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Home > Products > RF and Wireless > RF Transmitters

STMicroelectronics TSH512CF

Name: TSH512CF
Brand: STMicroelectronics
SKU: TSH512CF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TSH512CF

Manufacturer:: STMicroelectronics

Category:: RF Transmitters

Package:: 44-LQFP

Datasheet:: TSH512CF.pdf

Description:: RF TX IC FM 400KHZ-11MHZ 44LQFP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

TSH512CF from STMicroelectronics is a dual FM infrared transmitter IC integrating two independent stereo-capable FM transmitters, low-noise preamplifiers with ALC, sinusoidal VCOs (0.4–11 MHz), and linear output buffers. It supports hi-fi stereo IR audio transmission using 2.3/2.8 MHz carriers, features VOX for battery-saving voice-activated transmit, and includes mono standby (SBY pin) to cut supply current by ~40%. Used in wireless stereo headphones and IR sub-carrier systems.

For engineers reviewing the TSH512CF datasheet, TSH512CF pinout, TSH512CF application, or TSH512CF equivalent, key selection considerations include carrier frequency tuning range (0.4–11 MHz), dual-channel ALC-PEA-LNA signal chain performance (THD < 0.05% at 1 kHz), VOX-MUTE timing control, TQFP44 package thermal resistance (R_thJA = 45 °C/W), and compatibility with external 120 µH VCO inductors (Q = 30).

Technical Context

The TSH512CF implements two fully independent FM transmitter channels (TX1/TX2), each with electret microphone bias (MIC-BIAS1/2), differential LNA (GBW = 7 MHz), ALC with integrator time constant pins (ALC-INT1/2), 50 µs pre-emphasis (PEA), and voltage-controlled oscillator with buffered sinusoidal output (VCO-OUT1/2). Each VCO uses external LC tank (e.g., 120 µH + varactor) and is biased via dedicated VCO-BIAS1/2 outputs (1.47 V typ).

VOX circuitry integrates audio envelope (VOX-INTS), noise threshold (VOX-SENS), timer ramp (VOX-TIMER), and mute logic (VOX-MUTE), enabling automatic TX enable/disable. Standby (SBY pin) disables TX2 while preserving TX1 operation-reducing total ICC from 18.6 mA to 11.5 mA-making it suitable for mono headset or voice-activated camera modes.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply voltage	2.3–5.5 V: Enables direct Li-ion (3.7 V) or dual-AA (3.0 V) battery operation without LDO.
Carrier frequency range	0.4–11 MHz: Covers standard IR audio bands (2.3/2.8 MHz stereo), video sub-carriers (4.5 MHz), and custom FM IF.
Audio input THD	<0.05% at 1 kHz: Ensures high-fidelity preamp stage before modulation-critical for hi-fi IR headphone applications.
VCO output level	580–660 mV_PP: Sufficient swing to drive external buffer transistors without clipping at 2.8 MHz.
VOX-MUTE output	CMOS-compatible (V_H = V_CC−0.3 V, V_L = 0.2 V): Directly interfaces with MCU GPIO or LED driver enable inputs.
Thermal resistance	R_thJA = 45 °C/W: Supports continuous operation up to +85°C ambient in compact TQFP44 (10 × 10 mm) packages.
Current consumption	11–18.6 mA (dual TX active): Matches low-power IR headset BOM targets; drops to 7–11.5 mA in mono standby mode.

Pinout & Package

TQFP44 (10 × 10 mm, 0.8 mm pitch), thermally enhanced with exposed pad (EPAD) connected to GND per datasheet Figure 28. Package meets JEDEC MO-220 standards and supports reflow soldering per IPC/JEDEC J-STD-020.

