HC5526_03 Datasheet, PDF (9/20 Pages) Intersil Corporation – ITU CO/PABX SLIC with Low Power Standby

HC5526
Electrical Specifications T_A = 0^oC to 70^oC, V_CC = 5V ±5%, V_EE = -5V ±5%, V_BAT = -28V, AGND = BGND = 0V, R_DC1 = R_DC2 = 41.2kΩ,
R_D = 39kΩ, R_SG = ∞, R_F1 = R_F2 = 0Ω, C_HP = 10nF, C_DC = 1.5µF, Z_L = 600Ω. (Continued)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
SUPPLY CURRENTS (V_BAT = -28V)
I_CC, On-Hook
Open Circuit State (C1, 2 = 0, 0)
Standby State (C1, 2 = 1, 1)
-
-
1.5
mA
-
-
1.7
mA
Active State (C1, 2 = 0,1)
-
-
5.5
mA
I_EE, On-Hook
Open Circuit State (C1, 2 = 0, 0)
Standby State (C1, 2 = 1, 1)
-
-
0.8
mA
-
-
0.8
mA
Active State (C1, 2 = 0, 1)
-
-
2.2
mA
I_BAT, On-Hook
Open Circuit State (C1, 2 = 0, 0)
Standby State (C1, 2 = 1, 1)
-
-
0.4
mA
-
-
0.6
mA
Active State (C1, 2 = 0, 1)
-
-
3.9
mA
PSRR
V_CC to 2 or 4-Wire Port
V_EE to 2 or 4-Wire Port
V_BAT to 2 or 4-Wire Port
(Note 30, Figure 12)
(Note 30, Figure 12)
(Note 30, Figure 12)
-
40
-
dB
-
40
-
dB
-
40
-
dB
-48V SUPPLY
5V SUPPLY
-5V SUPPLY
R_L
600Ω
100mV_RMS, 50Hz TO 4kHz
TIP
V_TX
27
19
R_T
600kΩ
PSRR = 20 log (V_{T X}/V_IN)
V_TX
RING RSN
28
16
R_RX
300kΩ
FIGURE 12. POWER SUPPLY REJECTION RATIO
Circuit Operation and Design Information
The HC5526 is a current feed voltage sense Subscriber Line
Interface Circuit (SLIC). This means that for short loop
applications the SLIC provides a programmed constant
current to the tip and ring terminals while sensing the tip to
ring voltage.
The following discussion separates the SLIC’s operation into
its DC and AC paths, then follows up with additional circuit
and design information.
Constant Loop Current (DC) Path
SLIC in the Active Mode
The DC path establishes a constant loop current that flows
out of tip and into the ring terminal. The loop current is
programmed by resistors R_DC1, R_DC2 and the voltage on
the R_DC pin (Figure 13). The R_DC voltage is determined by
the voltage across R₁ in the saturation guard circuit. Under
constant current feed conditions, the voltage drop across R₁
sets the R_DC voltage to -2.5V. This occurs when current
flows through R₁ into the current source I₂. The R_DC voltage
establishes a current (I_RSN) that is equal to V_RDC/(R_DC1
+R_DC2). This current is then multiplied by 1000, in the loop
current circuit, to become the tip and ring loop currents.
For the purpose of the following discussion, the saturation
guard voltage is defined as the maximum tip to ring voltage
at which the SLIC can provide a constant current for a given
battery and overhead voltage.
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