DATASHEET

®
RE
ITU CO/PABX SLIC with Low Power
Standby
0 to 70
• Programmable Current Feed . . . . . . . . . . 20mA to 60mA
• Programmable Loop Current Detector Threshold and
Battery Feed Characteristics
• Ground Key and Ring Trip Detection
• Compatible with Ericsson’s PBL3764
• Thermal Shutdown
• On-Hook Transmission
• Wide Battery Voltage Range . . . . . . . . . . . . . -24V to -58V
• Low Standby Power
• Meets CCITT Transmission Requirements
• Ambient Temperature Range. . . . . . . . . . . -40oC to 85oC
Part Number Information
PACKAGE
28 Ld PLCC
PKG.
DWG. #
N28.45
Applications
• On-Premises (ONS)
• Key Systems
• PBX
• Related Literature
- AN9537, Operation of the HC5513/26 Evaluation Board
Pinout
1
VCC
N/C
BGND
RINGSENSE
RINGX
TIPX
TIPSENSE
HC5526 (PLCC)
TOP VIEW
4
3
2
1
28
27
26
RSG
7
23 DT
E1
8
22 RD
E0
9
21 HPT
N/C 10
20 HPR
DET 11
19 VTX
12
13
14
15
16
17
18
VEE
24 N/C
N/C
6
RSN
VBAT
AGND
25 DR
RDC
5
C1
RINGRLY
C2
HC5526CM
FN4151.8
• DI Monolithic High Voltage Process
The HC5526 is fabricated in a High Voltage Dielectrically
Isolated (DI) Bipolar Process that eliminates leakage
currents and device latch-up problems normally associated
with Junction Isolated (JI) ICs. The elimination of the
leakage currents results in improved circuit performance for
wide temperature extremes. The latch free benefit of the DI
process guarantees operation under adverse transient
conditions. This process feature makes the HC5526 ideally
suited for use in harsh outdoor environments.
TEMP.
RANGE (oC)
August 2003
Features
The HC5526 is a subscriber line interface circuit that is
compliant with CCITT standards. Enhancements include
immunity to circuit latch-up during hot plug and absence of
false signaling in the presence of longitudinal currents.
PART NUMBER
HC5526
CT
O D U EM EN T
R
P
TE
AC
OL E
E PL
O B S N D ED R
E
515
OMMSheet
HC5
CData
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2003. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
HC5526
Pin Descriptions
PLCC
1
SYMBOL
DESCRIPTION
RINGSENSE Internally connected to output of RING power amplifier.
2
BGND
Battery Ground - To be connected to zero potential. All loop current and longitudinal current flow from this ground.
Internally separate from AGND but it is recommended that it is connected to the same potential as AGND.
4
VCC
5
RINGRLY
6
VBAT
Battery supply voltage, -24V to -56V.
7
RSG
Saturation guard programming resistor pin.
8
E1
TTL compatible logic input. The logic state of E1 in conjunction with the logic state of C1 determines which detector is
gated to the DET output.
9
E0
TTL compatible logic input. Enables the DET output when set to logic level zero and disables DET output when set to
a logic level one.
11
DET
Detector output. TTL compatible logic output. A zero logic level indicates that the selected detector was triggered (see
Truth Table for selection of Ground Key detector, Loop Current detector or the Ring Trip detector). The DET output is
an open collector with an internal pull-up of approximately 15kΩ to VCC.
12
C2
TTL compatible logic input. The logic states of C1 and C2 determine the operating states (Open Circuit, Active, Ringing
or Standby) of the SLIC.
13
C1
TTL compatible logic input. The logic states of C1 and C2 determine the operating states (Open Circuit, Active, Ringing
or Standby) of the SLIC.
14
RDC
DC feed current programming resistor pin. Constant current feed is programmed by resistors RDC1 and RDC2
connected in series from this pin to the receive summing node (RSN). The resistor junction point is decoupled to AGND
to isolate the AC signal components.
15
AGND
16
RSN
Receive Summing Node. The AC and DC current flowing into this pin establishes the metallic loop current that flows
between tip and ring. The magnitude of the metallic loop current is 1000 times greater than the current into the RSN
pin. The constant current programming resistors and the networks for program receive gain and 2-wire impedance all
connect to this pin.
18
VEE
-5V power supply.
19
VTX
Transmit audio output. This output is equivalent to the TIP to RING metallic voltage. The network for programming the
2-wire input impedance connects between this pin and RSN.
20
HPR
RING side of AC/DC separation capacitor CHP . CHP is required to properly separate the ring AC current from the DC
loop current. The other end of CHP is connected to HPT.
21
HPT
TIP side of AC/DC separation capacitor CHP . CHP is required to properly separate the tip AC current from the DC loop
current. The other end of CHP is connected to HPR.
22
RD
Loop current programming resistor. Resistor RD sets the trigger level for the loop current detect circuit. A filter capacitor
CD is also connected between this pin and VEE.
23
DT
Input to ring trip comparator. Ring trip detection is accomplished by connecting an external network to a comparator in
the SLIC with inputs DT and DR.
25
DR
Input to ring trip comparator. Ring trip detection is accomplished by connecting an external network to a comparator in
the SLIC with inputs DT and DR.
26
TIPSENSE
27
TIPX
28
RINGX
3, 10, 17,
24
N/C
5V power supply.
Ring relay driver output.
Analog ground.
Internally connected to output of tip power amplifier.
Output of tip power amplifier.
Output of ring power amplifier.
No internal connection.
2
HC5526
Block Diagram
RINGRLY
DT
DR
RING RELAY
DRIVER
4-WIRE
INTERFACE
VF SIGNAL
PATH
RING TRIP
DETECTOR
VTX
RSN
TIP
RING
HPT
2-WIRE
INTERFACE
LOOP CURRENT
DETECTOR
E0
E1
HPR
GROUND KEY
DETECTOR
DIGITAL
MULTIPLEXER
C1
C2
VBAT
VCC
VEE
DET
BIAS
RD
AGND
RDC
BGND
RSG
3
HC5526
Absolute Maximum Ratings
Thermal Information
Operating Temperature Range . . . . . . . . . . . . . . . . -40oC to 110oC
Power Supply (-40oC ≤ TA ≤ 85oC)
Supply Voltage VCC to GND . . . . . . . . . . . . . . . . . . . . 0.5V to 7V
Supply Voltage VEE to GND . . . . . . . . . . . . . . . . . . . . -7V to 0.5V
Supply Voltage VBAT to GND . . . . . . . . . . . . . . . . . . -70V to 0.5V
Ground
Voltage between AGND and BGND. . . . . . . . . . . . . -0.3V to 0.3V
Relay Driver
Ring Relay Supply Voltage . . . . . . . . . . . . . . . . . . . . . 0V to 20V
Ring Relay Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA
Ring Trip Comparator
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VBAT to 0V
Input Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -5mA to 5mA
Digital Inputs, Outputs (C1, C2, E0, E1, DET)
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0V to VCC
Output Voltage (DET Not Active) . . . . . . . . . . . . . . . . . 0V to VCC
Output Current (DET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5mA
Tipx and Ringx Terminals (-40oC ≤ TA ≤ 85oC)
Tipx or Ringx Voltage, Continuous (Referenced to GND) VBAT to 2V
Tipx or Ringx, Pulse < 10ms, TREP > 10s . . . . . VBAT -20V to 5V
Tipx or Ringx, Pulse < 10µs, TREP > 10s . . . . VBAT -40V to 10V
Tipx or Ringx, Pulse < 250ns, TREP > 10s . . . VBAT -70V to 15V
Tipx or Ringx Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70mA
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500V
Thermal Resistance (Typical, Note 1)
θJA (oC/W)
28 Lead PLCC Package. . . . . . . . . . . . . . . . . . . . . .
53
Continuous Dissipation at 70oC
28 Lead PLCC Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5W
Package Power Dissipation at 70oC, t < 100ms, tREP > 1s
28 Lead PLCC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4W
Derate above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70oC
PLCC Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.8mW/oC
Maximum Junction Temperature Range . . . . . . . . . -40oC to 150oC
Maximum Storage Temperature Range . . . . . . . . . -65oC to 150oC
Maximum Lead Temperature (Soldering 10s). . . . . . . . . . . . . 300oC
(PLCC - Lead Tips Only)
Die Characteristics
Gate Count . . . . . . . . . . . . . . . . . . . . . . 543 Transistors, 51 Diodes
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
1. θJA is measured with the component mounted on an evaluation PC board in free air.
