AM7942-1JC_技术文档

Am7942

Subscriber Line Interface Circuit

DISTINCTIVE CHARACTERISTICS

Programmable constant-current feed

Receive current gain = 200

Programmable loop-detect threshold

Low standby power

Tip Open state for ground-start lines

–19 V to –58 V battery operation

Ideal for PBX and KTS applications

On-chip switching regulator for low-power

dissipation

Performs polarity reversal

Ground-key detector

Can be used with or without the on-chip

switching regulator

Pin for external ground-key noise filter

capacitor

Two-wire impedance set by single external

impedance

Test relay driver option

On-hook transmission

BLOCK DIAGRAM

TESTOUT

Test Relay Driver

Ring Relay Driver

RINGOUT

A(TIP)

C1

C2

C3

Ground-Key

Detector

Input Decoder

and Control

HPA

HPB

C4

E1

DET

Two-Wire

Interface

GKFIL

RSN

Signal

Transmission

VTX

Off-Hook

Detector

B(RING)

DA

RD

RDC

CAS

Power-Feed

Controller

Ring-Trip

Detector

DB

VREG

L

Switching

Regulator

VBAT

BGND

VCC

VEE

AGND/DGND

CHS

CHCLK

QBAT

15474A-001

Publication# 080127 Rev: F Amendment: /0

Issue Date: October 1999

ORDERING INFORMATION

Standard Products

Legerity standard products are available in several packages and operating ranges. The order number (Valid Combination) is

formed by a combination of the elements below.

Am7942

J

C

TEMPERATURE RANGE

C = Commercial (0°C to 70°C)*

PACKAGE TYPE

J = 32-pin Plastic Leaded Chip Carrier (PL 032)

PERFORMANCE GRADE

Blank = Standard specification

–1 = Performance Grading

–2 = Performance Grading

DEVICE NUMBER/DESCRIPTION

Am7942

Subscriber Line Interface Circuit

Valid Combinations

Valid Combinations lists configurations planned

to be supported in volume for this device. Consult

the local Legerity sales office to confirm

availability of specific valid combinations, to

check on newly released combinations, and to

obtain additional data on Legerity’s standard

military–grade products.

–1

Am7942

JC

–2

Note:

* Functionality of the device from 0°C to +70°C is guaranteed by production testing. Performance from –40°C to +85°C is guar-

anteed by characterization and periodic sampling of production units.

2

Am7942 Data Sheet

CONNECTION DIAGRAMS

Top View

32-Pin PLCC

4

3

2

1

32 31 30

TP

TESTOUT

L

5

6

29

28

TP

DA

RD

7

27

26

VBAT

8

HPB

HPA

QBAT

9

25

24

10

CHS

VTX

CHCLK

C4

11

12

VEE

23

22

RSN

13

AGND/DGND

E1

21

14 15 16 17 18 19 20

Notes:

1. Pin 1 is marked for orientation.

2. TP is a thermal conduction pin tied to substrate (QBAT).

SLIC Products

3

PIN DESCRIPTIONS

Pin Names

AGND/DGND

A(TIP)

Type

Gnd

Description

Analog and Digital ground.

Output

Gnd

Output of A(TIP) power amplifier.

Battery (power) ground.

BGND

B(RING)

C3–C1

Output

Input

Output of B(RING) power amplifier.

Decoder. TTL compatible. C3 is MSB and C1 is LSB.

C4

Input

Test Relay Driver Command. TTL compatible. A logic Low enables the driver.

CAS

Capacitor

Anti-saturation pin for capacitor to filter reference voltage when operating in anti-saturation

region.

CHCLK

CHS

Input

Chopper Clock. Input to switching regulator (TTL compatible). Freq = 256 kHz (typ). See

Note 1.

Chopper Stabilization. (See Note 1) Connection for external chopper stabilizing

components.

DA

Input

Ring-trip negative. Negative input to ring-trip comparator.

Ring-trip positive. Positive input to ring-trip comparator.

DB

Input

DET

Output

Switchhook detector. When enabled, a logic Low indicates the selected detector is tripped.

