The BCM4775 was announced on 21 Sep 2017 in GPSWorld. It is the first generation of dual-frequency GNSS receivers from Broadcom.
There are 4 different chipsets in the BCM4775X family - BCM47758 + BCM47755 (dual-frequency) and BCM47754 + BCM47752 (single-frequency).
The BCM47752 and BCM47755 are both mentioned in the article Dual-frequency GNSS on Android devices by Sean Barbeau in Apr 2018.
The GPSTest Database shows the BCM4775 in various Android phones and tablets:
The BCM47758 is a first generation dual-frequency GNSS chipset supporting L1 + L5. It is used in the Quectel LC29D(A) module, detailed in the announcement and specification document, which shows a 1 Hz update rate. It is tailored for wearable devices according to the product brief.
It is used in various Samsung products, including:
Synaptics may produce and sell the BCM47758, but calling it the SYN47758.
The BCM47755 is a first generation dual-frequency GNSS chipset supporting L1 + L5, now showing on the Broadcom website as “Not Recommended for New Design”. The conference paper Android GNSS Measurements Inside the BCM47755 (Broadcom, 2018) studies the performance in Android.
The BCM47755 is used in the Quectel LC29D(C) module, detailed in the specification document has a 1 Hz update rate. It can also be found in the Quectel LC79D, detailed in a product overview and product brochure.
The BCM47755 appears in several phones, tablets, and watches:
Synaptics may produce and sell the BCM47755, but it calling it the SYN47755.
The BCM47754 is a single-frequency GNSS chipset supporting GPS, GLONASS, BeiDou, Galileo, and QZSS.
It is used in the Apple Watch Series 6 and mentioned in a teardown on reverse-costing.com.
Aside from this it is rarely mentioned in Google results, possibly being specific to Apple watches?
The BCM47752 is a single-frequency GNSS chipset supporting GPS, GLONASS, BeiDou, Galileo, and QZSS.
Several Samsung phones use the BCM47752, including:
Synaptics may produce and sell the BCM47752, but it calling it the SYN47752.