Datasheet

LF155, LF156, LF355, LF356, LF357
www.ti.com SNOSBH0C –MAY 2000–REVISED MARCH 2013
Figure 44. Fast Logarithmic Converter
• Dynamic range: 100μA ≤ I
i
≤ 1mA (5 decades), |V
O
| = 1V/decade
• Transient response: 3μs for ΔI
i
= 1 decade
• C1, C2, R2, R3: added dynamic compensation
• V
OS
adjust the LF156 to minimize quiescent error
• R
T
: Tel Labs type Q81 + 0.3%/°C
Figure 45. Precision Current Monitor
• V
O
= 5 R1/R2 (V/mA of I
S
)
• R1, R2, R3: 0.1% resistors
• Use LF155 for
– Common-mode range to supply range
– Low I
B
– Low V
OS
– Low Supply Current
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