The detector is selected by the logic inputs (C3–C1, E1). The output is open-collector with

a built-in 15 kΩ pull-up resistor.

E1

Input

Ground-Key Enable. E1 = High connects the ground-key detector to DET. E1 = Low

connects the off-hook or ring-trip detector to DET.

GKFIL

HPA

HPB

L

—

Connection for external ground-key, noise-filter capacitor. See Note 2.

High-Pass Filter Capacitor. A(TIP) side of high-pass filter capacitor.

High-Pass Filter Capacitor. B(RING) side of high-pass filter capacitor.

Switching Regulator Power Transistor. Connection point for filter inductor and anode of

Capacitor

Output

(See Note 1) Switching Regulator Power Transistor. Connection point for filter inductor and anode of

catch diode. Has up to 60 V of pulse waveform on it and must be isolated from sensitive

circuits. Keep the diode connections short because of the high currents and high di/dt.

QBAT

RD

Battery

Resistor

Quiet Battery. (See Note 1). Filtered battery supply for the signal processing circuits.

Detector resistor. Detector threshold set and filter pin.

RDC

DC feed resistor. Connection point for the DC feed current programming network. The other

end of the network connects to the receiver summing node (RSN).

RINGOUT

RSN

Output

Input

Ring Relay Driver. Open-collector driver with emitter internally connected to BGND.

Receive Summing Node. The metallic current (AC and DC) between A(TIP) and B(RING) is

equal to 500 x the current into this pin. The networks that program receive gain, two-wire

impedance, and feed current all connect to this node.

TESTOUT

TP

Output

Test Relay Driver. Open collector driver with emitter internally connected to BGND.

Thermal

Thermal pin. Connection for heat dissipation. Internally connected to substrate (QBAT).

Leave as open circuit or connected to QBAT. In both cases, the TP pins can connect to an

area of copper on the board to enhance heat dissipation.

VBAT

VCC

Battery

Power

Input

Battery supply.

+5 V power supply.

–5 V power supply.

VEE

VREG

Regulated Voltage. (See Note 1.) Provides negative power supply for power amplifiers.

Connection point for inductor, filter capacitor, and chopper stabilization.

VTX

Output

Transmit Audio. This output is a unity gain version of the A(TIP) and B(RING) metallic

voltage. VTX also sources the two-wire input impedance programming network.

Notes:

1. All pins, except CHCLK, connect to VBAT when using SLIC without a switching regulator. CHCLK is connected to AGND/

DGND.

2. To prevent noise pickup by the detection circuits when using Ground-Key Detect state (E1 = logical 1), a 3300 pF minimum

bypass capacitor is recommended between the GKFIL pin and ground.

4

Am7942 Data Sheet

ABSOLUTE MAXIMUM RATINGS

OPERATING RANGES

Storage temperature . . . . . . . . . . . . –55°C to +150°C

Commercial (C) Devices

V

_CCwith respect to AGND/DGND . . .–0.4 V to +7.0 V

Ambient temperature . . . . . . . . . . . . . . 0°C to +70°C*

V_CC. . . . . . . . . . . . . . . . . . . . . . . . . . 4.75 V to 5.25 V

V_EE. . . . . . . . . . . . . . . . . . . . . . . . –4.75 V to –5.25 V

V_EEwith respect to AGND/DGND . . .+0.4 V to –7.0 V

V_BATwith respect to AGND/DGND. . . +0.4 V to –70 V

Note: Rise time of V_BAT(dv/dt) must be limited to 27 V/µs or

less when Q_BATbypass = 0.33 µF.

V

_BAT. . . . . . . . . . . . . . . . . . . . . . . . . . –19 V to –58 V

AGND/DGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V

BGND with respect to AGND/DGND .+1.0 V to –3.0 V

BGND with respect to

A(TIP) or B(RING) to BGND:

AGND/DGND. . . . . . . . . . . . –100 mV to +100 mV

Continuous . . . . . . . . . . . . . . . . . . –70 V to +1.0 V

10 ms (f = 0.1 Hz) . . . . . . . . . . . . . –70 V to +5.0 V

1 µs (f = 0.1 Hz) . . . . . . . . . . . . . . .–90 V to +10 V

250 ns (f = 0.1 Hz) . . . . . . . . . . . .–120 V to +15 V

Load Resistance on VTX to ground . . . . . . 10 kΩ min

The Operating Ranges define those limits between which the

functionality of the device is guaranteed.