Typical Operating Conditions
These represent the conditions under which the part was developed and are suggested as guidelines.
PARAMETER
CONDITIONS
Case Temperature
MIN
TYP
MAX
UNITS
-40
-
100
oC
VCC with Respect to AGND
0oC to 70oC
4.75
-
5.25
V
VEE with Respect to AGND
0oC to 70oC
-5.25
-
-4.75
V
VBAT with Respect to BGND
0oC to 70oC
-58
-
-24
V
TA = 0oC to 70oC, VCC = 5V ±5%, VEE = -5V ±5%, VBAT = -28V, AGND = BGND = 0V, RDC1 = RDC2 =
41.2kΩ , RD = 39kΩ , RSG = ∞ , RF1 = RF2 = 0Ω , CHP = 10nF, CDC = 1.5µF, ZL = 600Ω .
Electrical Specifications
PARAMETER
CONDITIONS
Overload Level
1% THD, ZL = 600Ω, (Note 2, Figure 1)
Longitudinal Impedance (Tip/Ring)
0 < f < 100Hz (Note 3, Figure 2)
MIN
TYP
MAX
UNITS
3.1
-
-
VPEAK
-
20
35
Ω/Wire
AT
TIP
27
1VRMS
TIP
27
RL
600Ω
0 < f < 100Hz
EL
C
VTX
19
RT
600kΩ
VTRO
IDCMET
23mA
RRX
RING
28
RSN
16
RT
600kΩ
2.16µF
300Ω
ERX
300kΩ
FIGURE 1. OVERLOAD LEVEL (TWO-WIRE PORT)
4
VT
300Ω
VTX
19
VR
AR
RRX
RING
28
LZT = VT/AT
RSN
16
300kΩ
LZR = VR/AR
FIGURE 2. LONGITUDINAL IMPEDANCE
HC5526
TA = 0oC to 70oC, VCC = 5V ±5%, VEE = -5V ±5%, VBAT = -28V, AGND = BGND = 0V, RDC1 = RDC2 =
41.2kΩ , RD = 39kΩ , RSG = ∞ , RF1 = RF2 = 0Ω , CHP = 10nF, CDC = 1.5µF, ZL = 600Ω . (Continued)
Electrical Specifications
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
LONGITUDINAL CURRENT LIMIT (TIP/RING)
Off-Hook (Active)
No False Detections (Loop Current),
LB > 45dB (Note 4, Figure 3A)
-
-
20
mAPEAK/
Wire
On-Hook (Standby), RL = ∞
No False Detections (Loop Current)
(Note 5, Figure 3B)
-
-
5
mAPEAK/
Wire
368Ω
368Ω
A
TIP
27
RSN
16
A
2.16µF
39kΩ
C
EL
RDC1
41.2kΩ
RD
-5V
2.16µF
A
368Ω
RDC2
CDC
RING
RDC
14 41.2kΩ
28
DET
1.5µF
C
TIP
27
RSN
16
39kΩ
EL
RDC1
41.2kΩ
RD
-5V
2.16µF
C
A
368Ω
FIGURE 3A. OFF-HOOK
RING
28
DET
RDC2
RDC
14 41.2kΩ
CDC
1.5µF
FIGURE 3B. ON-HOOK
FIGURE 3. LONGITUDINAL CURRENT LIMIT
OFF-HOOK LONGITUDINAL BALANCE
Longitudinal to Metallic
IEEE 455 - 1985, RLR, RLT = 368Ω ,
0.2kHz < f < 4.0kHz (Note 6, Figure 4)
53
60
-
dB
Longitudinal to Metallic
RLR, RLT = 300Ω, 0.2kHz < f < 4.0kHz
(Note 6, Figure 4)
53
60
-
dB
Metallic to Longitudinal
FCC Part 68, Para 68.310
0.2kHz < f < 1.0kHz
50
55
-
dB
1.0kHz < f < 4.0kHz (Note 7)
50
55
-
dB
Longitudinal to 4-Wire
0.2kHz < f < 4.0kHz (Note 8, Figure 4)
53
60
-
dB
Metallic to Longitudinal
RLR , RLT = 300Ω, 0.2kHz < f < 4.0kHz
(Note 9, Figure 5)
50
55
-
dB
4-Wire to Longitudinal
0.2kHz < f < 4.0kHz (Note 10, Figure 5)
50
55
-
dB
RLT
RLT
TIP
27
EL
VTX
19
C
2.16µF
RT
600kΩ
VTR
2.16µF
RRX
RLR
RING
28
RSN
16
5
RT
600kΩ
ETR
C
VL
RRX
RLR
RING
28
300Ω
300kΩ
FIGURE 4. LONGITUDINAL TO METALLIC AND
LONGITUDINAL TO 4-WIRE BALANCE
2-Wire Return Loss
CHP = 20nF
VTX
VTX
19
TIP
27
300Ω
RSN
16
ERX
300kΩ
FIGURE 5. METALLIC TO LONGITUDINAL AND 4-WIRE TO
LONGITUDINAL BALANCE
0.2kHz to 0.5kHz (Note 11, Figure 6)
25
-
-
dB
0.5kHz to 1.0kHz (Note 11, Figure 6)
27
-
-
dB
1.0kHz to 3.4kHz (Note 11, Figure 6)
23
-
-
dB
HC5526
TA = 0oC to 70oC, VCC = 5V ±5%, VEE = -5V ±5%, VBAT = -28V, AGND = BGND = 0V, RDC1 = RDC2 =
41.2kΩ , RD = 39kΩ , RSG = ∞ , RF1 = RF2 = 0Ω , CHP = 10nF, CDC = 1.5µF, ZL = 600Ω . (Continued)
Electrical Specifications
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
TIP IDLE VOLTAGE
Active, IL = 0
-
-4
-
V
Standby, IL = 0
-
<0
-
V
Active, IL = 0
-
-24
-
V
Standby, IL = 0
-
>-28
-
V
RING IDLE VOLTAGE
4-WIRE TRANSMIT PORT (VTX)
Overload Level
ZL > 20kΩ , 1% THD (Note 12, Figure 7)
3.1
-
-
VPEAK
Output Offset Voltage
EG = 0, ZL = ∞ (Note 13, Figure 7)
-60
-
60
mV
Output Impedance (Guaranteed by Design)
0.2kHz < f < 03.4kHz
2- to 4-Wire (Metallic to VTX) Voltage Gain
0.3kHz < f < 03.4kHz (Note 14, Figure 7)
TIP
27
VTX
19
RL
600Ω
VM
RT
600kΩ
VS
R
5
20
W
1.0
1.02
V/ V
2.16µF
ZD
R
0.98
EG
ZIN
RLR
TIP
27
C
VTX
19
VTR
RT
600kΩ
IDCMET
23mA
RSN
16
RING
28
300kΩ
FIGURE 6. TWO-WIRE RETURN LOSS
ZL
RRX
RRX
RING
28
VTXO
VTX
RSN
16
300kΩ
FIGURE 7. OVERLOAD LEVEL (4-WIRE TRANSMIT PORT),
OUTPUT OFFSET VOLTAGE, 2-WIRE TO 4-WIRE
VOLTAGE GAIN AND HARMONIC DISTORTION
4-WIRE RECEIVE PORT (RSN)
DC Voltage
IRSN = 0mA
-
0
-
V
RX Sum Node Impedance (Guaranteed by
Design)
0.3kHz < f < 3.4kHz
-
-
20
W
Current Gain-RSN to Metallic
0.3kHz < f < 3.4kHz (Note 15, Figure 8)
980
1000
1020
Ratio
2-Wire to 4-Wire
0dBm at 1.0kHz, ERX = 0V,
0.3kHz < f < 3.4kHz (Note 16, Figure 9)
-0.2
-
0.2
dB
4-Wire to 2-Wire
0dBm at 1.0kHz, EG = 0V,
0.3kHz < f < 3.4kHz (Note 17, Figure 9)
-0.2
-
0.2
dB
4-Wire to 4-Wire
0dBm at 1.0kHz, EG = 0V,
0.3kHz < f < 3.4kHz (Note 18, Figure 9)
-0.2
-
0.2
dB
2-Wire to 4-Wire
0dBm, 1kHz (Note 19, Figure 9)
-0.2
-
0.2
dB
4-Wire to 2-Wire
0dBm, 1kHz (Note 20, Figure 9)
-0.2
-
0.2
dB
2-Wire to 4-Wire
-40dBm to +3dBm (Note 21, Figure 9)
-0.1
-
0.1
dB
2-Wire to 4-Wire
-55dBm to -40dBm (Note 21, Figure 9)
-
±0.03
-
dB
4-Wire to 2-Wire
-40dBm to +3dBm (Note 22, Figure 9)
-0.1
-
0.1
dB
FREQUENCY RESPONSE (OFF-HOOK)
INSERTION LOSS
GAIN TRACKING (Ref = -10dBm, at 1.0kHz)
