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Analog Devices Inc. LT1621CGN#PBF
- Part No.:
- LT1621CGN#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LT1621CGN#PBF.pdf
- Description:
- IC CURR SENSE 2 CIRCUIT 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,700
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Product details
Overview
LT1621CGN#PBF from Analog Devices (formerly Linear Technology) is a dual-channel rail-to-rail current sense amplifier designed for high-accuracy, high-common-mode battery charging and DC/DC converter current control. It features independent ×1 (SENSE), ×10 (AVG), and ×20 (AVG2) gain outputs, supports 0V–32V input common mode range, delivers >10A load current capability, and enables end-of-charge flag generation in Li-ion systems.
For engineers reviewing the LT1621CGN#PBF datasheet, LT1621CGN#PBF pinout, LT1621CGN#PBF application, or LT1621CGN#PBF equivalent, key selection criteria include dual-loop current sensing capability, 32V common-mode tolerance, ±5mV input offset at ×1 output, programmable PROG/PROG2 thresholds, and GN (16-lead SSOP) package compatibility with industrial temperature range (–40°C to 85°C).
Technical Context
The LT1621CGN#PBF integrates two fully independent current control circuits: each channel includes a high-common-mode sense amplifier (0V–32V VCM), transconductance amplifier (gm = 3500 µmho typ), and dedicated IOUT sink output for PWM controller servoing. Its SENSE output provides level-shifted ×1 gain for direct connection to current-mode PWM controllers, while AVG and AVG2 serve as integration nodes for average current regulation and end-of-cycle detection.
Unlike single-channel variants, the LT1621CGN#PBF supports simultaneous load current (via IN+/IN– A) and input current (via IN+/IN– B) monitoring - enabling coordinated overcurrent protection in SEPIC/buck chargers. The MODE pin is absent in LT1621 (only present in LT1620GN), confirming its role as a dual-sense-only device without integrated comparator flag logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Common Mode Range | 0V to 32V - enables direct sensing across high-side or low-side shunts in buck, boost, SEPIC, and battery charger topologies up to 32V output. |
| SENSE Output Gain | ×1 - provides level-shifted, rail-to-rail output referenced to VCC for direct interface with PWM controller current sense inputs. |
| AVG Output Gain | ×10 - delivers scaled voltage for transconductance amplifier feedback loop; used to program average load current via PROG pin. |
| VOSSENSE (Input Offset) | ±5 mV - limits current sense accuracy to ±0.625% error at 80mV full-scale differential input (typical design point). |
| Supply Voltage (VCC) | 4.5V to 5.5V - requires stable 5V ±10% supply; not compatible with 3.3V systems without level-shifting or regulator. |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments; excludes commercial-grade 0°C–70°C variants like LT1621CS8. |
| Package | 16-lead plastic SSOP (GN) - 0.150" narrow body, 0.025" pitch; thermal resistance θJA = 149°C/W. |
Pinout & Package
LT1621CGN#PBF is housed in a 16-lead plastic SSOP (GN) package with exposed pad not electrically connected. Pin functions are validated per Linear Technology's LT1620/LT1621 datasheet Rev. G (1996), Figure "TOP VIEW GN PACKAGE".