Current from A(TIP) or B(RING). . . . . . . . . . . . 150 mA

Voltage on RINGOUT. . . . .BGND to 70 V above Q_BAT

Voltage on TESTOUT. . . . .BGND to 70 V above Q_BAT

Current through relay drivers . . . . . . . . . . . . . . 60 mA

* Functionality of the device from 0°C to +70°C is guaranteed

by production testing. Performance from –40°C to +85°C is

guaranteed by characterization and periodic sampling of

production units.

Can be used without switching regulator components in this

range of battery voltages, provided maximum power

dissipation specifications are not exceeded.

Voltage on ring-trip inputs

(DA and DB) . . . . . . . . . . . . . . . . . . . . . V_BATto 0 V

Current into ring-trip inputs . . . . . . . . . . . . . . . . . 10 mA

Peak current into regulator

switch (L pin). . . . . . . . . . . . . . . . . . . . . . . 150 mA

Switcher transient peak off

voltage on L pin. . . . . . . . . . . . . . . . . . . . . . +1.0 V

C4–C1, E1, CHCLK to

AGND/DGND . . . . . . . . . . . .–0.4 V to V_CC+ 0.4 V

Maximum power dissipation, T_A(see note) . . . . .70°C

In 32-pin PLCC package. . . . . . . . . . . . . . . 1.74 W

Note: Thermal limiting circuitry on chip will shut down the

circuit at a junction temperature of about 165°C. The device

should never be exposed to this temperature. Operation

above 145°C junction temperature may degrade device

reliability. See the SLIC Packaging Considerations for more

information.

Stresses above those listed under Absolute Maximum Ratings

may cause permanent device failure. Functionality at or above

these limits is not implied. Exposure to Absolute Maximum

Ratings for extended periods may affect device reliability.

SLIC Products

5

ELECTRICAL CHARACTERISTICS

Description

Analog (V_TX) output impedance

Analog (V_TX) output offset

Test Conditions (See Note 1)

Min

Typ

Max

Unit

Note

3

Ω

4

0°C to +70°C

–35

–30

+35

+30

–1*

–2

mV

–40°C to +85°C

300 Hz to 3.4 kHz

–40

–35

+40

+35

–1*

–2

4

Analog (RSN) input impedance

Longitudinal impedance at A or B

Overload level

1

20

35

Ω

4-wire

2-wire

–2.5

+2.5

Vpk

2

Transmission Performance, 2-Wire Impedance (See Test Circuit D)

2-wire return loss 300 Hz to 3400 Hz

Longitudinal Balance (2-Wire and 4-Wire, See Test Circuit C); R_L= 600 Ω

26

dB

4, 10

Longitudinal to metallic L-T, L-4

200 Hz to 1 kHz

52

63

58

54

normal polarity 0°C to +70°C

normal polarity –40°C to +85°C

reverse polarity

1, 2

1, 2, 4

1, 2

1 kHz to 3.4 kHz

52

58

54

normal polarity 0°C to +70°C

normal polarity –40°C to +85°C

reverse polarity

dB

1, 2

1, 2, 4

1, 2

Longitudinal signal generation 4-L

300 Hz to 800 Hz

Reverse polarity

–1*

–2

40

42

Active state

OHT state

all*

all

28

18

Longitudinal current capability per wire

mArms

Insertion Loss (2- to 4-Wire and 4- to 2-Wire, See Test Circuits A and B)

BAT = –48 V, R_LDC= R_LAC= 600 Ω; BAT = –24 V, R_LDC= 300 Ω, R_LAC= 600 Ω

Gain accuracy

0 dBm, 1 kHz

0°C to +70°C

–0.15

–0.10

+0.15

+0.10

–1*

–2

0 dBm, 1 kHz

–40°C to +85°C

–0.20

–0.15

+0.20

+0.15

—

4

—

–1*

–2

dB

Variation with frequency

300 Hz to 3400 Hz

Relative to 1 kHz

0°C to +70°C

–0.15

–0.10

+0.15

+0.10

–1*

–2

300 Hz to 3400 Hz

Relative to 1 kHz

–40°C to +85°C

–0.20

–0.15

+0.20

+0.15

—

4

–1*

–2

Note:

