OPA1688 - 36V 10MHz Low Noise Audio Op Amp | TI
MPN： OPA1688ID ✓ 啟用中OPA1688ID 概覽
An operational amplifier (op amp) is a high-gain voltage amplifier with differential inputs and a single-ended output, fundamental to analog signal conditioning, filtering, and amplification. The OPA1688 belongs to the SoundPlus family of audio op amps, optimized for low noise, low distortion, and high output drive within the broader linear amplifier category used across audio, instrumentation, and communication systems.
Key features include 4.5 nV/√Hz input voltage noise, an 8 V/µs slew rate, and low quiescent current of 1.5 mA per channel. Excellent capacitive load stability allows direct drive of up to 1000 pF without oscillation, and ±75 mA output current enables direct headphone drive. The rail-to-rail output (RRO) stage maximizes dynamic range in single-supply designs.
Technically, the OPA1688 uses a complementary bipolar input stage with laser-trimmed input offset voltage of 0.5 mV (typical). The wide supply range supports both battery-powered and industrial systems, and the -40C to +85C operating range ensures reliability in demanding environments. THD+N of 0.00005% at 1 kHz and high PSRR preserve signal fidelity in high-fidelity audio paths.
Typical applications include headphone amplifiers, audio DAC output buffers, active filters, and professional audio mixing consoles. High output current and capacitive load stability make it especially suited to direct headphone drive, while low noise and distortion preserve audio integrity in portable devices where 1.5 mA quiescent current extends battery life.
Design tip: decouple supply pins with 0.1 µF ceramic capacitors placed close to the device, keep feedback paths short to minimize parasitic capacitance, and use an isolation resistor for capacitive loads beyond 1000 pF. Pricing references are as of 2026-08-30.
直接替換替代品，適用於 OPA1688ID — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： OPA1688ID （相同外形與佔位） — 差異在於 Input Offset Voltage, Package, Supply Voltage Range, Gain Bandwidth Product, Amplifier Channels.
OPA1656IDR
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
OPA1611AID
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
OPA828IDR
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →OPA1689IDR
✅ 直接替換📋 參考替代品（不在目錄中）
AD8599
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
OPA1688ID 最大額定值與電氣特性
| Amplifier Channels | 1 |
| Supply Voltage Range | 4.5 V to 36 V (±2.25 V to ±18 V) |
| Gain Bandwidth Product | 10 MHz |
| Slew Rate | 8 V/µs |
| Input Voltage Noise | 4.5 nV/√Hz |
| 靜態電流 | 1.5 mA per channel |
| Output Current | ±75 mA |
| THD+N | 0.00005% at 1 kHz |
| Input Offset Voltage | 0.5 mV typical |
| 輸出類型 | Rail-to-Rail Output (RRO) |
| Capacitive Load Stability | Up to 1000 pF |
| 工作溫度 | -40C to +85C |
| 封裝 | SOIC-8 (D) / WSON-8 |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant |
OPA1688ID 腳位配置
| 腳位 1 | TRIM (NC/Offset) — No connect / offset trim per package variant |
| 腳位 2 | IN- — Inverting input |
| 腳位 3 | IN+ — Non-inverting input |
| 腳位 4 | V- — Negative supply |
| 腳位 5 | NC/TRIM — No connect / offset trim per package variant |
| 腳位 6 | OUT — Rail-to-rail output |
| 腳位 7 | V+ — Positive supply |
| 腳位 8 | NC/TRIM — No connect / offset trim per package variant |
典型應用
OPA1688ID 適用於 6 應用s: Headphone Amplifiers, Audio DAC Output Buffering, Active Filters and Equalization, Professional Audio Mixing Consoles, Portable and Battery-Powered Audio, Precision Sensor Signal Conditioning.
Headphone Amplifiers
The OPA1688 fits headphone amplification directly: its ±75 mA output current drives 16 to 32 ohm headphone loads without a discrete buffer stage, while 4.5 nV/√Hz noise and 0.00005% THD+N at 1 kHz keep the signal path transparent. Stability with capacitive loads up to 1000 pF tolerates long headphone cables. In battery-powered portable players, 1.5 mA quiescent current per channel significantly extends playtime compared to higher-current audio op amps like the OPA1622.
