Datasheet LT1970A (Analog Devices) - 8
| Manufacturer | Analog Devices |
| Description | 500mA Power Op Amp with Adjustable Precision Current Limit |
| Pages / Page | 24 / 8 — pin FuncTions. VEE (Pins 1, 10, 11, 20, 21):. FILTER (Pin 5):. SENSE– … |
| File Format / Size | PDF / 385 Kb |
| Document Language | English |
pin FuncTions. VEE (Pins 1, 10, 11, 20, 21):. FILTER (Pin 5):. SENSE– (Pin 6):. V– (Pin 2):. VCC (Pin 7):. OUT (Pin 3):. –IN (Pin 8):
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Text Version of Document
LT1970A
pin FuncTions VEE (Pins 1, 10, 11, 20, 21):
Minus Supply Voltage. VEE
FILTER (Pin 5):
Current Sense Filter Pin. This pin is connects to the substrate of the integrated circuit die, and normally not used and should be left open or shorted to therefore must always be the most negative voltage ap- the SENSE– pin. The FILTER pin can be used to adapt the plied to the part. Decouple VEE to ground with a low ESR response time of the current sense amplifiers with a 1nF capacitor. VEE may be a negative voltage or it may equal to 100nF capacitor connected to the SENSE– input. An ground potential. Any or all of the VEE pins may be used. internal 1k resistor sets the filter time constant. Unused VEE pins must remain open.
SENSE– (Pin 6):
Negative Current Sense Pin. This pin is
V– (Pin 2):
Output Stage Negative Supply. V– may equal normally connected to the load end of the external sense VEE or may be smaller in magnitude. Only output stage resistor. Sourcing current limit operation is activated when current flows out of V–, all other current flows out of VEE. the voltage VSENSE (VSENSE+ – VSENSE–) equals 1/10 of V– may be used to drive the base/gate of an external power the programming control voltage at VCSRC (Pin 13). Sink- device to boost the amplifier’s output current to levels above ing current limit operation is activated when the voltage the rated 500mA of the on-chip output devices. Unless VSENSE equals –1/10 of the programming control voltage used to drive boost transistors, V– should be decoupled at VCSNK (Pin 12). to ground with a low ESR capacitor.
VCC (Pin 7):
Positive Supply Voltage. All circuitry except
OUT (Pin 3):
Amplifier Output. The OUT pin provides the the output transistors draw power from VCC. Total supply force function as part of a Kelvin sensed load connection. voltage from VCC to VEE must be between 3.5V and 36V. OUT is normally connected directly to an external load cur- VCC must always be greater than or equal to V+. VCC should rent sense resistor and the SENSE+ pin. Amplifier feedback always be decoupled to ground with a low ESR capacitor. is directly connected to the load and the other end of the
–IN (Pin 8):
Inverting Input of Amplifier. –IN may be any current sense resistor. The load connection is also wired voltage from V directly to the SENSE– pin to monitor the load current. EE – 0.3V to VEE + 36V. –IN and +IN remain high impedance at all times to prevent current flow into The OUT pin is current limited to ±800mA typical. This the inputs when current limit mode is active. Care must current limit protects the output transistor in the event that be taken to ensure that –IN or +IN can never go to a volt- connections to the external sense resistor are opened or age below VEE – 0.3V even during transient conditions or shorted which disables the precision current limit function. damage to the circuit may result. A Schottky diode from
SENSE+ (Pin 4):
Positive Current Sense Pin. This lead is VEE to –IN can provide clamping if other elements in the normally connected to the driven end of the external sense circuit can allow –IN to go below VEE. resistor. Sourcing current limit operation is activated when
+IN (Pin 9):
Noninverting Input of Amplifier. +IN may be any the voltage VSENSE (VSENSE+ – VSENSE–) equals 1/10 of voltage from VEE – 0.3V to VEE + 36V. –IN and +IN remain the programming control voltage at VCSRC (Pin 13). Sink- high impedance at all times to prevent current flow into ing current limit operation is activated when the voltage the inputs when current limit mode is active. Care must VSENSE equals –1/10 of the programming control voltage be taken to ensure that –IN or +IN can never go to a volt- at VCSNK (Pin 12). age below VEE – 0.3V even during transient conditions or damage to the circuit may result. A Schottky diode from VEE to +IN can provide clamping if other elements in the circuit can allow +IN to go below VEE. 1970afc 8 For more information www.linear.com/LT1970A Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram And Test Circuit Applications Information Package Description Applications Information Related Parts
pin FuncTions VEE (Pins 1, 10, 11, 20, 21):
Minus Supply Voltage. VEE
FILTER (Pin 5):
Current Sense Filter Pin. This pin is connects to the substrate of the integrated circuit die, and normally not used and should be left open or shorted to therefore must always be the most negative voltage ap- the SENSE– pin. The FILTER pin can be used to adapt the plied to the part. Decouple VEE to ground with a low ESR response time of the current sense amplifiers with a 1nF capacitor. VEE may be a negative voltage or it may equal to 100nF capacitor connected to the SENSE– input. An ground potential. Any or all of the VEE pins may be used. internal 1k resistor sets the filter time constant. Unused VEE pins must remain open.
