DATA SHEET
OPA857 Ultralow-Noise, Wideband, Selectable-Feedback Resistance Transimpedance Amplifier
1 Features
- Internal Midscale Reference Voltage
- Pseudo-Differential Output Voltage
- Wide Dynamic Range
- Closed-Loop Transimpedance Bandwidth:
- 125 MHz (5-kΩ Transimpedance Gain,
1.5-pF External Parasitic Capacitance) - 105 MHz (20-kΩ Transimpedance Gain,
1.5-pF External Parasitic Capacitance)
- 125 MHz (5-kΩ Transimpedance Gain,
- Ultralow Input-Referred Current Noise
(Brickwall Filter BW = 135 MHz):
15 nARMS (20-kΩ Transimpedance) - Very Fast Overload Recovery Time: < 25 ns
- Internal Input Protection Diode
- Power Supply:
- Extended Temperature Range: –40°C to +85°C
2 Applications
3 Description
The OPA857 is a wideband, fast overdrive recovery, fast-settling, ultralow-noise transimpedance amplifier targeted at photodiode monitoring applications. With selectable feedback resistance, the OPA857 simplifies the design of high-performance optical systems. Very fast overload recovery time and internal input protection provide the best combination to protect the remainder of the signal chain from overdrive while minimizing recovery time. The two selectable transimpedance gain configurations allow high dynamic range and flexibility required in modern transimpedance amplifier applications. The OPA857 is available in a 3-mm × 3-mm VQFN package.
The device is characterized for operation over the full industrial temperature range from –40°C to +85°C.
Device Information(1)
| DEVICE NAME | PACKAGE | BODY SIZE |
|---|---|---|
| OPA857 | VQFN (16) | 3 mm × 3 mm |
- For all available packages, see the package option addendum at the end of the datasheet.
4 Revision History
Changes from C Revision (April 2014) to D Revision
- Changed Features bulletsGo
- Changed "Precision" to "High-Speed" in 2nd Applications bulletGo
- Changed pin configuration drawing and pin functions tableGo
- Changed Handling Ratings table to ESD Ratings and moved storage temperature to Absolute Maximum RatingsGo
- Changed Supply Input Voltage min value from 3.0 to 2.7 in Recommended Operating ConditionsGo
- Changed VOUT unit from VP to VPP in Electrical Charateristics condition lineGo
- Changed all AC Performance values except Closed-Loop Output ImpedanceGo
- Changed test conditions for Equivalent Input-Referred Current Noise parameter in Electrical CharacteristicsGo
- Deleted Operating Voltage from Electrical Characteristics; already in Recommended Operating ConditionsGo
- Deleted Temperature Range from Electrical Characteristics; already in Recommended Operating ConditionsGo
- Changed all plots in Typical Characteristics section except figures 17, 35, and 36 Go
- Changed 4.5 kΩ and 18.2 kΩ to 5 kΩ and 20 kΩ, respectively, in first paragrpah of Overview sectionGo
- Changed text in Transimpedance Amplifier (TIA) Block sectionGo
- Changed text in Reference Voltage (REF) Block sectionGo
- Changed text in Integrated Test Structure (TEST) Block sectionGo
- Changed Table 2 valuesGo
- Added Test Mode sectionGo
- Changed Application Information sectionGo
- Changed Figure 50; updated pin namesGo
Changes from B Revision (January 2014) to C Revision
- Changed document format to meet new data sheet standards; added Handling Ratings and Device and Documentation Support sections, and moved existing sectionsGo
