GF125 Series Metal Sealed Thermal Mass Flow Controllers & Meters

The MFC that has it all.
Models GF125 / GF126

Ultra-fast response times and the highest level of purity – the GF125 Series are second generation multi-variable, pressure transient insensitive (PTI), metal sealed mass flow controllers and meters. First to bring PTI mass flow control technology to market, GF125 minimizes process gas flow variation due to pressure and temperature fluctuations. Standard MultiFlo™ technology enables one MFC to support thousands of gas types and range combinations without removing it from the gas line or compromising on accuracy.

The result: reduced size and cost of gas panels, by eliminating the need for point of use pressure regulators, pressure transducers, and associated hardware, combined with the industry’s best PTI performance to maximize yields and productivity.


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GF125 Series Data Sheet


  • Long-term zero stability of <±0.5% full scale per year
  • Ultra-fast settling times: 300 ms - <700 ms
  • Full-scale flow rates up to 300 slpm
  • Ultra-high purity flow path - 4µ inch Ra surface finish
  • SEMI F20 compliant wetted materials
  • Corrosion-resistant Hastelloy® T-Rise sensor with high speed ARM processor
  • Fast acting, diaphragm-free valve assembly is unaffected by differential pressure and tested for over seven million cycles without any failures
  • MultiFloTM technology offers unparalleled flexibility—one device can be programmed for thousands of different gas and flow range configurations without removing the MFC from the gas line or compromising accuracy
  • Local display indicates flow, temperature, pressure and network address for easy troubleshooting of gas supply and isolation valve issues
  • DeviceNetTM, RS-485 L-Protocol and analog interfaces


  • By combining Brooks' patented flow sensor technology with a fast acting diaphragm free valve assembly, the GF125 Series delivers up to 3 times faster response and settling time compared to other mass flow controllers
  • Optimized wetted flow path for improved dry-down
  • With MultiFloTM, MFC full scale flow range can be re-scaled down typically by a factor of 3:1 with no impact on accuracy, turndown or leak by specifications, for optimum process and inventory flexibility 
  • A full gas database delivers the widest process gas coverage
  • Pressure Transient Insensitivity (PTI) capability overcomes limitations of conventional MFCs that react strongly to small inlet pressure fluctuations. The result is stable performance and predictable accuracy.
  • Convenient user display and independent diagnostic/service port aids device installation, monitoring and troubleshooting

Key Applications

  • Semiconductor
  • Gas flow control applications that require a high purity all-metal flow path
    Product Type

    Mass Flow Controller


    Ultra-High Purity

    Ultra-Fast Response Time

    Pressure Transient Insensitivity

    Flow Range (Full Scale Capacity)

    3 sccm - 300 slm


    ±1% S.P. > 35-100%

    ±0.35% F. S. 2-35%

    < ±0.15% S.P.

    ±0.5% F.S. (included in accuracy)

    Response Time

    300ms - < 1 sec

    Response Time

    Normally Open Valve: <1.5 sec

    (specific models only)

    Multi-Gas & Range Configurability
    MultiFlo™ Standard (most models)
    Pressure Transient Insensitivity

    <5% S.P. for up to 5 psi/sec upstream press. spike

    Control Range

    < 5 - 100%

    Number of Bins

    Standard GF Series: 11 bins

    High Flow GF Series: 4 bins

    Valve Shut Down

    < 2% F.S.

    Zero Stability
    < ±0.5% F.S. per year
    Flow Temperature Coefficient

    Span: 0.05% S.P. per °C

    Zero: 0.005% F.S. per °C

    Seal Material


    Level of Purity / Surface Finish
    4 - 5µ inch Ra
    Wetted Materials

    SEMI F20 HP Compliant

    316L VIM/VAR

    Hastelloy C-22

    316L Stainless Steel

    304 Stainless Steel


    Valve Options

    Normally Closed

    Normally Open (specific models)

    Meter (no valve)

    Max Temperature
    Differential Pressure Range

    3-860 sccm = 7-45 psid

    861 - 7200 sccm = 10 - 45 psid

    7201 - 55000 sccm = 15 - 45 psid

    51 - 300 slm = 30 - 90 psid

    *Typical pressure drops. Contacts Brooks Technical Support for more information.