SENSE– (Pin 6):
Negative Current Sense Pin. This pin is
V– (Pin 2):
Output Stage Negative Supply. V– may equal normally connected to the load end of the external sense VEE or may be smaller in magnitude. Only output stage resistor. Sourcing current limit operation is activated when current flows out of V–, all other current flows out of VEE. the voltage VSENSE (VSENSE+ – VSENSE–) equals 1/10 of V– may be used to drive the base/gate of an external power the programming control voltage at VCSRC (Pin 13). Sink- device to boost the amplifier’s output current to levels above ing current limit operation is activated when the voltage the rated 500mA of the on-chip output devices. Unless VSENSE equals –1/10 of the programming control voltage used to drive boost transistors, V– should be decoupled at VCSNK (Pin 12). to ground with a low ESR capacitor.
VCC (Pin 7):
Positive Supply Voltage. All circuitry except
OUT (Pin 3):
Amplifier Output. The OUT pin provides the the output transistors draw power from VCC. Total supply force function as part of a Kelvin sensed load connection. voltage from VCC to VEE must be between 3.5V and 36V. OUT is normally connected directly to an external load cur- VCC must always be greater than or equal to V+. VCC should rent sense resistor and the SENSE+ pin. Amplifier feedback always be decoupled to ground with a low ESR capacitor. is directly connected to the load and the other end of the
–IN (Pin 8):
Inverting Input of Amplifier. –IN may be any current sense resistor. The load connection is also wired voltage from V directly to the SENSE– pin to monitor the load current. EE – 0.3V to VEE + 36V. –IN and +IN remain high impedance at all times to prevent current flow into The OUT pin is current limited to ±800mA typical. This the inputs when current limit mode is active. Care must current limit protects the output transistor in the event that be taken to ensure that –IN or +IN can never go to a volt- connections to the external sense resistor are opened or age below VEE – 0.3V even during transient conditions or shorted which disables the precision current limit function. damage to the circuit may result. A Schottky diode from
SENSE+ (Pin 4):
Positive Current Sense Pin. This lead is VEE to –IN can provide clamping if other elements in the normally connected to the driven end of the external sense circuit can allow –IN to go below VEE. resistor. Sourcing current limit operation is activated when
+IN (Pin 9):
Noninverting Input of Amplifier. +IN may be any the voltage VSENSE (VSENSE+ – VSENSE–) equals 1/10 of voltage from VEE – 0.3V to VEE + 36V. –IN and +IN remain the programming control voltage at VCSRC (Pin 13). Sink- high impedance at all times to prevent current flow into ing current limit operation is activated when the voltage the inputs when current limit mode is active. Care must VSENSE equals –1/10 of the programming control voltage be taken to ensure that –IN or +IN can never go to a volt- at VCSNK (Pin 12). age below VEE – 0.3V even during transient conditions or damage to the circuit may result. A Schottky diode from VEE to +IN can provide clamping if other elements in the circuit can allow +IN to go below VEE. 1970afc 8 For more information www.linear.com/LT1970A Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram And Test Circuit Applications Information Package Description Applications Information Related Parts