6
HC5526
TA = 0oC to 70oC, VCC = 5V ±5%, VEE = -5V ±5%, VBAT = -28V, AGND = BGND = 0V, RDC1 = RDC2 =
41.2kΩ , RD = 39kΩ , RSG = ∞ , RF1 = RF2 = 0Ω , CHP = 10nF, CDC = 1.5µF, ZL = 600Ω . (Continued)
Electrical Specifications
PARAMETER
CONDITIONS
4-Wire to 2-Wire
-55dBm to -40dBm (Note 22, Figure 9)
MIN
TYP
MAX
UNITS
-
±0.03
-
dB
GRX = ((VTR1- VTR2)(300k))/(-3)(600)
Where: VTR1 is the Tip to Ring Voltage with VRSN = 0V
and VTR2 is the Tip to Ring Voltage with VRSN = -3V VRSN = 0V
RRX
TIP
27
RL
600Ω
RSN
16
VRSN = -3V
300kΩ
C
IDCMET
RDC1
41.2kΩ
VTR
TIP
27
RL
600Ω
VTX
19
RT
600kΩ
VTR
EG
RRX
RING
28
RDC
14
RDC2
CDC
41.2kΩ
1.5µF
FIGURE 8. CURRENT GAIN-RSN TO METALLIC
1/ωC << RL
RING
28
RSN
16
VTX
ERX
300kΩ
FIGURE 9. FREQUENCY RESPONSE, INSERTION LOSS, GAIN
TRACKING AND HARMONIC DISTORTION
NOISE
Idle Channel Noise at 2-Wire
C-Message Weighting (Note 23, Figure 10)
-
10
-
dBrnC
Idle Channel Noise at 4-Wire
C-Message Weighting (Note 24, Figure 10)
-
10
-
dBrnC
2-Wire to 4-Wire
0dBm, 1kHz (Note 25, Figure 7)
-
-65
-54
dB
4-Wire to 2-Wire
0dBm, 0.3kHz to 3.4kHz (Note 26,
Figure 9)
-
-65
-54
dB
HARMONIC DISTORTION
BATTERY FEED CHARACTERISTICS
Constant Loop Current Tolerance
RDCX = 41.2kΩ
IL = 2500/(RDC1 + RDC2),
0oC to 70oC (Note 27)
0.9IL
IL
1.1IL
mA
Loop Current Tolerance (Standby)
IL = (VBAT-3)/(RL +1800),
0oC to 70oC (Note 28)
0.8IL
IL
1.2IL
mA
Open Circuit Voltage (VTIP - VRING)
0oC to 70oC, (Active)
14
-
20
V
LOOP CURRENT DETECTOR
On-Hook to Off-Hook
RD = 39kΩ, 0oC to 70oC
372/RD
465/RD
558/RD
mA
Off-Hook to On-Hook
RD = 39kΩ, 0oC to 70oC
RD = 39kΩ, 0oC to 70oC
325/RD
405/RD
485/RD
mA
25/RD
60/RD
95/RD
mA
Loop Current Hysteresis
GROUND KEY DETECTOR
Tip/Ring Current Difference - Trigger
(Note 29, Figure 11)
8
12
17
mA
Tip/Ring Current Difference - Reset
(Note 29, Figure 11)
3
7
12
mA
7
HC5526
TA = 0oC to 70oC, VCC = 5V ±5%, VEE = -5V ±5%, VBAT = -28V, AGND = BGND = 0V, RDC1 = RDC2 =
41.2kΩ , RD = 39kΩ , RSG = ∞ , RF1 = RF2 = 0Ω , CHP = 10nF, CDC = 1.5µF, ZL = 600Ω . (Continued)
Electrical Specifications
PARAMETER
CONDITIONS
Hysteresis
(Note 29, Figure 11)
TIP
27
RL
600Ω
RT
600kΩ
RSN
16
MAX
UNITS
5
9
mA
RSN
16
RDC1
41.2kΩ
VTX
RRX
RING
28
TYP
0
TIP
27
VTX
19
VTR
MIN
RDC2
RING
RDC
28 DET 14 41.2kΩ
300kΩ
FIGURE 10. IDLE CHANNEL NOISE
CDC
1.5µF
E1 = C1 = 0, C2 = 1
FIGURE 11. GROUND KEY DETECT
RING TRIP DETECTOR (DT, DR)
Offset Voltage
Source Res = 0
-20
-
20
mV
Input Bias Current
Input Common-Mode Range
Source Res = 0
-500
-
500
nA
Source Res = 0
VBAT +1
-
0
V
Input Resistance
Source Res = 0, Balanced
3
-
-
MΩ
VSAT at 25mA
IOL = 25mA
-
1.0
1.5
V
Off-State Leakage Current
VOH = 12V
-
-
10
µA
0
-
0.8
V
RING RELAY DRIVER
DIGITAL INPUTS (E0, E1, C1, C2)
Input Low Voltage, VIL
Input High Voltage, VIH
2
-
VCC
V
Input Low Current, IIL: C1, C2
VIL = 0.4V
-200
-
-
µA
Input Low Current, IIL: E0, E1
VIL = 0.4V
-100
-
-
µA
Input High Current
VIH = 2.4V
-
-
40
µA
Output Low Voltage, VOL
IOL = 2mA
-
-
0.45
V
Output High Voltage, VOH
IOH = 100µA
DETECTOR OUTPUT (DET)
Internal Pull-Up Resistor
2.7
-
-
V
10
15
20
kΩ
23
mW
POWER DISSIPATION
Open Circuit State
C1 = C2 = 0
-
-
On-Hook, Standby
C1 = C2 = 1
-
-
30
mW
On-Hook, Active
C1 = 0, C2 = 1, RL = High Impedance
-
-
150
mW
Off-Hook, Active
RL = 0Ω
-
-
1.1
W
RL = 300Ω
-
-
0.75
W
RL = 600Ω
-
-
0.5
W
150
-
180
oC
TEMPERATURE GUARD
Thermal Shutdown
8
HC5526
TA = 0oC to 70oC, VCC = 5V ±5%, VEE = -5V ±5%, VBAT = -28V, AGND = BGND = 0V, RDC1 = RDC2 =
41.2kΩ , RD = 39kΩ , RSG = ∞ , RF1 = RF2 = 0Ω , CHP = 10nF, CDC = 1.5µF, ZL = 600Ω . (Continued)
Electrical Specifications
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Open Circuit State (C1, 2 = 0, 0)
-
-
1.5
mA
Standby State (C1, 2 = 1, 1)
-
-
1.7
mA
Active State (C1, 2 = 0,1)
-
-
5.5
mA
Open Circuit State (C1, 2 = 0, 0)
-
-
0.8
mA
Standby State (C1, 2 = 1, 1)
-
-
0.8
mA
Active State (C1, 2 = 0, 1)
-
-
2.2
mA
Open Circuit State (C1, 2 = 0, 0)
-
-
0.4
mA
Standby State (C1, 2 = 1, 1)
-
-
0.6
mA
Active State (C1, 2 = 0, 1)
-
-
3.9
mA
VCC to 2 or 4-Wire Port
(Note 30, Figure 12)
-
40
-
dB
VEE to 2 or 4-Wire Port
(Note 30, Figure 12)
-
40
-
dB
VBAT to 2 or 4-Wire Port
(Note 30, Figure 12)
-
40
-
dB
SUPPLY CURRENTS (VBAT = -28V)
ICC, On-Hook
IEE, On-Hook
IBAT, On-Hook
PSRR
-48V SUPPLY
5V SUPPLY
-5V SUPPLY
100mVRMS, 50Hz TO 4kHz
TIP
27
VTX
19
RT
600kΩ
RL
600Ω
PSRR = 20 log (VT X/VIN)
VTX
RRX
RING
28
RSN
16
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 RDC1 , RDC2 and the voltage on
the RDC pin (Figure 13). The RDC voltage is determined by
the voltage across R1 in the saturation guard circuit. Under
constant current feed conditions, the voltage drop across R1
9
sets the RDC voltage to -2.5V. This occurs when current
flows through R1 into the current source I2 . The RDC voltage
establishes a current (IRSN) that is equal to VRDC/(RDC1
+RDC2). 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.
