MCP603-E/ST - 2.8MHz Rail-to-Rail CMOS Op Amp, 8-TSSOP | Microchip
MPN: MCP603-E/ST ✓ ActiveMCP603-E/ST Overview
An operational amplifier, or op amp, is a differential-input voltage-amplifying building block in the linear amplifier family of analog integrated circuits. Within the broader hierarchy of signal-chain ICs, op amps sit above comparators and buffers and below the wider class of analog signal-conditioning devices used for instrumentation, control and conversion. The MCP603 belongs to the Microchip MCP600x family of low-power, rail-to-rail CMOS op amps that are specified for industrial process control, battery-powered equipment, portable instrumentation, data acquisition and low-end audio.
Key features include a 2.8 MHz typical gain-bandwidth product with unity-gain stability, so the amplifier can be used directly in follower and general closed-loop configurations without compensationation networks. Output swing is rail-to-rail, and the input common-mode range includes ground, allowing single-supply sensing of signals that approach the negative supply rail. Input offset voltage is specified below 2 mV, and the low bias current keeps errors small when driving high-impedance sources such as sensor elements and strain-gauge bridges.
Internally the MCP603 uses Microchip's advanced CMOS process, combining low power consumption with high open-loop gain and adequate speed for general-purpose signal conditioning. Because the amplifier is designed for low quiescent current, the supply current stays in the hundreds of microamps across the 2.7 V to 6.0 V range, which lets designers size battery budgets and heat dissipation around a few milliwatts of internal loss rather than tens of milliwatts.
Typical use cases include loop-powered industrial transmitters, portable battery-operated measurement instruments, low-side current monitoring with shunt amplifiers, precision sensor front ends for thermocouples and resistive bridges, buffer stages for data converters, and entry-level audio preamplifier or headphone-driver circuits in portable equipment.
When designing around the MCP603, keep the input network bias current path finite so that input bias current error does not dominate, and confirm that the signal source impedance stays within the range where phase margin is acceptable. Place a 100 nF ceramic bypass capacitor close to the supply pin and keep the feedback loop compact, since long traces add stray capacitance that can degrade stability at the 2.8 MHz gain-bandwidth product.
This page consolidates manufacturer specifications, package and pinout detail, drop-in replacement options, and application and layout guidance into a single engineering reference so that design decisions about supply budget, noise, accuracy and PCB layout can be made before schematic capture.
Drop-in alternatives for MCP603-E/ST — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MCP603-E/ST (same form factor and footprint) — differing in Amplifier Type, Quiescent Current, Slew Rate, Package, Gain-Bandwidth Product.
MCP601-E/ST
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →MCP602-E/ST
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →MCP603-I/ST
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →MCP601-I/ST
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →MCP602-I/ST
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →MCP603-E/ST Maximum Ratings & Electrical Characteristics
| Amplifier Type | General Purpose (Rail-to-Rail Output) |
| Number of Circuits | 1 |
| Technology | CMOS |
| Supply Voltage Range (Single Supply) | 2.7 V to 6.0 V |
| Gain Bandwidth Product | 2.8 MHz (typical) |
| Slew Rate | 2.3 V/us |
| Quiescent Current | 230 uA (typical, less than 325 uA) |
| Input Offset Voltage | Less than 2 mV |
| Input Common-Mode Range | Includes ground (rail-to-rail input) |
| Output Swing | Rail-to-Rail |
| Gain Stability | Unity-gain stable |
| Chip Select | Yes, active-high |
| Bias Current | Low (CMOS input stage) |
| Open-Loop Gain | High (CMOS process) |
| Package / Case | 8-TSSOP (0.173 in, 4.40 mm width) |
| Pin Count | 8 |
| Mounting Type | Surface Mount |
| Shipping Packaging | Tube |
MCP603-E/ST Pin Configuration
| Pin 1 | OUT — Amplifier output |
| Pin 2 | V- — Negative supply (ground for single-supply operation) |
| Pin 3 | IN+ — Non-inverting input |
| Pin 4 | IN- — Inverting input |
| Pin 5 | CS — Chip select (active-high on the MCP603) |
| Pin 6 | V+ — Positive supply (2.7 V to 6.0 V) |
| Pin 7 | NC — Not connected (per datasheet) |
| Pin 8 | NC — Not connected (per datasheet) |
Typical Applications
MCP603-E/ST is suitable for 6 applications: Industrial Process-Control Signal Conditioning, Battery-Powered Portable Sensor Nodes, Low-Side Current and Shunt Monitoring, Data-Acquisition and Sensor Front Ends, Portable Audio and Low-End Audio Preamplification, Communication and Interface Receive Buffers.
