My Inquiry
My Account
Asahi Kasei Microdevices/AKM AK7903
- Part No.:
- AK7903
- Manufacturer:
- Asahi Kasei Microdevices/AKM
- Package:
- 16-UFQFN Exposed Pad
- Datasheet:
-
AK7903.pdf
- Description:
- IC REG BUCK ADJ 400MA 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,468
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
AK7903 from Asahi Kasei Microdevices is a fixed-current-controlled DC-DC step-down converter optimized for NiH₂ battery charging, featuring integrated power MOSFET, built-in general-purpose op-amp with selectable gain (3.75× or 1.96×), ±5% charger current accuracy, and operation down to 3.8 V input. It supports 0.2–3.6 V output voltage, up to 400 mA charge current, and includes thermal shutdown (120°C) and overcurrent protection.
For engineers reviewing the AK7903 datasheet, AK7903 pinout, AK7903 application, or AK7903 equivalent, key selection considerations include its QFN-16 (3.0 × 3.0 mm) package, external resistor–adjustable switching frequency (<±2%), built-in SENSE-resistor current detection, and dual-role functionality as both charger controller and battery-monitoring amplifier in portable NiH₂ systems.
Technical Context
The AK7903 implements fixed-current regulation via real-time SENSE pin current monitoring and dynamic FB pin feedback to maintain constant output current across varying battery voltage-critical for safe NiH₂ charging profiles. Its internal PMOS bulk control and cycle-by-cycle current limiting (1.0 A typical) enable robust short-circuit and overload handling without external sensing components.
It integrates two independent op-amp paths with gain-selectable inputs (PIN1/PIN2), controlled by EN2 and CONT pins, allowing CPU-based battery voltage monitoring at either 3.75× or 1.96× amplification. The op-amp operates from a dedicated 2.8–3.2 V VDD supply and draws only 0.1 µA in shutdown mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.1 V to 5.5 V; guaranteed operation down to 3.8 V for single-cell NiH₂ charging |
| Output Current Accuracy | ±5 %; enables precise charge current setting using external SENSE resistor (e.g., 0.353 Ω for 400 mA) |
| Switching Frequency | Externally adjustable via RT pin resistor; ±2 % tolerance at 1.22 MHz nominal |
| Thermal Protection | Shuts down at 120 °C junction temperature; auto-recovers at ≤100 °C |
| Op-Amp Gain Options | Selectable 3.75× (PIN1→OPOUT) or 1.96× (PIN2→OPOUT) via CONT/EN2 logic |
| Shutdown Current | 2 µA typical; enables ultra-low-power battery-backed system monitoring |
| Package | 16-pin UQFN, 3.0 mm × 3.0 mm × 1.8 mm, 0.5 mm pitch, exposed thermal pad (must be grounded) |
Pinout & Package
AK7903 is housed in a 16-pin UQFN package (3.0 mm × 3.0 mm, 0.5 mm pitch) with an exposed thermal pad requiring PCB grounding for thermal performance and electrical stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| NIN | Op-amp inverting input | Accepts negative reference or feedback signal for differential monitoring |
| PIN2 | Op-amp non-inverting input (Gain = 1.96×) | Used with CONT = "H" to monitor battery voltage at reduced gain |
| PIN1 | Op-amp non-inverting input (Gain = 3.75×) | Used with CONT = "L" for higher-resolution battery voltage scaling |
| EN1 | Primary enable input | Active-high control of DC-DC regulator; low disables switching |
| ISET | Charge current configuration | Digital input selecting high/low current mode (e.g., 80 mA or 300/400 mA) |
| SENSE | Current-sense input | Connects to external SENSE resistor to close fixed-current control loop |
| FB | Feedback input | Monitors output voltage to regulate current via DC-DC duty cycle adjustment |
| SW | Switch node | Drives external inductor; connects to internal PMOS drain |
| VIN | DC-DC input supply | Accepts 4.1–5.5 V battery or adapter input; powers internal regulator |
| VDD | Op-amp supply | Separate 2.8–3.2 V rail for analog section; isolates noise from power stage |
| OPOUT | Op-amp output | Delivers amplified battery voltage to MCU ADC; load ≥10 kΩ required |