HC5526
VTX
IRSN
+
ITIP
-
LOOP CURRENT
CIRCUIT
TIP
RRX
RSN
RDC1
ITIP
IRING
RING
IRING
RDC2
RDC
-
SATURATION GUARD
CIRCUIT
+
CDC
-2.5V
+
A2
A1
-
+
RSG
-5V
-5V
HC5526
R1
I2
I1
RSG
-5V
FIGURE 13. DC LOOP CURRENT
2.5V
I L = -------------------------------------- × 1000
R DC1 + R DC2
(EQ. 1)
where: IL = Constant loop current.
RDC1 and RDC2 = Loop current programming resistors.
Capacitor CDC between RDC1 and RDC2 removes the VF
signals from the battery feed control loop. The value of CDC
is determined by Equation 2:
1
1
C DC = T ×  --------------- + ---------------
R

R
DC1
(EQ. 2)
DC2
where T = 30ms.
The minimum CDC value is obtained if RDC1 = RDC2 .
Figure 14 illustrates the relationship between the tip to ring
voltage and the loop resistance. For a 0Ω loop resistance both
tip and ring are at VBAT/2. As the loop resistance increases, so
does the voltage differential between tip and ring. When this
differential voltage becomes equal to the saturation guard
voltage, the operation of the SLIC’s loop feed changes from a
constant current feed to a resistive feed. The loop current in the
resistive feed region is no longer constant but varies as a
function of the loop resistance.
VBAT = -48V, IL = 23mA, RSG = 21.4kΩ
VTIP
TIP TO RING VOLTAGE (V)
0
SATURATION
GUARD VOLTAGE
-10
CONSTANT CURRENT
FEED REGION
RESISTIVE FEED
REGION
-20
-30
-40
SATURATION
GUARD VOLTAGE
-50
0
VRING
1.2K
LOOP RESISTANCE (Ω)
FIGURE 14. VTR vs RL
10
∞
Figure 15 shows the relationship between the saturation guard
voltage, the loop current and the loop resistance. Notice from
Figure 15 that for a loop resistance <1.2kΩ (RSG = 21.4kΩ) the
SLIC is operating in the constant current feed region and for
resistances >1.2kΩ the SLIC is operating in the resistive feed
region. Operation in the resistive feed region allows long loop
and off-hook transmission by keeping the tip and ring voltages
off the rails. Operation in this region is transparent to the
customer.
50
TIP TO RING VOLTAGE (V)
For loop resistances that result in a tip to ring voltage less than
the saturation guard voltage the loop current is defined as:
CONSTANT CURRENT
FEED REGION
VBAT = -48V, RSG = 21.4kΩ
40
SATURATION GUARD
VOLTAGE, VTR = 38V
30
VBAT = -24V, RSG = ∞
20
10
0
SATURATION GUARD
VOLTAGE, VTR = 13V
RESISTIVE FEED
REGION
0
10
20
30
LOOP CURRENT (mA)
RL
100kΩ
4kΩ
2kΩ
<1.2kΩ
RL
100kΩ
1.5kΩ
700Ω
<400Ω
RRSG = 21.4kΩ
RRSG = ∞ Ω
FIGURE 15. VTR vs IL and RL
The Saturation Guard circuit (Figure 13) monitors the tip to
ring voltage via the transconductance amplifier A1. A1
generates a current that is proportional to the tip to ring
voltage difference. I1 is internally set to sink all of A1’s
current until the tip to ring voltage exceeds 12.5V. When the
tip to ring voltage exceeds 12.5V (with no RSG resistor) A1
supplies more current than I1 can sink. When this happens
A2 amplifies its input current by a factor of 12 and the current
through R1 becomes the difference between I2 and the
output current from A2. As the current from A2 increases, the
voltage across R1 decreases and the output voltage on RDC
decreases. This results in a corresponding decrease in the
loop current. The RSG pin provides the ability to increase the
saturation guard reference voltage beyond 12.5V. Equation
HC5526
3 gives the relationship between the RSG resistor value and
the programmable saturation guard reference voltage:
5
5 • 10
V SGREF = 12.5 + -----------------R SG
(EQ. 3)
where:
IL = Loop current in the standby state,
RL = Loop resistance, and
VBAT = Battery voltage.
where:
(AC) Transmission Path
VSGREF = Saturation Guard reference voltage, and,
SLIC in the Active Mode
RSG = Saturation Guard programming resistor.
When the Saturation guard reference voltage is exceeded,
the tip to ring voltage is calculated using Equation 4:
5
16.66 + 5 • 10 ⁄ R SG
V TR = R L × ---------------------------------------------------------------------R L + ( R DC1 + R DC2 ) ⁄ 600
Figure 16 shows a simplified AC transmission model. Circuit
analysis yields the following design equations:
V TR = V TX + I M • 2R F
(EQ. 9)
(EQ. 4)
where:
VTR = Voltage differential between tip and ring, and,
RL = Loop resistance.
V TX V RX
IM
----------- + ----------- = ------------Z T Z RX
1000
(EQ. 10)
V TR = E G – I M • Z L
(EQ. 11)
where:
For on-hook transmission RL = ∞, Equation 4 reduces to:
5
5 • 10
V TR = 16.66 + -----------------R SG
(EQ. 5)
VTR = Is the AC metallic voltage between tip and ring,
including the voltage drop across the fuse resistors RF ,
VTX = Is the AC metallic voltage. Either at the ground
referenced 4-wire side or the SLIC tip and ring terminals,
The value of RSG should be calculated to allow maximum
loop length operation. This requires that the saturation guard
reference voltage be set as high as possible without clipping
the incoming or outgoing VF signal. A voltage margin of -4V
on tip and -4V on ring, for a total of -8V margin, is
recommended as a general guideline. The value of RSG is
calculated using Equation 6:
5
5 • 10
R SG = -------------------------------------------------------------------------------------------------------------------------------------------------( R DC1 + R DC2 )

( V BAT – V MARGIN ) ×  1 + ------------------------------------------ – 16.66V
600R L


(EQ. 6)
where:
VBAT = Battery voltage, and
VMARGIN = Recommended value of -8V to allow a maximum
overload level of 3.1VPEAK .
