ST7537HS1CFN Overview
For specific applications, there are several 28 pins available.
ST7537HS1CFN Features
28 pin count

ST7537HS1CFN Applications
There are a lot of STMicroelectronics
ST7537HS1CFN Modems ICs & Modules applications.

Wireless network systems
Satellite communications networks
Ethernet circuitry
Wired telephone
Cordless telephone
Desktop PC
Notebook
Pocket PC
Desktop radio
Clock radio

ECCN (US)	EAR99
Main Category	Single Chip
Maximum Data Rate Range	2.4Kbps to 20Kbps
Maximum Data Rate	2.4Kbps
Minimum Operating Supply Voltage (V)	9.5|4.75
Typical Operating Supply Voltage (V)	5|10
Maximum Operating Supply Voltage (V)	10.5|5.25
Typical Supply Current (mA)	1.5|30
Minimum Operating Temperature (°C)	0
Maximum Operating Temperature (°C)	70
Standard Package Name	LCC
Supplier Package	PLCC
Mounting	Surface Mount
Package Height	4.06(Max)
Package Length	11.58(Max)
Package Width	10.92(Max)
PCB changed	28
Lead Shape	J-Lead
Part Status	Obsolete
Pin Count	28
Modulation Technique	FSK
Power Supply Type	Analog|Digital
RoHS Status	RoHS non-compliant