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LTC7000JMSE-PBF

Fast 150V Protected High Side NMOS Static Switch Driver

Analog Devices 

LTC7000/LTC7000-1

OPERATION (Refer to Block Diagram)

Internal Charge Pump

The LTC7000/LTC7000-1 contains an internal charge

pump that enables the MOSFET gate drive to have 100%

duty cycle. The charge pump regulates the BST-TS volt-

age to 12V reducing external power losses associated

with external MOSFET on-resistance. The charge pump

uses the higher voltage of TS or VCC as the source for

the charge.

Start-Up and Shutdown

If the voltage on the RUN pin (LTC7000 only) is less than

0.7V, the LTC7000 enters a shutdown mode in which all

internal circuitry is disabled, reducing the DC supply cur-

rent to approximately 1µA. When the voltage on the RUN

pin exceeds 0.7V, the internal LDO connected to VIN is

enabled and regulates VCC to 10V. At VIN voltages less

than 10V, the LDO will operate in drop-out and VCC will

follow VIN. When the voltage on the RUN pin exceeds

1.21V, the input circuitry is enabled allowing TGUP and

TGDN to be driven high with respect to TS. The LTC7000-1

does not include the RUN pin. The internal LDO connected

to VIN and the input circuitry for the LTC7000-1 become

enabled when VIN is higher than 3.5V.

Protection Circuitry

When using the LTC7000/LTC7000-1, care must be taken

not to exceed any of the ratings specified in the Absolute

Maximum Ratings section. As an added safeguard, the

LTC7000/LTC7000-1 incorporates an overtemperature

shutdown feature. If the junction temperature reaches

approximately 180°C, the LTC7000/LTC7000-1 will enter

thermal shutdown mode and TGDN will be pulled to TS.

After the part has cooled below 160°C, TGDN will be

allowed to go back high. The overtemperature level is

not production tested. The LTC7000/LTC7000-1 is guar-

anteed to start a temperatures below 150°C.

The LTC7000/LTC7000-1 additionally implements protec-

tion features which prohibit TGUP being pulled to BST

when VIN, VCC or (VBST–VTS) are not within proper operat-

ing ranges. By using a resistive divider from VIN to ground

(LTC7000 only), the RUN and OVLO pins can serve as a

precise input supply overvoltage/undervoltage lockouts.

TGDN is pulled to TS when either RUN falls below 1.11V

or OVLO rises above 1.21V, which can be configured to

limit switching to a specific range on input supply volt-

ages. Furthermore, if VIN falls below 3.5V, an internal

undervoltage detector pulls TGDN to TS.

VCC contains an undervoltage lockout feature that will

pull TGDN to TS and is configured by the VCCUV pin. If

VCCUV is open, TGDN is pulled to TS until VCC is greater

than 7.0V. By using a resistor from VCCUV to ground, the

rising undervoltage lockout on VCC can be adjusted from

3.5V to 10.5V.

An additional internal undervoltage lockout is included

that will pull TGDN to TS when the floating voltage from

BST to TS is less than 3.1V (typical).

Rev. E

12

For more information www.analog.com

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