For on-hook transmission RL = ∞, Equation 6 reduces to:
5
5 • 10
R SG = ---------------------------------------------------------------------------V BAT – V MARGIN – 16.66V
(EQ. 7)
SLIC in the Standby Mode
Overall system power is saved by configuring the SLIC in the
standby state when not in use. In the standby state the tip
and ring amplifiers are disabled and internal resistors are
connected between tip to ground and ring to VBAT . This
connection enables a loop current to flow when the phone
goes off-hook. The loop current detector then detects this
current and the SLIC is configured in the active mode for
voice transmission. The loop current in standby state is
calculated as follows:
V BAT – 3V
I L ≈ -------------------------------R L + 1800Ω
(EQ. 8)
11
IM = Is the AC metallic current,
RF = Is a fuse resistor,
ZT = Is used to set the SLIC’s 2-wire impedance,
VRX = Is the analog ground referenced receive signal,
ZRX = Is used to set the 4-wire to 2-wire gain,
EG = Is the AC open circuit voltage, and
ZL = Is the line impedance.
(AC) 2-Wire Impedance
The AC 2-wire impedance (ZTR) is the impedance looking
into the SLIC, including the fuse resistors, and is calculated
as follows:
Let VRX = 0. Then from Equation 10:
IM
V TX = Z T • ------------1000
(EQ. 12)
ZTR is defined as:
V TR
Z TR = ----------IM
(EQ. 13)
Substituting in Equation 9 for VTR:
V TX 2R F • I M
Z TR = ----------- + ----------------------IM
IM
(EQ. 14)
Substituting in Equation 12 for VTX:
ZT
Z TR = ------------- + 2R F
1000
(EQ. 15)
HC5526
IM
TIP
A = 250
RF
ZL
VTR
+
VTX
+
ZTR
-
+
VTX
-
1
+
VTX
-
+
-
ZT
EG
-
IM
A=4
RSN
A = 250
RING
RF
ZRX
IM
1000
+
VRX
-
HC5526
FIGURE 16. SIMPLIFIED AC TRANSMISSION CIRCUIT
(AC) 4-Wire to 4-Wire Gain
Therefore:
(EQ. 16)
Z T = 1000 • ( Z TR – 2R F )
From Equations 9, 10 and 11 with EG = 0:
Equation 16 can now be used to match the SLIC’s
impedance to any known line impedance (ZTR).
Example:
Calculate ZT to make ZTR = 600Ω in series with 2.16µF.
RF = 20Ω.
1
Z T = 1000 •  600 + ----------------------------------------- – 2 • 20


–6
jω • 2.16 • 10
ZT = 560kΩ in series with 2.16nF.
(AC) 2-Wire to 4-Wire Gain
The 2-wire to 4-wire gain is equal to VTX/ VTR .
From Equations 9 and 10 with VRX = 0:
Z T ⁄ 1000
V TX
A 2 – 4 = ----------- = -----------------------------------------Z T ⁄ 1000 + 2R F
V TR
(EQ. 17)
V TX
ZT
Z L + 2R F
A 4 – 4 = ----------- = – ----------- • -------------------------------------------ZT
V RX
Z RX
------------- + 2R F + Z L
1000
The 4-wire to 2-wire gain is equal to VTR/VRX .
(EQ. 20)
Transhybrid Circuit
The purpose of the transhybrid circuit is to remove the receive
signal (VRX) from the transmit signal (VTX), thereby preventing
an echo on the transmit side. This is accomplished by using an
external op amp (usually part of the CODEC) and by the
inversion of the signal from the 4-wire receive port (RSN) to the
4-wire transmit port (VTX). Figure 17 shows the transhybrid
circuit. The input signal will be subtracted from the output signal
if I1 equals I2 . Node analysis yields the following equation:
V TX V RX
----------- + ----------- = 0
R TX Z B
(AC) 4-Wire to 2-Wire Gain
(EQ. 21)
The value of ZB is then:
From Equations 9, 10 and 11 with EG = 0:
V RX
Z B = – R TX • ----------V
For applications where the 2-wire impedance (ZTR ,
V TR
ZT
ZL
A 4 – 2 = ----------- = – ----------- • -------------------------------------------V RX
Z RX
ZT
------------- + 2R F + Z L
1000
The 4-wire to 4-wire gain is equal to VTX/VRX .
(EQ. 22)
TX
(EQ. 18)
Where VRX/VTX equals 1/ A4-4 .
Therefore:
Equation 15) is chosen to equal the line impedance (ZL), the
expression for A4-2 simplifies to:
ZT
- + 2R F + Z L
Z RX -----------1000
Z B = R TX • ----------- • -------------------------------------------Z L + 2R F
ZT
ZT 1
A 4 – 2 = – ----------- • --Z RX 2
Example:
(EQ. 19)
(EQ. 23)
Given: RTX = 20kΩ, ZRX = 280kΩ, ZT = 562kΩ (standard
value), RF = 20Ω and ZL = 600Ω .
The value of ZB = 18.7kΩ .
12
HC5526
The IRD current results in a voltage drop across RD that is
compared to an internal 1.25V reference voltage. When the
voltage drop across RD exceeds 1.25V, and the logic is
configured for loop current detection, the DET pin goes low.
RFB
I2
RTX
VTX
-
+
+
VTX
I1
-
HC5526
ZT
ZB
The hysteresis resistor RH adds an additional voltage
effectively across RD , causing the on-hook to off-hook
threshold to be slightly higher than the off-hook to on-hook
threshold.
Taking into account the hysteresis voltage, the typical value
of RD for the on-hook to off-hook condition is:
+
VRX
-
RSN
465
R D = -------------------------------------------------------------------------I ON – HOOK to OFF – HOOK
ZRX
CODEC/
FILTER
FIGURE 17. TRANSHYBRID CIRCUIT
The loop current, ground key and the ring trip detector
outputs are multiplexed to a single logic output pin called
DET. See Table 1 to determine the active detector for a
given logic input. For further discussion of the logic circuitry
see section titled “Digital Logic Inputs”.
Before proceeding with an explanation of the loop current
detector, ground key detector and later the longitudinal
impedance, it is important to understand the difference
between a “metallic” and “longitudinal” loop currents. Figure 18
illustrates 3 different types of loop current encountered.
Case 1 illustrates the metallic loop current. The definition of
a metallic loop current is when equal currents flow out of tip
and into ring. Loop current is a metallic current.
Cases 2 and 3 illustrate the longitudinal loop current. The
definition of a longitudinal loop current is a common mode
current, that flows either out of or into tip and ring
simultaneously. Longitudinal currents in the on-hook state
result in equal currents flowing through the sense resistors
R1 and R2 (Figure 18). And longitudinal currents in the offhook state result in unequal currents flowing through the
sense resistors R1 and R2 . Notice that for case 2,
longitudinal currents flowing away from the SLIC, the current
through R1 is the metallic loop current plus the longitudinal
current; whereas the current through R2 is the metallic loop
current minus the longitudinal current. Longitudinal currents
are generated when the phone line is influenced by
magnetic fields (e.g., power lines).
Loop Current Detector
Figure 18 shows a simplified schematic of the loop current
and ground key detectors. The loop current detector works by
sensing the metallic current flowing through resistors R1 and
R2 . This results in a current (IRD) out of the transconductance
amplifier (gm1) that is equal to the product of gm1 and the
metallic loop current. IRD then flows out the RD pin and
through resistor RD to VEE . The value of IRD is equal to:
I TIP – I RING
IL
I RD = ------------------------------------ = ---------600
300
(EQ. 24)
13
Taking into account the hysteresis voltage, the typical value
of RD for the off-hook to on-hook condition is:
375
R D = -------------------------------------------------------------------------I OFF – HOOK to ON – HOOK
Supervisory Functions
(EQ. 25)
(EQ. 26)
A filter capacitor (CD) in parallel with RD will improve the
accuracy of the trip point in a noisy environment. The value
of this capacitor is calculated using the following Equation:
T
C D = -------RD
(EQ. 27)
where: T = 0.5ms.