    Max Pressure

    Standard GF Series: 100 psia max

    High Flow GF Series: 75 psig (controller), 150 psig (meter)

    Leak Integrity
    1x10-10 atm cc/sec He
    Diagnostics & Display
    Diagnostic Capability

    Status Lights

    MFC Health

    Network Status


    Control Valve Output

    Network Interruption

    Diagnostic / Service Port

    RS485 via 2.5mm jack (all models)


    Top Mount Integrated LCD

    Viewing Angle: Fixed

    Viewing Distance: 10 feet

    Units Displayed: Flow (%), Temp (°C), Pressure (psia, kPa)

    Resolution: 0.1 (unit)

    Analog Communication

    0-5 Vdc

    Digital Communication


    RS485 L-Protocol

    Electrical Connection

    Analog/RS485 via 9-Pin "D" connector

    DeviceNet™ via 5-Pin "M12" connector

    Various cable adaptors available. See product data sheet for more information.

    Power Supply / Consumption

    Analog/RS485 L Protocol: 6 Watts max @ ±15 Vdc (±10%) or +24 Vdc (±10%)

    DeviceNet™: 545 mA max @ +11-25 Vdc, 250 mA max @ 24 Vdc

    (Under typical operating conditions)


    EC Directive 2004/108/EC

    CE: EN61326-1: 2006 (FCC Part 15 & Canada IC-subset of CE testing)

    Environmental Compliance

    RoHS Directive (2011/65/EU)

    REACH Directive EC 1907/2006

    GF125 GF126

    Ultra-High Purity

    Ultra-Fast Response Time

    Pressure Transient Insensitivity

    High Flow Rate

    Flow Range (Full Scale Capacity) 3 sccm - 55 slm

    55 slm - 300 slm

    Surface Finish 4µ inch Ra 4µ inch Ra

    ±1% S.P. > 35-100%

    ±0.35% F.S. 2-35%

    ±1% S.P. > 35-100%

    ±0.35% F.S. 2-35%

    Repeatability < ±0.15% S.P. < ±0.15% S.P.
    Response Time

    Normally Closed Valve

    300ms (3-860 sccm N2 Eq.)

    400ms (861-7200 sccm N2 Eq.)

    500ms (7201-30000 sccm N2 Eq.)

    <700ms (30001-55000 sccm N2 Eq.)


    Normally Closed Valve

    <1 sec


    Response Time

    Normally Open Valve

    <1.5 sec

    Normally Open Valve

    Multi-Gas & Range Configurability MultiFlo™ Standard MultiFlo™ Standard
    Pressure Transient Insensitivity

    ±5% S.P. up to 5 psi/sec upstream press. spike

    Ability to measure inlet pressure

    Diagnostic Capability

    Status Lights - MFC Health, Network Status

    Alarms - Control Valve Output, Network Interruption

    Status Lights: MFC Health & Network Status

    Alarms: Control Valve Output & Network Interruption

    Analog Communication

    0-5 Vdc

    0-5 Vdc

    Digital Communication

    RS485 L Protocol


    RS485 L Protocol



    Filename File Type Documents By Language
    Data Sheet - GF125 pdf English
    Data Sheet - GF126 pdf English
    Installation & Operation Manual pdf English
    DeviceNet™ Supplemental Manual - GF100 Series pdf English
    RS485 L-Protocol Supplemental Manual - GF100 Series pdf English

    Use the following guide (model code information from data sheet) to translate the CAD configurations available below. If you need assistance or can’t find what you’re looking for, please contact Applications Engineering or your local Brooks Instrument representative.