*P.G. = Performance Grade

6

Am7942 Data Sheet

ELECTRICAL CHARACTERISTICS (continued)

Description

Gain tracking

Test Conditions (See Note 1)

Min

Typ

Max

Unit

Note

0°C to +70°C

–0.10

+0.10

+7 dBm to –55 dBm

Reference: –0 dBm

dB

–40°C to +85°C

–0.15

+0.15

4

—

+7 dBm to –55 dBm

Reference: –0 dBm

Balance Return Signal (4- to 4-Wire, See Test Circuit B)

BAT = –48 V, R_LDC= R_LAC= 600 Ω; BAT = –24 V, R_LDC= 300 Ω, R_LAC= 600 Ω

Gain accuracy

0 dBm, 1 kHz

0°C to +70°C

–0.15

–0.10

+0.15

+0.10

—

3

—

–1*

–2

0 dBm, 1 kHz

–40°C to +85°C

–0.20

–0.15

+0.20

+0.15

—

3, 4

–1*

–2

Variation with frequency

300 Hz to 3400 Hz

Relative to 1 kHz

0°C to +70°C

–0.10

+0.10

3

dB

300 Hz to 3400 Hz

Relative to 1 kHz

–40°C to +85°C

3

3, 4

–0.15

–0.10

+0.15

+0.10

Gain tracking

0°C to +70°C

3

+3 dBm to –55 dBm

Reference: 0 dBm

–40°C to +85°C

+3 dBm to –55 dBm

Reference: 0 dBm

–0.15

3, 4

Group delay

f = 1 kHz

5.3

µs

4, 12

Total Harmonic Distortion (2- to 4-Wire and 4- to 2-Wire, See Test Circuits A and B)

BAT = –48 V, R_LDC= R_LAC= 600 Ω

Harmonic distortion

300 Hz to 3400 Hz

Idle Channel Noise

0 dBm

–64

–55

–50

–40

dB

+7 dBm

BAT = –48 V, R_LDC= R_LAC= 600 Ω; BAT = –24 V, R_LDC= 300 Ω, R_LAC= 600 Ω

C-message weighted noise

2-wire, 0°C to +70°C

+7

+10

+12

4

2-wire, –40°C to +85°C

dBrnC

dBmp

4-wire, 0°C to +70°C

4-wire, –40°C to +85°C

+10

+12

4

Psophometric weighted noise

2-wire, 0°C to +70°C

2-wire, –40°C to +85°C

–83

–80

–78

—

4

4-wire, 0°C to +70°C

4-wire, –40°C to +85°C

–80

–78

—

4

Note:

*P.G. = Performance Grade

SLIC Products

7

ELECTRICAL CHARACTERISTICS (continued)

Description

Test Conditions (See Note 1)

Min

Typ

Max

Unit

Note

Single Frequency Out-of-Band Noise (See Test Circuit E)

Metallic

4 kHz to 9 kHz

9 kHz to 1 MHz

256 kHz and harmonics**

–76

–63

4

4, 5, 8

4, 5

dBm

Longitudinal

1 kHz to 15 kHz

Above 15 kHz

256 kHz and harmonics**

–70

–85

–57

4

4, 5, 8

4, 5

Line Characteristics (See Figures 1a, 1b, 1c)

Short loops, Active state

Battery = –24 V, R_LDC= 300 Ω

Battery = –43 V, R_LDC= 600 Ω

Battery = –48 V, R_LDC= 600 Ω

4, 9

4

—

32.4

35.0

37.6

19.5

Long loops, Active state

Battery = –24 V, R_LDC= 640 Ω

Battery = –43 V, R_LDC= 1300 Ω

Battery = –48 V, R_LDC= 1900 Ω

20.0

23.0

18.0

4, 9

4

—

mA

OHT state

Battery = –24 V, R_LDC= 600 Ω

Battery = –48 V, R_LDC= 600 Ω

4, 9

—

15.5

17.5

70

Loop current

Tip Open state, R_L= 0

Disconnect state, R_L= 0

1.0

I_LLIM (ITip and IRing)

Tip and ring shorted to GND

105

Power Dissipation Battery, Normal Loop Polarity

On-hook Open Circuit state

Battery = –24 V, w/o switching reg.

