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Analog Devices Inc. LTC1556IGN#PBF
- Part No.:
- LTC1556IGN#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Translators, Level Shifters
- Package:
- Datasheet:
-
LTC1556IGN#PBF.pdf
- Description:
- IC TRNSLTR BIDIRECTIONAL 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,397
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Product details
Overview
LTC1556IGN#PBF from Analog Devices (formerly Linear Technology) is a SIM power supply and level translator IC designed for GSM cellular telephone interfaces. It integrates a step-up/step-down charge pump delivering programmable 3V or 5V VCC output (±5% regulation), 3V–5V bidirectional signal level translation for CLK/RST/I/O/DATA, >10kV HBM ESD protection on all SIM-contact pins, and an auxiliary 4.3V LDO/power switch - all in a 20-pin narrow SSOP package.
For engineers reviewing the LTC1556IGN#PBF datasheet, LTC1556IGN#PBF pinout, LTC1556IGN#PBF application, or LTC1556IGN#PBF equivalent, key selection considerations include its dual-mode VCC programming (3V/5V/VIN), soft-start-enabled inrush control, 60µA operating current, 650kHz charge pump frequency, and integrated LDO functionality exclusive to the LTC1556 variant.
Technical Context
The LTC1556IGN#PBF implements a gated-switch charge pump architecture supporting both step-up (VIN < VCC) and step-down (VIN > VCC) operation across 2.7V–10V input range. Its mode control pins (M0/M1) select VCC output between 3V, 5V, or direct VIN connection, while the SS pin enables/disables soft-start to limit inrush current to ~25mA with 10µF COUT.
Unlike the LTC1555, the LTC1556IGN#PBF includes an auxiliary LDO/power switch (EN/FB/LDO pins) delivering regulated 4.3V (when FB tied to LDO) or acting as ≤30Ω switch to VCC - usable only when VCC ≥ 5V. Level translation uses internal pull-ups (DATA: 13–28kΩ; I/O: 6.5–14kΩ) and open-drain drivers compatible with SIM protocol timing (CLK up to 5MHz, RST/I/O rise/fall ≤1µs).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 2.7V to 10V - enables direct battery connection without intermediate DC/DC conversion |
| VCC Output Options | Programmable 3V (±0.2V), 5V (±0.25V), or VIN - supports mixed 3V/5V SIM card compatibility |
| Output Current | 10mA at VIN ≥ 2.7V; 20mA at VIN ≥ 3V - sufficient for standard SIM card power requirements |
| Operating Current | 60µA typical (VIN = 2.7–5V) - minimizes battery drain in standby and active modes |
| Shutdown Current | <1µA (VIN = 2.7–5V) - ensures ultra-low quiescent power during system sleep |
| Charge Pump fOSC | 650kHz typical - balances efficiency, capacitor size, and EMI performance |
| Auxiliary LDO Output | 4.3V ±0.25V (ILDO ≤ 5mA) - powers low-noise circuitry like frequency synthesizers |
Pinout & Package
Package: 20-lead narrow plastic SSOP (GN20), 0.150" body width, RoHS-compliant (Pb-free #PBF suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CIN | Controller clock input | Accepts controller-side CLK signal; drives internal charge pump timing |
| RIN | Controller reset input | Level-shifts controller RST to SIM-compatible voltage rail |
| DATA | Bidirectional controller data I/O | Open-drain interface with 13–28kΩ internal pull-up; requires controller open-drain output for bidirectional use |
| DDRV | Optional controller-to-SIM data driver | Enables unidirectional data transmission to SIM when DATA is used for receive only |
| EN | Auxiliary LDO enable | Logic-high enables 4.3V LDO or ≤30Ω VCC switch; internal 1µA pull-down if floating |
| FB | LDO feedback control | Tie to LDO pin for regulation; ground or float to configure as power switch |
| DVCC | Controller I/O supply | Accepts 1.8V–5.5V - sets logic thresholds for M0/M1/SS/CLK/RST/DATA |
| SS | Soft-start enable | Low = enable inrush limiting (~1ms VCC ramp); high = fast turn-on (~6ms) |
| M1, M0 | VCC mode selection | Truth-table controlled: 00=shutdown, 01=VIN, 10=3V, 11=5V |
| CLK, RST, I/O | SIM-side level-translated signals | Drive SIM contacts with 5MHz CLK capability and 10kV ESD-hardened I/O paths |
