Datasheet LT1208, LT1209 (Analog Devices) - 8
| Hersteller | Analog Devices |
| Beschreibung | Dual and Quad 45MHz, 400V/µs Op Amps |
| Seiten / Seite | 12 / 8 — APPLICATI. S I FOR ATIO. Large-Signal Transient Response. Power … |
| Dateiformat / Größe | PDF / 277 Kb |
| Dokumentensprache | Englisch |
APPLICATI. S I FOR ATIO. Large-Signal Transient Response. Power Dissipation. Low Voltage Operation
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LT1208/LT1209
O U U W U APPLICATI S I FOR ATIO Large-Signal Transient Response Power Dissipation
The LT1208/LT1209 combine high speed and large output current drive in small packages. Because of the wide supply voltage range, it is possible to exceed the maxi- mum junction temperature under certain conditions. Maximum junction temperature (TJ) is calculated from the ambient temperature (TA) and power dissipation (PD) as follows: LT1208CN8: TJ = TA + (PD × 100°C/W) LT1208CS8: TJ = TA + (PD × 150°C/W) LT1209CN: TJ = TA + (PD × 70°C/W) AV = 1 1208/09 AI04 LT1209CS: TJ = TA + (PD × 100°C/W)
Large-Signal Transient Response
Maximum power dissipation occurs at the maximum supply current and when the output voltage is at 1/2 of either supply voltage (or the maximum swing if less than 1/2 supply voltage). For each amplifier PDMAX is as follows: (0.5V+)2 PDMAX = (V+ – V–)(ISMAX) + RL Example: LT1208 in S8 at 70°C, VS = ±10V, RL = 500Ω (5V)2 PDMAX = (20V)(10.5mA) + = 260mW 500Ω AV = –1 1208/09 AI06 TJ = 70°C + (2 × 260mW)(150°C/W) = 148°C
Low Voltage Operation DAC Current-to-Voltage Converter
The LT1208/LT1209 are functional at room temperature The wide bandwidth, high slew rate and fast settling time with only 3V of total supply voltage. Under this condition, of the LT1208/LT1209 make them well-suited for current- however, the undistorted output swing is only 0.8VP-P . A to-voltage conversion after current output D/A converters. more realistic condition is operation at ±2.5V supplies (or A typical application with a DAC-08 type converter (full- 5V and ground). Under these conditions, at room tem- scale output of 2mA) uses a 5k feedback resistor. A 7pF perature, the typical input common-mode range is 1.9V to compensation capacitor across the feedback resistor is –1.3V (for a VOS change of 1mV), and a 5MHz, 2VP-P sine used to null the pole at the inverting input caused by the wave can be faithfully reproduced. With 5V total supply DAC output capacitance. The combination of the LT1208/ voltage the gain-bandwidth is reduced to 26MHz and the LT1209 and DAC settles to less than 40mV (1LSB) in slew rate is reduced to 135V/µs. 140ns for a 10V step. 8
O U U W U APPLICATI S I FOR ATIO Large-Signal Transient Response Power Dissipation
The LT1208/LT1209 combine high speed and large output current drive in small packages. Because of the wide supply voltage range, it is possible to exceed the maxi- mum junction temperature under certain conditions. Maximum junction temperature (TJ) is calculated from the ambient temperature (TA) and power dissipation (PD) as follows: LT1208CN8: TJ = TA + (PD × 100°C/W) LT1208CS8: TJ = TA + (PD × 150°C/W) LT1209CN: TJ = TA + (PD × 70°C/W) AV = 1 1208/09 AI04 LT1209CS: TJ = TA + (PD × 100°C/W)
Large-Signal Transient Response
Maximum power dissipation occurs at the maximum supply current and when the output voltage is at 1/2 of either supply voltage (or the maximum swing if less than 1/2 supply voltage). For each amplifier PDMAX is as follows: (0.5V+)2 PDMAX = (V+ – V–)(ISMAX) + RL Example: LT1208 in S8 at 70°C, VS = ±10V, RL = 500Ω (5V)2 PDMAX = (20V)(10.5mA) + = 260mW 500Ω AV = –1 1208/09 AI06 TJ = 70°C + (2 × 260mW)(150°C/W) = 148°C
Low Voltage Operation DAC Current-to-Voltage Converter
The LT1208/LT1209 are functional at room temperature The wide bandwidth, high slew rate and fast settling time with only 3V of total supply voltage. Under this condition, of the LT1208/LT1209 make them well-suited for current- however, the undistorted output swing is only 0.8VP-P . A to-voltage conversion after current output D/A converters. more realistic condition is operation at ±2.5V supplies (or A typical application with a DAC-08 type converter (full- 5V and ground). Under these conditions, at room tem- scale output of 2mA) uses a 5k feedback resistor. A 7pF perature, the typical input common-mode range is 1.9V to compensation capacitor across the feedback resistor is –1.3V (for a VOS change of 1mV), and a 5MHz, 2VP-P sine used to null the pole at the inverting input caused by the wave can be faithfully reproduced. With 5V total supply DAC output capacitance. The combination of the LT1208/ voltage the gain-bandwidth is reduced to 26MHz and the LT1209 and DAC settles to less than 40mV (1LSB) in slew rate is reduced to 135V/µs. 140ns for a 10V step. 8