Application information

STLC3055N

18/34

4

RF1 sets the self generated battery voltage in Ring and Active (Il=0) mode as follows:

provided that the Vpos power supply current capability and the RSENSE programming allow to source all the current

requested by the particular ringer load configuration.

5

For high efficiency in HI-Z mode coil resistance @125 kHz must be < 3

Ω

CVpos

Positive supply filter capacitor

with low impedance for switch

mode power supply

100

CV

Battery supply filter capacitor

with low impedance for switch

mode power supply

100

CVB

High frequency noise filter

470 nF 20% 100 V

High frequency noise filter

100 nF 10% 15 V

Q1

DC/DC converter switch P-

channel MOS transistor

RDS(ON)

≤ 1.2 Ω,VDS = -100 V

Total gate charge = 20 nC max.

with VGS = 4.5 V and VDS = 1 V

ID > 500 mA

Possible choiches:

IRF9510 or IRF9520 or

IRF9120 or equivalent

D1

DC/DC converter series diode

SMBYW01-200

or equivalent

RSENSE

DC/DC converter peak current

limiting

110 m

Ω

RF1

Negative battery programming

level

250 k

300 k

Ω 1%

RF2

Negative battery programming

level

9.1 k

Ω 1%

L

DC/DC converter inductor

DC resistance

L=100

μH

SUMIDA CDRH125 or equivalent

1.

CVpos should be defined depending on the power supply current capability and maximum allowable ripple.

2.

For low ripple application use 2 x 47

μF in parallel.

3.

Can be saved if proper PCB layout avoid noise coupling on RD pin (high impedance input).

267 k

Ω

280 k

Ω

294 k

Ω

300 k

Ω

-46 V

-48 V

-49 V

-50 V

-62 V

-65 V

-68 V

-70 V

Table 10.

External components (continued)

Name

Function

Formula

Typ. value

Table 11.

External components @gain set = 0

Name

Function

Formula

Typ. value

RS

Protection resistance image

RS = 50

⋅ (2Rp)

5 k

Ω @ Rp = 50 Ω

ZAC

Two wire AC impedance

ZAC = 50

⋅ (Zs - 2Rp)

25 k

Ω 1% @ Zs = 600 Ω

SLIC impedance balancing

network

ZA = 50

⋅ Zs

30 k

Ω 1% @ Zs = 600 Ω