| LDO | Auxiliary regulated output | Delivers 4.3V (regulator mode) or switches to VCC (switch mode); bypass with ≥3.3µF capacitor |
| VIN, VCC, GND, C1+, C1− | Power and flying capacitor connections | VIN: 2.7–10V input; VCC: SIM power output; C1±: 0.1µF flying cap path for charge pump |
Key Features
| Feature | Design Value |
|---|---|
| Programmable dual-voltage SIM supply | Single IC supports 3V or 5V SIM cards via M0/M1 configuration - eliminates board-level voltage selection hardware |
| Integrated 4.3V auxiliary LDO | On-chip regulator powers noise-sensitive RF synthesizers without external LDO components or layout complexity |
| 10kV HBM ESD protection on SIM pins | Full protection on CLK, RST, I/O, VCC, and GND pins meets IEC 61000-4-2 Level 4 without external TVS diodes |
| Soft-start controlled inrush current | SS pin limits peak input current to ~25mA during startup - prevents brownout of shared battery or DC/DC rails |
| Ultra-low quiescent power | 60µA operating / <1µA shutdown current extends battery life in portable GSM handsets and smartcard readers |
Applications
| GSM Cellular Handset SIM Interface | Smart Card Reader Power & Translation |
|---|---|
Use Scenario: 3V GSM baseband processor interfacing with legacy 5V SIM cards in mobile handsets. IC Role / Device Role / Timing Role: Generates regulated 5V SIM supply, translates CLK/RST/I/O signals between 3V controller and 5V SIM, and provides ESD-hardened physical layer. Use Value: Enables single-chip compliance with ISO/IEC 7816-3 timing and voltage requirements while reducing BOM count by eliminating discrete level shifters and charge pumps. |
Use Scenario: Portable USB smart card reader supporting both 3V and 5V ICCs (integrated circuit cards). IC Role / Device Role / Timing Role: Dynamically selects VCC output mode (3V/5V) based on card detection, performs bidirectional level translation, and delivers clean power with soft-start sequencing. Use Value: Eliminates need for mechanical voltage-select jumpers or firmware-controlled external regulators - simplifies certification and field updates. |
| Secure Identity Token with Auxiliary Power | Multi-Mode SIM Module for IoT Devices |
Use Scenario: Hardware security token using SIM card for PKI authentication, requiring low-noise auxiliary supply for cryptographic RF frontend. IC Role / Device Role / Timing Role: Provides primary 5V SIM power and concurrently delivers 4.3V LDO output to frequency synthesizer with <1µA shutdown leakage. Use Value: Integrates two independent power domains (SIM + RF) in one 20-pin SSOP - saves PCB area vs. separate charge pump + LDO solution. |
Use Scenario: Cellular IoT module supporting global SIM variants (3V/5V) and optional embedded secure element requiring auxiliary bias. IC Role / Device Role / Timing Role: Serves as universal SIM interface with programmable VCC, ESD-protected signal translation, and configurable LDO for companion ICs. Use Value: Reduces SKU proliferation by enabling one hardware design to support multiple regional SIM standards and future secure element upgrades. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SIM power supply and level translation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1555IGN#PBF | No auxiliary LDO/FB/EN pins; 16-pin SSOP; identical core SIM supply and level translation functionality | Cannot power external RF synthesizers or provide auxiliary switched VCC; smaller footprint but no LDO capability | Select when auxiliary 4.3V supply is unnecessary and board space is constrained |
| LTC1516CS8#PBF | Standalone 5V-only micropower charge pump (20mA @ VIN ≥ 3V); no level translation, no SIM-specific ESD, 8-pin SO | Requires external level shifters and ESD protection; suitable only for basic 5V SIM power without integrated signal interface | Select only if level translation and SIM ESD are handled elsewhere in the design |
Compared with LTC1555IGN#PBF, the LTC1556IGN#PBF adds auxiliary LDO functionality at the cost of 4 extra pins and larger package; compared with LTC1516CS8#PBF, it integrates full SIM interface functions but requires more complex configuration and layout for ESD integrity.
