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Analog Devices Inc. LT1937ESC6#TRMPBF
- Part No.:
- LT1937ESC6#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 6-TSSOP, SC-88, SOT-363
- Datasheet:
-
LT1937ESC6#TRMPBF.pdf
- Description:
- IC LED DRV RGLTR PWM SC70-6
- Quantity:
- Payment:
- Shipping:
Inventory:4,286
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Product details
Overview
LT1937ESC6#TRMPBF from Analog Devices (formerly Linear Technology) is a constant-current step-up DC/DC converter IC designed specifically to drive white LED strings in portable electronics. It delivers up to 20mA per string, operates from 2.5V to 10V input, switches at 1.2MHz, and features a 95mV feedback reference for high-efficiency current regulation - used in Li-ion–powered devices requiring uniform brightness across 2–4 series LEDs.
For engineers reviewing the LT1937ESC6#TRMPBF datasheet, LT1937ESC6#TRMPBF pinout, LT1937ESC6#TRMPBF application, or LT1937ESC6#TRMPBF equivalent, key selection criteria include its SC70-6 package footprint, 36V bipolar switch rating, low 95mV FB voltage, 1.2MHz fixed-frequency current-mode control, and compatibility with compact 22µH inductors and 0.22µF ceramic output capacitors.
Technical Context
The LT1937ESC6#TRMPBF employs a constant-frequency, current-mode PWM architecture with an internal 1.2MHz oscillator and integrated 36V bipolar power switch. Its error amplifier compares the 95mV reference against the voltage across the external current-sense resistor to regulate LED current precisely.
It supports shutdown via a logic-level SHDN pin (1.5V high threshold), uses two ground pins (Pins 2 and 5) for improved thermal and noise performance in the SC70-6 package, and maintains stable operation down to 4mA LED current without pulse skipping under specified conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 10V - supports single-cell Li-ion (3.0–4.2V) and 5V USB-supplied systems without external LDO. |
| Switch Rating | 36V bipolar - enables driving up to six white LEDs (≈3.2V each) from 5V input while maintaining margin. |
| Feedback Voltage | 95mV (±9mV) - minimizes I²R loss in current-setting resistor, improving efficiency at high LED currents. |
| Switching Frequency | 1.2MHz (±0.4MHz) - allows use of sub-3mm tall, low-DCR inductors and ultra-small 0.22µF X5R/X7R output capacitors. |
| Efficiency | 84% typical at 15mA, 3.6V input, 3-LED string - reduces thermal load in space-constrained handheld enclosures. |
| Shutdown Current | ≤1.0µA - preserves battery life during display-off states in mobile devices. |
| Operating Temperature | –40°C to +85°C - qualified for extended commercial applications including GPS receivers and digital cameras. |
Pinout & Package
The LT1937ESC6#TRMPBF is housed in a 6-lead plastic SC70 package (JEDEC EIAJ SC-70, Analog Devices drawing #05-08-1638), measuring 2.20mm × 1.35mm × 0.95mm max height, with exposed pad not electrically connected. Pin 1 is marked by a dot or notch; Pin 5 is GND (second ground path); Pin 6 is VIN.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch Node | Connects to inductor and Schottky diode anode; carries high di/dt pulses - requires minimal trace area to reduce EMI. |
| GND (Pin 2) | Power Ground | Primary ground return for switch and internal circuitry; must connect directly to local ground plane. |
| FB (Pin 3) | Current-Sense Input | Monitors voltage across external RFB; 95mV reference sets ILED = 95mV / RFB. |
| SHDN (Pin 4) | Enable/Disable Control | Active-high logic input; ≥1.5V enables regulator, ≤0.4V disables it with <1µA quiescent draw. |
| GND (Pin 5) | Secondary Ground | Dedicated ground for FB and SHDN bias paths; improves noise immunity and thermal dissipation. |
| VIN (Pin 6) | Input Supply | Connects to bypass capacitor (≥1µF X5R/X7R); must be locally decoupled to suppress high-frequency ripple. |