Ground Key Detector
A simplified schematic of the ground key detector is shown in
Figure 18. Ground key, is the process in which the ring
terminal is shorted to ground for the purpose of signaling an
Operator or seizing a phone line (between the Central Office
and a Private Branch Exchange). The Ground Key detector is
activated when unequal current flow through resistors R1 and
R2 . This results in a current (IGK) out of the transconductance
amplifier (gm2) that is equal to the product of gm2 and the
differential (ITIP -IRING) loop current. If IGK is less than the
internal current source (I1), then diode D1 is on and the output
of the ground key comparator is low. If IGK is greater than the
internal current source (I1), then diode D2 is on and the output
of the ground key comparator is high. With the output of the
ground key comparator high, and the logic configured for
ground key detect, the DET pin goes low. The ground key
detector has a built in hysteresis of typically 5mA between its
trigger and reset values.
Ring Trip Detector
Ring trip detection is accomplished with the internal ring trip
comparator and the external circuitry shown in Figure 19. The
process of ring trip is initiated when the logic input pins are in the
following states: E0 = 0, E1 = 1/0, C1 = 1 and C2 = 0. This logic
condition connects the ring trip comparator to the DET output,
and causes the Ringrly pin to energize the ring relay. The ring
relay connects the tip and ring of the phone to the external
circuitry in Figure 19. When the phone is on-hook the DT pin is
more positive than the DR pin and the DET output is high. For
off-hook conditions DR is more positive than DT and DET goes
low. When DET goes low, indicating that the phone has gone
off-hook, the SLIC is commanded by the logic inputs to go into
the active state. In the active state, tip and ring are once again
connected to the phone and normal operation ensues.
HC5526
gm1(IMETALLIC)
-
CURRENT
LOOP
COMPARATOR
TIP
gm1
gm2(ITIP - IRING)
IRD
RD
CD
+
-
+
+
R1
RD
RH
-
VREF
1.25V
VEE
-5V
gm2
R2
IGK
RING
RH
+
CASE 1
IMETALLIC
←
CASE 2
-
CASE 3
ILONGITUDINAL
←
-
+
GROUND
KEY
COMPARATOR
ILONGITUDINAL
→
D2
D1
I1
DIGITAL MULTIPLEXER
DET
HC5526
FIGURE 18. LOOP CURRENT AND GROUND KEY DETECTORS
Figure 19 illustrates battery backed unbalanced ring injected
ringing. For tip injected ringing just reverse the leads to the
phone. The ringing source could also be balanced.
NOTE: The DET output will toggle at 20Hz because the DT input is
not completely filtered by CRT. Software can examine the duty cycle
and determine if the DET pin is low for more that half the time, if so
the off-hook condition is indicated.
RRT
R3
CRT
R1
DT
-
+
DET
DR
R4
TIP
R2
ERG
RING TRIP
COMPARATOR
VBAT
RING
RINGRLY
HC5526
RING
RELAY
amplifiers GT and GR accomplish this by sourcing or sinking
the required current to maintain VC at VBAT/2.
When a longitudinal current is injected onto the tip and ring
inputs, the voltage at VC moves from it’s equilibrium value
VBAT/2. When VC changes by the amount ∆VC , this change
appears between the input terminals of the differential
transconductance amplifiers GT and GR . The output of GT
and GR are the differential currents ∆I1 and ∆I2 , which in
turn feed the differential inputs of current sources IT and IR
respectively. IT and IR have current gains of 250 single
ended and 500 differentially, thus leading to a change in IT
and IR that is equal to 500(∆I) and 500(∆I2).
The circuit shown in Figure 20(B) illustrates the tip side of
the longitudinal network. The advantages of a differential
input current source are: improved noise since the noise due
to current source 2IO is now correlated, power savings due
to differential current gain and minimized offset error at the
Operational Amplifier inputs via the two 5kΩ resistors.
Digital Logic Inputs
FIGURE 19. RING TRIP CIRCUIT FOR BATTERY BACKED RINGING
Longitudinal Impedance
The feedback loop described in Figure 20(A, B) realizes the
desired longitudinal impedances from tip to ground and from
ring to ground. Nominal longitudinal impedance is resistive
and in the order of 22Ω .
In the presence of longitudinal currents this circuit attenuates
the voltages that would otherwise appear at the tip and ring
terminals, to levels well within the common mode range of
the SLIC. In fact, longitudinal currents may exceed the
programmed DC loop current without disturbing the SLIC’s
VF transmission capabilities.
The function of this circuit is to maintain the tip and ring
voltages symmetrically around VBAT/2, in the presence of
longitudinal currents. The differential transconductance
14
Table 1 is the logic truth table for the TTL compatible logic
input pins. The HC5526 has two enable inputs pins (E0, E1)
and two control inputs pins (C1, C2).
The enable pin E0 is used to enable or disable the DET
output pin. The DET pin is enabled if E0 is at a logic level 0
and disabled if E0 is at a logic level 1.
The enable pin E1 gates the ground key detector to the DET
output with a logic level 0, and gates the loop or ring trip
detector to the DET output with a logic level 1.
A combination of the control pins C1 and C2 is used to select
1 of the 4 possible operating states. A description of each
operating state and the control logic follow:
Open Circuit State (C1 = 0, C2 = 0)
In this state the SLIC is effectively off. All detectors and both
the tip and ring line drive amplifiers are powered down,
presenting a high impedance to the line. Power dissipation is
at a minimum.
HC5526
ILONG
ILONG
TIP CURRENT SOURCE
WITH DIFFERENTIAL INPUTS
20Ω
IT
TIP
∆I1
∆I1
+
∆VT
TIP
-
5kΩ
5kΩ
GT
RLARGE
-
+
RLARGE
VC
-
∆I1
∆I1
VBAT/2
+
VC
VBAT/2
GR
RLARGE
ILONG
∆VR+
ILONG
2I0
∆I2
-
∆I2
RLARGE
GT
RING
IR
HC5526
RING
FIGURE 20A.
TIP DIFFERENTIAL
TRANSCONDUCTANCE
AMPLIFIER
FIGURE 20B.
FIGURE 20. LONGITUDINAL IMPEDANCE NETWORK
Active State (C1 = 0, C2 = 1)
Thermal Shutdown Protection
The tip output is capable of sourcing loop current and for
open circuit conditions is about -4V from ground. The ring
output is capable of sinking loop current and for open circuit
conditions is about VBAT +4V. VF signal transmission is
normal. The loop current and ground key detectors are both
active, E0 and E1 determine which detector is gated to the
DET output.
The HC5526’s thermal shutdown protection is invoked if a
fault condition on the tip or ring causes the temperature of
the die to exceed 160oC. If this happens, the SLIC goes into
a high impedance state and will remain there until the
temperature of the die cools down by about 20oC. The SLIC
will return back to its normal operating mode, providing the
fault condition has been removed.
Ringing State (C1 = 1, C2 = 0)
The ring relay driver and the ring trip detector are activated.
Both the tip and ring line drive amplifiers are powered down.
Both tip and ring are disconnected from the line via the
external ring relay.
Standby State (C1 = 1, C2 = 1)
Both the tip and ring line drive amplifiers are powered down.
Internal resistors are connected between tip to ground and ring
to VBAT to allow loop current detect in an off-hook condition.
The loop current and ground key detectors are both active, E0
and E1 determine which detector is gated to the DET output.
AC Transmission Circuit Stability
To ensure stability of the AC transmission feedback loop two
compensation capacitors CTC and CRC are required.
Figure 21 (Application Circuit) illustrates their use.
Recommended value is 2200pF.
AC - DC Separation Capacitor, CHP
The high pass filter capacitor connected between pins HPT
and HPR provides the separation between circuits sensing
tip to ring DC conditions and circuits processing AC signals.
A 10nf CHP will position the low end frequency response
3dB break point at 48Hz. Where:
1
f 3dB = ----------------------------------------------------( 2 • π • R HP • C HP )
(EQ. 28)
where RHP = 330kΩ .