Battery = –48 V, with switching reg.

30

35

75

100

9

—

On-hook OHT state

Battery = –24 V, w/o switching reg.

Battery = –48 V, with switching reg.

175

135

9

—

100

225

On-hook Active state

Battery = –24 V, w/o switching reg.

Battery = –48 V, with switching reg.

135

180

225

300

9

—

mW

Off-hook OHT state

R_L= 50 Ω

Battery = –24 V, w/o switching reg.

Battery = –48 V, with switching reg.

500

400

800

750

9

—

Off-hook Active state

R_L= 50 Ω

Battery = –24 V, w/o switching reg.

Battery = –48 V, with switching reg.

800

1100

1000

9

—

Supply Currents, Battery = –24 V or –48 V

V_CCon-hook supply current

V_EEon-hook supply current

V_BATon-hook supply current

Note:

Open Circuit state

OHT state

Active state

3.0

6.0

7.5

4.5

10.0

12.0

Open Circuit state

OHT state

Active state

1.0

2.2

2.7

2.3

3.5

6.0

mA

9

Open Circuit state

OHT state

Active state

0.4

3.0

4.0

1.0

5.0

6.0

**Applies only when switching regulator is used.

8

Am7942 Data Sheet

ELECTRICAL CHARACTERISTICS (continued)

Description

Test Conditions (See Note 1)

Min

Typ

Max

Unit

Note

Power Supply Rejection Ratio (V_RIPPLE= 50 mVrms)

V_CC

V_EE

V_BAT

50 Hz to 3.4 kHz

3.4 kHz to 50 kHz

25

22

45

35

50 Hz to 3.4 kHz

3.4 kHz to 50 kHz

20

10

40

25

dB

6

4

50 Hz to 3.4 kHz

3.4 kHz to 50 kHz

27

20

45

40

Effective int. resistance

Off-Hook Detector

Current threshold

CAS to GND

85

170

255

+20

kΩ

I_DET= 365/R_D

–20

%

Ground-Key Detector Thresholds, Active State

Ground-key resistance threshold

Battery = –24 V, B(RING) to GND

Battery = –48 V, B(RING) to GND

1.0

2.0

2.2

5.0

4.5

10.0

9

—

kΩ

Ground-key current threshold

B(RING) to GND

Midpoint to GND

9

mA

7

4

Effective internal resistance

Ring-Trip Detector Input

Bias current

GKFIL to AGND/DGND

18

36

54

kΩ

–5

–0.05

µA

Offset voltage

Source resistance = 0 to 2 MΩ

–50

0

+50

mV

11

Logic Inputs (C4–C1, E0, E1, and CHCLK)

Input High voltage

2.0

V

Input Low voltage

0.8

40

45

Input High current

Input Low current

Logic Output (DET)

Output Low voltage

Output High voltage

All inputs except E1

–75

–0.4

µA

Input E1

mA

I_OUT= 0.8 mA

0.4

V

I_OUT= –0.1 mA

2.4

Relay Driver Outputs (RINGOUT, TESTOUT)

On voltage

Off leakage

25 mA sink

V_OH= +15 V

+1.5

100

V

µA

SLIC Products

9

RELAY DRIVER SCHEMATICS

RINGOUT

TESTOUT

BGND

15474A-002

2

1

0

T_A= 70°C

T_A= 25°C

ON Voltage

at RINGOUT or TESTOUT

(V)

0

30

Current into RINGOUT or TESTOUT (mA)

60

SWITCHING CHARACTERISTICS

Symbol

Parameter

Test Conditions

Temperature

Range

Min Typ Max Unit Note

tgkde

E1 Low to DET High (E0 = 1)