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 9, 10, 11, 12, 13, 14, 15, 16 | No Connect (NC) | Internally unconnected; must be left floating or tied to ground per layout best practice - no functional impact. |
| 5, 13 | GND A / GND B | Separate analog ground returns for Channel A and Channel B; improves PSRR and reduces crosstalk between dual loops. |
| 6, 7, 11, 12 | IN– A / IN+ A / IN– B / IN+ B | Differential inputs for two independent current sense channels; support bidirectional sensing with 0V–32V common mode. |
| 8, 15 | IOUT A / IOUT B | Unidirectional current sink outputs (130µA typical); drive PWM controller error amp pins to close current control loops. |
| 14 | VCC | 5V ±10% power supply input; powers all internal amplifiers and bias circuits - decoupling capacitor required. |
| 4, 10 | PROG A / PROG B | Negative inputs to transconductance amplifiers; set average current by voltage difference vs. AVG A/AVG B. |
| 3, 16 | AVG A / AVG B | ×10 gain outputs from sense amplifiers; serve as integration nodes for average current regulation in current-mode control. |
| 1, 2 | SENSE A / SENSE B | ×1 gain, level-shifted outputs; directly interface with current sense inputs of PWM controllers (e.g., LTC1435, LT1513). |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent current sense channels | Enables simultaneous monitoring of load current (Channel A) and input supply current (Channel B) without shared signal path or crosstalk. |
| Rail-to-rail 0V–32V input common mode range | Supports high-side or low-side shunt placement in 24V industrial supplies, 4-cell Li-ion (16.8V), and lead-acid (up to 32V float) systems. |
| Level-shifted ×1 SENSE output | Eliminates need for external level translators when interfacing with PWM controllers whose current sense inputs reference VCC or ground. |
| Programmable average current via PROG pin | Allows precise load current setting (e.g., 3.2A at 80mV across 0.025Ω shunt) using simple resistor divider from VCC. |
| Transconductance amplifier with 3500 µmho gm | Delivers accurate 130µA sink current at null error condition (VAVG = VPROG), minimizing offset-induced programming error in closed-loop control. |
Applications
| High-Efficiency Dual-Loop Battery Charger | Industrial DC/DC Converter Current Monitor |
|---|---|
Use Scenario: 4-cell Li-ion charger using LTC1435 synchronous buck regulator with independent control of battery charge current and wall-adapter input current limit. IC Role / Device Role / Timing Role: LT1621CGN#PBF senses battery current on Channel A and input current on Channel B, generating separate IOUT signals to servo both control loops. Use Value: Prevents adapter overload during peak system + battery demand while maintaining >96% efficiency and <0.5V dropout at 3.2A. | Use Scenario: 24V input, 12V/5A output industrial buck converter requiring real-time current limiting and fault reporting. IC Role / Device Role / Timing Role: LT1621CGN#PBF Channel A monitors output inductor current via low-side shunt; SENSE A feeds PWM controller, AVG A sets current limit threshold. Use Value: Enables fast overcurrent shutdown (<2ms) and stable constant-current regulation across line/load transients without external op-amps. |
| Programmable Constant Current Source | Electronic Circuit Breaker |
Use Scenario: Lab-grade 0–10A adjustable current source for LED driver testing or electrochemical applications. IC Role / Device Role / Timing Role: LT1621CGN#PBF Channel A operates in standalone current regulation mode; PROG A voltage sets output current, IOUT A drives external MOSFET gate. Use Value: Achieves ±1% current accuracy over temperature with 0.01Ω shunt and eliminates need for precision DAC or op-amp feedback network. | Use Scenario: 24V/3A power rail protection in factory automation PLC I/O module. IC Role / Device Role / Timing Role: LT1621CGN#PBF Channel A detects overcurrent; IOUT A triggers external comparator or microcontroller GPIO via optocoupler. Use Value: Provides adjustable trip threshold (e.g., 1.6A nominal, 3A fast-trip) with <2ms response and immunity to EMI due to differential sensing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel current sense amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA240A1QPWRQ1 | Single-channel, 80V common mode, ±20µV offset, 100kHz bandwidth; automotive AEC-Q100 qualified. | Lacks dual-channel integration; requires two devices for same function; higher precision but no PROG/AVG architecture. | Choose for automotive systems needing ASIL-B compliance and wider VCM, but expect added board area and component count. |
| LT6105IMS8#PBF | Single-channel, 60V common mode, ×20 gain only, no PROG/AVG/IOUT architecture; fixed-gain current sense amplifier. | No transconductance loop control; outputs voltage only - cannot directly servo PWM error amps. | Choose for simple voltage-output current monitoring where closed-loop current regulation is handled externally. |
Compared with INA240A1QPWRQ1 and LT6105IMS8#PBF, the LT1621CGN#PBF uniquely combines dual independent current sensing, ×1/×10/×20 gain outputs, and transconductance IOUT sinks - enabling compact, self-contained dual-loop current control without external op-amps or DACs.