15
Surge Voltage Protection
The HC5526 must be protected against surge voltages and
power crosses. Refer to “Maximum Ratings” TIPX and
RINGX terminals for maximum allowable transient tip and
ring voltages. The protection circuit shown in Figure 21
utilizes diodes together with a clamping device to protect tip
and ring against high voltage transients.
Positive transients on tip or ring are clamped to within a
couple of volts above ground via diodes D1 and D2. Under
normal operating conditions D1 and D2 are reverse biased
and out of the circuit.
Negative transients on tip and ring are clamped to within a
couple of volts below ground via diodes D3 and D4 with the
help of a Surgector. The Surgector is required to block
conduction through diodes D3 and D4 under normal
operating conditions and allows negative surges to be
returned to system ground.
The fuse resistors (RF) serve a dual purpose of being
nondestructive power dissipaters during surge and fuses
when the line in exposed to a power cross.
HC5526
SLIC Operating States
TABLE 1. LOGIC TRUTH TABLE
E0
E1
C1
C2
SLIC OPERATING STATE
ACTIVE DETECTOR
DET OUTPUT
0
0
0
0
Open Circuit
No Active Detector
Logic Level High
0
0
0
1
Active
Ground Key Detector
Ground Key Status
0
0
1
0
Ringing
No Active Detector
Logic Level High
0
0
1
1
Standby
Ground Key Detector
Ground Key Status
0
1
0
0
Open Circuit
No Active Detector
Logic Level High
0
1
0
1
Active
Loop Current Detector
Loop Current Status
0
1
1
0
Ringing
Ring Trip Detector
Ring Trip Status
0
1
1
1
Standby
Loop Current Detector
Loop Current Status
1
0
0
0
Open Circuit
No Active Detector
1
0
0
1
Active
Ground Key Detector
1
0
1
0
Ringing
No Active Detector
1
0
1
1
Standby
Ground Key Detector
1
1
0
0
Open Circuit
No Active Detector
1
1
0
1
Active
Loop Current Detector
1
1
1
0
Ringing
Ring Trip Detector
1
1
1
1
Standby
Loop Current Detector
Logic Level High
Power-Up Sequence
The HC5526 has no required power-up sequence. This is a
result of the Dielectrically Isolated (DI) process used in the
fabrication of the part. By using the DI process, care is no
longer required to insure that the substrate be kept at the
most negative potential as with junction isolated ICs.
Printed Circuit Board Layout
Care in the printed circuit board layout is essential for proper
operation. All connections to the RSN pin should be made as
close to the device pin as possible, to limit the interference
that might be injected into the RSN terminal. It is good
practice to surround the RSN pin with a ground plane.
The analog and digital grounds should be tied together at the
device.
Notes
2. Overload Level (Two-Wire port). The overload level is specified
at the 2-wire port (VTR0) with the signal source at the 4-wire
receive port (ERX). IDCMET = 30mA, increase the amplitude of
ERX until 1% THD is measured at VTRO . Reference Figure 1.
3. Longitudinal Impedance. The longitudinal impedance is
computed using the following equations, where TIP and RING
voltages are referenced to ground. LZT , LZR , VT , VR , AR and
AT are defined in Figure 2.
4. Longitudinal Current Limit (Off-Hook Active). Off - Hook
(Active, C1 = 1, C2 = 0) longitudinal current limit is determined
by increasing the amplitude of EL (Figure 3A) until the 2-wire
longitudinal balance drops below 45dB. DET pin remains low
(no false detection).
5. Longitudinal Current Limit (On-Hook Standby). On - Hook
(Active, C1 = 1, C2 = 1) longitudinal current limit is determined
by increasing the amplitude of EL (Figure 3B) until the 2-wire
longitudinal balance drops below 45dB. DET pin remains high
(no false detection).
6. Longitudinal to Metallic Balance. The longitudinal to metallic
balance is computed using the following equation:
BLME = 20 • log (EL / VTR), where: EL and VTR are defined in
Figure 4.
7. Metallic to Longitudinal FCC Part 68, Para 68.310. The
metallic to longitudinal balance is defined in this spec.
8. Longitudinal to Four-Wire Balance. The longitudinal to 4-wire
balance is computed using the following equation:
BLFE = 20 • log (EL / VTX),: EL and VTX are defined in Figure 4.
9. Metallic to Longitudinal Balance. The metallic to longitudinal
balance is computed using the following equation:
BMLE = 20 • log (ETR / VL), ERX = 0,
where: ETR , VL and ERX are defined in Figure 5.
10. Four-Wire to Longitudinal Balance. The 4-wire to longitudinal
balance is computed using the following equation:
(TIP) LZT = VT /AT ,
(RING) LZR = VR /AR ,
BFLE = 20 • log (ERX / VL), ETR = source is removed,
where: EL = 1VRMS (0Hz to 100Hz).
16
where: ERX , VL and ETR are defined in Figure 5.
HC5526
11. Two-Wire Return Loss. The 2-wire return loss is computed
using the following equation:
r = -20 • log (2VM / VS),
where: ZD = The desired impedance; e.g., the characteristic
impedance of the line, nominally 600Ω. (Reference Figure 6).
12. Overload Level (4-Wire port). The overload level is specified at
the 4-wire transmit port (VTXO) with the signal source (EG) at
the 2-wire port, IDCMET = 23mA, ZL = 20kΩ (Reference Figure
7). Increase the amplitude of EG until 1% THD is measured at
VTXO. Note that the gain from the 2-wire port to the 4-wire port
is equal to 1.
13. Output Offset Voltage. The output offset voltage is specified
with the following conditions: EG = 0, IDCMET = 23mA, ZL = ∞
and is measured at VTX . EG , IDCMET , VTX and ZL are defined
in Figure 7. Note: IDCMET is established with a series 600Ω
resistor between tip and ring.
14. Two-Wire to Four-Wire (Metallic to VTX) Voltage Gain. The 2wire to 4-wire (metallic to VTX) voltage gain is computed using
the following equation.
G2-4 = (VTX / VTR), EG = 0dBm0, VTX , VTR , and EG are defined
in Figure 7.
15. Current Gain RSN to Metallic. The current gain RSN to Metallic is
computed using the following equation:
K = IM [(RDC1 + RDC2)/(VRDC - VRSN)]
VRDC and VRSN are defined in Figure 8.
K, IM , RDC1, RDC2 ,
16. Two-Wire to Four-Wire Frequency Response. The 2-wire to 4wire frequency response is measured with respect to EG = 0dBm at
1.0kHz, ERX = 0V, IDCMET = 23mA. The frequency response is
computed using the following equation:
F2-4 = 20 • log (VTX / VTR), vary frequency from 300Hz to 3.4kHz
and compare to 1kHz reading.
VTX , VTR , and EG are defined in Figure 9.
17. Four-Wire to Two-Wire Frequency Response. The 4-wire to
2-wire frequency response is measured with respect to
ERX = 0dBm at 1.0kHz, EG = 0V, IDCMET = 23mA. The
frequency response is computed using the following equation:
F4-2 = 20 • log (VTR /ERX), vary frequency from 300Hz to 3.4kHz
and compare to 1kHz reading.
VTR and ERX are defined in Figure 9.
18. Four-Wire to Four-Wire Frequency Response. The 4-wire to
4-wire frequency response is measured with respect to
ERX = 0dBm at 1.0kHz, EG = 0V, IDCMET = 23mA. The
frequency response is computed using the following equation:
F4-4 = 20 • log (VTX /ERX), vary frequency from 300Hz to 3.4kHz
and compare to 1kHz reading.
VTX and ERX are defined in Figure 9.
19. Two-Wire to Four-Wire Insertion Loss. The 2-wire to 4-wire
insertion loss is measured with respect to EG = 0dBm at 1.0kHz
input signal, ERX = 0, IDCMET = 23mA and is computed using
the following equation:
L2-4 = 20 • log (VTX / VTR).
where: VTX , VTR , and EG are defined in Figure 9. (Note: The
fuse resistors, RF , impact the insertion loss. The specified
insertion loss is for RF = 0).