Industrial Process-Control Signal Conditioning
The MCP603-E/ST suits loop-powered transmitters and process-control front ends where the sensed value arrives as a small differential signal riding on a 4-20 mA loop or a 0-5 V line. Its 2.8 MHz gain-bandwidth product gives roughly 280 kHz of closed-loop bandwidth at a gain of 10, so the amplifier settles quickly after a step and rejects 50/60 Hz line noise without needing a multi-stage filter. The input common-mode range that includes ground is important because process signals referenced to the negative rail would otherwise clip at the input stage. With a 230 uA typical quiescent current, the device adds negligible load to the transmitter budget, and the under-2 mV input offset keeps the measurement error small relative to typical process spans. Place a 100 nF bypass capacitor at pin 6 and keep the feedback loop short so that sensor cable pickup does not convert into output noise. This class of amplifier is intended for industrial process control loops, low-power battery devices and portable test equipment.
Recommended
Battery-Powered Portable Sensor Nodes
In a coin-cell or lithium-powered environmental node, every microamp counts, and the MCP603-E/ST is specified for exactly this regime. It runs from 2.7 V to 6.0 V, so it can sit directly on a 3 V cell or a 3.3 V regulated rail, and it draws 230 uA typical with less than 325 uA guaranteed quiescent current, translating to well under 1 mW of internal dissipation at 3.0 V. Low input bias current keeps the error small when the amplifier buffers a resistive humidity, pressure or thermistor bridge, while the rail-to-rail output swing allows the signal to use nearly the full supply range and improves the resolution of the follow-on converter. Because the part is unity-gain stable, it can be used as a low-cost buffer directly ahead of an ADC input, removing the need for an additional dedicated buffer. The chip-select function on pin 5 lets a duty-cycled design hold the amplifier in a low-power state between conversions.
Recommended
Low-Side Current and Shunt Monitoring
The MCP603-E/ST is a natural fit for low-side shunt amplifiers in power-supply and battery-monitoring designs because the input common-mode range includes ground, so a shunt placed in the 0 V return path can be sensed without a negative supply. The 2.8 MHz gain-bandwidth product and 2.3 V/us slew rate let the amplifier track fast current transients, which matters for limit-cycling detection in a DC-DC converter or for capturing inrush on a capacitive load. The under-2 mV input offset maps directly onto a measurement error across a typical 10 mOhm shunt, and the low input bias current avoids loading the shunt. Because supply current is only a few hundred microamps, the amplifier adds little to the efficiency of a battery-powered monitor. A single 100 nF bypass capacitor near the supply pins and a compact Kelvin-connected feedback layout keep the sense path accurate.
Recommended
Data-Acquisition and Sensor Front Ends
In a compact data-acquisition board, the MCP603-E/ST can serve as the buffer or gain stage ahead of a converter, providing the low input bias current needed to work with resistive dividers, thermistors and bridge sensors without loading the source. Unity-gain stability means the same part serves both as a follower for impedance buffering and as a modest-gain amplifier (10x to 100x) when offset needs to be trimmed. The 2.8 MHz gain-bandwidth product comfortably exceeds the sample rates of typical multiplexed slow-resolution SAR and sigma-delta converters used in acquisition systems, so the amplifier is not the limiting element in the signal chain. Rail-to-rail output swing maximises the usable ADC input range, and the low quiescent current suits multi-channel boards where several amplifiers are powered from the same rail. Place the amplifier close to the converter input and bypass the supply locally to minimise coupling between channels.
Recommended
Portable Audio and Low-End Audio Preamplification
The MCP603-E/ST can be used in entry-level audio paths such as microphone preamplifiers, headphone-driver stages in portable equipment, and line-level buffer sections. Its 2.3 V/us slew rate and 2.8 MHz gain-bandwidth product are more than adequate for audio-band signals and give low distortion at typical listening levels, while the rail-to-rail output swing means the amplifier can drive the full amplitude of a 3.3 V or 5 V rail for maximum headroom. The rail-to-rail output, combined with the input common-mode range including ground, allows a single-supply design to bias the signal at mid-supply and accept inputs that swing to the 0 V rail. Low quiescent current is valuable in battery-powered speakers and personal audio products. Care should still be taken with output drive into low impedances; consult the output current and capacitive load limits in the manufacturer datasheet and add an isolation resistor if the load is highly capacitive.
Recommended
Communication and Interface Receive Buffers
The MCP603-E/ST works well as the receive-side buffer in transceiver interfaces, where a differential or single-ended signal from a line driver must be conditioned before being presented to a controller or comparator. The input common-mode range that includes ground is useful for single-ended receive lines referenced to 0 V, and the low bias current avoids disturbing the line termination. Because the chip-select function on pin 5 can disable the amplifier, a multi-channel interface board can tie the amplifier off when the bus is idle, saving a few hundred microamps in battery-powered nodes. The 2.8 MHz gain-bandwidth product provides ample margin for signalling rates in the megabit range while still providing gain for restoring signal levels attenuated by cabling. Keep the buffer close to the transceiver pins and use a solid ground plane connection to limit the common-mode pickup that dominates errors in long-cable receive paths.
