Datasheet LUCL7590CAE Datasheet (AGERE)

Data Sheet
June 1998

L7590C Telephone Ringing Driver

Features

■

Applies a battery-backed, single-ended, sinusoidal
ringing signal to the telephone loop

■

Ringing capability:
— 40 Vrms into 5 North American REN
— 30 mApeak into 4 German REN

■

Built-in current limiting

■

Low power dissipation in idle and ringing modes

■

Requires 5 V, a high-value negative dc supply, and
a digital input sequence

Description

The L7590C Telephone Ringing Driver produces a
low-frequency sinusoidal ringing signal for analog
telephone loops. This is accomplished by producing
an output pulse stream that is an amplified replica of
the digital input. The output is then filtered to produce
a sine wave. The peak-to-peak output level is deter­mined by the magnitude of the negative high-voltage
dc applied to the device (up to –170 V).

The required input is a 100 kHz CMOS-compatible
pulse stream, pulse-width modulated (PWM) at the
desired ringing frequency. The output stage consists
of one upper and one lower drive transistor with an
internal control circuit.

The L7590C IC is optimized for low po wer dissipation
and is available in a 16-pin, surface-mount package.

12-3057a (f)

Figure 1. Block Diagram

CLOCK

CONTROL

LEVEL

SHIFT

AND

OUTPUT

TIMING

CURRENT

LIMIT

BIAS

CIRCUIT

OUT

GNDD

V

DD

CLK

V

REF

VNEG

GNDR

CB1 CB2

EN

30 Ω

L1

L2

VNEG

2 Lucent Technologies Inc.

Data Sheet

June 1998

L7590C Telephone Ringing Driver

Pin Information

Absolute Maximum Ratings

(T

A

= 25 ° C)

Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are abso­lute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operational sections of this data sheet. Exposure to absolute maximum ratings for extended
periods may adversely affect device reliability.

Pin Symbol Type Name/Function

14 V

DD

—

+5 V Power Supply .

3 GNDD — Digital Ground .

12 GNDR — Ringing Ground .

8V

NEG

—

Negative Power Supply . Determines the swing of the ringing generator. Connect

a 1 µ F capacitor from V

NEG

to V

REF

.

5V

REF

—

Internal Reference Voltage . Connect a 1 µ F capacitor from V

REF

to V

NEG

.

16 CLK I

Clock . Modulated pulse stream. Low = 0 V. High = V

DD

.
7 OUT O Ringing Generator Output . Connect to ringing relay contact through a filter.
1 CB1 — Bootstrap Capacitor . Connect a 0.1 µ F capacitor between CB1 and CB2.
2 CB2 — Bootstrap Capacitor . Connect a 0.1 µ F capacitor between CB1 and CB2.
9L1—

Filter Inductor . Connect an inductor to pin L2.

10 L2 — Filter Inductor . Connect an inductor to pin L1.
15

EN

—

Not Enable . A logic lo w activates the internal circuitry. A logic high puts the device

in a low-power powerdown mode.

Parameter Min Typ Max Unit

V

DD

— 7.0 — V

V

NEG

— –200 — V
Timing Input Voltage –0.5 — 7.0 V
Storage Temperature Range –40 — 125

°

C

Maximum Junction Temperature — 150 —

°

C

Relative Humidity Range 5 — 95 %

Lucent Technologies Inc. 3

Data Sheet
June 1998

L7590C Telephone Ringing Driver

Recommended Operating Conditions

Electrical Characteristics

Electrical characteristics apply for 25 ° C. Unless noted, V

DD

= +5 V, V

NEG

= –170 V,

EN

= low, L1 = 20 mH

(Rdc = 20 Ω , Ceff = 20 pF), CLK = 100 kHz. Positive currents flow into the device. Typical is defined as 25 ° C.

Parameter Min Typ Max Unit

Ambient Temperature –40 — 85

°

C

V

DD

Supply Voltage 4.75 5.0 5.25 V

V

NEG

Supply V oltage –170 — –130 V

Parameter Min T yp Max Unit

Power Supply—Idle (CLK = H or L,

EN

= high, dc):

I

DD

I

NEG

Power Dissipation

—
—
—

—
—
—

1

–50

13.5

mA

µ

A

mW

Power Supply—Active, No Load:

I

DD

I

NEG

Power Dissipation

—
—
—

—

–3.2

—

3

–8

1.38

mA
mA

W

Efficiency =

{[

(V

OUT

)

2

/R

LOAD

]/(V

NEG

•

I

NEG

)

}

:

Sinking Current, R

LOAD

= 1400 Ω Load to GND

Sourcing Current, R

LOAD

= 1400 Ω Load to V

NEG

40
40

80
80

—
—

%
%

ON-resistance:

CLK = H, I

OUT

= –20 mA

CLK = L, I

OUT

= +20 mA

0
0

10
10

20
20

Ω
Ω

Current Limit 25 — 40 mApeak

44 Lucent Technologies Inc.

Data Sheet

June 1998

L7590C Telephone Ringing Driver

Functional Description

Ringer Requirements

This discussion highlights some of the requirements in
the United States and Germany. Beginning with the
telephone set ringer to be powered, the United States
requires 40 Vrms to be delivered to the equivalent of
five parallel telephone sets, or 5 REN (Ringer Equiva­lence Number), that translates to 1386 Ω + 40 µ F. In
Germany , 30 mApeak must be deliv ered to f our parallel
telephone sets. In Germany, 4 REN have an imped­ance of 450 Ω + 3.4 µ F. The difference results from the
impedance of the telephone-set ringers of the two
countries.

Ringing Requirements

In Germany, both single-ended ringing and balanced
ringing can be used. This is not so in the United States,
where some ringers on older equipment have a ground
connection at the telephone set, and the signal lead is
either the Tip or Ring wire of the twisted pair. This has
led to the recommended use of single-ended ringing.
Both administrations allow ringing with a negative dc
level, known as battery-backed ringing, but in the
United States, there is a constraint that this level can­not be more negative than –75 V.

With the exception of the United States, most world­wide administrations require an injection of a pure sine
wave. Depending on the country, the distortion require­ment is in the range of 3% to 5%. In the United States,
the wave does not need to resemb le a sine w a ve, but it
cannot be a square wave. The shape requirement of
the wave in the United States is expressed as a crest
factor (c.f.). This is the ratio of the peak to the rms volt­age of the signal. The requirement is 1.2 < c.f. < 1.6.

Operation

On the L7590C, the prefiltered output is a high­voltage replica of the PWM digital signal that is applied
to the CLK input. The signal at OUT is produced by
level shifting and control of the high-v oltage transistors .
The level is determined by the magnitude of the nega­tive dc voltage applied to the output stage transistors.
The output, ideally, should be an exact time replica of
the CLK input to faithfully reproduce the modulating
waveform. This high-voltage replica of the CLK input is
filtered to leave only the low-frequency, high-voltage
sine wave ringing signal. Figure 3, parts A and B, illus­trates the PWM signal with relation to the modulating
signal frequency. The PWM signal is at a 100 kHz rate
and modulated at the desired ringing signal frequency,
typically 20 Hz to 30 Hz. Laboratory equipment genera­tion of the required signal is shown in Figure 5. Propa­gation delays and switching parameters associated
with the control circuitry and output stage transistors
can cause skewing which will produce a distorted out­put of the modulating waveform. Skewing is illustrated
in Figure 4, parts A, B, and C. The skewing can be
seen as an increase in the duty cycle of the L7590C
output compared to the input signal duty cycle.

Using the test arrangement as shown in Figure 5, the
harmonic distortion of the filtered output of the L7590C
was measured with two different loading circuits. With
the North American 5 REN (1386 Ω + 40 µ F) load, the
THD was typically 2.0% to 2.5%. With the Germany
4 REN (450 Ω + 3.4 µ F) load, the THD was typically

1.5% to 2.0%. The 25 Hz output of the

HP

* 3311A
generator showed a typical THD of 1.5% when supply­ing a signal to the

HP

8116A.

A 20 Ω resistor (R

ILIM

) must be added between L1 and

OUT for 5 REN loads.

*

HP

is a registered trademark of Hewlett-Packard Company.

Lucent Technologies Inc. 5

Data Sheet
June 1998

L7590C Telephone Ringing Driver

Application

* C

NEG

connects to V

NEG

pin at chip.

12-3058.E (F)

Figure 2. Basic Battery-Backed Ringing Application

Table 1. Parts List for Application, Ringing Driver IC

Name Value Function

L1 20 mH Part of LC output filter
C1 1 µ F, 250 V, 20% Part of LC output filter
C2 1 µ F, 20 V, 20% V

REF

filter

CB 0.1 µ F, 10 V, 20% Voltage doubling capacitor

Rx 15 Ω , 1 W Hot insertion limiter

R

ILIM

20 Ω to 100 Ω Current-limiter adjustment

VDD GNDD

V

REF

VNEG

CLK

OUT

TIP

RP

20 Ω

RING

L7581

RELAY

PWM

SIGNAL

C1

1.0 µF

V

DD

L7590C

RINGING

GENERATOR

C2

1 µF

R

TS1

400 Ω

250 V PROT

PT

PR

RING TRIP
DETECT

SLIC

XMT

RCV

CODEC

RP

20 Ω

VNEG

L2

L1

L1

20 mH

GNDR

CB

0.1 µF

CB1 CB2

EN

RILIM

RX 15 Ω

DX

DR

CNEG*

1.0 µF

6 Lucent Technologies Inc.

Data Sheet

June 1998

L7590C Telephone Ringing Driver

Application (continued)