E1 Low to DET Low (E0 = 1)

E1 High to DET Low (E0 = 1)

E1 High to DET High (E0 = 1)

0°C to +70°C

3.8

4.0

Ground-Key Detect state

R_Lopen, R_Gconnected

(See Figure H)

–40°C to +85°C

0°C to +70°C

–40°C to +85°C

1.1

1.6

µs

4

tshde

0°C to +70°C

–40°C to +85°C

1.2

1.7

Switchhook Detect state

R_L= 600 Ω, R_Gopen

(See Figure G)

0°C to +70°C

–40°C to +85°C

3.8

4.0

SWITCHING WAVEFORMS

E1 to DET

E1

DET

tgkde

tshde

tgkde

tshde

Note:

All delays measured at 1.4 V levels.

15474A-003

10

Am7942 Data Sheet

Notes:

1. Unless otherwise noted, test conditions are BAT = –48 V, V_CC= +5 V, V_EE= –5 V, R_L= 600 Ω, C_HP= 0.33 µF,

R

_DC1= R_DC2= 7.14 kΩ, C_DC= 0.47 µF, R_D= 35.4 kΩ, C_CAS= 0.47 µF, no fuse resistors, R_T=120 kΩ, and R_RX= 60 kΩ.

Switching regulator components: L = 1 mH, C_FIL= 0.47 µF (see Application Circuit).

2. Overload level is defined when THD = 1%.

3. Balance return signal is the signal generated at V_TXby V_RX. This specification assumes the two-wire AC load impedance

matches the programmed impedance.

4. Not tested in production. This parameter is guaranteed by characterization or correlation to other tests.

5. For frequencies below 12 kHz, these tests are performed with a longitudinal impedance of 90 Ω and metallic impedance of

300 Ω. For frequencies greater than 12 kHz, a longitudinal impedance of 90 Ω and a metallic impedance of 135 Ω is used.

These tests are extremely sensitive to circuit board layout. Please refer to application notes for details.

6. This parameter is tested at 1 kHz in production. Performance at other frequencies is guaranteed by characterization.

7. “Midpoint” is defined as the connection point between two 300 Ω series resistors connected between A(TIP) and B(RING).

8. Fundamental and harmonics from 256 kHz switch regulator chopper are not included.

9. For –24 V battery, switching regulator is disabled. L, CHS, and VREG pins connected to VBAT pin; CHCLK pin connected to

AGND/DGND.

10. Assumes the following Z_Tnetwork:

VTX

RSN

60 kΩ

150 pF

11. Tested with 0 Ω source impedance. 2 MΩ is specified for system design purposes only.

12. Group delay can be considerably reduced by using a Z_Tnetwork such as that shown in Note 10 above. The network reduces

the group delay to less than 2 µs. The effect of group delay on linecard performance may be compensated for by using the

QSLAC™ or DSLAC™ device.

Table 1. SLIC Decoding

DET Output

State

C3 C2 C1

Two-Wire Status

Open Circuit

E1 = 0

Ring trip

E1 = 1

Ring trip

0

1

2

3

4

5

6

7

0

1

0

1

0

1

0

1

0

1

0

1

0

1

Ringing

Ring trip

Ground key

—

Active

Loop detector

On-Hook TX (OHT)

Tip Open

Reserved

—

Active Polarity Reversal

OHT Polarity Reversal

Ground key

SLIC Products

11

Table 2. User-Programmable Components

Z_Tis connected between the VTX and RSN pins. The fuse re-

∗

Z_T= 200(Z_2WIN– 2R_F

)

sistors are R_F, and Z_2WINis the desired 2-wire AC input im-

pedance. When computing Z_T, the internal current amplifier

pole and any external stray capacitance between VTX and

RSN must be taken into account.

Z_RXis connected from V_RXto the R_SN. Z_Tis defined above,

and G_42Lis the desired receive gain.

Z_L

200Z_T

------------ -------------------------------------------------

Z_RX

=

•

G42_LZ_T+ 200(Z_L+ 2R_F)

R_DC1, R_DC2, and C_DCform the network connected to the

RDC pin. R_DC1and R_DC2are approximately equal. I_LOOPis

the desired loop current in the constant-current region.

