Data Sheet
June 1998
L7590C Telephone Ringing Driver
Features
Description
■
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
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 power dissipation
and is available in a 16-pin, surface-mount package.
GNDD
VDD
GNDR
CB1
CB2
OUT
CURRENT
LIMIT
30 Ω
L1
EN
CLOCK
CONTROL
CLK
LEVEL
SHIFT
AND
OUTPUT
TIMING
L2
BIAS
CIRCUIT
VNEG
VREF
VNEG
12-3057a (f)
Figure 1. Block Diagram
Data Sheet
June 1998
L7590C Telephone Ringing Driver
Pin Information
Pin
Symbol
Type
Name/Function
14
3
12
8
VDD
GNDD
GNDR
VNEG
—
—
—
—
5
16
7
1
2
9
10
15
VREF
CLK
OUT
CB1
CB2
L1
L2
—
I
O
—
—
—
—
—
+5 V Power Supply.
Digital Ground.
Ringing Ground.
Negative Power Supply. Determines the swing of the ringing generator. Connect
a 1 µF capacitor from VNEG to VREF.
Internal Reference Voltage. Connect a 1 µF capacitor from VREF to VNEG.
Clock. Modulated pulse stream. Low = 0 V. High = VDD.
Ringing Generator Output. Connect to ringing relay contact through a filter.
Bootstrap Capacitor. Connect a 0.1 µF capacitor between CB1 and CB2.
Bootstrap Capacitor. Connect a 0.1 µF capacitor between CB1 and CB2.
Filter Inductor. Connect an inductor to pin L2.
Filter Inductor. Connect an inductor to pin L1.
Not Enable. A logic low activates the internal circuitry. A logic high puts the device
in a low-power powerdown mode.
EN
Absolute Maximum Ratings (TA = 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.
Parameter
Min
Typ
Max
Unit
VDD
VNEG
Timing Input Voltage
Storage Temperature Range
Maximum Junction Temperature
Relative Humidity Range
—
—
–0.5
–40
—
5
7.0
–200
—
—
150
—
—
—
7.0
125
—
95
V
V
V
°C
°C
%
2
Lucent Technologies Inc.
Data Sheet
June 1998
L7590C Telephone Ringing Driver
Recommended Operating Conditions
Parameter
Ambient Temperature
VDD Supply Voltage
VNEG Supply Voltage
Min
Typ
Max
Unit
–40
4.75
–170
—
5.0
—
85
5.25
–130
°C
V
V
Electrical Characteristics
Electrical characteristics apply for 25 °C. Unless noted, VDD = +5 V, VNEG = –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
Power Supply—Idle (CLK = H or L, EN = high, dc):
IDD
INEG
Power Dissipation
Power Supply—Active, No Load:
IDD
INEG
Power Dissipation
Efficiency = {[(VOUT)2/RLOAD]/(VNEG • INEG)}:
Sinking Current, RLOAD = 1400 Ω Load to GND
Sourcing Current, RLOAD = 1400 Ω Load to VNEG
ON-resistance:
CLK = H, IOUT = –20 mA
CLK = L, IOUT = +20 mA
Current Limit
Lucent Technologies Inc.
Min
Typ
Max
Unit
—
—
—
—
—
—
1
–50
13.5
mA
µA
mW
—
—
—
—
–3.2
—
3
–8
1.38
mA
mA
W
40
40
80
80
—
—
%
%
0
0
25
10
10
—
20
20
40
Ω
Ω
mApeak
3
Data Sheet
June 1998
L7590C Telephone Ringing Driver
Functional Description
Operation
Ringer Requirements
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-voltage 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.
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 µF. In
Germany, 30 mApeak must be delivered to four parallel
telephone sets. In Germany, 4 REN have an impedance of 450 Ω + 3.4 µF. 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 resemble a sine wave, 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.
4
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 µF) load, the
THD was typically 2.0% to 2.5%. With the Germany
4 REN (450 Ω + 3.4 µF) 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 (RILIM) must be added between L1 and
OUT for 5 REN loads.
* HP is a registered trademark of Hewlett-Packard Company.
Lucent Technologies Inc.