| CONT | Gain select control | Digital input determining whether PIN1 (L) or PIN2 (H) is active |
| EN2 | Op-amp enable | Activates/deactivates op-amp section independently of DC-DC stage |
| RT | Frequency set | Resistor-connected pin to adjust switching frequency (1.22 MHz nominal) |
| COMP | Compensation | Connects external RC network to stabilize control loop dynamics |
| GND | Ground reference | Common return for power, analog, and thermal pad; must tie to exposed pad |
Key Features
| Feature | Design Value |
|---|---|
| Integrated power MOSFET | Eliminates need for external high-side switch; reduces BOM count and layout area |
| Dual-gain programmable op-amp | Enables flexible battery voltage scaling (1.96× or 3.75×) without external amplifiers |
| External resistor–tuned frequency | Allows optimization of efficiency vs. EMI trade-off via single RT resistor |
| Auto-recovering protections | Thermal shutdown and cycle-by-cycle current limit recover automatically when fault clears |
| Low-shutdown quiescent current | 2 µA shutdown current preserves battery life during idle or storage modes |
Applications
| NiH₂ Battery Charger | Portable Medical Device Power |
|---|---|
Use Scenario: Charging 1- or 2-series NiH₂ battery packs in handheld diagnostic tools with limited board space and strict thermal constraints. IC Role / Device Role / Timing Role: Fixed-current DC-DC charger controller with integrated op-amp for real-time battery voltage telemetry. Use Value: Enables compact, thermally safe charging without external current-sense ICs or op-amps-reducing component count by ≥4. | Use Scenario: Power management in battery-operated infusion pumps requiring accurate charge control and battery health monitoring. IC Role / Device Role / Timing Role: Dual-function IC providing regulated charging current and amplified battery voltage feedback to MCU. Use Value: Delivers ±5% current accuracy and 0.1 µA op-amp standby current-extending runtime between charges by >12% versus discrete solutions. |
| Space-Constrained Satellite Payload | Industrial Handheld Scanner |
Use Scenario: Rechargeable NiH₂ power subsystem in CubeSat payloads where mass, volume, and reliability are critical. IC Role / Device Role / Timing Role: Radiation-tolerant–capable charger IC with thermal foldback and short-circuit protection. Use Value: Built-in 120°C thermal shutdown and auto-recovery allow unattended operation in sealed enclosures without forced cooling. | Use Scenario: Ruggedized barcode scanner with replaceable NiH₂ battery pack and embedded battery fuel gauge. IC Role / Device Role / Timing Role: Combined charger and analog front-end for battery voltage sensing and state-of-charge estimation. Use Value: Integrated op-amp with selectable gain eliminates external signal conditioning, reducing calibration complexity and BOM cost. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NiH₂ battery charger applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231RHLT | Fixed-output buck regulator (not current-mode); no integrated op-amp; requires external current sense and monitoring circuitry | Designed for general LDO replacement, not NiH₂-specific charging profiles or battery telemetry | Choose only if fixed-voltage regulation suffices and external sensing/amplification is acceptable |
| MAX1555 | Dedicated Li-ion charger IC; incompatible chemistry support; lacks op-amp, SENSE-based current control, and NiH₂ voltage range | Targeted at single-cell Li-ion; no provision for NiH₂'s lower voltage per cell or charge termination behavior | Not suitable for NiH₂ systems-chemistry mismatch invalidates charge algorithm and safety margins |
Compared with TPS62231RHLT and MAX1555, the AK7903 uniquely combines NiH₂-optimized fixed-current regulation, integrated op-amp telemetry, and thermal/auto-recovery protection in a single 3 mm × 3 mm package-eliminating design compromises required when mixing discrete charger + monitor functions.