Key Features
| Feature | Design Value |
|---|---|
| Inherently matched LED current | Series LED configuration ensures identical current through all diodes - eliminates brightness variation without ballast resistors. |
| High-efficiency 1.2MHz operation | Enables use of miniature 22µH inductors (e.g., Murata LQH3C-220) and 0.22µF output caps - saves >30% board area vs. lower-frequency alternatives. |
| Low 95mV feedback voltage | Reduces power loss in current-sense resistor by ~70% versus 1.25V references - critical for battery runtime in 15–20mA LED strings. |
| Rugged 36V bipolar switch | Supports up to six white LEDs from 5V input while maintaining 4V safety margin - avoids overvoltage failure during transient load changes. |
| Two-GND-pin SC70 layout | Separates power and signal ground returns - lowers noise coupling into FB node and improves dimming linearity in analog/PWM schemes. |
Applications
| Cellular Phones | Digital Cameras |
|---|---|
Use Scenario: Backlighting for small OLED or TFT displays in clamshell and slider form factors. IC Role / Device Role / Timing Role: Constant-current boost controller regulating 3-series white LEDs from 3.6V Li-ion supply. Use Value: Delivers uniform brightness with 84% efficiency at 15mA, minimizing heat buildup in thermally constrained RF modules. |
Use Scenario: Flash illumination for 5–8MP image sensors in pocket-sized cameras. IC Role / Device Role / Timing Role: High-brightness LED driver supporting short-duration (100–500ms), high-current (20mA) bursts. Use Value: Fast 1.2MHz switching enables rapid on/off transitions with minimal output capacitor size (0.22µF), reducing flash latency. |
| GPS Receivers | MP3 Players |
Use Scenario: Status and navigation indicator backlighting in outdoor-use handheld GPS units. IC Role / Device Role / Timing Role: Low-quiescent (≤1µA shutdown) LED driver operating across –40°C to +85°C ambient range. Use Value: Maintains consistent LED intensity across temperature extremes using dual-GND SC70 layout and 95mV FB reference. |
Use Scenario: UI button and display backlighting in battery-powered audio players with tight PCB real estate. IC Role / Device Role / Timing Role: Compact boost converter driving 2–4 white LEDs from single Li-ion cell with PWM dimming via SHDN pin. Use Value: SC70-6 footprint (2.2 × 1.35mm) and support for 1mm-tall inductors enable integration into sub-100mm² front-end layouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1932ES5#TRMPBF | Same 1.2MHz frequency and 95mV FB, but rated for up to eight LEDs and supplied in TSOT-23-5 (5-pin, single GND). | Higher LED count capability; less suitable for space-critical 6-pin layouts requiring dual-GND noise isolation. | Choose when driving ≥5 LEDs from 3V input and board area permits TSOT-23-5; avoid if dual-GND noise rejection is required. |
| LTC3200ES6#TRMPBF | Inductorless charge-pump topology; 2MHz switching; no magnetic components; max 6 LEDs; 100mA output. | No EMI from inductor; lower peak currents; limited to lower-voltage LED strings (≤18V); higher IQ (60µA active). | Prefer for ultra-low-EMI designs where inductor placement is prohibitive; not suitable for >6-LED strings or 36V SW requirements. |
Compared with LT1937ESC6#TRMPBF, LT1932ES5#TRMPBF offers greater LED scalability but lacks dual-GND noise control, while LTC3200ES6#TRMPBF eliminates magnetics at the cost of voltage headroom and peak current capability - making LT1937ESC6#TRMPBF optimal for compact, high-brightness, 2–4 LED strings demanding low-noise regulation.
Availability
LT1937ESC6#TRMPBF is available at Aetrix Electronics and suitable for cellular phones, digital cameras, and GPS receivers requiring stable component supply, long-lifecycle availability, and guaranteed parametric compliance over –40°C to +85°C.
