Low-Power, Current Feedback Operational Amplifier With Disable - OPA684

OPA684 (ACTIVE)

Low-Power, Current Feedback Operational Amplifier With Disable

 

Description

The OPA684 provides a new level of performance in low-power, wideband, current-feedback (CFB) amplifiers. This CFBplus amplifier is the first to use an internally closed-loop input buffer stage that enhances performance significantly over earlier low-power CFB amplifiers. While retaining the benefits of very low power operation, this new architecture provides many of the benefits of a more ideal CFB amplifier. The closed-loop input stage buffer gives a very low and linearized impedance path at the inverting input to sense the feedback error current. This improved inverting input impedance retains exceptional bandwidth to much higher gains and improves harmonic distortion over earlier solutions limited by inverting input linearity. Beyond simple high-gain applications, the OPA684 CFBplus amplifier permits the gain setting element to be set with considerable freedom from amplifier bandwidth interaction. This allows frequency response peaking elements to be added, multiple input inverting summing circuits to have greater bandwidth, and low-power line drivers to meet the demanding requirements of studio cameras and broadcast video.

The output capability of the OPA684 also sets a new mark in performance for low-power current feedback amplifiers. Delivering a full ±4Vpp swing on ±5V supplies, the OPA684 also has the output current to support this swing into a 100 load. This minimal output headroom requirement is complemented by a similar 1.2V input stage headroom giving exceptional capability for single +5V operation.

The OPA684’s low 1.7mA supply current is precisely trimmed at 25°C. This trim, along with low shift over temperature and supply voltage, gives a very robust design over a wide range of operating conditions. System power may be further reduced by using the optional disable control pin. Leaving this disable pin open, or holding it HIGH, gives normal operation. If pulled LOW, the OPA684 supply current drops to less than 100µA while the I/O pins go to a high impedance state.

Features

  • MINIMAL BANDWIDTH CHANGE VERSUS GAIN
  • > 120MHz BANDWIDTH TO GAIN > +10
  • LOW DISTORTION: < –78dBc at 5MHz
  • HIGH OUTPUT CURRENT: 120mA
  • SINGLE +5V TO +12V SUPPLY OPERATION
  • DUAL ±2.5 TO ±6.0V SUPPLY OPERATION
  • LOW SUPPLY CURRENT: 1.7mA
  • LOW SHUTDOWN CURRENT: 100µA
  • APPLICATIONS
    • LOW-POWER BROADCAST VIDEO DRIVERS
    • EQUALIZING FILTERS
    • SAW FILTER HIGH GAIN POST AMPLIFIERS
    • MULTICHANNEL SUMMING AMPLIFIERS
    • PROFESSIONAL CAMERAS
    • ADC INPUT DRIVERS

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Parametrics Compare all products in High-Speed Op Amps (>=50MHz)

 
Architecture
Number of Channels (#)
Total Supply Voltage (Min) (+5V=5, +/-5V=10)
Total Supply Voltage (Max) (+5V=5, +/-5V=10)
BW @ Acl (MHz)
Acl, min spec gain (V/V)
Slew Rate (Typ) (V/us)
Vn at Flatband (Typ) (nV/rtHz)
Vn at 1kHz (Typ) (nV/rtHz)
Iq per channel (Typ) (mA)
Vos (Offset Voltage @ 25C) (Max) (mV)
Rail-to-Rail
Features
Rating
Operating Temperature Range (C)
Package Group
Package Size: mm2:W x L (PKG)
CMRR (Typ) (dB)
Input Bias Current (Max) (pA)
Offset Drift (Typ) (uV/C)
GBW (Typ) (MHz)
Output Current (Typ) (mA)
2nd Harmonic (dBc)
3rd Harmonic (dBc)
@ MHz
OPA684 OPA2684 OPA3684 OPA4684
Bipolar
Current FB   
Bipolar
Current FB   
Bipolar
Current FB   
Bipolar
Current FB   
1    2    3    4   
5    5    5    5   
12    12    12    12   
210    210    210    210   
1    1    1    1   
820    820    820    820   
3.7    3.7    3.7    3.7   
3.7    3.7    3.7    3.7   
1.7    1.7    1.7    1.7   
3.5    3.5    3.5    3.5   
No    No    No    No   
Shutdown    Small Size
Shutdown   
Shutdown    Shutdown   
Catalog    Catalog    Catalog    Catalog   
-40 to 85    -40 to 125    -40 to 85    -40 to 85   
SOIC
SOT-23   
SOIC
SOT-23   
SOIC
SSOP   
SOIC
TSSOP   
8SOIC: 29 mm2: 6 x 4.9(SOIC)
6SOT-23: 8 mm2: 2.8 x 2.9(SOT-23)   
8SOIC: 29 mm2: 6 x 4.9(SOIC)
8SOT-23: 8 mm2: 2.8 x 2.9(SOT-23)   
14SOIC: 52 mm2: 6 x 8.65(SOIC)
16SSOP: 19 mm2: 3.9 x 4.9(SSOP)   
14SOIC: 52 mm2: 6 x 8.65(SOIC)
14TSSOP: 32 mm2: 6.4 x 5(TSSOP)   
60    60    60    60   
10000000    10000000    10000000    10000000   
12    12    12    12   
210    210    210    210   
120    120    120    120   
67    67    67    67   
70    70    70    70   
5    5    5    5