Availability
AK7903 is available at Aetrix Electronics and suitable for portable medical devices, satellite power systems, industrial handheld scanners, and NiH₂-based instrumentation requiring stable component supply and long-term lifecycle support.
Supply support for AK7903 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
Asahi Kasei Microdevices (AKM) is a Japanese semiconductor company specializing in analog, sensor, and mixed-signal ICs for industrial, automotive, and consumer applications.
The AK7903 belongs to AKM's battery management IC product line, designed specifically to simplify NiH₂ charging and monitoring in space-constrained, thermally sensitive portable systems.
FAQ
What is the minimum input voltage required for stable operation of the AK7903?
The AK7903 guarantees full specification compliance at VIN ≥ 4.1 V. However, it maintains functional operation-including fixed-current regulation-for single-cell NiH₂ charging even when VIN drops to 3.8 V, as confirmed in the datasheet's "Operation Overview" section. Below 3.8 V, output current regulation may degrade or cease.
How does the AK7903 achieve fixed-current regulation without an external current-sense amplifier?
The AK7903 achieves fixed-current regulation by directly measuring voltage across the external SENSE resistor via the SENSE pin and dynamically adjusting the FB pin reference to modulate DC-DC output voltage-thereby maintaining constant current through the battery. This closed-loop method eliminates the need for external amplifiers or DACs, as the internal comparator and PWM controller handle all regulation.
Can the AK7903 be used with lithium-ion batteries?
No-the AK7903 is explicitly designed and characterized for NiH₂ battery chemistry, including its voltage range (0.2–3.6 V output), charge profile, and thermal response. Lithium-ion batteries require different termination voltages, CC/CV stages, and safety thresholds; using AK7903 with Li-ion risks undercharging, overvoltage, or thermal runaway due to fundamental algorithm and parameter mismatches.
What is the purpose of the exposed thermal pad on the AK7903 QFN package?
The exposed thermal pad on the AK7903's UQFN package serves dual roles: it provides a low-thermal-resistance path to dissipate heat generated during high-current charging (up to 400 mA), and it acts as the primary ground reference for internal circuits. Per the datasheet, this pad must be soldered to a PCB ground plane-failure to do so risks thermal shutdown, regulation inaccuracy, or device damage under sustained load.
How does the AK7903's op-amp section interface with a microcontroller ADC?
The AK7903's op-amp outputs a scaled version of battery voltage at OPOUT (e.g., 3.75× or 1.96×), referenced to GND and powered by a clean VDD rail. With output swing specified from 0.05 V to VDD−0.05 V and load capability ≥10 kΩ, it drives standard 10-bit or 12-bit MCU ADC inputs directly-enabling precise state-of-charge calculation without external level-shifting or buffering. The AK7903's op-amp also draws only 0.1 µA in shutdown, preserving battery life.
AK7903 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Asahi Kasei Microdevices/AKM
- Series:
- -
- Package/Case:
- 16-UFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.1V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.2V
- Voltage - Output (Max):
- 3.6V
- Current - Output:
- 400mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -30°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (3x3)
AK7903 FAQ
1.How can I place an order for AK7903 through Aetrix?
Please submit a Request for Quotation (RFQ) for AK7903 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 AK7903 reliable?
The price and inventory of AK7903 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AK7903 is usually 5 days.
3.What payment methods are accepted for AK7903?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AK7903 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AK7903?
AK7903 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AK7903 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 AK7903?
For technical support, including AK7903 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AK7903 requirements.
6.How does Aetrix verify that AK7903 is sourced from the original manufacturer or authorized distributors?
All AK7903 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 AK7903 meets industry standards.
7.What is the process for return or replacement of AK7903?
All AK7903 units undergo pre-shipment inspection (PSI). If there is an issue with AK7903, 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 AK7903 part is unused and in its original packaging.
Return procedure for AK7903:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AK7903 Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