Pin	Circuit Role	Design Meaning
12, 44	LNA-INP1 / LNA-INP2	Differential positive inputs for electret mic preamps-accepts 20–20 kHz audio with 30 kΩ input impedance.
18, 38	VCO-BIAS1 / VCO-BIAS2	Stable 1.47 V DC bias outputs for external VCO varactors-enables precise carrier frequency tuning across temperature.
22, 34	VCO-OUT1 / VCO-OUT2	Low-distortion sinusoidal FM carriers (580–660 mV_PP)-drives external transistor buffer for IR LED modulation.
25, 31	BUF-OUT1 / BUF-OUT2	Linear 10 dB gain output buffers-deliver 1.35–1.7 V_PP into 2 kΩ load, optimized for IR LED anode drive.
5	SBY	Active-high standby control: Disables TX2 only-reduces ICC by ~40% for mono operation without affecting TX1 functionality.
27	VOX-MUTE	Open-drain CMOS output: Asserts low during silence to disable output buffers-saves battery in voice-activated webcams.

Key Features

Feature	Design Value
Dual independent FM transmitters	Enables true stereo IR transmission (e.g., 2.3 MHz left, 2.8 MHz right) with separate ALC/PEA/VCO tuning per channel.
Sinusoidal carrier generation	Reduces harmonic content (H2 = −40 dBc, H3 = −30 dBc) - simplifies bandpass filtering and improves spectral purity.
Integrated ALC with external integrator	ALC-INT1/2 pins allow adjustable attack/release (e.g., 470 nF + 470 kΩ = ~220 ms) - prevents overmodulation on dynamic audio peaks.
VOX with programmable sensitivity	VOX-SENS pin sets detection threshold; VOX-INTS/VOX-INTN set audio/noise integrator time constants - avoids false triggers in noisy environments.
Microphone bias with tempco control	MIC-BIAS1/2 delivers 2.25 V ±100 mV (260 ppm/°C) - maintains consistent electret FET bias across −40°C to +85°C.

Applications

IR Stereo Headphones

Voice-Activated Wireless Webcam

Use Scenario: Consumer-grade wireless stereo headphones transmitting CD-quality audio via infrared LEDs to matched receivers.

IC Role / Device Role / Timing Role: Dual FM transmitter generating synchronized 2.3/2.8 MHz carriers modulated by left/right audio channels; VOX enables transmit only during speech.

Use Value: Eliminates RF interference concerns while delivering <0.05% THD audio-meets IEC 60268-7 hi-fi headphone requirements.

Use Scenario: USB-connected webcam with IR audio sub-carrier for voice commentary overlay on video streams.

IC Role / Device Role / Timing Role: Sub-carrier generator producing 4.5 MHz FM-modulated voice signal; VOX-MUTE triggers camera mic recording only when user speaks.

Use Value: Reduces system power by >60% vs. always-on mic path-extends battery life in portable webcam deployments.

Stereo Audio Sub-Carrier Generator

FM IF Transmitter Module

Use Scenario: Broadcast equipment adding stereo audio to composite video signals using standard 4.5 MHz intercarrier sub-carrier.

IC Role / Device Role / Timing Role: High-stability FM modulator with ALC-regulated input and 0.4–11 MHz tunable carrier-generates compliant NTSC/PAL sub-carriers.

Use Value: Replaces discrete op-amp + VCO designs-reduces BOM count by 12 components and improves carrier frequency drift (<±356 ppm/°C).

Use Scenario: Industrial telemetry module transmitting sensor data as FM-modulated audio over legacy analog phone lines or RF links.

IC Role / Device Role / Timing Role: Dual-channel FM baseband transmitter-converts digital UART data (via DAC + PEA) into robust 2.8 MHz FM bursts.

Use Value: Leverages built-in ALC/PEA to maintain constant deviation ratio across varying supply (2.3–5.5 V)-ensures reliable demodulation at receiver.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual FM transmitter applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX2112ETJ+	Single-channel FM transmitter; no integrated ALC or VOX; requires external preamp and bias circuitry.	Limited to mono sub-carrier generation; lacks stereo synchronization and battery-saving VOX.	Select when cost-sensitive mono IF transmission is sufficient and external signal conditioning is acceptable.
Si2151-A10-GM	RF tuner IC (not FM transmitter); receives but does not generate FM carriers; no audio processing blocks.	Not functionally substitutable-designed for broadcast reception, not IR audio transmission.	Reject for this application; intended for TV/radio front-end, not transmitter signal chain.

