| Amplifier Type | Instrumentation | Instrumentation |
| Number of Circuits | 1 | 1 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 0.8V/µs | 2V/µs |
| -3 dB Bandwidth | 250 kHz | 1.5 MHz |
| Current - Input Bias | 20 nA | 25 pA |
| Voltage - Input Offset | 200 µV | 250 µV |
| Supply Current | 350µA | 750µA |
| Current - Output / Channel | 13 mA | 15 mA |
| Voltage - Supply Span(Min) | 2.2 V | 4.5 V |
| Voltage - Supply Span(Max) | 36 V | 36 V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the primary functional differences between the AD8227ARMZ and AD8220ARMZ-RL?
The AD8227ARMZ is a wide supply range, rail-to-rail output instrumentation amplifier with a fixed gain set by an external resistor, featuring a supply range of ±2.3 V to ±18 V (or 4.6 V to 36 V single-supply). The AD8220ARMZ-RL is a JFET-input instrumentation amplifier with rail-to-rail output, optimized for high input impedance and low input bias current, operating on a supply range of ±4.5 V to ±18 V (or 9 V to 36 V single-supply). The AD8220 is particularly suited for applications requiring very low input bias current, while the AD8227 offers a wider low-voltage supply range and is designed for general-purpose precision signal conditioning.
Are the AD8227ARMZ and AD8220ARMZ-RL pin-compatible in the MSOP-8 package?
Yes, both devices are offered in an 8-lead MSOP package and share the same pinout: pin 1 is -IN, pin 2 is +IN, pin 3 is -VS, pin 4 is +VS, pin 5 is REF, pin 6 is VOUT, pin 7 is -RG, and pin 8 is +RG. This pin compatibility allows for evaluation of both amplifiers on the same PCB layout, though external gain resistor values and supply decoupling must be verified for each device.
How do the input bias currents of the AD8227ARMZ and AD8220ARMZ-RL compare?
The AD8220ARMZ-RL, with its JFET input stage, specifies a typical input bias current of 10 pA (maximum 20 pA at 25°C), making it suitable for high-impedance sensor interfaces. The AD8227ARMZ, using a bipolar input stage, specifies a typical input bias current of 20 nA (maximum 50 nA at 25°C). The AD8220 is therefore preferable when extremely low input bias current is required, such as with photodiode or pH sensor front ends.
What are the gain-setting configurations for the AD8227ARMZ and AD8220ARMZ-RL?
Both amplifiers use a single external resistor (RG) to set the gain. For the AD8227ARMZ, the gain equation is G = 1 + (49.4 kΩ / RG). For the AD8220ARMZ-RL, the gain equation is G = 1 + (49.4 kΩ / RG). Both devices support gains from 1 to 1000, but the user must select RG values based on the respective datasheet's gain table and verify stability and bandwidth at the desired gain.
How do the supply voltage ranges of the AD8227ARMZ and AD8220ARMZ-RL differ?
The AD8227ARMZ operates on a dual supply of ±2.3 V to ±18 V or a single supply of 4.6 V to 36 V. The AD8220ARMZ-RL operates on a dual supply of ±4.5 V to ±18 V or a single supply of 9 V to 36 V. The AD8227ARMZ can therefore operate at lower supply voltages, making it suitable for 5 V or 3.3 V single-supply systems, while the AD8220ARMZ-RL requires a minimum 9 V single supply or ±4.5 V dual supply.
Which device is better suited for high-impedance sensor interfaces?
The AD8220ARMZ-RL is better suited for high-impedance sensor interfaces due to its JFET input stage, which provides very low input bias current (typically 10 pA) and high input impedance. The AD8227ARMZ, with its bipolar input stage and typical input bias current of 20 nA, is more appropriate for lower-impedance sources or applications where the bias current error is negligible relative to the source impedance.
What are the typical noise specifications for the AD8227ARMZ and AD8220ARMZ-RL?
The AD8227ARMZ specifies an input voltage noise density of 22 nV/√Hz at 1 kHz (typical). The AD8220ARMZ-RL specifies an input voltage noise density of 14 nV/√Hz at 1 kHz (typical). For low-noise applications, the AD8220ARMZ-RL offers lower voltage noise, but the designer must also consider current noise, which is higher for the JFET input stage at higher frequencies.
Can the AD8227ARMZ and AD8220ARMZ-RL be used in bridge sensor applications?
Yes, both amplifiers are suitable for bridge sensor signal conditioning. The AD8227ARMZ offers a wide supply range and rail-to-rail output, making it flexible for various bridge excitation voltages. The AD8220ARMZ-RL provides low input bias current, which minimizes offset errors in high-impedance bridges. The choice depends on the bridge impedance, supply voltage, and required noise performance, and both should be evaluated against the specific bridge specifications.