500

R

_DC1+ R_DC2= -------------

I_LOOP

R

_DC1+ R_DC2

-------------------------------

C_DC= 1.5 ms •

R_DC1R_DC2

R_Dand C_Dform the network connected from RD to –5 V, and

I_Tis the threshold current between on hook and off hook.

365

0.5 ms

--------

I_T

R_D

=

, C_D= ----------------

R_D

C_CASis the regulator filter capacitor, and f_cis the desired filter

cut-off frequency.

1

C_CAS= -----------------------------

3.4 • 10⁵πf_c

Note:

*R_FUSE= 20 Ω–50 Ω, user selectable.

12

Am7942 Data Sheet

DC FEED CHARACTERISTICS

R_DC1+ R_DC2= R_DC= 14.28 kΩ

Active state

OHT state

Notes:

1. Constant-current region:

500

Active state:

OHT state:

I_L= ----------

R_DC

250

I_L= ---------

R_DC

2. Anti-saturation turn-on (Active state):

a. Battery independent:

b. Battery tracking:

V_AB= 35.5 V,

(|V_BAT| > 46.2 V)

V_AB= 1.1 |V_BAT| – 15,

(|V_BAT| ≥ 46.2 V)

(|V_BAT| < 46.2 V)

V_AB= 0.7 |V_BAT| + 3.5,

3. Open circuit voltage:

Active state:

V_AB= 42.6,

_AB= 0.7 |V_BAT| + 5.89,

(|V_BAT| > 53 V)

(|V_BAT| ≤ 53 V)

V

OHT state,

V_AB= 39.1,

(|V_BAT| > 49.8 V)

V_AB= 0.7 |V_BAT| + 4.7,

(|V_BAT| ≤ 49.8 V)

4. Anti-saturation 1 region:

Active state:

R_DC

æ

è

ö

----------

70.4

V_AB= 46.2 – I_L

V_AB= 39.1 – I_L

ø

R_DC

----------

70.4

æ

è

ö

ø

OHT state:

5. Anti-saturation 2 region:

Active state:

R_DC

æ

è

ö

----------

210

V_AB= 0.7 V_BAT+ 5.89 – I_L

ø

R_DC

æ

è

ö

----------

210

OHT state:

V_AB= 0.7 V_BAT+ 4.7 – I_L

ø

a. V_A–V_B(V_AB) Voltage vs. Loop Current (Typical)

SLIC Products

13

DC FEED CHARACTERISTICS (continued)

R_DC1+ R_DC2= R_DC= 14.28 kΩ

V_BAT= 47.3 V

b. Loop Current vs. Load Resistance (Typical)

A

RSN

RDC

a

b

R_DC1

SLIC

I_L

R_L

R_DC2

C_DC

B

Feed current programmed by R_DC1and R_DC2

c. Feed Programming

15474A-004

Figure 1. DC Feed Characteristics

14

Am7942 Data Sheet

TEST CIRCUITS

(TIP)

A

VTX

(TIP)

A

R_L

2

R_T

SLIC

V_L

V_AB

R_T

V_AB

R_L

AGND

R_L

2

R_RX

RSN

(RING)

B

(RING)

V_RX

I_L4-2= –20 log (V_AB/ V_RX

)

I_L2-4= –20 log (V_TX/ V_AB

)

BRS = 20 log (V_TX/ V_RX

)

A. Two- to Four-Wire Insertion Loss

B. Four- to Two-Wire Insertion Loss and Balance Return Signal

Z_D

A

(TIP)

VTX

(TIP)

A

1/ωC << R_L

R_L

2

R_T

S1

C

SLIC

R

AGND

V_L

R_T

S2

V_M

AGND

V_S

SLIC

V_L

Z_IN

R_L

2

R_RX

VRX

RSN

B(RING)

RSN

(RING)

B

R_RX

S2 Open, S1 Closed:

L-T Long. Bal. = 20 log (V_AB/ V_L)

L-4 Long. Bal. = 20 log (V_TX/ V_L)

Note:

Z_Dis the desired impedance (e.g., the characteristic

impedance of the line).