Data Sheet
June 1998
L7590C Telephone Ringing Driver
Application
RP
20 Ω
PT
TIP
L7581
RELAY
250 V PROT
DR
RCV
RP
20 Ω
SLIC
PR
RING
DX
XMT
CODEC
RING TRIP
DETECT
RTS1
400 Ω
CB
0.1 µF
VDD
VDD
GNDD
CB1
CB2
EN
OUT
CLK
RILIM
L7590C
RINGING
GENERATOR
PWM
SIGNAL
L2
C1
1.0 µF
L1
L1
20 mH
GNDR
VREF
C2
1 µF
VNEG
CNEG*
1.0 µF
RX 15 Ω
VNEG
* CNEG connects to VNEG 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
L1
C1
C2
CB
Rx
RILIM
20 mH
1 µF, 250 V, 20%
1 µF, 20 V, 20%
0.1 µF, 10 V, 20%
15 Ω, 1 W
20 Ω to 100 Ω
Lucent Technologies Inc.
Function
Part of LC output filter
Part of LC output filter
VREF filter
Voltage doubling capacitor
Hot insertion limiter
Current-limiter adjustment
5
Data Sheet
June 1998
L7590C Telephone Ringing Driver
Application (continued)
12-3381 (F)
12-3380 (F)
A. Upper = PWM Signal Centered at 100 kHz
Lower = Modulating Signal
B. Same as A but Expanded
Figure 3. Modulation Waveforms
6
Lucent Technologies Inc.
Data Sheet
June 1998
L7590C Telephone Ringing Driver
Application (continued)
12-3379 (F)
A. Upper = 10% Duty Cycle—CLK Input
Lower = L7590C Output
12-3377 (F)
B. 50% Duty Cycle
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
Lucent Technologies Inc.
7
Data Sheet
June 1998
L7590C Telephone Ringing Driver
Application (continued)
HP 3311A
HP 8116A
SIGNAL
GENERATOR
PULSE/FUNCTION
GENERATOR
100 kHz RATE
25 Hz
+5 V
SIGNAL LEVEL = 0 V TO 5 V
100 kHz (PWM)
0.1 µF
GNDD VDD CB1 CB2
OUT
CLK
RILIM
C1
1.0 µF
L1
L7590C
450 Ω
1386 Ω
20 mH
EN
VREF
VNEG
3.4 µF
L2
GNDR
40 µF
CNEG
1.0 µF
C2
1 µF
RX
HP 3585A
VNEG = –170 V
SPECTRUM
ANALYZER
12-3375.B(F)
Notes:
2
2
2
E2 + E3 + E4 + . . .
THD % = ----------------------------------------------------------------------------------x 100.
2
2
2
2
E1 + E2 + E3 + E4 + . . .
RX = 15 Ω.
Figure 5. L7590C Test Connections
8
Lucent Technologies Inc.
Data Sheet
June 1998
L7590C Telephone Ringing Driver
Outline Diagram
16-Pin, Plastic SOG
Dimensions are in millimeters.
L
N
B
1
PIN #1 IDENTIFIER ZONE
W
H
SEATING PLANE
0.10
1.27 TYP
0.51 MAX
0.61
0.28 MAX
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
5-4414r2 (C)
Lucent Technologies Inc.
9
Data Sheet
June 1998
L7590C Telephone Ringing Driver
Ordering Information
Device Part No.
LUCL7590CAE-D
LUCL7590CAE-DT
Description
Telephone Ringing Driver
Telephone Ringing Driver
Package
16-Pin SOG
16-Pin SOG (Tape and Reel)
Comcode
108191107
108191115
For additional information, contact your Microelectronics Group Account Manager or the following:
INTERNET:
http://www.lucent.com/micro
E-MAIL:
[email protected]
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1-800-372-2447, FAX 610-712-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106)
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Tel. (65) 778 8833, FAX (65) 777 7495
CHINA:
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Shanghai 200233 P. R. China Tel. (86) 21 6440 0468, ext. 316, FAX (86) 21 6440 0652
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Tel. (81) 3 5421 1600, FAX (81) 3 5421 1700
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Data Requests: MICROELECTRONICS GROUP DATALINE: Tel. (44) 1189 324 299, FAX (44) 1189 328 148
Technical Inquiries: GERMANY: (49) 89 95086 0 (Munich), UNITED KINGDOM: (44) 1344 865 900 (Bracknell),
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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)