- Changed OUTN to OUT in Output Voltage Swing parameter test conditions Go
- Changed Functional Block Diagram Go
Changes from A Revision (December 2013) to B Revision
- Changed document status to Production DataGo
- Changed transimpedance value in both sub-bullets of Bandwidth Features bulletGo
- Changed Extended Temperature Range Features bullet to a range of –40°C to +85°CGo
- Changed first sentence of Description section: added "targeted at photodiode monitoring applications"Go
- Changed temperature range to –40°C to +85°C in last sentence of Description sectionGo
- Changed front-page graphicGo
- Added pages 2 through end of documentGo
Changes from * Revision (December 2013) to A Revision
5 Pin Configuration and Functions
Pin Functions
6 Specifications
6.1 Absolute Maximum Ratings(1)
over operating free-air temperature range (unless otherwise noted)| MIN | MAX | UNIT | ||
|---|---|---|---|---|
| Voltage | Supply voltage, VS– to VS+ | 3.8 | V | |
| Input and output voltage, VIN, VOUT pins | (VS–) – 0.7 | (VS+) + 0.7 | ||
| Differential input voltage | 1 | |||
| Current | Output current | 50 | mA | |
| Input current, VIN pin | 10 | |||
| Continuous power dissipation | See Thermal Information table | |||
| Temperature | Maximum junction, TJ | 150 | °C | |
| Maximum junction, TJ (continuous operation, long-term reliability) | 140 | |||
| Operating free-air, TA | –40 | 85 | ||
| Storage, Tstg | –65 | 150 | ||
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
6.2 ESD Ratings
| VALUE | UNIT | |||
|---|---|---|---|---|
| V(ESD) | Electrostatic discharge | Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) | ±2000 | V |
| Charged-device model (CDM), per JEDEC specification JESD22-C101(2) | ±500 | |||
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)| MIN | NOM | MAX | UNIT | ||
|---|---|---|---|---|---|
| VSS | Supply input voltage | 2.7 | 3.3 | 3.6 | V |
| TJ | Operating junction temperature | –40 | 85 | °C | |
6.4 Thermal Information
| THERMAL METRIC(1) | OPA857 | UNIT | |
|---|---|---|---|
| RGT (VQFN) | |||
| 16 PINS | |||
| RθJA | Junction-to-ambient thermal resistance | 67.1 | °C/W |
| RθJC(top) | Junction-to-case(top) thermal resistance | 91.6 | °C/W |
| RθJB | Junction-to-board thermal resistance | 41.6 | °C/W |
| ψJT | Junction-to-top characterization parameter | 7.1 | °C/W |
| ψJB | Junction-to-board characterization parameter | 41.7 | °C/W |
| RθJC(bot) | Junction-to-case(bottom) thermal resistance | 23.1 | °C/W |
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report (SPRA953).
6.5 Electrical Characteristics
at TA = 25°C(2), VS = 3.3 V, VS+ – VS– = 3.3 V, CSource = 1.5 pF, VOUT = 0.5 VPP (differential), RL = 500-Ω differential, single-ended input, pseudo-differential output, and input and output referenced to midsupply (unless otherwise noted)| PARAMETER | TEST CONDITIONS | MIN | TYP | MAX | UNIT | TEST LEVEL(1) | |
|---|---|---|---|---|---|---|---|
| AC PERFORMANCE | |||||||
| Small-signal bandwidth | CTRL = 1, TA = –40°C to +85°C | 105 | MHz | C | |||
| CTRL = 0, TA = –40°C to +85°C | 125 | MHz | C | ||||
| SR | Slew rate (differential) | VOUT = 1-V step | 215 | V/μs | C | ||
| tS | Settling time to 1% | VOUT = 0.5-V step, CTRL = 0, TA = 25°C | 8 | ns | B | ||
| VOUT = 0.5-V step, CTRL = 1, TA = 25°C | 8 | ns | B | ||||