17
20. Four-Wire to Two-Wire Insertion Loss. The 4-wire to 2-wire
insertion loss is measured based upon ERX = 0dBm, 1.0kHz
input signal, EG = 0, IDCMET = 23mA and is computed using
the following equation:
L4-2 = 20 • log (VTR /ERX).
where: VTR and ERX are defined in Figure 9.
21. Two - Wire to Four - Wire Gain Tracking. The 2-wire to 4-wire
gain tracking is referenced to measurements taken for
EG = -10dBm, 1.0kHz signal, ERX = 0, IDCMET = 23mA and is
computed using the following equation.
G2-4 = 20 • log (VTX / VTR) vary amplitude -40dBm to +3dBm,
or -55dBm to -40dBm and compare to -10dBm reading.
VTX and VTR are defined in Figure 9.
22. Four-Wire to Two-Wire Gain Tracking. The 4-wire to 2-wire
gain tracking is referenced to measurements taken for
ERX = -10dBm, 1.0kHz signal, EG = 0, IDCMET = 23mA and is
computed using the following equation:
G4-2 = 20 • log (VTR /ERX) vary amplitude -40dBm to +3dBm,
or -55dBm to -40dBm and compare to -10dBm reading.
VTR and ERX are defined in Figure 9. The level is specified at the
4-wire receive port and referenced to a 600Ω impedance level.
23. Two-Wire Idle Channel Noise. The 2-wire idle channel noise at
VTR is specified with the 2-wire port terminated in 600Ω (RL)
and with the 4-wire receive port grounded (Reference
Figure 10).
24. Four-Wire Idle Channel Noise. The 4-wire idle channel noise at
VTX is specified with the 2-wire port terminated in 600Ω (RL).
The noise specification is with respect to a 600Ω impedance
level at VTX. The 4-wire receive port is grounded (Reference
Figure 10).
25. Harmonic Distortion (2-Wire to 4-Wire). The
harmonic
distortion is measured with the following conditions. EG = 0dBm
at 1kHz, IDCMET = 23mA. Measurement taken at VTX.
(Reference Figure 7).
26. Harmonic Distortion (4-Wire to 2-Wire). The
harmonic
distortion is measured with the following conditions. ERX =
0dBm0. Vary frequency between 300Hz and 3.4kHz, IDCMET =
23mA. Measurement taken at VTR. (Reference Figure 9).
27. Constant Loop Current. The constant loop current is calculated
using the following equation:
IL = 2500 / (RDC1 + RDC2).
28. Standby State Loop Current. The standby state loop current is
calculated using the following equation:
IL = [|VBAT| - 3] / [RL +1800], TA = 25oC.
29. Ground Key Detector. (TRIGGER) Increase the input current to
8mA and verify that DET goes low.
(RESET) Decrease the input current from 17mA to 3mA and
verify that DET goes high.
(Hysteresis) Compare difference between trigger and reset.
30. Power Supply Rejection Ratio. Inject a 100mVRMS signal
(50Hz to 4kHz) on VBAT, VCC and VEE supplies. PSRR is
computed using the following equation:
PSRR = 20 • log (VTX / VIN). VTX and VIN are defined in
Figure 12.
HC5526
Application Circuit
RRT
CRT
CHP (NOTE 32)
R1
RFB
R3
RD
21 HPT
-5V
R2
R4
VBAT
PTC
TIP
D1
D3
PTC
HPR 20
RTX
22 RD
VTX 19
23 DT
VEE 18
25 DR
RF1
U1
RF2
-5V
RT
RB
RRX
AGND 15
2 BGND
RDC 14
RDC1
CODEC/FILTER
CTC
RDC2
CRC
D4
-
+
RSN 16
27 TIPX
NOTE 31
RING
4 VCC
C1 13
28 RINGX
C2 12
CDC
D2
Surgector
K
A
VBAT
DET 11
6 VBAT
G
D5
RINGING
(VBAT + 90VRMS)
+5V
OR
12V
5 RINGRLY
EO 9
7 RSG
E1 8
RSG
RELAY
-5V
D6
U1 SLIC (Subscriber Line Interface Circuit)
HC5526
U2 Combination CODEC/Filter e.g.
CD22354A or Programmable CODEC/
Filter, e.g. SLAC
CDC 1.5µF, 20%, 10V
CHP 10nF, 20%, 100V (Note 2)
CRT 0.39µF, 20%, 100V
R1, R3 200kΩ, 5%, 1/4W
R2 910kΩ, 5%, 1/4W
R4 1.2MΩ, 5%, 1/4W
RB 18.7kΩ,1%, 1/4W
RD 39kΩ, 5%, 1/4W
RDC1, RDC2 41.2kΩ, 5%, 1/4W
RFB 20.0kΩ, 1%, 1/4W
RRX 280kΩ, 1%, 1/4W
CTC, CRC 2200pF, 20%, 100V
Relay Relay, 2C Contacts, 5V or 12V Coil
D1 - D5 MOR120 Diode
RT 562kΩ, 1%, 1/4W
RTX 20kΩ, 1%, 1/4W
RRT 150Ω, 5%, 2W
Surgector SGT27S10
RSG VBAT = -28V, RSG = ∞
VBAT = -48V, RSG = 21.4kΩ, 1/4W 5%
PTC Polyswitch TR600-150
D6 Diode, 1N4454
RF1, RF2 Line Resistor, 20Ω, 1% Match, 2 W
Carbon column resistor or thick film on
ceramic
NOTES:
31. It is recommended that the anodes of D3 and D4 be shorted to ground through a battery referenced surgector (SGT27S10).
32. To meet the specified 25dB 2-wire return loss at 200Hz, CHP needs to be 20nF, 20%, 100V.
FIGURE 21. APPLICATION CIRCUIT
18
U2
HC5526
Plastic Leaded Chip Carrier Packages (PLCC)
0.042 (1.07)
0.048 (1.22)
PIN (1) IDENTIFIER
N28.45 (JEDEC MS-018AB ISSUE A)
0.042 (1.07)
0.056 (1.42)
0.004 (0.10)
C
0.025 (0.64)
R
0.045 (1.14)
0.050 (1.27) TP
C
L
D2/E2
C
L
E1 E
D2/E2
VIEW “A”
0.020 (0.51)
MIN
A1
A
D1
D
28 LEAD PLASTIC LEADED CHIP CARRIER PACKAGE
INCHES
MILLIMETERS
SYMBOL
MIN
MAX
MIN
MAX
NOTES
A
0.165
0.180
4.20
4.57
-
A1
0.090
0.120
2.29
3.04
-
D
0.485
0.495
12.32
12.57
-
D1
0.450
0.456
11.43
11.58
3
D2
0.191
0.219
4.86
5.56
4, 5
E
0.485
0.495
12.32
12.57
-
E1
0.450
0.456
11.43
11.58
3
E2
0.191
0.219
4.86
5.56
4, 5
N
28
28
6
Rev. 2 11/97
SEATING
-C- PLANE
0.020 (0.51) MAX
3 PLCS
0.026 (0.66)
0.032 (0.81)
0.013 (0.33)
0.021 (0.53)
0.025 (0.64)
MIN
0.045 (1.14)
MIN
VIEW “A” TYP.
NOTES:
1. Controlling dimension: INCH. Converted millimeter dimensions are
not necessarily exact.
2. Dimensions and tolerancing per ANSI Y14.5M-1982.
3. Dimensions D1 and E1 do not include mold protrusions. Allowable
mold protrusion is 0.010 inch (0.25mm) per side. Dimensions D1
and E1 include mold mismatch and are measured at the extreme
material condition at the body parting line.
4. To be measured at seating plane -C- contact point.
5. Centerline to be determined where center leads exit plastic body.
6. “N” is the number of terminal positions.
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
19
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