ISL28005_11 Datasheet, PDF (12/14 Pages) Intersil Corporation – Micropower, Rail-to-Rail Input Current Sense Amplifier

ISL28005
I = 2.86µA
(1mΩ
R_S
TO
0.1Ω)
C_M
R_S+
C_D
R_S-
R_P
+ 0.1VDC
TO
-
28VDC
LOAD
gm_HI
1.35V
gm_LO
V_CC
2.7VDC
TO
28VDC
+
OUT
-
GND
FIGURE 22. TYPICAL APPLICATION CIRCUIT
Overall Accuracy (V_OA %)
V_OA is defined as the total output accuracy Referred-to-Output
(RTO). The output accuracy contains all offset and gain errors, at
a single output voltage. Equation 2 is used to calculate the %
total output accuracy.
V_OA
=
100
×
⎛
⎜
⎝
V_{----O----U---T---}a_----c_--V-t_--O-u_---Ua_---T-l_---e–---_x--V_{-p--O-e---U-c--T-t---ee---}xd_---p_---e_----c_---t_---e_---d_{--⎠⎟⎞}
(EQ. 2)
where
V_OUT Actual = V_SENSE x GAIN
Example: Gain = 100, For 100mV V_SENSE input we measure
10.1V. The overall accuracy (V_OA) is 1% as shown in Equation 3.
V_OA
=
100
×
⎛
⎝
-¹---⁰----^.-¹-₁---₀-–----¹----⁰--_⎠⎞
=
1percent
(EQ. 3)
Power Dissipation
It is possible to exceed the +150°C maximum junction
temperatures under certain load and power supply conditions. It
is therefore important to calculate the maximum junction
temperature (T_JMAX) for all applications to determine if power
supply voltages, load conditions, or package type need to be
modified to remain in the safe operating area. These parameters
are related using Equation 4:
T_JMAX = T_MAX + θ_JAxPD_MAXTOTAL
(EQ. 4)
where:
• P_DMAXTOTAL is the sum of the maximum power dissipation of
each amplifier in the package (PD_MAX)
• PD_MAX for each amplifier can be calculated using Equation 5:
PD_MAX
=
V_S × I_qMAX + (V_S
-
V_O
U
TM
A
X
)
×
V_{----O----U---T---M-----A---X--}
R_L
(EQ. 5)
where:
• T_MAX = Maximum ambient temperature
• θ_JA = Thermal resistance of the package
• PD_MAX = Maximum power dissipation of 1 amplifier
• V_CC = Total supply voltage
• I_qMAX = Maximum quiescent supply current of 1 amplifier
• V_OUTMAX = Maximum output voltage swing of the application
• R_L = Load resistance
12
FN6973.4
July 1, 2011