Availability
LT1621CGN#PBF is available at Aetrix Electronics and suitable for high-efficiency battery chargers, industrial DC/DC converters, programmable current sources, and electronic circuit breakers requiring stable component supply and long-term industrial temperature support.
Supply support for LT1621CGN#PBF 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
Analog Devices acquired Linear Technology in 2017 and maintains full product support, datasheets, and application notes for legacy Linear parts including the LT1621 series.
The LT1620/LT1621 family was designed specifically for high-accuracy, high-common-mode current sensing in battery charging and switching regulator applications - emphasizing rail-to-rail operation, level-shifted outputs, and seamless integration with current-mode PWM controllers.
FAQ
What is the maximum input common mode voltage supported by the LT1621CGN#PBF?
The LT1621CGN#PBF supports an input common mode voltage range of 0V to 32V on both current sense channels. This allows direct high-side or low-side shunt sensing in 24V industrial systems and 4-cell Li-ion battery chargers (16.8V float). Operation above 32V violates absolute maximum ratings and may cause permanent damage to the LT1621CGN#PBF.
Does the LT1621CGN#PBF include an end-of-charge comparator like the LT1620GN?
No, the LT1621CGN#PBF does not include the MODE output or PROG2/AVG2 comparator circuit found in the LT1620GN. It contains two fully independent current sense and transconductance amplifier channels only. End-of-charge flag functionality requires external circuitry or use of the LT1620GN variant. This distinction is confirmed in the Functional Block Diagram and Applications Information sections of the LT1620/LT1621 datasheet.
What is the typical transconductance (gm) value of the LT1621CGN#PBF's amplifier?
The LT1621CGN#PBF features a transconductance amplifier with a typical gm of 3500 µmho (3.5 mS), specified over temperature and supply voltage. This value determines the IOUT sink current generated per volt of error between VPROG and VAVG - enabling precise current loop control. The LT1621CGN#PBF's gm remains stable across its –40°C to +85°C operating range, supporting robust performance in industrial environments.
Can the LT1621CGN#PBF operate from a 3.3V supply?
No, the LT1621CGN#PBF requires a 4.5V to 5.5V supply on the VCC pin and is not rated for 3.3V operation. Attempting to power the LT1621CGN#PBF from 3.3V will result in undefined behavior, degraded offset performance, and potential failure to regulate current. A dedicated 5V LDO or DC/DC converter is required - as demonstrated in reference designs using the LTC1435's INTVCC output.
How many independent current sense channels does the LT1621CGN#PBF provide?
The LT1621CGN#PBF provides two fully independent current sense channels (Channel A and Channel B), each with dedicated IN+, IN–, SENSE, AVG, PROG, and IOUT pins. These channels operate simultaneously with no shared internal circuitry, enabling true dual-loop control - for example, regulating battery charge current while independently limiting input supply current in a SEPIC charger. This architecture is explicitly defined in the LT1621CGN#PBF's pinout diagram and functional description.
LT1621CGN#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- Current Sense
- Number of Circuits:
- 2
- Output Type:
- -
- Slew Rate:
- -
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- -
- Current - Input Bias:
- 4 mA
- Voltage - Input Offset:
- 8 mV
- Current - Supply:
- 2.8mA (x2 Channels)
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 3 V
- Voltage - Supply Span (Max):
- 5.5 V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
LT1621CGN#PBF FAQ
1.How can I place an order for LT1621CGN#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1621CGN#PBF 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 LT1621CGN#PBF reliable?
The price and inventory of LT1621CGN#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1621CGN#PBF is usually 5 days.
3.What payment methods are accepted for LT1621CGN#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1621CGN#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1621CGN#PBF?
LT1621CGN#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1621CGN#PBF 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 LT1621CGN#PBF?
For technical support, including LT1621CGN#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1621CGN#PBF requirements.
6.How does Aetrix verify that LT1621CGN#PBF is sourced from the original manufacturer or authorized distributors?
All LT1621CGN#PBF 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 LT1621CGN#PBF meets industry standards.
7.What is the process for return or replacement of LT1621CGN#PBF?
All LT1621CGN#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1621CGN#PBF, 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 LT1621CGN#PBF part is unused and in its original packaging.
Return procedure for LT1621CGN#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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