S2 Closed, S1 Open:

R_L= –20 log (2 V_M/ V_S)

4-L Long. Sig. Gen. = 20 log (V_L/ V_RX

)

C. Longitudinal Balance

D. Two-Wire Return Loss Test Circuit

SLIC Products

15

TEST CIRCUITS (continued)

R_L

C

A(TIP)

68 Ω

S_M

R_L

R_E

56 Ω

IDC

V_N

SLIC

B(RING)

68 Ω

B(RING)

S_E

Current Feed or Ground Key

C

1/ωC << 90 Ω

E. Single-Frequency Noise

F. Ground-Key Detection Center Point Test

V_CC

6.2 kΩ

A(TIP)

DET

E1

15 pF

R_L= 600 Ω

B(RING)

R_G

B(RING)

R_G: 2 kΩ at V_BAT= –48 V

1 kΩ at V_BAT= –24 V

H. Ground-Key Switching

G. Loop-Detector Switching

16

Am7942 Data Sheet

PHYSICAL DIMENSIONS

PL032

SLIC Products

17

REVISION SUMMARY

Revision C to Revision D

•

Minor changes were made to the data sheet style and format to conform to Legerity standards.

Table 1—Some information in the table was revised, including the addition of the Reserved status.

Revision D to Revision E

•

Minor changes were made to the data sheet style and format to conform to Legerity standards.

In the Pin Description table, the TP pin description was inserted/changed to: “Thermal pin. Connection for heat

dissipation. Internally connected to substrate (QBAT). Leave as open circuit or connected to QBAT. In both cases,

the TP pins can connect to an area of copper on the board to enhance heat dissipation."

Revision E to Revision F

•

The physical dimension (PL032) was added to the Physical Dimensions section.

Deleted the Ceramic DIP and Plastic DIP packages and references to them.

Updated the Pin Description table to correct inconsistencies.

Legerity provides silicon solutions that enhance the performance, speeds time-to-market, and lowers the system

cost of our customers' products. By combining process, design, systems architecture, and a complete set of

software and hardware support tools with unparalleled factory and worldwide field applications support, Legerity

ensures its customers enjoy a smoother design experience. It is this commitment to our customers that places

Legerity in a class by itself.

18

Am7942 Data Sheet

The contents of this document are provided in connection with Legerity, Inc. products. Legerity makes no representations or warranties with re-

spect to the accuracy or completeness of the contents of this publication and reserves the right to make changes to specifications and product

descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights

is granted by this publication. Except as set forth in Legerity's Standard Terms and Conditions of Sale, Legerity assumes no liability whatsoever,

and disclaims any express or implied warranty, relating to its products including, but not limited to, the implied warranty of merchantability, fitness

for a particular purpose, or infringement of any intellectual property right.

Legerity's products are not designed, intended, authorized or warranted for use as components in systems intended for surgical implant into the

body, or in other applications intended to support or sustain life, or in any other application in which the failure of Legerity's product could create

a situation where personal injury, death, or severe property or environmental damage may occur. Legerity reserves the right to discontinue or

make changes to its products at any time without notice.

Trademarks

Legerity, the Legerity logo, and combinations thereof, DSLAC and QSLAC are trademarks of Legerity, Inc.

Other product names used in this publication are for identification purposes only and may be trademarks of their respective companies.

P.O. Box 18200

Austin, Texas 78760-8200

Telephone: (512) 228-5400

Fax: (512) 228-5510

North America Toll Free: (800) 432-4009

To contact the Legerity Sales Office nearest you,

or to download or order product literature, visit

our website at www.legerity.com.

To order literature in North America, call:

(800) 572-4859

or email:

americalit@legerity.com

To order literature in Europe or Asia, call:

44-0-1179-341607

or email:

Europe — eurolit@legerity.com

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型号：	AM7942-1JC
厂家：	ETC
描述：	Telecommunication IC 电信IC\n 电信
文件：	总20页 (文件大小：244K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

AM7942-1JC [ETC]

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