Datasheet LTC6087, LTC6088 (Analog Devices) - 10

LTC6087/LTC6088
APPLICATIONS INFORMATION Rail-to-Rail Output
10k 10k 5V The output stage of the LTC6087/LTC6088 swings within 5V 30mV of the supply rails when driving high impedance + loads, in other words when no DC load current is present. LTC6087 A (DD PACKAGE) See the Typical Performance Characteristics for curves of 10k INA – SHDN output swing versus load current. The class AB design of A 10k the output stage enables the op amp to supply load cur- rents which are much greater than the quiescent supply 10k current. For example, the room temperature short circuit 10pF OUT 5V + current is typically 45mA. 10k B 10k INB –
Capacitive Load
10pF SEL = 5V, OUT = –INA SEL = 0V, OUT = –1NB LTC6087/LTC6088 can drive capacitive load up to 100pF in 10k unity gain. The capacitive load driving capability increases 5V SHDN as the amplifier is used in higher gain configurations. A B SEL small series resistance between the output and the load FAIRCHILD NC7SZ04 OR further increases the amount of capacitance the amplifier EQUIVALENT 60878 F03 can drive.
Figure 3. Inverting Amplifier with Muxed Output SHDN Pins Noise
Pins 5 and 6 are used for power shutdown when the In the frequency region above 1kHz, the LTC6087/LTC6088 LTC6087 is in the DD package. If they are floating, internal shows good noise voltage performance. In this region, current sources pull Pins 5 and 6 to V+ and the amplifiers noise can be dominated by the total source resistance of operate normally. In shutdown the amplifier output is the particular application. Specifically, these amplifiers high impedance and each amplifier draws less than 5µA exhibit the noise of a 10k resistor, meaning it is desirable current. This feature allows the part to be used in muxed to keep the source and feedback resistance at or below output applications as shown in Figure 3. this value, i.e., RS + RG||RFB ≤ 10k. Above this total source impedance, the noise voltage is dominated by the resistor.
ESD
At low frequency, noise current can be estimated from the The LTC6087/LTC6088 has reverse-biased ESD protection expression in = √2qIB, where q = 1.6 • 10–19 coulombs. diodes on all inputs and outputs as shown in the Simplified Equating √4kTR∆f and R√2qIB∆f shows that for source Schematic. If these pins are forced beyond either supply, resistor below 50GΩ the amplifier noise is dominated by unlimited current will flow through these diodes. If the the source resistance. Noise current rises with frequency. current is transient and limited to one hundred milliamps See the curve Noise Current vs Frequency in the Typical or less, no damage to the device will occur. Performance Characteristics section. The amplifier input bias current is the leakage current of these ESD diodes. This leakage is a function of the tem- perature and common mode voltage of the amplifier, as shown in the Typical Performance Characteristics. 60878fd 10 For more information www.linear.com/LTC6087 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Applications Information Simplified Schematic Package Description Revision History Typical Applications Related Parts