Recommended
Recommended Products Summary
Engineering reference data for MCP603-E/ST — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MCP601-E/ST | MCP602-E/ST | MCP603-I/ST | MCP601-I/ST | MCP602-I/ST |
|---|---|---|---|---|---|---|
| Package | 8-TSSOP (0.173 in, 4.40 mm width) | 8-TSSOP - same | 8-TSSOP - same | 8-TSSOP - same | 8-TSSOP - same | 8-TSSOP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Number of Circuits | 1 | 1 | 1 | 1 | 1 | 1 |
| Supply Voltage Range | 2.7 V to 6.0 V single supply | 2.7 V to 6.0 V single supply | 2.7 V to 6.0 V single supply | 2.7 V to 6.0 V single supply | 2.7 V to 6.0 V single supply | 2.7 V to 6.0 V single supply |
| Gain Bandwidth Product | 2.8 MHz typical | 1 MHz (-64%) | 1 MHz (-64%) | 2.8 MHz (identical) | 1 MHz (-64%) | 1 MHz (-64%) |
| Slew Rate | 2.3 V/us | Lower (1 MHz family) | Lower (1 MHz family) | 2.3 V/us (identical) | Lower (1 MHz family) | Lower (1 MHz family) |
| Quiescent Current | 230 uA typical (less than 325 uA) | 230 uA typical | 230 uA typical | 230 uA typical (identical) | 230 uA typical | 230 uA typical |
| Temperature Grade | E grade | E grade | E grade | I grade (industrial) | I grade (industrial) | I grade (industrial) |
Key Differentiators
- Roughly 2.8 times the closed-loop bandwidth of the 1 MHz family members in the same package (vs MCP601-E/ST)
- Active-high chip select matches standard active-high enable conventions in low-power designs (vs MCP602-E/ST)
- Single-supply operation down to 2.7 V with rail-to-rail output and ground-referenced inputs (vs TL051IP)
- Chip-select shutdown plus low quiescent current simplifies duty-cycled, battery-powered designs (vs MCP601-E/ST)
Design Notes
The MCP603-E/ST draws only about 230 uA of quiescent current, so supply-side design is rarely the limiting factor. Place a 100 nF X7R ceramic bypass capacitor between pin 6 (V+) and pin 2 (V-) as close to the device as possible, with a short ground return to the ground plane. If the amplifier sits far from the supply source, add a 1 uF bulk capacitor locally to support output slewing currents. Estimated: with a 2.8 MHz gain-bandwidth product and 2.3 V/us slew rate, driving a 1 nF load at 2 V peak into 100 ohms, the peak output current is roughly 20 mA; the supply rail must be able to source that transient, which the bypass capacitor provides locally.
Keep the feedback loop physically small: route the output from pin 1 directly to the inverting input at pin 4 rather than taking the long way around the circuit, and place the non-inverting input at pin 3 close to the source. Because the amplifier is unity-gain stable with a 2.8 MHz gain-bandwidth product, stray capacitance across the feedback network can reduce phase margin and provoke ringing. High-impedance nodes should be kept short and guarded, because the low input bias current of the device means PCB contamination and flux residue produce significant DC error rather than being masked by input current.
Two substitution traps catch engineers here. First, MCP602-E/ST and MCP602-I/ST use an active-low chip select on pin 5 while the MCP603-E/ST chip select is active-high, so a board that hardwires pin 5 to a microcontroller GPIO will behave differently after substitution. Second, the MCP601 and MCP602 members of the family have a 1 MHz gain-bandwidth product versus 2.8 MHz on the MCP603, so a design that relies on high closed-loop bandwidth or fast settling will degrade even though the footprint, supply range and quiescent current are identical. Verify the pin 5 logic polarity and the required closed-loop bandwidth before fitting any family member.
For low-side shunt and bridge sensing, connect the sense traces as a differential pair with a solid ground reference, and keep the amplifier ground pin tied directly to the ground plane rather than through the sensor return path. The input common-mode range includes ground, but the offset accuracy of the measurement still depends on avoiding ground gradients, which appear directly as measurement error when amplified by 100x. Estimated: with a 10 mOhm shunt and a gain of 100, a 1 mV ground gradient produces a 1 V output error, far exceeding the under-2 mV input offset of the device.
Compliance Information
The MCP603-E/ST is a general-purpose industrial analog device and is not an AEC-Q100 qualified automotive part. RoHS, REACH, lead-free and halogen-free declarations are not stated on the manufacturer product material reviewed here; check the current material declaration on the Microchip product page for the exact package and order codes.