推薦
Audio DAC Output Buffering
As a DAC output buffer or I/V converter, the OPA1688 combines 10 MHz bandwidth with 0.00005% THD+N, preserving converter linearity at audio frequencies. The rail-to-rail output maximizes swing on 4.5 V single supplies common in portable DAC designs, and the wide 36 V range supports professional +18 V rails. Low input offset (0.5 mV typical) minimizes DC across headphone loads, eliminating the need for output coupling capacitors in many designs.
推薦
Active Filters and Equalization
For active crossover, tone control, and RIAA equalization stages, the OPA1688's 10 MHz gain-bandwidth product ensures stable closed-loop gains with minimal phase error at 20 kHz. Low offset voltage (0.5 mV typical) reduces DC offset accumulation through cascaded filter stages, and the 36 V supply range allows high headroom in professional console architectures where interconnect noise immunity depends on maximum signal swing.
推薦
Professional Audio Mixing Consoles
Console channel strips and bus summing amplifiers benefit from the OPA1688's balance of low noise, low distortion, and 36 V (±18 V) operation for maximum headroom on balanced lines. Its high output current handles low-impedance bus networks, while 1.5 mA quiescent current matters in large-format consoles where hundreds of op amps determine total power consumption and thermal load.
推薦
Portable and Battery-Powered Audio
In smartphones, portable recorders, and wireless audio devices, the OPA1688's 1.5 mA quiescent current and 4.5 V minimum supply suit single-cell lithium (3.7 V nominal, boosted) systems. Micro package options reduce board area, and the rail-to-rail output extracts maximum swing as the battery discharges, keeping distortion low even near supply limits - a key advantage over conventional op amps whose output stages collapse near the rails.
推薦
Precision Sensor Signal Conditioning
Beyond audio, the OPA1688 serves as a general-purpose 36 V amplifier for transducer front ends: 4.5 nV/√Hz noise resolves microvolt-level sensor signals, the wide supply range fits industrial 24 V rails, and -40C to +85C operation covers harsh environments. Capacitive load stability allows driving shielded cable directly, simplifying filtering at the sensor boundary in measurement instrumentation.
推薦
推薦產品摘要
工程參考資料，適用於 OPA1688ID — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | OPA1656IDR | OPA1611AID | OPA828IDR | OPA1689IDR |
|---|---|---|---|---|---|
| Package | SOIC-8 (D) / WSON-8 | SOIC-8 | SOIC-8 | SOIC-8 | SOIC-8 |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Channels | 1 | 1 | 1 | 1 | 2 |
| Supply Voltage | 4.5 V to 36 V | 4.5 V to 36 V | 4.5 V to 36 V | 10 V to 40 V | 4.5 V to 36 V |
| Gain Bandwidth | 10 MHz | 22 MHz | 80 MHz | 33 MHz | 10 MHz |
| Voltage Noise | 4.5 nV/√Hz | 2.9 nV/√Hz | 1.2 nV/√Hz | 3.3 nV/√Hz | 4.5 nV/√Hz |
| Quiescent Current | 1.5 mA/ch | 1 mA/ch | 3.6 mA/ch | 2.5 mA/ch | 1.5 mA/ch |
| Headphone Drive | Yes (±75 mA) | Limited | Limited | No | Yes (±75 mA) |
主要差異化特點
- Direct headphone drive without buffer stage (對比OPA1611AID)
- Lower cost and lower power than precision audio flagships (對比OPA1656IDR)
- Single-supply operation down to 4.5 V (對比OPA828IDR)
設計說明
Decouple both supply pins with 0.1 µF ceramic capacitors placed within 2 mm of the V+ and V- pins, plus a 2.2-10 µF bulk capacitor per supply rail. Per TI datasheet SBOS724A layout guidance, keep the feedback path short to minimize parasitic capacitance at the inverting input, which can degrade phase margin at gains above 10.
Although the OPA1688 is stable with up to 1000 pF capacitive load, higher capacitive loads such as long shielded cables require an isolation resistor (typically 10-50 ohm) in series with the output to guarantee stability. Do not exceed the 36 V absolute maximum supply, and observe the -40C to +85C operating range; derate output current at elevated ambient temperatures.
When driving headphone loads directly, remember the ±75 mA output current rating is temperature dependent. At 32 ohm loads and high output swing, verify peak current stays within rating to avoid clipping-induced distortion. The RRO stage minimizes crossover artifacts, but source impedance before the amp should stay below 10 kohm to limit noise contribution and offset drift from bias currents.
合規資訊
RoHS compliant per TI product page. AEC-Q100 qualification not indicated for this device.
