ATMEGA161L-4AC - 16KB Flash 4MHz AVR MCU 44-TQFP | Microchip
Référence : ATMEGA161L-4AC ✗ Fin de vie| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $8.5 | $8,50 |
| 10 | $7.85 | $78,50 |
| 100 | $7.15 | $715,00 |
| 500 | $6.65 | $3 325,00 |
| 1 000 | $6.2 | $6 200,00 |
ATMEGA161L-4AC Présentation
An 8-bit microcontroller is a complete computing system on a single chip, combining a processor core, program memory, data memory, timers, and serial communication peripherals into one package. Within the embedded hierarchy, the AVR ATmega family sits under Microchip's (formerly Atmel's) microcontroller product line, which itself belongs to the broader categories of MCU, integrated circuit, and semiconductor.
Key features include the Advanced RISC architecture executing 130 powerful instructions, most in a single clock cycle; 32 general-purpose working registers; three flexible Timer/Counters with compare modes; a real-time counter; and a programmable Watchdog Timer with an internal oscillator.
Technically, the ATmega161 integrates two programmable serial UARTs - a distinguishing feature for its class - plus an SPI serial interface and internal and external interrupt sources. The external oscillator type supports precise clocking, and the device supports In-System Programming and Self-programming of Flash for field updates. External memory expansion is supported through an address/data bus interface.
Typical applications include legacy industrial control systems, dual-UART communication gateways, appliance control boards, and maintenance/repair of existing ATmega161-based equipment.
Design consideration: since the ATmega161 family is discontinued, new designs should target its pin-compatible successor ATmega162, while repair programs can fall back on this L-grade 4MHz variant for low-voltage systems.
This page synthesizes distributor availability, drop-in alternatives, pricing history, and practical design notes not found in the manufacturer datasheet.
Alternatives de remplacement direct pour ATMEGA161L-4AC — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec ATMEGA161L-4AC (même facteur de forme et même empreinte) — différant par Supply Voltage Range, Flash Memory, Instruction Set, Package, Mounting Type.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
ATMEGA161L-4PI
✅ Remplacement direct✓ En stock
$6.35 / unité
Voir la fiche technique →ATMEGA161-4AC
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
ATMEGA162-16AU
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$2.45 / unité
Voir la fiche technique →ATMEGA16-16AU
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$4.41 / unité
Voir la fiche technique →ATMEGA128-16AU
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$14.3 / unité
Voir la fiche technique →ATMEGA161L-4AC Valeurs maximales et caractéristiques électriques
| Core Processor | AVR 8-bit |
| Core Size | 8-bit |
| Speed | 4 MHz |
| Program Memory Size | 16 KB (8K x 16) FLASH |
| Program Memory Type | FLASH (In-System or Self-programmable) |
| RAM Size | 1 KB (1K x 8) SRAM |
| EEPROM Size | 512 bytes |
| Number of I/O | 35 |
| Working Registers | 32 general purpose |
| Instruction Set | 130 powerful instructions, most single-cycle |
| Connectivity | SPI, 2x UART/USART |
| Peripherals | 3x Timer/Counter with Compare, WDT, Real-time Counter |
| Oscillator Type | External |
| Boîtier / Format | 44-TQFP (10x10 mm) |
| Type de montage | Surface Mount |
| Packaging | Tray |
Configuration des broches de ATMEGA161L-4AC
| Broche 1 | PB0/SS — Port B bit 0 / SPI Slave Select |
| Broche 2 | PB1/T1 — Port B bit 1 / Timer1 external clock input |
| Broche 3 | PB2/AIN0 — Port B bit 2 / Analog Comparator input 0 |
| Broche 4 | PB3/AIN1 — Port B bit 3 / Analog Comparator input 1 |
| Broche 5 | PB4/OC0 — Port B bit 4 / Timer0 Output Compare |
| Broche 6 | PB5/SCK — Port B bit 5 / SPI Serial Clock |
| Broche 7 | PB6/MISO — Port B bit 6 / SPI Master In Slave Out |
| Broche 8 | PB7/MOSI — Port B bit 7 / SPI Master Out Slave In |
| Broche 9 | RESET — Active-low reset input |
| Broche 10 | VCC — Digital supply voltage |
| Broche 11 | GND — Ground |
| Broche 12 | XTAL1 — External oscillator input |
| Broche 13 | XTAL2 — External oscillator output |
| Broche 14 | PD0/RXD0 — Port D bit 0 / UART0 receive |
| Broche 15 | PD1/TXD0 — Port D bit 1 / UART0 transmit |
| Broche 16 | PD2/RXD1 — Port D bit 2 / UART1 receive |
| Broche 17 | PD3/TXD1 — Port D bit 3 / UART1 transmit |
| Broche 18 | PD4/INT0 — Port D bit 4 / External interrupt 0 |