Availability
LTC1556IGN#PBF is available at Aetrix Electronics and suitable for GSM handset design, smart card reader development, secure identity token production, and cellular IoT module manufacturing requiring stable component supply across extended temperature ranges (–40°C to 85°C).
Supply support for LTC1556IGN#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 its precision analog and power management portfolio. Linear pioneered high-performance power ICs for portable communications.
The LTC1556IGN#PBF belongs to Linear's SIM interface power and translation product line, engineered specifically for GSM/3G mobile handsets and smart card systems requiring integrated, ESD-hardened, low-quiescent-power SIM supply solutions.
FAQ
What is the maximum output current capability of the LTC1556IGN#PBF at 5V VCC output?
The LTC1556IGN#PBF delivers up to 10mA continuous output current when VIN ≥ 2.7V, and up to 20mA when VIN ≥ 3V - verified under typical conditions with 10µF output capacitance and 25°C ambient. This meets ISO/IEC 7816-3 requirements for Class A (5V) SIM cards, which specify 10mA minimum supply capability.
Does the LTC1556IGN#PBF support both 3V and 5V SIM cards in the same design?
Yes, the LTC1556IGN#PBF supports both 3V and 5V SIM cards through its programmable VCC output. Setting M0 = DVCC and M1 = 0V configures 3V output (2.8–3.2V), while M0 = M1 = DVCC configures 5V output (4.75–5.25V). The same LTC1556IGN#PBF hardware can be reused across designs targeting either SIM voltage class.
How does the auxiliary LDO function in the LTC1556IGN#PBF differ from the main VCC regulator?
The auxiliary LDO in the LTC1556IGN#PBF is a separate 4.3V regulator (or ≤30Ω switch) powered from VCC - not VIN - and only functional when VCC ≥ 5V. Unlike the main charge pump, it provides low-noise, low-ripple output for sensitive RF circuitry and is enabled independently via the EN pin, allowing dynamic control without affecting SIM power.
What is the purpose of the SS (Soft-Start) pin on the LTC1556IGN#PBF?
The SS pin on the LTC1556IGN#PBF controls inrush current limiting during VCC turn-on. When pulled low, it enables soft-start, extending VCC ramp time to ~1ms and limiting peak input current to ~25mA - critical when powered from low-current DC/DC converters. When pulled high, VCC ramps in ~6ms with higher inrush, suitable for robust battery supplies.
Can the LTC1556IGN#PBF be used with a 1.8V controller supply (DVCC)?
Yes, the LTC1556IGN#PBF supports DVCC from 1.8V to 5.5V. At 1.8V DVCC, logic thresholds scale accordingly (e.g., VIH = 0.7 × DVCC ≈ 1.26V), and internal pull-ups remain functional. However, DATA and I/O timing margins tighten slightly; verify setup/hold times against your controller's 1.8V I/O specs when operating at maximum CLK frequency (5MHz).
LTC1556IGN#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- Packaging:
- Tube
- Product Status:
- Active
- Translator Type:
- Voltage Level
- Channel Type:
- Bidirectional
- Number of Circuits:
- 1
- Channels per Circuit:
- 1
- Voltage - VCCA:
- 1.8 V ~ 5.5 V
- Voltage - VCCB:
- 2.7 V ~ 10 V
- Input Signal:
- -
- Output Signal:
- -
- Output Type:
- Open Drain
- Data Rate:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Features:
- SIM Card Interface, Thermal-Shutdown Protection
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP (0.154", 3.90mm Width)
LTC1556IGN#PBF FAQ
1.How can I place an order for LTC1556IGN#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1556IGN#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 LTC1556IGN#PBF reliable?
The price and inventory of LTC1556IGN#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1556IGN#PBF is usually 5 days.
3.What payment methods are accepted for LTC1556IGN#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1556IGN#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1556IGN#PBF?
LTC1556IGN#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1556IGN#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 LTC1556IGN#PBF?
For technical support, including LTC1556IGN#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1556IGN#PBF requirements.
6.How does Aetrix verify that LTC1556IGN#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1556IGN#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 LTC1556IGN#PBF meets industry standards.
7.What is the process for return or replacement of LTC1556IGN#PBF?
All LTC1556IGN#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1556IGN#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 LTC1556IGN#PBF part is unused and in its original packaging.
Return procedure for LTC1556IGN#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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