    Example: GF125 - WX (Fitting) - GX (Connector) - STEP

    Model Series
    Fitting Connector File Type
     GF1xx AS - 1-1/2” body width, 92 mm 0.440” large bore C Seal (only for bins SH45-SH50) BX - Cable adapter to 15 pin D Brooks (Unit “B”,”N”) adapts G1 base  STEP
      CX - 1-1/8” body width, 92 mm C Seal
    *DX - DeviceNet™ 5 pin micro  
      VX - 1-1/2” body width, 124mm 1/4” VCR male EX - Cable adapter to Card Edge (w/o VTP), RS485 through RJ11 jacks (Unit”E”; IN “L”, “R”) adapts GX base  
      WX - 1-1/8” body width, 92mm W Seal GX - 9-Pin D with RS485 (Unit”G”); display and overlay 180 degree orientation  
        G1 - 9-Pin D with RS485 (Unit”G”)  
        SX - 9 pin D with STEC pin-out (w/VTP) (Unit”S”,”Q”)  
    Filename File Type
    GF100-GF120-GF125-AS-G1 STEP
    GF100-GF120-GF125-AS-SX DXF
    GF100-GF120-GF125-AS-SX IGS
    GF100-GF120-GF125-AS-SX STEP
    GF100-GF120-GF125-AX-G1 STEP
    GF100-GF120-GF125-AX-G1 IGS
    GF100-GF120-GF125-CX-DX STEP
    GF100-GF120-GF125-CX-SX DXF
    GF100-GF120-GF125-CX-SX STEP
    GF100-GF120-GF125-CX-TX STEP
    GF100-GF120-GF125-CX-TX IGS
    GF100-GF120-GF125-CX-TX DXF
    GF100-GF120-GF125-DX-DX DXF
    GF100-GF120-GF125-DX-DX IGS
    GF100-GF120-GF125-DX-DX STEP
    GF100-GF120-GF125-DX-TX DXF
    GF100-GF120-GF125-DX-TX IGS
    GF100-GF120-GF125-DX-TX STEP
    GF100-GF120-GF125-LX-DX DXF
    GF100-GF120-GF125-LX-DX IGS
    GF100-GF120-GF125-LX-DX STEP
    GF100-GF120-GF125-VS-E0 DXF
    GF100-GF120-GF125-VS-E0 IGS
    GF100-GF120-GF125-VS-E0 STEP
    GF100-GF120-GF125-VS-G1 DXF
    GF100-GF120-GF125-VS-G1 IGS
    GF100-GF120-GF125-VS-G1 STEP
    GF100-GF120-GF125-VS-GX DXF
    GF100-GF120-GF125-VS-GX IGS
    GF100-GF120-GF125-VS-GX STEP
    GF100-GF120-GF125-VS-SX DXF
    GF100-GF120-GF125-VS-SX STEP
    GF100-GF120-GF125-VS-SX IGS
    GF100-GF120-GF125-VX-BX STEP
    GF100-GF120-GF125-VX-DX STEP
    GF100-GF120-GF125-VX-E0 DXF
    GF100-GF120-GF125-VX-E0 IGS
    GF100-GF120-GF125-VX-E0 STEP
    GF100-GF120-GF125-VX-EX STEP
    GF100-GF120-GF125-VX-G1 STEP
    GF100-GF120-GF125-VX-GX STEP
    GF100-GF120-GF125-VX-KX DXF
    GF100-GF120-GF125-VX-KX IGS
    GF100-GF120-GF125-VX-KX STEP
    GF100-GF120-GF125-VX-SX STEP
    GF100-GF120-GF125-WX-GX STEP
    GF100-GF120-GF-125-WX-SX DXF
    GF100-GF120-GF-125-WX-SX IGS
    GF100-GF120-GF-125-WX-SX STEP
    GF101-GF121-GF126-V1-D0 DXF
    GF101-GF121-GF126-V1-D0 IGS
    GF101-GF121-GF126-V1-D0 STEP
    GF101-GF121-GF126-V1-DX DXF
    GF101-GF121-GF126-V1-DX IGS
    GF101-GF121-GF126-V1-DX STEP
    GF101-GF121-GF126-V1-G1 DXF
    GF101-GF121-GF126-V1-G1 IGS
    GF101-GF121-GF126-V1-G1 STEP
    GF101-GF121-GF126-V2-G1 DXF
    GF101-GF121-GF126-V2-G1 IGS
    GF101-GF121-GF126-V2-G1 STEP
    GF101-GF121-GF126-V2-SX DXF
    GF101-GF121-GF126-V2-SX IGS
    GF101-GF121-GF126-V2-SX STEP
    0250 Series
    Controls and powers up to 4 devices
    MultiFlo™ Configurator
    A comprehensive gas database enabling you to configure your MultiFlo™ capable MFC for thousands of gas types and ranges without removing it from the gas line.