| Broche 19 | PD5/INT1 — Port D bit 5 / External interrupt 1 |
| Broche 20 | PD6/ICP1 — Port D bit 6 / Timer1 Input Capture |
| Broche 21 | PD7/OC2 — Port D bit 7 / Timer2 Output Compare |
| Broche 22 | PC0 — Port C bit 0 / general purpose I/O |
| Broche 23 | PC1 — Port C bit 1 / general purpose I/O |
| Broche 24 | PC2 — Port C bit 2 / general purpose I/O |
| Broche 25 | PC3 — Port C bit 3 / general purpose I/O |
| Broche 26 | PC4 — Port C bit 4 / general purpose I/O |
| Broche 27 | PC5 — Port C bit 5 / general purpose I/O |
| Broche 28 | PC6 — Port C bit 6 / general purpose I/O |
| Broche 29 | PC7/TOSC2 — Port C bit 7 / RTC oscillator output |
| Broche 30 | PC8/TOSC1 — RTC oscillator input pin (TOSC1) |
| Broche 31 | PA7 — Port A bit 7 / address/data bus (external memory) |
| Broche 32 | PA6 — Port A bit 6 / address/data bus (external memory) |
| Broche 33 | PA5 — Port A bit 5 / address/data bus (external memory) |
| Broche 34 | PA4 — Port A bit 4 / address/data bus (external memory) |
| Broche 35 | PA3 — Port A bit 3 / address/data bus (external memory) |
| Broche 36 | PA2 — Port A bit 2 / address/data bus (external memory) |
| Broche 37 | PA1 — Port A bit 1 / address/data bus (external memory) |
| Broche 38 | PA0 — Port A bit 0 / address/data bus (external memory) |
| Broche 39 | VCC — Digital supply voltage |
| Broche 40 | GND — Ground |
| Broche 41 | PE0/ALE — Port E bit 0 / External memory Address Latch Enable |
| Broche 42 | PE1/OC1B — Port E bit 1 / Timer1 Output Compare B |
| Broche 43 | PE2/OC1A — Port E bit 2 / Timer1 Output Compare A |
| Broche 44 | WR/RD — External memory write/read strobes |
Applications typiques
ATMEGA161L-4AC convient pour 6 applications: Legacy Industrial Control Systems, Dual-UART Communication Gateways, SPI Peripheral Expansion and Monitoring, Appliance and Consumer Equipment Control, Battery-Powered Low-Voltage Instruments, External-Memory Expandable Data Loggers.
Legacy Industrial Control Systems
The ATMEGA161L-4AC fits legacy industrial control boards originally designed around the ATmega161 because it is the exact silicon that these controllers were qualified with. Its 16KB Flash holds ladder-style or state-machine control firmware, while 1KB SRAM and 512B EEPROM retain setpoints and counters across power cycles. The 35 I/O lines directly drive relays, contactors, and indicator stacks through the three Timer/Counters with compare modes for deterministic PWM and timing. In repair and sustaining programs, swapping a failed device with the identical 4MHz L-grade part avoids any requalification: no firmware changes, no crystal retuning, and identical electrical behavior on 24V industrial panel boards. Supply from broker stock is the trade-off, so maintenance planners should buy spares in batches while stock persists.
Recommandé
Dual-UART Communication Gateways
The distinguishing feature of the ATMEGA161L-4AC for protocol conversion work is its pair of programmable serial UARTs, rare in 8-pin-count AVRs of its generation. A gateway can simultaneously listen on an RS-485 field bus on UART0 and stream to an RS-232 service port on UART1, buffering messages in the 1KB SRAM. At 4MHz, the AVR core sustains baud rates up to 38.4 kbps on both ports concurrently with headroom for framing and CRC checks in the 130-instruction single-cycle RISC core. The external oscillator ensures the baud-rate generator accuracy needed for multi-drop buses, and the Watchdog Timer with internal oscillator recovers the link after bus faults. This makes the part well suited to maintaining installed Modbus-RTU style bridges and repeater nodes that cannot be redesigned.
Recommandé
SPI Peripheral Expansion and Monitoring
With its hardware SPI interface, the ATMEGA161L-4AC acts as an efficient master for serial EEPROMs, RTCs, ADCs, and display drivers in existing designs. The SPI bus plus the parallel external-memory interface let one low-cost MCU coordinate both fast local peripherals and memory-mapped I/O, using ALE and read/write control lines on the expansion port. The 4MHz external clock gives deterministic SPI SCK rates suitable for legacy data-acquisition cards where cycle-accurate sampling intervals are enforced by Timer/Counter interrupts. Three flexible Timer/Counters with compare modes timestamp events without core intervention, conserving the 1KB SRAM for data staging. In sustaining engineering, this part keeps 1990s-era SPI-based instrument control boards running without any layout or firmware changes.
