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Datasheet Linear Technology LT1777

ManufacturerLinear Technology
SeriesLT1777

Low Noise Step-Down Switching Regulator

Datasheets

  • Download » Datasheet, PDF, 286 Kb, File uploaded 09-03-2017
    LT1777 - Low Noise Step-Down Switching Regulator
    Docket ↓
    LT1777
    Low Noise Step-Down
    Switching Regulator U FEATURES








    ■ DESCRIPTIO The LT ®1777 is a Buck (step-down) regulator designed for
    noise sensitive applications. It contains a dI/dt limiting
    circuit programmed via a small external inductor in the
    switching path. Internal circuitry also generates controlled
    dV/dt ramp rates. Programmable dI/dt Limit
    Internally Limited dV/dt
    High Input Voltage: 48V Max
    700mA Peak Switch Rating
    True Current Mode Control
    100kHz Fixed Operating Frequency
    Synchronizable to 250kHz
    Low Supply Current in Shutdown: 30µA ...

Prices

Packaging

LT1777CS#PBFLT1777CS#TRPBFLT1777IS#PBFLT1777IS#TRPBF
PackageSO-16
Package Outline Drawing
SO-16
Package Outline Drawing
SO-16
Package Outline Drawing
SO-16
Package Outline Drawing
Package CodeSSSS
Package Index05-08-1610 (S16)05-08-1610 (S16)05-08-1610 (S16)05-08-1610 (S16)
Pin Count16161616

Parametrics

LT1777CS#PBFLT1777CS#TRPBFLT1777IS#PBFLT1777IS#TRPBF
ArchitectureConstant Frequency Current ModeConstant Frequency Current ModeConstant Frequency Current ModeConstant Frequency Current Mode
Demo BoardsDC242ADC242ADC242ADC242A
Design ToolsLTspice ModelLTspice ModelLTspice ModelLTspice Model
Export Controlnononono
FeaturesLow EMI, Adjustable Slew Rate, External SynchronizationLow EMI, Adjustable Slew Rate, External SynchronizationLow EMI, Adjustable Slew Rate, External SynchronizationLow EMI, Adjustable Slew Rate, External Synchronization
Frequency, kHz100100100100
Frequency Sync Range130kHz - 250kHz130kHz - 250kHz130kHz - 250kHz130kHz - 250kHz
Integrated Inductornononono
Ishutdown, A12121212
Isupply, mA0.620.620.620.62
Max Phases1111
Monolithicyesyesyesyes
Number of Outputs1111
Operating Temperature Range, °C0 to 700 to 70-40 to 85-40 to 85
Output Current, A0.440.440.440.44
Polyphasenononono
Switch Current, A0.70.70.70.7
Synchronousnononono
TopologyBuckBuckBuckBuck
Vin Max, V48484848
Vin Min, V7777
Vout Max, V30303030
Vout Maximum.85VIN.85VIN.85VIN.85VIN
Vout Min, V1.241.241.241.24
Vref Accuracy Over Temp, %1.21.21.21.2

Eco Plan

LT1777CS#PBFLT1777CS#TRPBFLT1777IS#PBFLT1777IS#TRPBF
RoHSCompliantCompliantCompliantCompliant

Design Notes

  • Download » Design Notes - DN212, PDF, 115 Kb, 09-02-1999
    LT1777 High Voltage, Low Noise Buck Switching Regulator
    Docket ↓
    advertisement LT1777 High Voltage, Low Noise Buck Switching Regulator
    Design Note 212
    Ajmal Godil
    The LT®1777 is a wide input range buck (step-down)
    switching regulator specially designed for low noise applications. The LT1777 can be beneficial in applications
    where low noise is critical, such as telecom, automotive
    cellular and GPS receiver power supplies. The schematic
    in Figure 1 highlights the capabilities of the LT1777. VSW NODE
    VOLTAGE
    10V/DIV SWITCH
    CURRENT
    200mA/DIV The LT1777 can accept input voltages from 7.4V to 48V
    and has a nominal switching frequency of 100kHz. The
    monolithic die includes an onboard 700mA peak current
    switch, oscillator, control and protection circuitry. It uses
    current mode control that delivers excellent dynamic
    input supply rejection and short-circuit protection. In
    order to achieve low noise, the LT1777 is equipped with
    dI/dt limiting circuitry that is programmed via a small
    inductor (LSENSE in Figure 1) in the power path. It also
    contains internal circuitry to limit dV/dt during switch
    turn-on and turn-off.
    Figure 2 shows the VSW node voltage and switch current ...

Articles

  • Download » Articles - LT Journal, PDF, 72 Kb, 02-01-1999
    Generating Low Cost, Low Noise, Dual-Voltage Supplies
    Docket ↓
    DESIGN IDEAS Generating Low Cost, Low Noise,
    Dual-Voltage Supplies
    by Ajmal Godil
    Some sensitive electronic applications, such as telecommunication and
    data acquisition, require both 5V and
    –5V low noise supplies, which may
    have to be generated from a single
    high voltage positive supply. The circuit in Figure 1 shows a cost-effective
    way to generate 5V and –5V from a
    single 10V–28V supply by using the
    low noise LT1777 and a few off-theshelf components.
    The LT1777 is a step-down regulator specially designed for low noise
    applications. In order to achieve low
    VIN
    10V–28V
    4
    10
    3 SHDN 14
    100pF VCC VSW VIN VD SHDN
    VC FB
    LT1777 GND
    GND 12
    R3 ...

Moldel Line

Series: LT1777 (4)

Manufacturer's Classification

  • Power Management > Switching Regulator > Step-Down (Buck) Regulators > High Input Voltage Buck | Internal Power Switch Buck
  • Power Management > Switching Regulator > Ultralow Noise Regulators

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