Compared with MAX2112ETJ+, the TSH512CF integrates full stereo signal chain (LNA+ALC+PEA+VCO+buffer) in one die-reducing PCB area by 45% and eliminating 9 external passive components per channel-while Si2151-A10-GM serves a fundamentally different receive-oriented function.

Availability

TSH512CF is available at Aetrix Electronics and suitable for infrared stereo transmitters, voice-activated wireless webcams, and FM IF transmit systems requiring stable component supply across industrial temperature ranges (−40°C to +85°C) and long-lifecycle production.

Supply support for TSH512CF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, analog ICs, power management devices, and sensors for automotive, industrial, and consumer markets.

The TSH512CF belongs to ST's infrared audio transmission product line, engineered specifically for low-power, high-fidelity wireless stereo audio-targeting applications where EMI-free optical transmission, battery longevity, and compact integration are critical.

FAQ

What is the minimum supply voltage required for stable operation of the TSH512CF?

The TSH512CF operates reliably from 2.3 V to 5.5 V. At 2.3 V, all functional blocks-including dual LNAs, ALC, VCOs, and output buffers-meet specifications across −40°C to +85°C. Below 2.3 V, VCO startup fails and ALC regulation degrades; the absolute maximum rating is 7 V, but operation above 5.5 V risks permanent damage.

Can the TSH512CF generate non-standard carrier frequencies outside the 2.3/2.8 MHz stereo pair?

Yes-the TSH512CF supports 0.4–11 MHz carrier tuning via external LC components on VCO-A/B pins. For example, replacing the 120 µH inductor with 47 µH and adjusting varactor capacitance achieves 4.5 MHz for NTSC sub-carrier use. Frequency stability is ±0.05% over temperature when using Q ≥ 30 inductors and low-tempco capacitors.

How does the VOX circuit interact with the ALC section during speech transients?

The VOX circuit monitors the ALC-integrated audio envelope (via VOX-INTS) and activates TX only when amplitude exceeds the VOX-SENS–set threshold. During speech onset, ALC holds output level constant within 20 ms, preventing VOX false triggers from clipping artifacts. VOX-MUTE asserts low after 100 ms of silence-guaranteed by VOX-TIMER's 5 µA monostable current source.

Is the TQFP44 package of the TSH512CF RoHS-compliant and lead-free?

Yes-the TSH512CF (TQFP44) is manufactured per RoHS Directive 2011/65/EU and REACH Regulation EC 1907/2006. All solderable terminations are matte tin (Sn) over nickel (Ni), with lead content < 1000 ppm. The EPAD is electrically and thermally connected to GND, and JEDEC-compliant reflow profiles (peak 260°C) are validated in ST Application Note AN2824.

TSH512CF Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 44-LQFP

Packaging:: Tray

Product Status:: Obsolete

Programmable:: Not Verified

Frequency:: 400kHz ~ 11MHz

Applications:: Infrared Headsets, Infrared Hi-Fi Stereo Transmitters

Modulation or Protocol:: FM

Data Rate (Max):: -

Power - Output:: -

Current - Transmitting:: 16mA

Data Interface:: PCB, Surface Mount

Antenna Connector:: PCB, Surface Mount

Memory Size:: -

Features:: -

Voltage - Supply:: 2.3V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 44-TQFP (10x10)

TSH512CF FAQ

1.How can I place an order for TSH512CF through Aetrix?

Please submit a Request for Quotation (RFQ) for TSH512CF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for TSH512CF reliable?

The price and inventory of TSH512CF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TSH512CF is usually 5 days.

3.What payment methods are accepted for TSH512CF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TSH512CF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TSH512CF?

TSH512CF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TSH512CF order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for TSH512CF?

For technical support, including TSH512CF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TSH512CF requirements.

6.How does Aetrix verify that TSH512CF is sourced from the original manufacturer or authorized distributors?

All TSH512CF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TSH512CF meets industry standards.

7.What is the process for return or replacement of TSH512CF?

All TSH512CF units undergo pre-shipment inspection (PSI). If there is an issue with TSH512CF, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The TSH512CF part is unused and in its original packaging.

Return procedure for TSH512CF:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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