Supply support for LT1937ESC6#TRMPBF 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, manufacturing, and documentation for legacy Linear parts including the LT1937 family.
The LT1937 belongs to Linear's precision LED driver product line, engineered for portable battery-powered devices where efficiency, small solution size, and uniform LED brightness are critical design constraints.
FAQ
What is the maximum number of white LEDs the LT1937ESC6#TRMPBF can drive from a 3.6V Li-ion source?
The LT1937ESC6#TRMPBF can reliably drive up to four white LEDs (typical VF ≈ 3.2V each) from a 3.6V input, delivering 15mA with 84% efficiency. Driving five LEDs would exceed the practical output headroom given the 36V switch rating and diode forward drop - confirmed by Figure 1937 TA03a/b showing stable operation only up to four LEDs at 3.6V.
Does the LT1937ESC6#TRMPBF require an external soft-start circuit?
No internal soft-start is included in the LT1937ESC6#TRMPBF to minimize start-up delay. Inrush current reaches ~200mA at turn-on (Figure 1937 F10), so an external RC soft-start network (e.g., 100kΩ + 1nF to SHDN) is recommended only if system-level inrush limits are violated - not required for standard portable device operation.
Can the LT1937ESC6#TRMPBF operate below 4mA LED current?
Yes - the LT1937ESC6#TRMPBF regulates down to ~4mA without pulse skipping using standard external components. Below that, it enters pulse-skipping mode, maintaining average current regulation to zero, though low-frequency ripple appears (Figure 1937 F03). This behavior is documented in the "Minimum Output Current" section of the datasheet.
What is the purpose of Pin 5 (GND) in the SC70-6 package of the LT1937ESC6#TRMPBF?
Pin 5 provides a dedicated ground path for the FB and SHDN bias circuits, separate from the main power ground (Pin 2). This dual-GND structure reduces noise coupling into the sensitive 95mV feedback node and improves dimming accuracy - a layout advantage not present in the 5-pin TSOT-23 variant (LT1937ES5#TRMPBF).
Which Schottky diode is recommended for use with the LT1937ESC6#TRMPBF in a 3-LED, 15mA application?
The Central Semiconductor CMDSH-3 (100mA rated, 0.58V @ 100mA, 7pF capacitance) is explicitly recommended in the LT1937ESC6#TRMPBF datasheet (Table 3) for 3-LED, 15mA applications. Its low capacitance minimizes switching losses at 1.2MHz, and its forward voltage balances conduction efficiency with thermal performance in SC70 layouts.
LT1937ESC6#TRMPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 6-TSSOP, SC-88, SOT-363
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 2.5V
- Voltage - Supply (Max):
- 10V
- Voltage - Output:
- 36V
- Current - Output / Channel:
- 320mA (Switch)
- Frequency:
- 1.2MHz
- Dimming:
- Analog, PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-6
LT1937ESC6#TRMPBF FAQ
1.How can I place an order for LT1937ESC6#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1937ESC6#TRMPBF 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 LT1937ESC6#TRMPBF reliable?
The price and inventory of LT1937ESC6#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1937ESC6#TRMPBF is usually 5 days.
3.What payment methods are accepted for LT1937ESC6#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1937ESC6#TRMPBF transactions.
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LT1937ESC6#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1937ESC6#TRMPBF 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 LT1937ESC6#TRMPBF?
For technical support, including LT1937ESC6#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1937ESC6#TRMPBF requirements.
6.How does Aetrix verify that LT1937ESC6#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LT1937ESC6#TRMPBF 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 LT1937ESC6#TRMPBF meets industry standards.
7.What is the process for return or replacement of LT1937ESC6#TRMPBF?
All LT1937ESC6#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1937ESC6#TRMPBF, 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 LT1937ESC6#TRMPBF part is unused and in its original packaging.
Return procedure for LT1937ESC6#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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