Recommandé
Appliance and Consumer Equipment Control
White-goods and small-appliance controllers from the ATmega161 generation used exactly this L-grade part for its low-voltage tolerance and robust I/O count. The 35 general-purpose I/O lines cover keypads, seven-segment or LCD drive, triac controls, and door-interlock sensing without port expanders, while the 512-byte EEPROM stores cycle counters and user preferences through power interruptions. The programmable Watchdog Timer with its own internal oscillator guarantees recovery from lockups even if the main 4MHz external oscillator fails - an important safety behavior in heater and motor-control appliances. Because the die is unchanged from fielded units, a service replacement restores original firmware behavior, EMC characteristics, and safety qualifications, avoiding the recertification cost that any redesign would trigger.
Recommandé
Battery-Powered Low-Voltage Instruments
The 'L' speed grade of the ATMEGA161L-4AC is the low-voltage member of the family, characterized for operation down to approximately 2.7V at 4MHz, which makes it appropriate for 3-cell battery instruments designed to run without a 5V regulator stage. The external oscillator allows a low-cost 4MHz crystal chosen for accurate Timer/Counter timing during measurement windows, while idle and power-down sleep modes stretch battery life between readings. The real-time counter keeps long-interval logs independent of the main clock, and 512 bytes of EEPROM retains calibration constants across battery swaps. For repair of portable gauges, meters, and loggers, specifying the identical L-grade die preserves the validated power budget of the original design.
Recommandé
External-Memory Expandable Data Loggers
Unlike many small AVRs, the ATMEGA161L-4AC includes a full external memory expansion interface with address latching (ALE) and read/write strobes, letting designs extend beyond the internal 1KB SRAM using standard SRAM or memory-mapped peripherals. A data logger can thus dedicate internal SRAM as a fast ring buffer while cycling large external SRAM banks for extended event storage, timed by the three compare-mode Timer/Counters. The dual UARTs allow one port for sensor intake and a second for periodic offload to a host, and the Watchdog Timer guarantees logger recovery in unattended installations. For keeping aging logger platforms in service, the identical 44-TQFP device drops onto the existing board with the original 4MHz crystal and bus timing fully preserved.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour ATMEGA161L-4AC — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | ATMEGA161L-4PI | ATMEGA162-16AU | ATMEGA16-16AU | ATMEGA128-16AU |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (AVR TQFP family) |
| Max Speed | 4 MHz | 4 MHz | 16 MHz | 16 MHz | 16 MHz |
| Flash | 16 KB | 16 KB | 16 KB | 16 KB | 128 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 1 KB | 4 KB |
| EEPROM | 512 bytes | 512 bytes | 512 bytes | 512 bytes | 4 KB |
| UART / USART Count | 2 | 2 | 2 | 1 | 2 |
| ADC | No | No | No | Yes, 8ch 10-bit | Yes, 8ch 10-bit |
| Lifecycle Status | Obsolete | Obsolete (broker stock only) | Active | Active | Active |
Principaux différenciateurs
- Dual UARTs in a 16KB AVR (vs ATMEGA16-16AU)
- True ATmega161 silicon for legacy repair (vs ATMEGA162-16AU)
- External memory expansion interface (vs ATMEGA16-16AU)
Notes de conception
The ATMEGA161L-4AC is an obsolete part sourced from broker inventory, so date codes and plating may vary between batches. Before committing to a production repair run, verify the package suffix (C = commercial grade, lead finish may be legacy tin-lead on older stock) against your RoHS obligations, and request date-code photos. The 'L' grade is rated at 4MHz only; do not substitute a higher-speed clock expecting full characterization, as the low-voltage speed limit is the binding constraint on this die.
The 44-TQFP (10x10 mm) footprint requires the 0.8mm pitch land pattern per the Atmel package drawing; keep the crystal within 15mm of XTAL1/XTAL2 with short return grounds, since the 4MHz external oscillator drives both UART baud-rate generators and any timing error shifts both serial ports simultaneously. Decouple both VCC pins (10 and 39) individually with 100nF ceramics placed within 5mm of each pin, and provide a solid ground plane for the SPI bus integrity.
Estimated: the L-grade ATmega161 is characterized for operation down to approximately 2.7V at 4MHz per the family datasheet. When powering from a 3V battery rail, budget for active current in the low single-digit mA range at 4MHz plus peripheral current for two UARTs and SPI. If your board must also accept a 5V supply during programming, check the ISP programmer voltage compatibility - programming a 3V system with a 5V-only ISP tool risks overstressing the die.
Informations de conformité
Compliance status not stated in reviewed distributor listings. Commercial-grade ('C' suffix) legacy part may have tin-lead plating depending on date code; the industrial 4PI variant carries Pb-free plating per suffix coding. Request material declarations from the seller.