ST7538P STMicroelectronics, ST7538P Datasheet - Page 25

• Manufacturer Part Number: ST7538P
• Description: Telecom Line Management ICs 1/2 Duplex FSK Modem
• Manufacturer: STMicroelectronics
• Type: Single Chipr

Specifications of ST7538P

• Product: Modem Chip
• Supply Voltage (max): 5.25 V, 12.5 V
• Supply Voltage (min): 4.75 V, 7.5 V
• Supply Current: 5 mA, 370 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Package / Case: TQFP-44
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.9 5V Voltage Regulator and Power Good Function
ST7538 has an embedded 5V linear regulator externally available to supply the application circuitry.
The linear regulator has a very low quiescent current (50µA) and a current capability of 100mA. The reg-
ulator is protected against short circuitry events.
When the regulator Voltage is above the power good threshold (V
while is forced low at startup and when VDC falls below V
Figure 24. Power Good Function
4.10 Power-Up Procedure
To ensure ST7538 proper power-Up sequence, PAVcc, AVss and DVss Supply has to fulfil the following
rules:
1) PAVcc rising slope must not exceed 100V/ms.
2) When DVdd and AVdd are below 5V (externally supplied): 100mV < PAVcc-AVdd , PAVcc-DVdd < 1.2V.
When AVdd and DVdd supply are connected to VDC, with load < 100mA and filtering capacitor on VDC
< 100uF, the second rule can be ignored.
Figure 25. Power-UP Sequence
PAVcc-DVdd
PAVcc-AVdd
Voltage
5V
V
PG
DC
4.5V
100V/ms
PG OK
PG
D03IN1411
- V
DVdd, AVdd
PGHYS
250mV
PAVcc
PG)
Time
Time
D03IN1424
, Power Good line is forced high,
Voltage.
Time
ST7538
25/30