12-3381 (F)

12-3380 (F)

B. Same as A but Expanded

A. Upper = PWM Signal Centered at 100 kHz

Lower = Modulating Signal

Figure 3. Modulation Waveforms

Data Sheet
June 1998

Lucent Technologies Inc. 7

L7590C Telephone Ringing Driver

Application (continued)

12-3379 (F) 12-3377 (F)

B. 50% Duty Cycle

A. Upper = 10% Duty Cycle—CLK Input

Lower = L7590C Output

12-3376 (F)

C. 90% Duty Cycle

Note: For all three illustrations above, the positive portion of the L7590C output is skewed to be greater than the CLK input.

Figure 4. Skewing Illustration Waveforms

8 Lucent Technologies Inc.

Data Sheet

June 1998

L7590C Telephone Ringing Driver

Application (continued)

12-3375.B(F)

Notes:

THD % =

x 100.

RX = 15 Ω.

Figure 5. L7590C Test Connections

HP

3311A

SIGNAL

GENERATOR

25 Hz

+5 V

0.1 µF

100 kHz (PWM)

SIGNAL LEVEL = 0 V TO 5 V

PULSE/FUNCTION

GENERATOR

100 kHz RATE

HP

8116A

VDD CB1 CB2GNDD

OUT

L1

GNDR

L2

RILIM

20 mH

C1

1.0 µF

450 Ω

3.4 µF

1386 Ω

40 µF

HP

3585A

SPECTRUM

ANALYZER

V

NEG = –170 V

RX

C2
1 µF

CLK

EN

VNEGVREF

L7590C

CNEG

1.0 µF

E22E32E42. . .+++

E1

2E22E32E42

. . .++++

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

Lucent Technologies Inc. 9

Data Sheet
June 1998

L7590C Telephone Ringing Driver

Outline Diagram

16-Pin, Plastic SOG

Dimensions are in millimeters.

5-4414r2 (C)

Number

of Pins

(N)

Maximum

Length

(L)

Maximum Width

Without Leads

(B)

Maximum Width
Including Leads

(W)

Maximum Height

Above Board

(H)

16 10.49 7.62 10.64 2.67

W

0.61

0.51 MAX

H

0.28 MAX

0.10

SEATING PLANE

1.27 TYP

N

L

B

1

PIN #1 IDENTIFIER ZONE

Data Sheet

June 1998

L7590C Telephone Ringing Driver

Lucent Technologies Inc. reserves the right to make changes to the product(s) or information contained herein without notice. No liability is assumed as a result of their use or application. No
rights under any patent accompany the sale of any such product(s) or information.

Copyright © 1998 Lucent Technologies Inc.
All Rights Reserved

June 1998
DS98-340ALC (Replaces DS97-512ALC)

For additional information, contact your Microelectronics Group Account Manager or the following:

INTERNET: http://www.lucent.com/micro
E-MAIL: [e-mail]
N. AMERICA: Microelectronics Group, Lucent Technologies Inc., 555 Union Boulevard, Room 30L-15P-BA, Allentown, PA 18103

1-800-372-2447, FAX [phone] (In CANADA: 1-800-553-2448, FAX [phone])

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Tel. [phone], FAX [phone]

CHINA: Microelectronics Group, Lucent Technologies (China) Co., Ltd., A-F2, 23/F, Zao Fong Universe Building, 1800 Zhong Shan Xi Road,

Shanghai 200233 P. R. China

Tel. [phone], ext. 316, FAX [phone]

JAPAN: Microelectronics Group, Lucent Technologies Japan Ltd., 7-18, Higashi-Gotanda 2-chome, Shinagawa-ku, Tokyo 141, Japan

Tel. [phone], FAX [phone]

EUROPE: Data Requests: MICROELECTRONICS GROUP DATALINE: Tel. [phone], FAX [phone]

Technical Inquiries:GERMANY: (49) 89 95086 0 (Munich), UNITED KINGDOM: (44) 1344 865 900 (Bracknell),

FRANCE: (33) 1 48 83 68 00 (Paris), SWEDEN: (46) 8 600 7070 (Stockholm), FINLAND: (358) 9 4354 2800 (Helsinki),
ITALY: (39) 2 6608131 (Milan), SPAIN: (34) 1 807 1441 (Madrid)

Ordering Information

Device Part No. Description Package Comcode

LUCL7590CAE-D Telephone Ringing Driver 16-Pin SOG 108191107

LUCL7590CAE-DT Telephone Ringing Driver 16-Pin SOG (Tape and Reel) 108191115