| Settling time to 0.001% | VOUT = 0.5-V step, CTRL = 0 | 600 | ns | C | |||
| VOUT = 0.5-V step, CTRL = 1 | 700 | ns | C | ||||
| HD2 | Second-harmonic distortion | VOUT = 0.5 VPP, f = 10 MHz, RF = 5 kΩ, TA = 25°C | –80 | dBc | C | ||
| VOUT = 0.5 VPP, f = 10 MHz, RF = 20 kΩ, TA = 25°C | –83 | dBc | C | ||||
| HD3 | Third-harmonic distortion | VOUT = 0.5 VPP, f = 10 MHz, RF = 5 kΩ, TA = 25°C | –88 | dBc | C | ||
| VOUT = 0.5 VPP, f = 10 MHz, RF = 20 kΩ, TA = 25°C | –83 | dBc | C | ||||
| Equivalent input-referred current noise | CTRL = 0, using 135-MHz brickwall filter | 25 | nARMS | C | |||
| CTRL = 1, using 135-MHz brickwall filter | 15 | nARMS | C | ||||
| Overdrive recovery time | IIN = 2x overload, CTRL = 1, settling to 1% of final value | 25 | ns | B | |||
| Closed-loop output impedance | f = 1 MHz (differential) | 50 | Ω | C | |||
| DC PERFORMANCE | |||||||
| Transimpedance gain | CTRL = 1 into 500 Ω(4)(5) | 18.2 | kΩ | C | |||
| CTRL = 0 into 500 Ω(4)(5) | 4.5 | kΩ | C | ||||
| Transimpedance gain error | TA = 25°C, RF = 20 kΩ and RF = 5 kΩ | ±1% | ±15% | A | |||
| VOO | Output offset voltage | TA = +25°C | ±1 | ±5 | mV | A | |
| TA = –40°C to +85°C(3) | ±6 | mV | B | ||||
| Output offset voltage drift | TA = –40°C to +85°C(3) | ±15 | μV/°C | C | |||
| VICR | Common-mode voltage range | TA = 25°C, OUTN | 1.78 | 1.83 | 1.88 | V | A |
| INPUT | |||||||
| Input pin capacitance | 2 | pF | C | ||||
| OUTPUT | |||||||
| Output voltage swing | OUT, TA = 25°C | 0.6 | 1.9 | V | A | ||
| TA = –40°C to +85°C(3) | 1.9 | V | B | ||||
| Output current drive (for linear operation) |
OUT, differential 50-Ω between OUT and OUTN | +5 | mA | C | |||
| –20 | mA | C | |||||
| POWER SUPPLY | |||||||
| Quiescent operating current | CTRL = 0, TA = 25°C | 20.5 | 23.4 | 26.3 | mA | A | |
| CTRL = 0, TA = –40°C to +85°C(3) | 20.0 | 26.8 | mA | B | |||
| CTRL = 1, TA = 25°C | 20.5 | 23.4 | 26.3 | mA | A | ||
| CTRL = 1, TA = –40°C to +85°C(3) | 20.0 | 26.8 | mA | B | |||
| PSRR | Power-supply rejection ratio | At dc, TA = 25°C | 70 | 80 | dB | A | |
| f = 10 MHz, TA = –40°C to +85°C(3) | 15 | 18 | dB | B | |||
| LOGIC LEVEL (CTRL) | |||||||
| VIH | High-level input voltage | 2 | V | A | |||
| VIL | Low-level input voltage | 0.8 | V | A | |||
| High-level control pin input bias current | 1 | µA | A | ||||
| Low-level control pin input bias current | 1 | µA | A | ||||
(1) Test levels: (A) 100% tested at 25°C. Overtemperature limits set by characterization and simulation. (B) Limits set by characterization and simulation. (C) Typical value only for information.
(2) Junction temperature = ambient for 70°C specifications.
(3) Junction temperature = ambient at low temperature; junction temperature = ambient + 3.5°C for overtemperature specifications.
(4) See the Application and Implementation section for details on loading and effective transimpedance gain.
(5) Note that the effective transimpedance gain is reduced to 18.2 kΩ and 4.5 kΩ, respectively, with a 500-Ω load resulting from the internal series resistance on OUT and OUTN.
6.6 Typical Characteristics
At TA = 25°C, CS = 1.5 pF, and RL = 500-Ω differential between OUT and OUTN (unless otherwise noted).
vs Temperature
| TZ Gain = 20 kΩ, TA = 25°C, RLOAD = 500 Ω, f = 50 MHz | ||
